Self Assessment and Review of Anatomy PDF

Jaypee Brothers Medical Publishers (P) Ltd Headquarters Jaypee Brothers Medical Publishers (P) Ltd 4838/24, Ansari Road, Daryaganj New Delhi 110 002, India Phone: +91-11-43574357 Fax: +91-11-43574314 Email: [email protected] Overseas Office J.P. Medical Ltd 83, Victoria Street, London SW...

Jaypee Brothers Medical Publishers (P) Ltd Headquarters Jaypee Brothers Medical Publishers (P) Ltd 4838/24, Ansari Road, Daryaganj New Delhi 110 002, India Phone: +91-11-43574357 Fax: +91-11-43574314 Email: [email protected] Overseas Office J.P. Medical Ltd 83, Victoria Street, London SW1H 0HW (UK) Phone: +44 20 3170 8910 Fax: +44 (0)20 3008 6180 Email: [email protected] Website: www.jaypeebrothers.com Website: www.jaypeedigital.com © 2020, Jaypee Brothers Medical Publishers The views and opinions expressed in this book are solely those of the original contributor(s)/author(s) and do not necessarily represent those of editor(s) of the book. All rights reserved. No part of this publication may be reproduced, stored or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission in writing of the publishers. All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The publisher is not associated with any product or vendor mentioned in this book. Medical knowledge and practice change constantly. This book is designed to provide accurate, authoritative information about the subject matter in question. However, readers are advised to check the most current information available on procedures included and check information from the manufacturer of each product to be administered, to verify the recommended dose, formula, method and duration of administration, adverse effects and contraindications. It is the responsibility of the practitioner to take all appropriate safety precautions. Neither the publisher nor the author(s)/editor(s) assume any liability for any injury and/or damage to persons or property arising from or related to use of material in this book. This book is sold on the understanding that the publisher is not engaged in providing professional medical services. If such advice or services are required, the services of a competent medical professional should be sought. Every effort has been made where necessary to contact holders of copyright to obtain permission to reproduce copyright material. If any have been inadvertently overlooked, the publisher will be pleased to make the necessary arrangements at the first opportunity. The CD/DVD-ROM (if any) provided in the sealed envelope with this book is complimentary and free of cost. Not meant for sale. Inquiries for bulk sales may be solicited at: [email protected] Self Assessment and Review of Anatomy First Edition: 2017 Second Edition: 2018 Third Edition: 2019 Fourth Edition: 2020 ISBN: 978-93-90020-46-1 Long ago I thought of a mission—Human Anatomy Made Simple. Then it was a dream, now realizing that dream into a concrete reality is a profound matter of satisfaction and joy. As Steve Maraboli mentioned: ‘The best way to succeed is to have a specific Intent, a clear Vision, a plan of Action, and the ability to maintain Clarity.’ Anatomy is an integral component of PG Entrance examinations at multiple levels. It is not an important individual subject in itself, but, in terms of conceptual and clinical correlates, touches and fetches improved scoring in almost all the major and minor subjects, once mastered well. The present book is a simplistic quintessential approach to master basic and conceptual Anatomy and its clinical application. Maximum possible content has been covered under various sub-sections of Anatomy, so that the student does not need to look into a plethora of books—in a sense it is ‘all in one approach’. It is written in a simple, lucid language with neatly labelled line diagrams, along with tables and flowcharts to improve memorization and recall of the vast content. The latest edition of Gray’s Anatomy has an abundance of updated information, which is not in accordance with the traditional/conventional teaching. Such information has been included in the present book, but its usage in the examinations is not yet advisable, and depends upon the discretion of the teacher and the students. Controversies arise when different authors follow different standard textbooks, for example, a particular question on pemphigus vulgaris may be asked by Anatomy department, but may also interest, Pathology, Dermatology and Medicine departments equally. Such questions have been dealt with profound and relentless research, referring to respective department standard textbooks and Journals to bring you the most appropriate answer possible. Dear students, I was a medical student, and will remain so throughout my life. We all have been trained to work hard in the best interest of our patients and peers. I respect and honour your tenacity in keeping the fire and zeal alive in your heart and mind, and remain highly motivated despite tough scenarios in life keep presenting in front of you, every possible moment. 1. Quick revision of entire Anatomy subsections, along with authentic questions and answers with explanations. 2. Additional content and MCQs available on www.accesspgmee.com 3. Chapter grading has been done to ensure maximum focus on important chapters. 1. Read the chapter theory and practice MCQs upon the topic. 2. Revise the content two times. Wishing a great success to all the students, in all arenas of life ! Rajesh K Kaushal I would like to thank Shri Jitendar P Vij (Group Chairman), Mr Ankit Vij (Managing Director) and Mrs Chetna Malhotra Vohra (Associate Director–Content Strategy) of Jaypee Brothers Medical Publishers (P) Ltd. New Delhi, India, for enabling me to publish this book. I would also like to thank Ms Saima Rashid (Manager—Publishing), and the complete Production Team for helping me in the whole process.  Recent Questions and Answers with Explanation 1. General Anatomy 2. Embryology 3. Histology 4. Neuroanatomy 5. Head and Neck 6. Back Region 7. Thorax 8. Upper Limb 9. Abdomen 10. Pelvis and Perineum 11. Lower Limb NEET Pattern 2020 1. Meiosis occurs in: a. Prepubertal testis b. Ovary c. Adrenal d. Hypothalamus 2. Fertilization occurs in which part of the fallopian tube? a. Ampulla b. Isthmus c. Interstitial d. Infundibular 3. Identify the type of cartilage: a. Fibro b. Hyaline c. Elastic d. Articular 4. In a preterm baby with respiratory distress syndrome, which of the following type of cell is deficient? a. Alveolar capillary endothelial cell b. Bronchial mucosal epithelial cell c. Type 1 alveolar cell d. Type 2 alveolar cell 5. In a preterm baby with respiratory distress syndrome, which of the following lipid would be deficient? a. Sphingomyelin  b. Cardiolipin c. Dipalmitoyl phosphatidyl choline d. None of the above 6. A 45-year-old chronic smoker presented with the complaints of cough. A biopsy was taken after the preliminary examination. What is cellular change visible on the biopsy? a. Hyperplasia b. Metaplasia c. Dysplasia d. IEN 7. A young male met with a motor bike accident and had severe injury to ileum and jejunum. Therefore, the entire ileum and partial jejunum was resected. Which of the following would the patient suffer from? a. Vitamin B12 deficiency b. Constipation c. Gastric ulcer d. Pernicious anemia 8. A 35-year-old female was watching TV for long hours with hands under the head. She complaints of tingling sensation over the arm. Which type of nerve fibre is most likely to be affected? a. A b. B c. C d. Sympathetic 9. A 65-year-old lady presents with a cerebrovascular accident involving inferior frontal gyrus. Which functional area would mostly be affected? a. Visual b. Auditory c. Sensory speech d. Motor speech 10. A boy met with a motor bike accident. CT brain shows injury to posterior end of superior temporal gyrus. He is likely to suffer from: a. Fluent aphasia b. Non-fluent aphasia  c. Conduction aphasia d. Global aphasia 11. Incongruous homonyms hemianopia with Wernicke’s hemianopic pupil is seen in the lesion of: a. Optic tract b. Lateral geniculate body c. Anterior occipital cortex d. Optic radiation 12. Identify the cell marked in the histological image of the cerebellum: a. Purkinje cells b. Basket cells c. Golgi cells d. Granular cells 13. A patient presented with clinical features of ataxia and incoordination. It is most likely due to involvement of which artery among the following? a. Anterior cerebral b. Middle cerebral c. Posterior cerebral d. Superior cerebellar 14. A patient presented with weakness of the right side of the face. There is associated ipsilateral loss of pain and temperature on face and contralateral body. The lesion is most likely located at: a. Medial medulla b. Lateral pons c. Medial pons d. Lateral medulla 15. In multiple sclerosis, slow conduction of motor and sensory pathway is due to: a. Defect in node of Ranvier b. Loss of myelin sheath c. Leaking sodium channels d. Loss of oligodendrocytes 16. Left recurrent laryngeal nerve has a comparatively longer course due to the persistence of which pharyngeal arch artery? a. 3 b. 4 c. 5 d. 6 17. The upward extension of thyroid swelling is prevented by which of the following structure attached to thyroid cartilage? a. Sternothyroid b. Pretracheal fascia c. Ligament of Berry d. Thyrohyoid membrane 18. A 70-year-old patient presented with history of fever, halitosis, night cough and regurgitation of food in the mouth. On examination there is a pulsatile swelling on left side of neck which produces gurgling sound on compression. What is the most likely diagnosis, by looking at the given barium swallow study of the patient? a. Laryngocele b. Dysphagia lusoria c. Zenker’s diverticulum d. Plummer Vinson syndrome 19. Saccule of inner ear develops from: a. Pars superior b. Pars inferior c. Saccus anticus d. Saccus posticus 20. Intractable cough reflex on scratching the floor of external auditory meatus is due to which nerve?  