Anatomy Revision E6.5 -Medicalstudyzone.com-.pdf

Www.Medicalstudyzone.comAnatomy Revision 1 01 1 ANATOMY REVISION 1 ----- Active space ----- General Embryology...

Www.Medicalstudyzone.comAnatomy Revision 1 01 1 ANATOMY REVISION 1 ----- Active space ----- General Embryology 00:00:27 Pre embryonic period : 0-2 weeks. Embryonic period : 2-8 weeks. Fetal period : 9 weeks - Till birth. Primordial Germ Cell : Pluripotent cell. Produced by epiblast : 2nd week. Migrate to endodermal wall of yolk sac : 4th week. Reach gonads : 5th week. Abnormal migration of PGC results in teratoma. Neck : Craniopharyngeal teratoma. Sacrum and coccyx : Sacro coccygeal teratoma. Oogenesis : (Diplotene stage) Graafian follicle after ovulation : Corpus luteum. Degenerated corpus luteum : Corpus albicans. Anatomy Revision v1.0 Marrow 6.5 2023 This PDF was created and uploaded by www.medicalstudyzone.com which is one the biggest free resources platform for medical students and healthcare professionals. You can access all medical Video Lectures, Books in PDF Format or kindle Edition, Paid Medical Apps and Softwares, Qbanks, Audio Lectures And Much More Absolutely for Free By visiting our Website https://medicalstudyzone.com all stuff are free with no cost at all. Furthermore You can also request a specific Book In PDF Format OR Medical Video Lectures.  2 01 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Spermatogenesis : Spermatogenesis completed in 74 days > 64 days > 60 days. Meiosis occurs in seminiferous tubule. Maturation of sperms occurs in : epididymis. Capacitation of sperms : 6 ~ 8 hours, in female genital tract. Fertilisation : LH surge : 36 hours before ovulation. LH peak : 12 hours before ovulation > at ovulation. Sperms viable for 48 hours. Most fertile period : 2 days before ovulation to one day after ovulation. First week of development 00:13:00 Zygote : 12-24 hours of ovulation. 2 cell : 24 hours after fertilisation. 8-16 cell : 3rd day. Morula : 16 cell stage > 8 cell stage. Advance morula (32 cell stage) : 4th day. Enters uterine cavity : 4th- 5th day. Blastocyst : 4-5 days. Zona pellucida : a. Prevents implantation. b. Prevents polyspermy. c. Disappears : 5th day. Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 1 01 3 Implantation begins at 6-7th day. zona pellucida embryoblast ----- Active space ----- Completes by 10-11 day. th Bleeding at the time of implantation : Hartman’s sign. trophoblast Outer cell mass : Trophoblast → Forms placenta. Inner cell mass : Embryoblast → Forms embryo. blastocyst Intra decidual sign : Blastocyst implanted in the deep layer of decidua. First fetal part to appreciate in USG : Gestational Sac. USG: Intradecidual sign Second week of development 00:18:51 Inner cell mass Epiblast : Hypoblast : Columnar cells. Cuboidal cells. Forms amniotic cavity. Forms primary yolk sac. Heuser’s membrane : Double bleb sign : Exocelomic membrane derived from Two bubbles formed by amniotic cavity hypoblast; flat cells. and primary yolk sac Anatomy Revision v1.0 Marrow 6.5 2023  4 01 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Outer cell mass : Cytotrophoblast : Well defined cell wall. Syncytiotrophoblast : No defined cell wall ( Hormone factory of placenta). Chorion : Chorion : Extraembryonic somatic mesoderm + Cytotrophoblast + Syncytiotrophoblast. Extra embryonic mesoderm derived Chorion from primary yolk sac > hypoblast > epiblast. Third week of development 00:26:32 Important events in third week : Gastrulation. Neurulation. Prochordal plate : Columnar hypoblast cells. Forms oropharyngeal membrane. Ruptures and forms oral cavity. Forms head end. Primitive streak : Epiblast proliferate & forms primitive streak on 14-15th day. Forms tail end. Formation of primitive streak indicates beginning of gastrulation. Gastrulation : Endoderm (1st formed) → Meso- derm → Ectoderm (last formed). All 3 layers are derived from epiblast. Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 1 01 5 Notochord : ----- Active space ----- Midline mesoderm from primitive streak. Remnants : Nucleus pulposus > Apical ligament of dens. If it persists : forms chordoma. Mesoderm : Intraembryonic Mesoderm Paraxial Mesoderm Intermediate Mesoderm Lateral plate Mesoderm Somites : Uro genital Somatopleuric Splanchnopleuric Sclerotome : system : mesoderm : mesoderm Axial skeleton. kidney. Appendicular (cardiogenic layer) : Myotome : Testis. skeleton. smooth muscles, Skeletal muscles. Ovary. Parietal lay- cardiac muscles. Dermatome : Mesonephric & er of body Visceral layer of Dermis. paramesone- cavity and body cavity and phric duct. linings. linings. Intraembryonic Mesoderm Anatomy Revision v1.0 Marrow 6.5 2023  6 01 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Double decidual sac sign : Inner ring : Decidua capsularis. Outer ring : Decidua parietalis. Histology 00:38:19 Epithelium Characteristics Examples Simple epithelium Simple squamous Breadth > length. Blood vessels. Flat nucleus. Body cavities. Bowmans capsule. Alveoli. Simple cuboidal Length = breadth. Thyroid follicles. Round nucleus. Germinal epithelium of ovary. Tubules of kidney. Simple columnar Length > breadth. Stomach. Elongated nucleus. Large intestine. Uterus. Pseudostratified columnar Nuclei arranged Trachea. at different levels. bronchus. Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 1 01 7 ----- Active space ----- Epithelium Characteristics Examples Stratified epithelium Stratified squamous Many layers. Skin - Keratinised. Apical layer is Tongue. squamous. Tonsil. Non Esophagus. keratinised Cornea. Stratified cuboidal Ducts of exocrine glands and sweat glands. Stratified columnar Membranous urethra. Penile urethra. Transitional epithelium (Urothelium) Apical layer Ureter. cells are Bladder. umbrella Prostatic urethra. shaped. Modifications : Cilia : Structure for motility Microvilli : Simple ciliated columnar epithelium : Increases surface area. Eustachian tube. Simple columnar epithelium Middle ear. with microvilli : Fallopian tube. Small intestine. ventricles of brain. Gall bladder. Trachea & bronchus : Pseudostratified ciliated columnar epithelium. Anatomy Revision v1.0 Marrow 6.5 2023  8 01 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Cartilage 00:46:56 Charac- Hyaline cartilage Elastic cartilage Fibrocartilage teristic Chondro- In groups In groups In rows cytes Matrix Glossy. Elastin fibres & Type 1 collagen Type II collagen Type II collagen fibres present fibres present. fibres present. : long wavy Elastin : Short, bundles. single, non wavy fibres. Does not calcify. Perichon- Present Present Absent drium Examples Articular cartilage. Epiglottis. Meniscus. Costal cartilage. Ear lobe. Articular disc. Embryonic cartilage. Eustachian tube. Glenoidal Epiphyseal cartilage. labrum. Respiratory carti- Intervertebral lage. disc. Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.comAnatomy Revision 2 02 9 ANATOMY REVISION 2 ----- Active space ----- Neuron 00:00:32 Collection of cell bodies in : CNS : Nucleus PNS : Ganglion Collection of axons in : CNS : Tract - white matter PNS : Nerve Cell Function Origin Astrocyte Blood brain barrier Neuro ectoderm Microglia Phagocytosis Mesodermal Oligodendrocyte Myelin sheath - CNS Neuro ectoderm Schwann cell Myelin sheath - PNS Neural crest cell Ependymal cells Lines ventricles Neuro ectoderm Development Of Neural Tube/Neurulation 00:03:27 Occurs in the 3rd week. Notochord : Gives signal to ectoderm Ectoderm forms neural plate (Neuroectoderm) Neural