a. Auriculotemporal nerve b. Auricular branch of Vagus c. Greater auricular nerve d. Facial nerve 21. NOT an anatomical landmark of facial nerve identification in parotid surgery: a. Tympano-mastoid suture line b. Inferior belly of omohyoid c. Digastric groove d. Tragal cartilage pointer 22. Which layer maintains hydration of corneal stroma? a. Descemet’s membrane b. Endothelium c. Anterior epithelium d. Corneal stroma 23. A patient presented with squint in right eye, as shown below. Identify the nerve lesioned in this case: a. Occulomotor b. Trochlear c. Trigeminal d. Abducent 24. Highest oxygen concentration in fetal circulation is at which site? a. Superior vena cava b. Inferior vena cava c. Right ventricle d. Aorta 25. Type of joint at site marked by the arrow:  a. Syndesmosis b. Synarthrosis c. Symphysis d. Synovial joint 26. Nerve supply of the shown muscle is: a. Supra scapular b. Dorsal scapular c. Subscapular d. Dorsal rami of C1 27. What is the most likely age of this child, a victim of rape being examined under POCSO act.  a. 4 years b. 7 years c. 10 years d. 14 years 28. A 30 years female patient is presenting with wrist pain on lateral side. On examination the following test was positive. Tendon sheaths of which two muscle have been involved? a. Abductor pollicis longus and extensor pollicis brevis b. Abductor pollicis longus and extensor pollicis longus c. Abductor pollicis brevis and extensor pollicis brevis d. Abductor pollicis brevis and extensor pollicis longus 29. Hand deformity presenting as hyper-extension at the metacarpo-phalangeal joint and flexion at inter-phalangeal joint, occurs due to paralyzed: a. Flexor digitorum profundus b. Lumbricals  c. Lumbricals and interossei d. Extensor digitorum 30. Clinical diagnosis for the patient shown in the diagram is: a. Meckel’s diverticulum b. Urachal diverticulum c. Gastroschisis d. Omphalocele 31. Ligation of the common hepatic artery will compromise blood flow in: a. Right and left gastric artery b. Right gastric and short gastric arteries c. Right gastroepiploic and short gastric arteries d. Right gastric and right gastroepiploic artery 32. A 54-year-old man comes to a hospital with abdominal pain, jaundice, loss of appetite, and weight loss. On examination of his radiograms and CT scans, a physician finds a slowly growing tumor in the uncinate process of the pancreas. Which of the following structures is most likely compressed by this tumor? a. Splenic artery b. Portal vein c. Superior mesenteric artery d. Superior pancreaticoduodenal artery 33. Remnants of Wolffian ducts in a female are found in: a. Pouch of Douglas b. Uterovesical pouch c. Broad ligament d. Iliac fossa 34. A man was brought to the emergency after meeting with an accident and injured perineum. He feels an urge to micturate but is unable to pass urine. There is blood at the tip of the meatus with extensive swelling of the penis and scrotum. What is the possible site of the injury? a. Penile urethra rupture b. Bulbar urethra  c. Membranous urethra d. Urinary bladder 35. Episiotomy incision was extended posteriorly beyond perineal body injuring the structure immediately posterior to it. Which structure has been injured? a. External anal sphincter b. Ischiocavernosus c. Bulbospongiosus d. Urethral sphincter 36. Painless cancerous lesion with inguinal lymph node involvement is due to carcinoma: a. Testis b. Penis c. Prostate d. Urinary bladder 37. A 68-year-old man, who is a heavy smoker, complains of pain in his right thigh, buttock and calf region on walking about 400 metres. Once he stops, the pain disappears and returns when he walks a similar distance again. a. Aorto-iliac obstruction b. Iliac obstruction c. Femoro-popliteal obstruction d. Distal obstruction 38. The sign seen on USG while locating the long saphenous vein and common femoral vein lying medial to the common femoral artery is called as: a. String sign b. Saphenous eye c. Mickey mouse sign d. Stemmer sign AIIMS November 2019 39. Arterial supply of marked structure: a. Anterior cerebral b. Middle cerebral  c. Vertebral d. Internal carotid 40. A lesion in the marked structure leads to: a. Ataxia b. Vertigo c. Ipsilateral facial nerve palsy d. Contralateral hemiplegia 41. The marked structure is supplied by: a. Occulomotor nerve b. Trochlear nerve c. Trigeminal nerve d. Abducent nerve 42. Identify the marked layer in the given histological section:  a. Outer plexiform b. Inner plexiform c. Ganglion cell d. Photoreceptor 43. Patient undergoing surgery at the lateral part of skull. Post-operatively patient had aspirations without voice change. Nerve lesioned is: a. Vagus b. Recurrent laryngeal c. Superior laryngeal d. Glossopharyngeal 44. Embryological origin of the marked structure:  a. Septum primum b. Endocardial cushion c. Bulbo ventricular flange d. Neural crest cells 45. Marked structure is supplied by all the following arteries except: a. Marginal b. Diagonal c. Right coronary  d. Interventricular branch 46. Which of the following does NOT have branches in brachial plexus? a. Roots b. Trunks c. Divisions d. Cords 47. Lesion of the marked nerve leads to: a. Wrist drop b. Claw hand c. Ape thumb deformity d. Claudication 48. Lesion of the marked nerve leads to loss of sensation at:  a. Nail of index finger b. Hypothenar eminence c. Tip of radial bone d. 4th interdigital cleft 49. Identify the marked structure: a. Radial artery b. Radial nerve c. Ulnar artery d. Ulnar nerve 50. Which of the structure does not contribute to the pointed structure? a. Extensor digitorum b. Lumbricals c. Palmar interossei d. Dorsal interossei 51. Marked area is related to:  a. Duodenum b. Spleen c. Liver d. Stomach 52. Which of the following nerves are related with the marked structure? a. Obturator b. Pudendal c. Femoral d. Sciatic AIIMS May 2019 53. Arrange the steps of spermatogenesis in a sequence. 1. Spermatid 2. Spermatocyte 3. Spermatogonium 4. Spermatozoa a. 3 → 2 → 1 → 4 b. 3 → 2 → 4 → 1 c. 3 → 1 → 2 → 4 d. 2 → 3 → 1 → 4 54. Arrange the following structures (in peripheral to central order) constituting the auditory pathway: 1. Lateral lemniscus 2. Cochlear neuron 3. Medial geniculate body 4. Inferior colliculus a. 2 → 3 → 4 → 1 b. 2 → 1 → 4 → 3 c. 2 → 3 → 4 →1 d. 2 → 3 → 4 →1 55. Lesion of the marked structure affects all except: a. Superior rectus b. Superior oblique c. Inferior oblique d. Medial rectus 56. Mark TRUE/FALSE regarding Carotid Sheath and contents a. Receive contribution from investing layer of cervical fascia b. Cranial nerves 9, 10, 11 never lies within sheath c. Ansa cervicalis lies on posterior wall of sheath d. Sympathetic chain lies between internal carotid artery and internal jugular vein e. Common carotid artery bifurcates at the level of superior lamina of thyroid cartilage 57. Post parotidectomy, patient feels numb while shaving. Which nerve was involved? a. Facial b. Mandibular c. Auriculotemporal d. Greater auricular 58. External carotid artery supplies nasal septum by all of the following branches except: a. Superior labial b. Anterior ethmoidal c. Sphenopalatine d. Greater palatine 59. Surface marking of which of the following is demonstrated in the video. A convex line (towards right) is being drawn, starting at right 3rd costal cartilage to the right 6th costal cartilage, as shown in the diagram below:  a. Hilum of right lung b. Inferomedial pulmonary segment c. Right atrium d. Thoracic duct 60. Identify the marked structures in the image given below and match with the following options: Column A Column A 1. Anterior Papillary muscle of right ventricle 2. Posterior Tricuspid leaflet 3. Anterior cusp of mitral valve 4. Pectinate muscles of right atrium 5. Membranous interventricular septum a. A – 4 ,B – 1, C – 3, D – 4 b. A – 4, B – 1, C – 3, D – 5 c. A – 4, B – 1, C – 2, D – 5 d. A – 4, B – 1, C – 3, D – 2 61. Which of the following finger has two dorsal interossei? a. Little b. Ring  c. Middle d. Index 62. Assertion and Reason:Assertion: In Scaphoid fracture, distal portion gets necrosedReason: Scaphoid has arterial supply in retrograde fashion a. Both assertion and reason are correct, and reason is correct explanation of assertion b. Both assertion and reason are correct, but reason is not a correct explanation of assertion c. Assertion is correct but reason is wrong d. Reason is correct and assertion is wrong e. Both assertion and reason are wrong 63. Liver is divided into eight segments according to Couinaud’s classification based upon. a. Bile duct b. Portal vein c. Hepatic vein d. Hepatic artery 64. All of the following are true regarding levator ani except: a. Levator ani muscle is attached at pelvic brim b. Pubococcygeus and iliococcygeus are components c. Fibres are directed posterior and medial d. Supports pelvic viscera 65. Action of muscle attached to the area marked on the image shown: a. Abduction b. Adduction c. Flexion d. Extension ANSWERS WITH EXPLANATION NEET Pattern 2020 1. Ans. b. Ovary Explanation: Meiosis is a reduction division which occurs in the gonads (ovary and testis). Oogenesis begins before birth (in-utero) in females.  q Spermatogenesis begins in males after puberty. Till that time primordial germ cells are dormant. Note: Please refer page no. 18 for additional details. 2. Ans. a. Ampulla Explanation: Fertilization of secondary oocyte by sperm, occurs in ampullary part of the fallopian tube. Note: Please refer page no. 22 for additional details. 3. Ans. c. Elastic Explanation: The figure shows a histological specimen of elastic cartilage, identified by the presence of chondrocytes, interspersed with prominent elastic fibres. q Perichondrium with fibrous and cellular layers is evident on left side of the figure. Note: Please refer page no. 85 for additional details. 4. Ans. d. Type 2 alveolar cell Explanation: Respiratory distress syndrome shows deficient/ immature type II alveolar cells, which produce less surfactant, causing an increase in alveolar surface tension and a decrease in compliance.  q The resultant atelectasis causes pulmonary vascular constriction, hypoperfusion, and lung tissue ischemia. q Hyaline membranes form through the combination of sloughed epithelium, protein, and edema. q Persistent respiratory distress syndrome leads to bronchopulmonary dysplasia, characterized by typical chest radiography findings and chronic oxygen dependence Note: Please refer page no. 100 for additional details. 5. Ans. c. Dipalmitoyl phosphatidyl choline Explanation: Pulmonary surfactant is a complex mix of lecithins, the most important of which is di- palmitoyl-phosphatidyl-choline (DPPC). Note: Please refer page no. 100 for additional details. 6. Ans. b. Metaplasia Explanation: The given diagram is histopathological specimen showing lumen of the bronchus with marked thickening of the mucous gland layer (approximately twice-normal) and squamous metaplasia of lung epithelium. q Squamous metaplasia and dysplasia of bronchial mucosa, seen in habitual smokers—a risk factor for lung carcinoma.  Note: Please refer page no. 103 for additional details. 