plate invaginates Neural groove (Due to signal from notochord) Neural crest cells Neural groove Neural crest cells are formed at the junction of neural plate and surface ectoderm Neural groove invaginates Neural Tube Anatomy Revision v1.0 Marrow 6.5 2023  10 02 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Cranial neuropore closes by 25th day. Cranial neuropore fails to close : Anencephaly. Caudal neuropore closes by 27/28th day. Caudal neuropore fails to close : Spina bifida anomalies. Neural tube defects occur due to deficiency of folic acid. CSF And Ventricles 00:06:24 Choroid plexus : Actively secretes CSF. Choroid plexus of lateral & IIIrd ventricle : From anterior and posterior choroidal artery. IVth ventricle : From PICA > AICA. Ventricle Location Lateral ventricles Telencephalon Third ventricle Diencephalon Cerebral aqueduct of Mid-brain Sylvius Pons, Medulla & Cere- Fourth ventricle bellum Flow of CSF : Lateral ventricle → Foramen of Monro → Third ventricle → Cerebral aqueduct of Sylvius → Fourth ventricle → Foramen of Magendie (Median) & Foramen of Luschka (Lateral) → Subarachnoid space → Arachnoid villi → Dural venous sinus (Superior sagittal sinus). Applied Anatomy : M/c cause of congenital hydrocephalus : Congenital aqeductal stenosis. Dandy Walker Syndrome : Atresia of foramen of Magendie & foramen of Luschka. Occurs d/t posterior cranial fossa cyst leading to dilated fourth ventricle. Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 2 02 11 Dura mater : ----- Active space ----- 2 layers → Endosteal layer & meningeal layer. Between the two layers is Dural venous sinus. Space Content Applied anatomy Subarachnoid CSF through arachnoid granulations CSF space drain into dural venous sinus Subdural Injury leading to subdural hematoma. Bridging veins space NCCT : ‘C’/crescent shaped Middle meningeal Injury leading to epidural hematoma. Epidural space artery NCCT : Lens/biconvex shaped Pterion : Meeting point of 4 bones → Frontal, parietal, temporal & sphenoid. Anterior/frontal division of middle meningeal artery present beneath pterion. Relations of third ventricle : Tubercinereum Anatomy Revision v1.0 Marrow 6.5 2023  12 02 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Lamina terminalis : Formed at the site of cranial neuropore. No blood brain barrier (Circumventricular organ). Pineal gland is also circumventricular organ. Interpeduncular fossa contents : Oculomotor nerve. Infundibulum. Mamillary bodies. Posterior perforating substance. Tubercinerium. Hippocampus : Framing recent memory Connected to mamillary body through fornix. Fornix : Fornix Mammilothalamic tract Hippocampus Mammillary body Anterior nucleus of thalamus. Contains : Association > commissural > projection fibres. Fourth ventricle : Trochlear nerve Pons Medulla Stria medullaris Floor : Lower Pons & Upper medulla. Stria medullaris : Transverse white matter fibres b/w pons & medulla. Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 2 02 13 Facial colliculus : 00:26:31 ----- Active space ----- Swelling due to axons of facial nerve winding around abducent nucleus in floor of fourth ventricle. Damage to Facial colliculus : CN7 > CN6. Spinal Cord 00:28:00 Structure Ends at Spinal cord in adults Lower border of L1 Spinal cord in newborn Upper border of L3 Pia mater Coccyx Arachnoid membrane & Lower border of s2 subarachnoid space Converge at s2 and Dura mater ends at coccyx Level of lumbar puncture : L3-4 or L4-5 Descending tracts/motor tracts : Tract Functions Pyramidal Tracts : Corticospinal tract Fine, distal, skilled & voluntary movement. Corticonuclear tract Extra Pyramidal Tracts : Rubrospinal tract Tectospinal tract Plan, program, regulate, modulate the movement. Vestibulospinal tract