7. Ans. a. Vitamin B12 deficiency Explanation: Terminal ileum surgical resection may result in Vitamin B12 (Cobalamin) deficiency. q It is found in animal products. Once bound with Intrinsic Factor (IF) in stomach, vitamin B12 is resistant to further digestion. The complex travels to the distal ileum and binds to a specific mucosal brush border receptor, cublin, which facilitates the internalization of cobalamin-IF complex in an energy-dependent process. Once internalized, IF is removed and cobalamin is transferred to other transport proteins, transcobalamin towards portal circulation. q It is found in animal products. Synthesized only by microorganisms. Very large reserve pool (several years) stored primarily in the liver. q Deficiency may be caused by insufficient intake (e.g., veganism), achlorhydria, bacterial over growth, alcohol excess, lack of intrinsic factor e.g., pernicious anemia, absence of terminal ileum surgical resection, e.g., for Crohn disease). 8. Ans. a. A Explanation: Pressure on a nerve can cause loss of conduction in large diameter motor, touch, and pressure fibers while pain sensation remains relatively intact. q Patterns of this type are sometimes seen in individuals who sleep with their arms under their heads for long periods, causing compression of the nerves in the arms. q Because of the association of deep sleep with alcoholic intoxication, the syndrome is most common on weekends and has acquired the interesting name Saturday night or Sunday morning paralysis. q Nerves differ in their sensitivity to Pressure, hypoxia and anaesthetics (Table). This fact has clinical as well as physiologic significance. q Local anaesthetics depress transmission in the unmyelinated group C fibers before they affect the myelinated group A fibers. Fiber type Function Fiber diameter Conduction (µm) velocity (m/s) Aα Proprioception; 12–20 70–120  somatic motor Aβ Touch, pressure 5–12 30–70 Aγ Motor to muscle 3–6 15–30 spindles Aδ Pain, temperature 2–5 12–30 B Preganglionic a) Sternothyroid Explanation: Superior extension of the thyroid gland is limited by the superior attachment of pretracheal fascia and the attachment of the strap muscles (like sternothyroid). q Few authors mention: The lateral surface of the thyroid is covered by the sternothyroid muscle, and its attachment to the oblique line of the thyroid cartilage prevents the superior pole from extending superiorly under the thyrohyoid muscle. Pretracheal layer of deep cervical fascia covers the front and sides of trachea, splits to enclose the thyroid gland forming its capsule and is attached to the oblique line of thyroid cartilage and to the arch of cricoid cartilage anteriorly. The superior extension of the thyroid gland is limited by the superior attachment of pretracheal fascia. Lateral surface of the thyroid is covered by the sternothyroid muscle, and its attachment to the oblique line of the thyroid cartilage prevents the superior pole from extending superiorly under the thyrohyoid muscle. Note: Please refer page no. 241 for additional details. 18. Ans. c. Zenker’s diverticulum Explanation: Zenker’s diverticulum is a pharyngoesophageal false diverticulum. Esophageal dysmotility causes herniation of mucosal tissue at Killian triangle between the thyropharyngeal and cricopharyngeal parts of the inferior pharyngeal constrictor. q Presenting symptoms are dysphagia, obstruction, gurgling, aspiration, foul breath (halitosis), neck mass. q Most common seen in elderly males. Note: Please refer page no. 258 for additional details. 19. Ans. b. Pars inferior Explanation: Saccule of inner ear develops from pars inferior of the otic vesicle.  q The terminal end of the tubotympanic recess (developing from pharyngeal pouch 1) buds into sacci. Saccus anticus and posticus contribute to the middle ear components. q Ear develops in week 4 from a thickening of the cells in the surface ectoderm called the otic placode. q The otic placode invaginates into the connective tissue (mesenchyme) adjacent to the rhombencephalon and becomes the otic vesicle. q The otic vesicle divides into utricular and saccular portions. Note: Please refer page no. 273 for additional details. 20. Ans. b. Auricular branch of vagus Explanation: In a small portion of population, the auricular branch of vagus nerve is the afferent limb of the Ear-Cough or Arnold Reflex. q Physical stimulation (like scratching) of the external acoustic meatus or its floor and posterior wall innervated by the auricular nerve elicits a cough, much like the other cough reflexes associated with the vagus nerve. q The stimuli may reflexly produce persistent/intractable cough, vomiting, and even death due to sudden cardiac inhibition. Note: Please refer page no. 268 for additional details. 21. Ans. b. Inferior belly of omohyoid Explanation: Inferior belly of omohyoid is not related to facial nerve course, as such, to serve as a surgical landmark. Anatomical landmarks of facial nerve identification in parotid surgery : q Tragal cartilaginous pointer is a sharp triangular piece of cartilage of the pinna and ‘points’ to the nerve. q Tympano-mastoid suture line lies between the mastoid and tympanic segments of the temporal bone and is approximately 6–8 mm lateral to the stylomastoid foramen. q Styloid process - The nerve crosses lateral to styloid process. q Posterior belly of digastric, as traced backwards along its upper border to its attachment to the digastric groove, nerve is found to lie between it and the styloid process. 22. Ans. b. Endothelium Explanation: The endothelium maintains Descemet’s membrane and includes the most metabolically active cells of the cornea. Na+/K+ ATPase pumps in the basolateral membranes of these cells are largely responsible for regulating the proper hydration state of the corneal stroma to provide maximal transparency and optimal light refraction. 23. Ans. b. Trochlear Explanation: The patient has an internal squint with elevated eyeball (up and in), which suggests overactive muscles supplied by occulomotor nerve, which may occur in a lesion of balancing nerve - trochlear nerve that supplies superior oblique muscle (action: Abduction and Depression; especially in abducted eye). q Lesion in trochlear nerve results in diplopia and inability to rotate the eye infero-laterally. So, the eye deviates; upward and slightly inward. The person has difficulty in walking downstairs. Note: Please refer page no. 294 for additional details. 24. Ans. b. Inferior vena cava Explanation: Inferior vena cava (IVC) lying between liver and heart carries blood at moderate oxygenation. It brings the deoxygenated blood of body below diaphragm, but receives oxygenated blood of umbilical vein (via ductus venosus). q IVC drains this moderately oxygenated blood into the right atrium → left atrium, through foramen ovale. Left atrium pushes it into left ventricle, which subsequently enters aorta  (moderately oxygenated blood), to reach the developing brain (though carotids). q Superior vena cava brings the deoxygenated blood of body above diaphragm, into the right ventricle. Note: Please refer page no. 320 for additional details. 25. Ans. d. Synovial joint Explanation: The joint at the marked region is called costo-transverse joint, which is a plane synovial joint. 26. Ans. b. Dorsal scapular Explanation: The shown muscle is levator scapulae, which is supplied by the dorsal scapular nerve. 27. Ans. b. 7 years Explanation: The X-ray of the carpal bones shows absence of pisiform bone, which ossifies appears at the age of 9 –12 years after birth. Since, Trapezoid is evident, the age of the individual is more than 5 years.  Carpal bones: Age of appearance of ossification centres Note: Please refer page no. 405 for additional details. 28. Ans. a. Abductor pollicis longus and extensor pollicis brevis Explanation: The test shown is Finkelstein test used to diagnose de Quervain’s tenosynovitis in people who have wrist pain. The examiner grasps the thumb and ulnar deviates the hand sharply. If sharp pain occurs along the distal radius, it is the tenosynovitis of tendons forming antero-lateral wall of anatomical snuff box (abductor pollicis longus and extensor pollicis brevis). Note: Please refer page no. 403 for additional details. 29. Ans. c. Lumbricals and interossei Explanation: Hand deformity presenting as hyper-extension at the metacarpo-phalangeal joint and flexion at inter-phalangeal joint, represents claw hand deformity and may occur due to paralysed lumbricals and interossei. (A) Lumbricals and interossei together lead to metacarpo-phalangeal (MCP) flexion and interphalangeal (IP) extension. (B) Their paralysis leads to unopposed activity of posterior forearm muscles (MCP hyperextension) and anterior forearm muscles (IP flexion). Claw hand deformity. Note: Please refer page no. 378 for additional details. 30. Ans. c. Gastroschisis Explanation: Gastroschisis is an anterior abdominal wall defect, through which the intestines protrude, located to the right side of the umbilical ring with an intact umbilical cord on the left side. q The herniated contents are not covered by amnion. q Meckel’s diverticulum presents as a slight bulge outside the umbilicus, containing a small part of distal ileum. q Omphalocele is a midline anomaly (not to the right side). Umbilical cord is not normal. q Urachal diverticulum do not present with intestinal herniation. Note: Please refer page no. 53 for additional details. 31. Ans. d. Right gastric and right gastroepiploic artery Explanation: Ligation of the common hepatic artery will compromise blood flow in distal branches including right gastric artery, hepatic artery proper and gastroduodenal artery ((which further give superior pancreatico-duodenal and right gastroepiploic artery).  Note: Please refer page no. 465 for additional details. 32. Ans. c. Superior mesenteric artery Explanation: The close anatomical relationship between the uncinate process and the superior mesenteric vessels results in early vascular involvement in these cancers. q The uncinate process of the pancreas is a projection of the lower part of its head to the left behind the superior mesenteric vessels. q The superior pancreaticoduodenal artery runs between the duodenum and the head of the pancreas. q The splenic artery runs along the superior border of the pancreas. q The portal vein runs behind the neck of the pancreas. Note: Please refer page no. 486 for additional details. 33. Ans. c. Broad ligament Explanation: Vestigial remnants of Wolffian (mesonephric) ducts in a female like Gartner’s duct may be seen in the anterolateral wall of vagina and broad ligament.  Note: Please refer page no. 66 for additional details. 34. Ans. b. Bulbar urethra Explanation: Blood at the tip of the meatus with extensive swelling of the penis and scrotum suggest bulbar rupture of urethra. Occurs almost exclusively in men. Suspect if blood seen at urethral meatus. Urethral injury Urethral catheterization is relatively contraindicated. Anterior urethral injury Posterior urethral injury Part of urethra Bulbar (spongy) urethra Membranous urethra Mechanism Perineal straddle injury Pelvic fracture Location of urine Blood accumulates in scrotum Urine leaks into retropubic space leak/blood If Buck fascia is torn, urine escapes into perineal space Presentation Blood at urethral meatus and scrotal Blood at urethral meatus and high- hematoma riding prostate Contd… Contd… The urinary bladder can be injured through iatrogenic and classic traumatic mechanisms. Indications for bladder imaging include gross hematuria in the setting of injuries with a correlation for bladder injury. Note: Please refer page no. 534 for additional details. 35. Ans. a. External anal sphincter Explanation: Episiotomy incision extended posteriorly beyond perineal body injuring the external anal sphincter immediately posterior to it. Note: Please refer page no. 507 for additional details. 36. Ans. b. Penis Explanation: This is a case of cancer penis in intermediate stage, with involvement of inguinal lymph node. Note: Most penile cancers are painless. Stages of cancer are: q Early disease: The cancer only affects the foreskin or the surface of the head of the penis. q Intermediate disease: The cancer has spread below the surface of the skin into the shaft of the penis and/or tiny amounts of cancer cells can be found in one of the lymph nodes in the groin (microscopic disease). q Advance disease: The cancer is found in one or more lymph nodes in the groin and /or has spread to other parts of the body. q Testicular cancer lymphatics lumbar (para and pre-aortic) lymph nodes. q Lymphatic vessels from the superior parts of the seminal glands and prostate terminate chiefly in the internal iliac lymph nodes, but some drainage from the latter may pass to the sacral nodes. q Urinary bladder : Lymphatics from superolateral aspects pass to the external iliac lymph nodes; fundus and neck: Internal iliac lymph nodes. Some vessels from the neck of the bladder drain into the sacral or common iliac lymph nodes. Note: Please refer page no. 510 for additional details. 37. Ans. b. Iliac obstruction Explanation: In iliac artery obstruction, patient presents with unilateral pain (of claudication) in gluteal, thigh and calf regions. q Aorto-iliac obstruction presents with bilateral pain. Chronic iliac artery occlusion. (A) After guide wire traversal of the occluded segment, primary stenting is performed. (B) After placement of a self-expanding nitinol stent and subsequent percutaneous transluminal angioplasty, the segment is recanalized. Aortoiliac obstruction Claudication in both buttocks, thighs and calves Femoral and distal pulses absent in both limbs Bruit over aortoiliac region Impotence (Leriche) Iliac obstruction Unilateral claudication in the thigh and calf and sometimes the buttock Bruit over the iliac region Unilateral absence of femoral and distal pulses Femoropopliteal obstruction Unilateral claudication in the calf Femoral pulse palpable with absent unilateral distal pulses Distal obstruction Femoral and popliteal pulses palpable Ankle pulses absent Claudication in calf and foot Note: Please refer page no. 574 for additional details. 38. Ans. c. Mickey mouse sign Explanation: Mickey Mouse sign is said to represent the normal anatomy of the femoral artery, femoral vein and great saphenous vein on ultrasound at the level just inferior the inguinal crease.  Note: Please refer page no. 579 for additional details. AIIMS November 2019 39. Ans. a. Anterior cerebral Explanation: The marked structure is fornix, which is chiefly supplied by the branches of anterior cerebral artery. q Fornix is additionally supplied by the branches of posterior cerebral artery and internal carotid artery as well. Note: Please refer page no. 191 for additional details. 40. Ans. d. Contralateral hemiplegia  Explanation: The marked structure is pyramid on the anterior aspect of medulla oblongata. A lesion may lead to contralateral spastic hemiplegia, due to injured pyramidal (corticospinal) tract, running deep to it. q This may happen in a case of medial medullary syndrome, due to block in anterior spinal artery. q Ataxia and vertigo are features of lateral medullary syndrome. Which may occur in occlusion of PICA (Posterior Inferior Cerebellar Artery). q Ipsilateral facial nerve palsy may be seen in lateral pontine syndrome, due to a block in AICA (Anterior Inferior Cerebellar Artery). Note: Please refer page no. 153 for additional details. 41. Ans. b. Trochlear nerve Explanation: The marked structure is superior oblique (located superior and medial in orbit), supplied by the trochlear nerve. Note: Please refer page no. 291 for additional details. 42. Ans. b. Inner plexiform Explanation: This is a histological diagram of retina, the marker put at inner plexiform layer. q The inner plexiform layer is an area of the retina that is made up of a dense reticulum of fibrils formed by interlaced dendrites of retinal ganglion cells and cells of the inner nuclear layer (Bipolar and Amacrine cells).  Note: Please refer page no. 288 for additional details. 43. Ans. d. Glossopharyngeal Explanation: Glossopharyngeal nerve injury may happen in surgeries at lateral part of neck for e.g., during dissection of the internal carotid artery above the level of the hypoglossal nerve (carotid endarterectomy). q The consequences of glossopharyngeal nerve injury range from mild dysphagia only, to recurrent aspiration and respiratory failure. Note: Injury to vagus or its branches usually present with voice change. Note: Please refer page no. 252 for additional details. 44. Ans. b. Endocardial cushion Explanation: The arrow mark represents membranous part of interventricular septum, which develops from the endocardial cushions (which themselves are derivatives of neural crest cells). q Bulbo ventricular flange contributes to the lower muscular portion of interventricular septum.  Note: Please refer page no. 315 for additional details. 45. Ans. b. Diagonal Explanation: The arrow mark shows right ventricle, which is not supplied by the diagonal artery. It receives arterial supply from right coronary artery, acute marginal artery, anterior interventricular artery.  Note: Please refer page no. 352 for additional details. 46. Ans. c. Divisions Explanation: Divisions of brachial plexus pass behind the clavicle bone and give no branches. q Dorsal scapular nerve and long thoracic nerves arise from the roots. Trunks give suprascapular nerve. Cords have branches like radial, ulnar nerve etc. Note: Please refer page no. 365 for additional details. 47. Ans. a. Wrist drop Explanation: The marked structure is radial nerve, the lateral most content of cubital fossa. Its lesion results in features of wrist drop (weakness of wrist extension).  Note: Please refer page no. 400 for additional details. 48. Ans. a. Nail of index finger Explanation: The marked structure is median nerve, the medial most content of cubital fossa. Its lesion leads to sensory loss in the skin of lateral 3 1/2 fingers (including nail beds). Note: Please refer page no. 400 for additional details. 49. Ans. d. Ulnar nerve Explanation: The marked structure is ulnar nerve passing superficial to flexor retinaculum at the front of the wrist. Note: Please refer page no. 406 for additional details. 50. Ans. c. Palmar interossei Explanation: The structure marked is dorsal digital expansion on the dorsum of middle finger (a modification of extensor digitorum tendon), which receives no insertion of palmar interossei.  q It receives insertion of two dorsal interossei (2 and 3) and 2nd lumbrical, from hand muscles. Note: Please refer page no. 410 for additional details. 51. Ans. d. Stomach Explanation: The specimen shown is the anterior view of left kidney, with marker at the gastric area, related to stomach anteriorly. Note: Please refer page no. 491 for additional details. 52. Ans. b. Pudendal Explanation: The specimen given is the right hip bone (medial view), showing the ischial spine related to the pudendal nerve.  Note: Please refer page no. 503 for additional details. AIIMS May 2019 53. Ans. a. 3 → 2 → 1 → 4 Explanation: The sequence is: Spermatogonium → Spermatocyte → Spermatid → Spermatozoa. q Spermatogonium matures into primary spermatocyte, which undergoes meiosis I to form secondary spermatocyte, which passes through meiosis II to give spermatid, that matures into spermatozoa. Note: Please refer page no. 16 for additional details. 54. Ans. b. 2 → 1 → 4 →3 Explanation: Arrangement of the given structures (in peripheral to central order) constituting the auditory pathway is:  Cochlear neuron → Lateral lemniscus → Inferior colliculus → Medial geniculate body Mnemonic (SLIM – 41, 42) : Superior olivary nucleus → Lateral lemniscus → Inferior Colliculus → Medial geniculate body → Temporal auditory cortex (Brodmann number 41, 42). Note: Please refer page no. 277 for additional details. 55. Ans. b. Superior oblique Explanation: The diagram shows, occulomotor nerve marked at the floor of cranial cavity, which supplies all the skeletal muscles of eyeball except superior oblique (supplied by trochlear nerve) and lateral rectus (supplied by abducent nerve). Note: Please refer page no. 204 for additional details. 56. Ans. a. Receive contribution from investing layer of cervical fascia–TRUE b. Cranial nerves 9, 10, 11 never lies within sheath–FALSE c. Ansa cervicalis lies on posterior wall of sheath–FALSE d. Sympathetic chain lies between internal carotid artery and internal jugular vein–FALSE e. Common carotid artery bifurcates at the level of superior lamina of thyroid cartilage– TRUE Explanation: Carotid sheath receive contributions from 3 layers of deep cervical fascia: Investing layer (laterally), Pretracheal fascia (anteriorly) and prevertebral fascia (posteriorly).  