Anatomy Revision v1.0 Marrow 6.5 2023  14 02 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Types of motor neuron : Upper motor neuron (UMN). Lower motor neuron (LMN). UMN controls LMN (Mostly by inhibition). Features UMN lesion LMN lesion Paralysis Spastic Flaccid Tone Hypertonia Hypotonia Deep tendon reflex Exaggerated Areflexia Babinski sign Positive Negative All cranial nerve nuclei controlled by both cortex (Except lower facial nucleus : Controlled only by opposite cortex). Corticospinal tract (CST) : Motor tract Origin from Betz cells : 30% from primary motor area. 30% from premotor area. 40% from primary sensory area. Lesion in corticospinal tract In brain stem → C/L weakness In spinal cord → I/L weakness Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 2 02 15 Ascending tracts /Sensory tracts : ----- Active space ----- Start at the spinal cord from dorsal root ganglion & reach thalamus (VPL nucleus) → To sensory cortex (Area 3, 1, 2). Dorsal column tract (DCT) : 1. Nucleus gracilis : Carries fibres from lower limb Located medially. 2. Nucleus cuneatus Carries fibres from upper limb Located laterally. Carries : Fine touch, proprioception Vibration, stereognosis Position sense 2 point discrimination Fibres from these nuclei cross to opposite side (In medulla) & ascend as medial lemniscus. Spinothalamic tract : Spinothalamic tract : Decussate in spinal cord & ascend as spinal lemniscus. Lesion to spinothalamic tract in spinal cord or in brain stem → C/l loss of pain, temperature, crude touch & pressure. Applied Anatomy : Tabes Dorsalis : Syphilitic degeneration of dorsal column tract. Romberg’s sign : Positive. Brown-Sequard Syndrome : Hemisection of spinal cord. At the site of lesion : Loss of all sensation. CST : I/L weakness. DCT : I/L loss of vibration, stereognosis etc. Spinothalamic tract : C/L loss of pain & temperature. Anatomy Revision v1.0 Marrow 6.5 2023  16 02 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Brain stem 00:45:40 Medulla : Pyramid : Median elevation. Olive : Inferior olivary nucleus present lateral to pyramid. Hypoglossal nerve : Between pyramid and olive. 9, 10, 11th nerve : Lateral to olive. Pons : Trigeminal nerve : Large sensory root & small motor root. Abducent nerve : At pontopyramidal junction. Facial nerve : Ponto olivary junction. Lateral to 7th nerve : 8th nerve. Midbrain 00:47:33 Corpora quadrigemina : 4 swellings in posterior midbrain : 2 Superior colliculus connected to lateral geniculate body involved in optic pathway (SLOW). 2 Inferior colliculus connected to medial geniculate body involved in auditory pathway (IMA) At the level of : Superior colliculus → IIIrd nerve. Midbrain : Posterior view Inferior colliculus → IVth nerve. Facts about cranial nerves : Trochlear nerve : Slender cranial nerve (smallest). Longest intracranial course. Dorsal exit. Cranial nerve with internal decussation. Longest intra dural course, common nerve to get affected in raised intra cranial pressure : Abducens Nerve. Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 2 02 17 Longest interosseous course : Facial Nerve. ----- Active space ----- Longest extra cranial course : Vagus Nerve. Largest nerve : Trigeminal nerve. Shortest nerve : Olfactory Nerve. Basal ganglia 00:50:30 Fornix Corpus Callosum Thalamus Third ventricle Substantia nigra Pons Medulla Corpus striatum (Nuclei inside the cerebrum) : Lateral to thalamus & 3rd ventricle. Corpus striatum Caudate Lentiform nucleus Nucleus GP externus Putamen Globus pallidus GP internus Neostriatum Paleostriatum Substantia nigra : Contains melanin (Precursor for dopamine). Fibres to neostriatum via nigrostriatal pathway. Applied anatomy : Lesions of Basal ganglia 00:54:43 Lesion Defect Globus pallidus