q Cranial nerves 9, 10, 11 and 12 lies within the carotid sheath in their earlier course, as they leave the cranial cavity, later only CN 10 (vagus) continues in carotid sheath inferiorly, as other cranial nerve pierce the carotid sheath and leave the carotid space. q The carotid artery is the center of the carotid space, and the jugular vein lies posterolateral to the carotid artery. The 10th cranial nerve lies in the posterior groove between these two vessels. The remaining cranial nerves 9, 11, and 12 all pierce the carotid sheath anteriorly. The ansa cervicalis is embedded in the anterior (not posterior) carotid sheath, and the sympathetic plexus/chain is found posteriorly. q Normally, the bifurcation of common carotid artery is at the level of superior lamina of thyroid cartilage (at C3/C4 in vertebral level) into external and internal carotid artery. The carotid space. Illustration demonstrating the contents and configuration of the left carotid space, including cranial nerves IX, X, XI, and XII Note: Please refer page no. 241 for additional details. 57. Ans. d. Greater auricular nerve Explanation: The great auricular nerve (GAN) is often sacrificed during parotidectomy, and one of the most important side effect is anaesthesia (numbness) of the region innervated by the nerve itself. q Self-inflicted skin lesion after GAN sacrifice during parotidectomy are reported. In few patients, lesion of the skin shaving due to numbness of the preauricular area is documented, whereas, in the other patients, the lesions were localized at the earlobe.  Note: Please refer page no. 250 for additional details. 58. Ans. b. Anterior ethmoidal Explanation: Anterior ethmoidal artery is a branch of internal (not external) carotid artery. Note: Please refer page no. 280 for additional details. 59. Ans. c. Right atrium Explanation: Right border of the heart can be surface marked by drawing a convex line (towards right) starting at right 3rd costal cartilage and reaching the right 6th costal cartilage. Surface marking for heart can be done joining four points in a sequence: Point A: Lower border of left CC 2 Point B: Upper border of right CC 3 Point C: Right CC 6 Point D: Apex –9.5 cm from the midline in ICS 5, medial to MCL, on the level of diaphragm Procedure: Upper border (Point A to B) of heart can be marked by a line joining a point on the lower border of the 2nd left costal cartilage, 1.5 in from the median plane to a point on the upper border of 3rd right costal cartilage, 1 inch away from the median plane. The right border (Point B to C) is a gently curved line, convex to the right, running from the third to the sixth right costal cartilages, usually 1–2 cm lateral to the sternal edge. The inferior border (Point C to D) reaches the cardiac apex, which is almost always from the level of the fifth to the sixth rib, and a mean of 8.7 ± 1 cm from the midline. The left border (Point D to A) is convex towards left and extends superomedially from the cardiac apex to meet the second left costal cartilage approximately 1 cm from the left sternal edge.  Note: Please refer page no. 345 for additional details. 60. Ans. b. A–4, B–1, C–3, D–5 Explanation: Marker ‘A’ represents right atrium (showing pectinate muscles); marker ‘B’ denotes the anterior papillary muscle in the right ventricle; marker ‘C’ is at the anterior cusp of mitral valve and ‘D’ marker at membranous portion of interventricular septum. Note: Please refer page no. 349 for additional details. 61. Ans. c. Middle  Explanation: Middle finger receives insertion of 2 dorsal interossei muscles for abduction to either side. q Dorsal interossei are four muscles in hand that act to abduct (spread) the index, middle, and ring fingers away from hand’s midline (middle finger) and assist in flexion at the metacarpophalangeal joints and extension at the interphalangeal joints of the index, middle and ring fingers. Note: Please refer page no. 407 for additional details. 62. Ans. d. Reason is correct and assertion is wrong Explanation: In scaphoid fractures proximal (not distal) portion of bone gets necrosed. This happens because scaphoid has arterial supply in retrograde fashion. q Posttraumatic AVN (AVascular Necrosis) of the scaphoid occurs as a result of impairment of the vascular supply to the involved bone fragment. There is a strikingly poor blood supply to the proximal pole, particularly in comparison with the abundant supply to the distal two-thirds of the scaphoid. 63. Ans. b. Portal vein Explanation: Liver is divided into eight segments according to Couinaud’s classification based upon branches of the portal vein (chiefly), hepatic artery and bile duct. q Couinaud classification of liver anatomy divides the liver into eight functionally independent segments. Each segment has its own vascular inflow, outflow and biliary drainage. In the centre of each segment there is a branch of the portal vein, hepatic artery and bile duct.  Note: Please refer page no. 478 for additional details. 64. Ans. a. Levator ani muscle is attached at pelvic brim Explanation: Levator ani muscle is attached to pubis bone (anteriorly), tendinous arch (obturator internus fascia) laterally. It is not attached to pelvic brim. Note: Pelvic brim is formed by the outer bony edges of the pelvic inlet. q Levator ani muscle is a broad, thin muscle, situated on the side of the pelvis. It is attached to the inner surface of the side of the lesser pelvis, and unites with its fellow of the opposite side to form the greater part of the floor of the pelvic cavity. Note: Please refer page no. 505 for additional details. 65. Ans. a. Abduction Explanation: The diagram shows the insertion of gluteus medius muscle, into the lateral surface of greater trochanter (femur) which works for abduction at hip joint. q Gluteus medius originates from gluteal surface of ilium and inserts into lateral surface of greater trochanter of the femur. Note: Please refer page no. 567 for additional details. SKELETON Bone is a calcified connective tissue consisting of cells (osteocytes) embedded in a matrix of ground substance and collagen fibers. q It has a superficial thin layer of compact bone around a central mass of spongy bone, and contain internal soft tissue, the marrow, where blood cells are formed. q It serve as a reservoir for calcium and phosphorus and act as biomechanical levers on which muscles act to produce the movements permitted by joints. Long bones have a shaft (diaphysis) and two ends (epiphyses). The metaphysis is a part of the diaphysis adjacent to the epiphyses. q Diaphysis Ø Forms the shaft (central region) and is composed of a thick tube of compact bone that encloses the marrow cavity. q Metaphysis Ø Is a part of the diaphysis, the growth zone between the diaphysis and epiphysis during bone development. q Epiphyses Ø Are expanded articular ends, separated from the shaft by the epiphyseal plate during bone growth and composed of a spongy bone surrounded by a thin layer of compact bone. OSSIFICATION q Ossification is the process of laying down new bone material by cells called osteoblasts. It is of two types: Ø Membranous ossification is the direct laying down of bone into the mesenchyme (embryonic connective tissue). Ø Endochondral ossification involves osteogenesis in a precursor model of cartilage. q Membrane (dermal) bones ossify in membrane (intramembranous ossification), and are thus derived from mesenchymal condensations. The flat bones of the skull and face, the mandible, and the clavicle develop by intramembranous ossification. q Cartilaginous bones ossify in cartilage (endochondral ossification), and are thus derived from preformed cartilaginous models. The bones of the extremities (limbs) and those parts of the axial skeleton that bear weight (vertebral column and thoracic cage) develop by endochondral ossification. q Membrano-cartilaginous bones are initially formed in membrane but later partly in cartilage. Examples: clavicle, mandible, occipital, temporal, sphenoid. q Cartilaginous ossification involves primary and secondary centers of ossification: q Primary center of ossification Ø In long bones, bone tissue first appears in the diaphysis (middle of shaft). Ø Primary centers starts appearing at week 6 of intrauterine life. Ø Chondrocytes multiply and form trabeculae and cartilage is progressively eroded and replaced by bone, extending towards the epiphysis. Ø A perichondrium layer surrounding the cartilage forms the periosteum, which generates osteogenic cells that make a collar to encircles the exterior of the bone and remodels the  medullary cavity on the inside. Ø The nutrient artery enters via the nutrient foramen from a small opening in the diaphysis. Ø It invades the primary center of ossification, bringing osteogenic cells (osteoblasts on the outside, osteoclasts on the inside.) n The canal of the nutrient foramen is directed away from more active end of bone when one end grows more than the other. n When bone grows at same rate at both ends, the nutrient artery is perpendicular to the bone. q Secondary center of ossification Ø The secondary centers generally appear at the ends (epiphysis) of long bones. Ø Secondary ossification mostly occurs after birth except for secondary centers around knee joint (distal femur and proximal tibia), which appear during last weeks of fetal life (or immediately after birth). Ø The epiphyseal arteries and osteogenic cells invade the epiphysis, depositing osteoblasts and osteoclasts which erode the cartilage and build bone. This occurs at both ends of long bones but only one end of digits and ribs. Ossification centers which appear prenatally (ossified at birth) are: diaphysis of long bones, skull bones, vertebral column, ribs and sternum, few foot bones (talus, calcaneum, cuboid). Primary center of all carpal and tarsal bones (except talus, calcaneum and cuboid) appear after birth. Figs. 2A and B: Growth of bone—lengthwise: (A) Four Fig. 1: Ossification of a long bone epiphyseal cartilage; (B) Conversion of calcified cartilage in GROWING END q The growing ends of bones in upper limb are upper end of humerus and lower ends of radius and ulna. q In lower limb, the lower end of femur and upper end of tibia are the growing ends. q The nutrient foramen is directed away from the growing end of the bone; their directions are indicated by a memory aid: ‘Towards the elbow I go, from the knee I flee’. Fig. 3: Parts of a young Fig. 4: Direction of nutrient Fig. 5: Arterial supply of a long bone. The upper epiphysis (growing long bone foramina in the limb bones end) has not yet fused with the diaphysis BLOOD SUPPLY Nutrient artery enters the diaphysis (shaft) through