Athetosis : Spontaneous writhing movements of hand, arm, neck & face. Putamen Chorea : Involuntary flicking movements of hands, face and shoulders. Substantia nigra Parkinson’s disease Subthalamus Hemiballismus : Sudden flailing movements of an entire limb. Anatomy Revision v1.0 Marrow 6.5 2023  18 02 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Internal capsule : 00:55:50 Projection fibres : Connects cortex to subcortical structures. Part of Inter- Fibres carried Blood supply nal capsule Superior/Dorsal Inferior/Ventral Anterior Limb Recurrent artery of Huebner/ MCA : Striate branch/ medial striate artery Lateral Striate Genu Internal carotid artery Corticonuclear tract artery/artery of (capsular branch) Charcot hemorrhage Posterior Limb Corticospinal tract Anterior Choroidal artery Sublentiform Auditory fibres Anterior Choroidal artery Retrolentiform Optic fibres Cerebellum 01:00:05 Cells : All cells are inhibitory except Granule cell. Purkinje cell : Flask shaped. Gives dendrites to outer molecular layer. Gives axons to cerebellar nuclei → Other parts of brain. Output from cerebellar cortex : Purkinje cell. Output from cerebellum : Cerebellar nuclei. Input to cerebellum : Climbing fibres (Inferior olivary nucleus → One purkinje cell). Cerebello glomeruli : 1 terminal of mossy fibre + 1 granule cell + 1 golgi cell. From granule cell → T shaped fibre arises →Joins thousands of purkinje cells. Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 2 02 19 Purkinje cell : Cerebellar Nuclei : ----- Active space ----- Cerebellar peduncles : Superior cerebellar peduncle : Connects cerebellum to midbrain. Afferent : Anterior spinocerebellar tract, tectocerebellar tract. Efferents from dentate, emboliform, globose nucleus. Fibres from superior cerebellar peduncle → Decussate at midbrain → Inferior colliculus → End in red nucleus & thalamus. Middle cerebellar peduncle : Connects cerebellum to pons. Ponto cerebellar fibres. Inferior cerebellar peduncle : Connects cerebellum to medulla. Cerebrum 01:07:15 Anatomy Revision v1.0 Marrow 6.5 2023  20 02 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Gyrus Area/Function Area number Pre central gyrus Primary motor area 4 Superior Premotor area 6 frontal gyrus Frontal Middle Frontal eye field 8 lobe frontal gyrus Inferior Broca’s area (Motor area for 44, 45 frontal gyrus speech) Post central gyrus Primary sensory area 3, 1, 2 Superior Sensory association area 5, 7 Parietal parietal lobule lobe Inferior Hand eye co-ordination - parietal lobule Primary visual area 17 Occipital lobe : Visual cortex Visual association area 18, 19 Superior Anterior part Primary auditory area 41, 42 temporal Wernicke’s area (Sensory area gyrus Posterior part 22 for speech) Gyrus Function Integrates sensory input to emotion. Emotional response to pain. Cingulate gyrus Regulates aggressive behavior. Highest centre for satiety. Lower limb & perineum are represented. Paracentral lobule Highest centre for micturition & defecation. Parahippocampal gyrus Area No. 28 (Olfactory area) & uncus Smell mediated sexual behavior Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 2 02 21 Aphasia : 01:07:15 ----- Active space ----- Disorder of language : In dominant lobe lesions. Aphasia Comprehension Fluency Repetition One word speech Broca’s Present Absent ( Telegraphic speech ) Present Jargon aphasia Wernicke’s Absent Absent Neologism Paraphasia Conduction aphasia (Le- Present Present Absent sion in arcuate fasciculus) Blood supply of Brain 01:14:48 Carotido Basilar system Vertebral artery : Branch of first part of subclavian artery. 1st part → In neck : Very close to stellate ganglion. 2nd part → Pass through foramen transversorium of C6 to C1. 3rd part → In sub-occipital triangle. 