the nutrient foramen, runs obliquely through the cortex, and divides into ascending and descending branches in the medullary cavity. q Each branch divides into a number of small parallel channels which terminate in the adult metaphysis by anastomosing with the epiphysial, metaphysial and periosteal arteries. q It supplies medullary cavity, inner 2/3 of cortex and metaphysis. q The nutrient foramen is directed away from the growing end of the bone. Memory aid: Towards the elbow I go, from the knee I flee. q Bony skeleton is divided into two parts: the axial skeleton and the appendicular skeleton. Ø Axial skeleton is the central core unit, consisting of the skull, vertebrae, ribs, and sternum. Ø Appendicular skeleton comprises the bones of the extremities. SESAMOID BONES Sesamoid bones develop in certain tendons and reduce friction on the tendon, thus protecting it from excessive wear. q They are commonly found where tendons cross the ends of long bones in the limbs. q Sites of sesamoid bones: Ø In the ear: The lenticular process of incus is a sesamoid bone and therefore is considered the fourth ossicle of middle ear. Ø In the hand: Two sesamoid bones in the distal portions of the first metacarpal bone (within the tendons of adductor pollicis and flexor pollicis brevis). Ø In the wrist: The pisiform of the wrist is a sesamoid bone (within the tendon of flexor carpi ulnaris), develops at age 9–12. Ø In the knee: The patella (within the quadriceps tendon). Ø Fabella in the lateral head of gastrocnemius behind the knee joint. Ø Sesamoid bone in the tendon of peroneus longus where it binds around the cuboid bone. Ø In the foot: Two sesamoid bones in the distal portions of the first metatarsal bone (within the tendons of flexor hallucis brevis. PNEUMATIC BONES Note: Pneumatic bones are the irregular bones which contain air-filled cavities within them. q They are generally produced during development by excavation of bone by pneumatic diverticula (air sacs) from an air-filled space such as the nasal cavity. q E.g., maxilla, frontal, sphenoid, and ethmoid bones and a part of the mastoid part of the temporal bone. Note: At birth, the mastoid is not pneumatized, but becomes aerated over the first year of life. Epiphysis There are four types of epiphysis: q Pressure epiphysis are the parts of bone involved in weight transmission (and are intracapsular), e.g. head of humerus and femur and condyles of humerus, femur, tibia, etc. Figs. 6A to D: Types of epiphyses: (A) Pressure and traction epiphyses; (B) and (D) Atavistic epiphyses; (C) Aberrant epiphysis q Traction epiphysis are present at the ends of bones and develop due to traction by the attached muscles (and are therefore extracapsular), e.g. greater (and lesser) tubercles in humerus and greater (and lesser) trochanter in femur. Ø These epiphyses ossify later than pressure epiphyses. Ø Examples of traction epiphyses are tubercles of the humerus (greater tubercle and lesser tubercle), and trochanters of the femur (greater and lesser). Mastoid process is also a traction epiphysis. q Atavistic epiphysis: These types of fused bones are called atavistic, another example is the coracoid process of the scapula, posterior tubercle of talus (as trigonum), which has been fused in humans with the main bone, but is separate in lower animals. q Aberrant (unusual) epiphysis are deviations from the norm and are not always present. E.g., Epiphyses at the head of the first metacarpal and at the base of other metacarpals. Q 1. Endochondral ossification is/are seen in: 2. Bones ossified at birth: (PGIC 2015) (PGIC 2015) a. Long bones a. Upper end of humerus b. Clavicle b. Lower end of humerus c. Mandible c. Lower end of femur d. Nasal bones d. Upper end of tibia e. Flat bones of skull e. Calcaneum 3. Nutriient artery runs: 4. All of the following statements are true for (NEET Pattern 2012) metaphysis of bone EXCEPT: a. Towards metaphysis (AIPG 2003) b. Away from metaphysis a. It is the strongest part of bone c. Away from epiphysis d. None b. It is the most vascular part of bone c. Growth activity is maximized here d. It is the region favouring hematogenous spread of infection 5. TRUE statement is: 6. Traction epiphysis (AIPG 2000) is/are: (PGIC) a. Osteoblasts give rise to osteocytes a. Head of humerus  b. Growth of bone occurs at diaphysis b. Lesser tubercle c. Epiphysis is present between metaphysis c. Deltoid tuberosity and diaphysis d. Coracoid process d. Interphalangeal joint is a saddle joint e. Greater trochanter 7. Which of the following is an aberrant 8. Bones which is/are pneumatic: epiphysis: (PGIC May 2015) a. Coracoid process a. Maxillary (NEET Pattern 2015) b. Parietal b. Greater tubercle of humerus c. Temporal c. Base of 1st metacarpal d. Base of 2nd d. Frontal metacarpal e. Ethmoidal 1. a. Long bones; b. Clavicle q Long bones and medial end of clavicle bone develop by endochondral ossification. q Flat bones of skull; facial skeleton; mandible and lateral end of clavicle develop by intramembranous ossification. 2. c. Lower end of femur; d. Upper end of tibia; e. Calcaneum q Secondary centers around knee joint (distal femur and proximal tibia) appear during last weeks of intrauterine life (or immediately after birth). q Primary center of all tarsal bones (except talus, calcaneum and cuboid) appear after birth. 3. a. Towards metaphysis q Nutrient artery enters the shaft (diaphysis) of the bone, divides into ascending and descending branches, which run towards and terminate in the adult metaphysis by anastomosing with the epiphyseal, metaphyseal and periosteal arteries. 4. a. It is the strongest part of bone q The strongest part of bone is diaphysis (not metaphysis). q During growth of bone maximum activity occurs at growth plate (physis) and the adjacent section of the metaphysis. q Metaphysis is richly supplied with arteries forming hairpin bends, hence becomes a common site of osteomyelitis in children, as infectious agents are easily trapped in sluggish blood flow in hairpin bends. 5. a. Osteoblasts give rise to osteocytes q Osteoblasts that get trapped in Haversian lamellae become osteocyte and assume the function of A bone maintenance. They are no longer involved in bone formation. q Growth activity is maximum at the growth plate (physis) and adjacent metaphysis. q Metaphysis is present between diaphysis and epiphysis. q Interphalangeal joint is a hinge variety of synovial joint. 6. b. Lesser tubercle; e. Greater trochanter q Traction epiphysis are usually present at the ends of bones and develop due to traction by the attached muscles (and are therefore extracapsular), e.g. Greater (and lesser) tubercles in humerus and greater (and lesser) trochanter in femur. q Pressure epiphysis are involved in weight transmission (and are intracapsular) e.g. head of humerus and femur and condyles of humerus, femur, tibia, etc. q Coracoid process in scapula is an example of atavistic epiphysis. q Deltoid tuberosity is not an epiphysis (it is present on the shaft/diaphysis). 7. d. Base of 2nd metacarpal q Aberrant epiphyses are deviations from the normal anatomy and are not always present. For example, the epiphysis at the head of the first metacarpal bone and at the bases of other metacarpals. 8. a. Maxillary; c. Temporal; d. Frontal; e. Ethmoidal q Pneumatic bones have air spaces within them and are present around the nasal cavity. q Temporal bone is morphologically classified as pneumatic bone because it has an internal air sinus and mastoid air cells. q Parietal bone is not a pneumatic bone. Ø Trochanter of femur is an example of traction epiphysis (NEET Pattern 2012) Ø Mastoid process is traction epiphysis (NEET Pattern 2015) Ø Mandible is not a pneumatic bone (AIPG 2011) Ø Metaphysis is the epiphyseal end of the diaphysis. Ø Parietal bone is not a pneumatic bone (AIIMS 2003) Ø Pisiform is a sesamoid bone (NEET Pattern 2015) JOINTS Union between bones can be in one of three types: by fibrous tissue; by cartilage; or by synovial joints. Classification The structural classification divides joints into fibrous, cartilaginous, and synovial joints depending on the material composing the joint and the presence or absence of a cavity in the joint. The functional classification divides joints into three categories: synarthroses, amphiarthroses, and diarthroses. Synarthrosis (immovable) Fibrous joints Amphiarthrosis (slight mobile) Cartilaginous joint Diarthrosis (freely mobile) Synovial joints Fibrous joints occur where bones are separated only by connective tissue and movement between them is negligible. Examples of fibrous joints are the sutures that unite the bones of the vault of the skull and the syndesmosis between the lower ends of the tibia and fibula. Types of fibrous joint Examples Suture Spheno-vomerine joint (schindylesis) Gomphosis Tooth and socket joints Syndesmosis Middle radioulnar joint Inferior radioulnar joint Cartilaginous joints are of two varieties, primary and secondary. q Primary Cartilaginous Joints (synchondroses) are united by hyaline cartilage and permit no movement but growth in the length. Ø A primary cartilaginous joint (synchondrosis) is one where bone and hyaline cartilage meet. Thus, all epiphyses are primary cartilaginous joints, as are the junctions of ribs with their own costal cartilages. Ø All primary cartilaginous joints are quite immobile and are very strong. The adjacent bone may fracture, but the bone–cartilage interface will not separate. Ø They Includes epiphyseal cartilage plates (the union between the epiphysis and the diaphysis of a growing bone) and spheno-occipital and manubrio-sternal synchondroses. q Secondary cartilaginous joints (Symphysis) have bones are united by hyaline plus fibrocartilage. Ø These joints are usually in the midline and are slightly mobile. Ø Include pubis symphysis, midline intervertebral joints. n Symphysis is a union between bones whose articular surfaces are covered with a thin lamina of hyaline cartilage. The hyaline laminae are united by fibrocartilage. n There may be a cavity in the fibrocartilage, but it is never lined with synovial membrane and it contains only tissue fluid. n Examples are the pubic symphysis and the joint of the sternal angle (between the manubrium and the body of the sternum).  