4th part → Passes through foramen magnum and joins with opposite side to form basilar artery. Internal carotid artery : Branch of common carotid at the level of C3-C4. In neck : No branches. Petrous part : ICA → Enters cranial cavity through carotid canal → Pass inside the petrous temporal bone → Traverse the superior part of foramen lacerum. Cavernous part : Pass inside the cavernous sinus. Cerebral part : Gives terminal branch (middle & anterior cerebral artery). Anatomy Revision v1.0 Marrow 6.5 2023  22 02 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Circle of Willis : Blood supply of Medulla : Anterior spinal artery : Supplies medulla → Passes through foramen magnum → Supplies anterior 2/3rd of spinal cord. Posterior spinal artery : Branches of vertebral artery in medulla. Supplies medulla → Descends posteriorly through foramen magnum → Supplies posterior 1/3rd of spinal cord. Posterior inferior cerebellar artery (PICA) : Branch of vertebral artery in medulla → Supplies medulla & cerebellum. Basilar artery : Gives branches to medulla. Medial medullary syndrome : Anterior spinal artery involved. Lateral medullary syndrome (Wallenberg syndrome) : Vertebral artery > PICA. Blood supply of Pons : 1. Anterior inferior cerebellar artery : Gives labyrinthine artery in 80% (20% from basilar artery). 2. Pontine branches from basilar artery. 3. Superior cerebellar artery. Blood supply of cerebellum : Superior cerebellar artery. Anterior inferior cerebellar artery. Posterior inferior cerebellar artery. Blood supply of midbrain, thalamus, visual cortex : Posterior cerebral artery. Note : MCA is not involved in formation of Circle of Willis. Aneurysms : Aneurysms of anterior communicating artery : Compress optic chiasma. Aneurysms of posterior communicating artery : Compress oculomotor nerve. Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.comAnatomy Revision 3 03 23 ANATOMY REVISION 3 ----- Active space ----- Development of head and neck 00:00:12 Development and derivatives of pharyngeal arch : Endodermal pouches Ectodermal clefts Pharyngeal arches Arise from neural crest cells > mesoderm. Mesoderm 5th arch disappears Endoderm Ectoderm Pharyngeal arches Pharyngeal arch derivatives : Artery, cartilage, bone, ligaments, muscle, nerve. Pharyngeal Cartilage Muscle Nerve arch Mastication muscles, tensor palatini, 1st arch Malleus, incus, skull. tensor tympani, mylohyoid, anterior Mandibular belly of digastric. Stapes, Styloid, Stylohyoid lig., Small Facial muscles, stylohyoid, posterior 2nd arch horn of hyoid, Sup. Facial belly digastric, Stapedius surface of hyoid (5S). Greater horn of 3rd arch hyoid, Inferior Stylopharyngeus Glossopharyngeal surface of hyoid. 4th arch Cartilages of larynx Muscles of pharynx, palate, cricothyroid Superior laryngeal 6th arch except epiglottis. Muscles of larynx except cricothyroid Recurrent laryngeal High yield points : All muscles of larynx develop from 6th arch except cricothyroid : 4th. All muscles of pharynx develop from 4th arch except stylopharyngeus : 3rd. All muscles of palate develop from 4th arch except tensor palatini : 1st. All muscles of tongue derived from somites except palatoglossus : 4th. Anterior belly of digastric derived from 1st arch. Posterior belly derived from 2nd arch. Tensor tympani derived from 1st arch. Stapedius derived from 2nd arch. Anatomy Revision v1.0 Marrow 6.5 2023  24 03 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Pharyngeal pouch derivatives : Primitive tympanic cavity Tubotympanic recess Auditory tube 1st pouch Palatine tonsil 11nd pouch Inferior parathyroid gland 111rd pouch Thymus Di George syndrome : 22q11 deletion syndrome. Superior parathyroid gland 3rd pouch fails to differentiate. Ultimobranchial