n An intervertebral disc is part of a secondary cartilaginous joint, but here the cavity in the fibrocartilage contains a gel. n A limited amount of movement is possible in secondary cartilaginous joints, depending on the amount of fibrous tissue within them. All symphyses occur in the midline of the body. Types of cartilaginous joint Examples Synchondrosis Spheno-occipital joint Epiphysio-diaphyseal joint (growing bone) Symphysis Midline intervertebral joint Sacrococcygeal joint q Synovial joints are freely mobile joints. q Synovial joints are uniaxial: Plane, hinge and pivot; Biaxial: Condylar and ellipsoid; Multiaxial: Saddle, ball and socket. Figs. 7A to E: Fibrous joints (A to C) and Cartilaginous joints (D and E) SYNOVIAL JOINTS Synovial joints are freely mobile joints. They are uniaxial: Plane, hinge and pivot; Biaxial: Condylar and ellipsoid and Multiaxial: Saddle, ball and socket. Some authors consider these joints condylar: Atlanto-occipital, wrist (radio-carpal), metacarpo- phalangeal (knuckle). Some authors consider these joints as modified hinge: Temporo-mandibular, knee joint. Fig. 8: Types of synovial joints Figs. 9A and B: An ellipsoid joint (A) is shown as analogous to Figs. 10A and B: A saddle joint (A) is illustrated as analog the radiocarpal joint (wrist) (B) The two axes of rotation are to the carpometacarpal joint of the thumb (B). The saddle in shown by the intersecting pins Represents the trapezium bone. The rider, if present, wo represent the base of the thumb's metacarpal. The two axes rotation are shown in (B) q Knee joint is a complex joint (involving more than two bones). q Femoro-tibial joint structurally resembles a hinge joint, but is considered as a condylar type of synovial joint between two condyles of the femur and tibia. In addition, it includes a saddle joint between the femur and the patella. Hilton’s law: A joint is innervated by articular branches of the nerves that supply the muscles acting on the joint and that also supply the skin covering the joint. Q 1. What type of joint is the growth plate? 2. Atlanto-occipital joint is of synovial variety: (AIPG 2010) a. Trochoid  a. Fibrous b. Ellipsoid b. Primary cartilaginous c. Condylar d. Saddle c. Secondary cartilaginous d. Plane joint 3. Which of the following is a compound condylar 4. Metacarpophalangeal joint is: joint? a. Condylar (NEET Pattern 2012) b. Ellipsoid a. Knee c. Saddle d. Hinge b. TM joint c. Wrist d. Elbow 5. Which of the following is a synovial joint of the 6. Vomer ala and sphenoidal rostrum junction condylar variety? is: (NEET Pattern 2012) (NEET Pattern 2013) a. First carpometacarpal joint a. Syndesmosis b. Metacarpophalangeal joint b. Synostosis c. Interphalangeal joint d. Radiocarpal joint c. Schindylesis d. Gomphosis Special AIIMS Pattern Question 7. Synchondrosis is/are seen in: (AIIMS 2019 Pattern) a. Costo-sternal joints b. Spheno-occipital joint c. Epiphysio-diaphyseal joint d. Manubrio-sternal joint e. Xiphisternal joint A 1. b. Primary cartilaginous q Growing bones have epiphyseal (growth) plate between the epiphysis and diaphysis, this epiphyseo- diaphyseal joint is primary cartilaginous (synchondrosis). q It is found in the growing bone, where the growth plate (hyaline cartilage) connects the epiphysis with the diaphysis, creating a hyaline cartilaginous joint. q At this site the fate of synchondrosis is synostosis (bony fusion) after the growth plate gets removed and replaced by the bone. 2. b. Ellipsoid > c. Condylar q Functionally it is an ellipsoid synovial joint but structurally it is a condylar synovial joint. q Head flexion and extension occurs at this joint for the nodding (yes) movement. 3. a. Knee q Knee joint has more than two bones participating (hence compound joint). It is formed by the lateral and medial femorotibial and the femoropatellar joints. q It is a compound synovial joint incorporating two condylar joints between the condyles of the femur and tibia and one saddle joint between the femur and the patella. q TM joint is a condylar joint but it involves only 2 bones (not a compound joint). q Wrist joint is an ellipsoid synovial joint and elbow is a hinge synovial joint. 4. b. Ellipsoid > a. Condylar q Metacarpophalangeal joint has a condyle with elliptical articular surface. q Structurally it is condylar but functionally ellipsoid synovial joint. 5. b. Metacarpophalangeal joint > d. Radiocarpal joint q This a wrong Questions, since both the joints have condyles with ellipsoid articular surface - are structurally condylar but functionally ellipsoid synovial joints. q Some authors mention metacarpophalangeal as condylar synovial joint only (hence the answer of first preference). 6. c. Schindylesis q Spheno-vomerine joint is a schindylesis suture at the roof of the nasal cavity.  Special AIIMS Pattern Answer 7. b. Spheno-occipital joint; c. Epiphysio-diaphyseal joint; e. Xiphisternal joint q Synchondroses are primary cartilaginous unions between bone composed entirely of hyaline cartilage. These joints are immovable and mostly temporary in nature. As the growth ceases they undergo synostosis (i.e. plate of hyaline cartilage is completely replaced by bone). q Spheno-occipital joint is a synchondrosis joint between the basisphenoid and basiocciput bones, which together when joined from the clivus. When fused, the synchondrosis is often called the spheno-occipital suture- this is a misnomer-as anatomically it is not a suture. q Epiphysio-diaphyseal joint between the epiphyses and diaphysis of a growing long bone, is a synchondrosis, which later undergoes synostosis. q Xiphisternal joint is a synchondrosis joint. Some authors mention it as symphysis. q Costo-sternal joints are plane synovial joints of the costal cartilages of the true ribs with the sternum, with the exception of the first, which is the so called synchondrosis (a misnomer) since the cartilage is directly united with the sternum. q Manubrio-sternal joint is a secondary cartilaginous (symphysis) joint. Ø Innervated structures of joints are Synovium, Capsule and Ligaments (NEET Pattern 2013) – Articular cartilage has no neurovascular bundle Ø Hilton’s law is related to Nerve innervation (NEET Pattern 2016) Ø Knee is a diarthrosis type of joint. Ø Joint between epiphysis and diaphysis of a long bone is a type of Synchondrosis (AIIMS 2004) Ø Ear ossicles articulate with each other through Synovial type of joints (NEET Pattern 2012) – Malleus-incus joint is a saddle synovial joint and incus -stapes is ball and socket synovial joint. Ø Intracapsular articular disc is present in Sternoclavicular joint (NEET Pattern 2012) Ø Vomerine ala and sphenoidal rostrum junction is a Schindylesis (NEET Pattern 2013) Ø Pubic symphysis is Cartilaginous type of joint (NEET Pattern 2015) Ø Inferior tibio-fibular joint is a Syndesmosis. Ø Midline intervertebral joint with intervertebral disc is Secondary cartilagenous (NEET Pattern 2016) Ø The type of joint between the sacrum and the coccyx is a Symphysis (AIPG 2005) Ø Atlantoaxial joint is a Pivot synovial joint (NEET Pattern 2015, 16) MUSCLES The orientation of individual skeletal muscle fibers is either parallel or oblique to the line of pull of the whole muscle. The range of contraction is long with the former arrangement, while the latter provides increased force of contraction. Sartorius is an example of a muscle with parallel fibers. Muscles with an oblique disposition of fibers fall into several patterns: q Muscles with parallel fasciculi: These are muscles in which the fasciculi are parallel to the line of pull and have greater degree of movement. These muscles may be: Ø Quadrilateral, e.g. thyrohyoid, Pronator quadratus Ø Strap-like, e.g. sternohyoid and sartorius Ø Strap-like, with tendinous intersections, e.g. rectus abdominis Ø Fusiform, e.g. biceps brachii, digastric q Muscles with oblique fasciculi: When the fasciculi are oblique to the line of pull, the muscle may be triangular, or pennate (feather-like) in the construction. This arrangement makes the muscle more powerful, although the range of movement is reduced. Oblique arrangements are of the following types: q Convergent fasciculi: The muscle fibers or fasciculi converge at the insertion point to maximize contraction. Such muscles may be: (a) Triangular, e.g. temporalis (b) Fan-shaped, e.g. temporalis.  Fig. 11: Morphological ‘types’ of muscle based on their general form and fascicular architecture. q Spiral or twisted fasciculi: In some muscles the fibers are twisted or spiraled, e.g. trapezius, latissimus dorsi, pectoralis major, supinator. q Cruciate muscles: In some muscles, fibers or fasciculi are arranged in superficial and deep planes and crossed ‘X’, e.g. sterno-cleidomastoid, masseter, adductor magnus. q Sphincteric fasciculi: In some muscles, the muscle fibers or fasciculi surround an opening or orifice, thus when they contract the opening is closed or constricted, e.g. orbicularis oculi around the eye and orbicularis oris surrounding the oral orifice. q Pennate fasciculi: The pennate-fiber muscles resemble the feather, the fleshy fibers correspond to the bars of the feather and the tendon to the shaft, as they are all inserted by tendon. They may be: Ø Uni pennate, e.g. flexor pollicis longus, extensor digitorum longus Ø Bipennate, e.g. rectus femoris, flexor hallucis longus Ø Multipennate, e.g. tibialis anterior, subscapularis, deltoid (acromial fibers). q Common sites of intramuscular injection Upper arm Ø 5 cm distal to the acromion or (Deltoid) Ø 4 cm proximal to the insertion of deltoid Ø This is to prevent injury to circumflex humeral nerve. Gluteal region Ø Upper outer (superolateral) quadrant Ø This is to avoid damage to superior and inferior gluteal vessels and scia nerve.  Ø The muscle in which the injection is given is gluteus medius. Thigh (lateral aspect)(vastus lateralis) Ø Infant: Upper lateral quadrant of thigh below GT Ø Adult: Middle third of lateral aspect. Hybrid (composite) muscles have more than one set of muscles fibers and more than one nerve supply. q They lie at the boundaries between muscle groups. Usually it incorporates fibers from two adjoining groups and is therefore supplied by two nerves usually. Muscle Ø Nerve supply (Part of muscle) Trapezius Ø Spinal accessory nerve (motor) Ø Ventral rami of C3, C4 (proprioception) Digastric Ø Trigeminal nerve (anterior belly) Ø Facial nerve (posterior belly) Pectoralis major Ø Medial pectoral nerve Ø Lateral pectoral nerve Subscapularis Ø Upper subscapular nerve Ø Lower subscapular nerve Brachialis Ø Musculocutaneous nerve (motor) Ø Radial nerve (proprioceptive) Flexor digitorum profundus Ø Median nerve (lateral half) Ø Ulnar nerve (medial half) Opponens pollicis Ø Median nerve (superficial part) Ø Ulnar nerve (deep part) Ilio-psoas Ø Direct branches of the anterior rami of L1-L3 (psoas major) Ø Femoral nerve (iliacus) Pectineus Ø Femoral nerve (anterior fibers) Ø Obturator nerve (posterior fibers) Biceps femoris Ø Tibial part of sciatic nerve (long head) Ø Common peroneal nerve (short head) Adductor magnus Ø Tibial part of sciatic nerve (ischial part) Ø Obturator nerve (adductor part) 1. All are composite muscles EXCEPT: 2. Muscle having double nerve supply: (AIPG 2009) (PGIC 2015) a. Pectineus a. Digastric muscle b. Flexor carpi ulnaris b. Omohyoid muscle c. Biceps femoris c. Trapezius d. Flexor digitorum profundus d. Thyrohyoid muscle e. Adductor magnus Q 3. Digastric muscles are the following EXCEPT: 4. Which of the following is multipennate (AIPG 2008) muscle: a. Occipitofrontalis (NEET Pattern 2015) b. Sternocleidomastoid a. Flexor pollicis longus c. Omohyoid b. Extensor pollicis longus d. Muscular fibers in the ligament of Treitz c. Deltoid d. Flexor hallucis longus 5. Muscle with parallel fibers are all EXCEPT: 6. Which of the following muscle has (AIIMS 2016) intracapsular origin: a. Sartorius (PGIC 2012) b. Rectus abdominis a. Anconeus b. Coracobrachialis  c. Sternohyoid d. Tibialis c. Long head of biceps femoris anterior d. Popliteus e. Peroneus longus 7. Identify the type of muscle shown in the image (NEET Pattern 2018) a. Cruciate b. Spiral c. Multipennate d. Convergent Q A 1. b. Flexor carpi ulnaris q Flexor carpi ulnaris is supplied by a single nerve and is not a composite/hybrid muscle. q Composite/hybrid muscles have more than one set of fibers and are supplied usually by different nerves for different set of fibers. q Pectineus has anterior set of fibers supplied by the femoral nerve, whereas, posterior set of fibers may be supplied by the obturator nerve. q Long head of biceps femoris is supplied by the tibial part of sciatic nerve, and the short head is supplied by the common peroneal nerve. This reflects the composite derivation from the flexor and extensor musculature. q Radial half of flexor digitorum profundus is supplied by the median nerve and the ulnar half is supplied by the ulnar nerve. 2. a. Digastric muscle; c. Trapezius; e. Adductor magnus q Anterior belly of digastric is supplied by trigeminal nerve and posterior belly by facial nerve. q Spinal accessory nerve gives motor fibers to trapezius muscle, whereas ventral rami of C3,C4 are proprioceptive. q Adductor magnus ischial part is supplied by tibial part of sciatic nerve and adductor part by obturator nerve. q Inferior belly of the omohyoid is innervated by C1-C3 and the superior belly C1 fibers of ansa cervicalis. q Thyrohyoid muscle is innervated by C1 fibers traveling with the hypoglossal nerve. 3. b. Sternocleidomastoid q Sternocleidomastoid is a muscle with two heads and one belly, like the biceps brachii. q Digastric muscles have two bellies. q Occipitofrontalis muscle has two bellies: Occipital belly and frontal belly. q Omohyoid: Superior and inferior belly. q Ligament of Treitz is a digastric muscle with a skeletal muscle belly, which arises from the left crus of diaphragm and a smooth muscle belly which arises from the duodeno-jejunal junction. It has an intermediate tendon attaching to the connective tissue around the celiac trunk of aorta. 4. c. Deltoid q Multipennate muscle has the fiber bundles converge to several tendons. 5. d. Tibialis anterior q The individual fibers of a muscle are arranged either parallel or oblique to the long axis of the muscle. q Tibialis anterior muscle is a multipennate muscle with oblique fibers. q Muscles with parallel fasciculi: These are muscles in which the fasciculi are parallel to the line of pull and have greater degree of movement. Few examples are: n Strap-like, e.g. sternohyoid and sartorius n Strap-like with tendinous intersections, e.g. rectus abdominis  6. d. Popliteus q Long head of biceps brachii and the popliteus muscle has intracapsular origin. 7. Ans. b. Spiral> d. Convergent q Muscles may exhibit a spiral or twisted arrangement (e.g. sternocostal fibres of pectoralis major or latissimus dorsi, which undergo a 180°-twist between their medial and lateral attachments). q Some authors consider it as a muscle with convergent fibres as well. The muscle fibers or fasciculi converge at the insertion point to maximize contraction. q Muscles may spiral around a bone (e.g. supinator, which winds obliquely around the proximal radial shaft), or contain two or more planes of fibres arranged in differing directions, a type of spiral sometimes referred to as cruciate (sternocleidomastoid, masseter and adductor magnus are all partially spiral and cruciate). Ø Smallest muscle in the body is Stapedius (NEET Pattern 2015) – The smallest skeletal muscle in the body is stapedius. – The smallest muscle in the body is arrector pilorum, a smooth muscle in the skin for erection of hair. Ø Longest muscle in the body is Sartorius (NEET Pattern 2012) Ø Flexor digitorum superficialis does not have dual nerve supply (NEET Pattern 2012) Ø Most common muscle to be congenitally absent is Pectoralis major (AIPG 2009) Ø Popliteus muscle has an intra-articular tendon (JIPMER 2016) Ø Rectus femoris is not a hybrid muscle (AIPG 2008) Ø Flexor carpi ulnaris is not a hybrid muscle. Ø All the muscles of body develop from mesenchyme except arrector pili, muscles of iris and myoepithelial cells, which develop from ectoderm. Ø Largest muscle in the body is gluteus maximus. Ø Functional unit of a muscle is sarcomere. Ø Most variable muscle in the body is palmaris longus. Ø Longest tendon in the body is plantaris in the leg. Ø Largest tendon in the body is tendo calcaneus (Achilles tendon). Ø Most commonly used muscle for intramuscular injection is deltoid. Ø Muscles with smallest motor unit are extraocular muscles and largest are lower limb muscles like gluteus maximus. Ø Talus bone in the foot and Incus bone in the middle ear cavity have no muscle attachments. PORTAL VENOUS CIRCULATION q Portal circulation is a capillary network that lies between two veins. Blood supplying the organ thus passes through two sets of capillaries before it returns to the heart. q In hepatic portal system blood supplying the abdominal organs passes through two sets of capillaries before it returns to the heart. q A portal circulation also connects the median eminence and infundibulum of the hypothalamus with the adenohypophysis. q In the renal glomeruli. The glomerular capillary bed lies between afferent and efferent arterioles and may be considered as a portal circulation, but most of the authors do not mention so (including Gray’s anatomy). MISCELLANEOUS 1. In the following nutrient arteries to bones, 2. All are Valveless EXCEPT: choose the WRONG pair: a. Dural venous sinus a. Humerus: Profunda brachii b. Hepatic veins Q b. Radius: Anterior interosseous c. Inferior vena cava d. Femoral vein c. Fibula: Peroneal d. Tibia: Anterior tibial A 1. d. Tibia: Anterior tibial  q Nutrient artery to tibia is a branch of posterior tibial artery. 2. d. Femoral vein q Femoral veins contain between one and six valves, and popliteal veins contain between zero and four valves. q Deep vein valves are consistently located in the common femoral vein (within 5 cm of the inguinal ligament), the femoral vein (within 3 cm of the deep femoral vein tributary) and in the popliteal vein near the adductor hiatus. Prenatal period is divided into three parts: Pre-embryonic, embryonic and fetal period. q Pre-embryonic period extends from fertilization to the end of second week of intrauterine life. q Embryonic period extends from beginning of the third week to the end of eighth week of intrauterine life. q Fetal stage extends from beginning of the ninth week to birth. Note: Some authors consider the embryonic period from fertilization to the end of eight week. Flowchart 1: Subdivision of prenatal period and events occurring in these periods. 1. At the end of 5th week of gestation, how many 2. Embryonic period of development is: (NEET number of somites can be Pattern 2012) seen? (NEET Pattern) a. Up to 16 weeks a. 24 b. Up to 12 weeks b. 26 c. Up to 10 weeks d. Up to 8 c. 38 d. 44 weeks Q 3. Identify the CORRECT pair: (NEET Pattern 2013) a. Embryonic period: 9–20 weeks b. Fertilization to implantation: 0–4 weeks c. Embryonic period: 4–8 weeks d. None 1. d. 44 q The first pair of somites arises in the occipital region of the embryo at approximately the 20th day of A development. q From here, new somites appear in craniocaudal sequence at a rate of approximately three pairs per day until, at the end of the fifth week, 42 to 44 pairs are present. A q The first occipital and the last five to seven coccygeal somites later disappear (now the total is 37), these remaining somites form the axial skeleton.  q The age of an embryo can be accurately determined by counting number of somites 2. d. Up to 8 weeks q Embryonic period extends from beginning of the third week to the end of eighth week of intrauterine life. q Some authors consider the embryonic period from fertilization to the end of eight week. 3. c. Embryonic period: 4–8 weeks q Embryonic period extends from beginning of the third week to the end of eighth week of intrauterine life. q There is no correct answer, the most appropriate option has been chosen as the answer. q Total number of somites developing in fetus are 42 pair (NEET Pattern 2016) CELL DIVISION Mitosis Meiosis Table 2: Distinguishing features between mitosis and meiosis Mitosis Meiosis Ø Takes place in somatic cells Ø Takes place in germ cells Ø Completes in one sequence Ø Completes in two sequences, i.e., there are two successive divisions, viz., meiosis I and meiosis II Ø Crossing over of chromatids does not take place Ø Crossing over of chromatids takes place Ø Daughter cells have the same number of chromosomes as Ø Daughter cells have half the number of chromosomes as parent cells parent cells Ø Daughter cells are identical to each other and to the parent Ø Daughter cells are not identical to each other and to the cell parent cell Ø Equational division Ø Reductional division  Figs. 2A and B: Types of cell division. (A) Mitosis. (B) Meiosis 1. Prophase of meiosis-I, TRUE statement is/are: (PGIC 2017) a. Chromosomes separate Q b. Resultant cell is diploid c. Resultant cell is haploid d. Sister chromatids replicate e. Sister chromatids separate 1. b. Resultant cell is diploid q During prophase of meiosis-I, pairing of maternal and paternal (homologous) chromosomes (synapsis) occu