body IVth pouch (Parafollicular C cells) Pharyngeal pouch derivatives Note : Parafollicular C cells arise from neural crest cells > ultimobranchial body. Development of tongue : Developed from : 2 Floor of 1st arch. I II III Floor of 3rd arch. IV Floor of 4th arch. VI Note : 2nd arch is not contributing to the development of tongue Osteology of head and neck 00:10:36 Foramina in the skull : Foramen Contents Optic nerve. Optic canal Ophthalmic artery. Mandibular nerve. Accessory meningeal artery. Ovale Lesser petrosal nerve. Emissary vein connecting cavernous sinus & pterygoid venous plexus. Middle meningeal artery and vein. Spinosum Emissary vein. Nervous spinosum. Rotundum Maxillary nerve. Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 3 03 25 ----- Active space ----- Cribriform plate of ethmoid Pierced by CN 1 Optic canal (Olfactory nerve) Lesser wing of sphenoid Present between Superior orbital fissure lesser and greater Foramen rotundum wing of sphenoid Greater wing of sphenoid Foramen ovale Foramen spinosum Present b/w Petrous temporal bone Carotid canal sphenoid, Internal acoustic temporal & Foramen lacerum occipital bone meatus is present here. Jugular foramen Present b/w temporal & occipital Hypoglossal canal bone Occipital bone Foramen magnum Facial nerve (CN 7) (GPN + DPN) /AKA Sphenopalatine ganglion Carotid canal Structures passing through foramen lacerum (CN VII) Internal auditory meatus (mnemonic : 7 up COKE down) Anatomy Revision v1.0 Marrow 6.5 2023  26 03 Anatomy Www.Medicalstudyzone.com ----- Active space ----- 1 st tributary of IJV Anterior Posterior Intermediate Jugular foramen Lower part Foramen magnum Incisive foramen : Transmits Nasopalatine N. & Greater palatine vessels. Foramen lacerum Foramen ovale Greater palatine foramen Foramen spinosum Lesser palatine foramen Carotid canal Styloid process Jugular fossa Stylomastoid foramen : Transmits CN VII. Mastoid process Mastoid foramen Hypoglossal canal Foramen magnum Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 3 03 27 ----- Active space ----- Anterior view of sphenoid bone Inner view of mandible Transmits Inferior alveolar nerve & vessels. Deep cervical fascia of the neck 00:24:34 Deep cervical fascia Superficial Middle Deep Investing layer Muscular layer Visceral layer Anterior Posterior Superficial (Investing) layer : Splits to enclose 2 muscles : sternocleidomastoid and trapezius. It forms the roof of posterior triangle. It provides capsule for 2 glands : Parotid & submandibular. Applied aspect : Parotid swellings are painful due to unyielding nature of the capsule. Middle layer : 1. muscular : Infrahyoid muscle. 2. Visceral A. Pretracheal layer: Splits to enclose thyroid gland, trachea & esophagus Ligament of berry: Post. thickening of fascia Connecting thyroid gland to cricoid cartilage. Hence thyroid gland and it’s swellings moves with deglutition. Note : Thyroglossal cyst moves with the protrusion of tongue. B. Bucco pharyngeal layer. Anatomy Revision v1.0 Marrow 6.5 2023  28 03 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Deep layer : Anterior: Alar fascia fuses with buccopharyngeal fascia at C7. Posterior : prevertebral fascia. a. Covering for prevertebral muscles. b. Forms floor of posterior triangle. c. Contributes to axillary sheath. Contents : Axillary A. & Deep fascia in the neck Brachial plexus. Axillary vein is not present inside the axillary sheath. Note : Posterior triangle lies in between Sternocleidomastoid and Trapezius. Carotid sheath : All the layers of deep cervical fascia contribute to carotid sheath. Contents : Vessels : CCA, ICA, IJV, Nerves : CN X ± CN IX, X1, X11 (only near base of skull). Note : Cervical sympathetic chain is present behind the carotid sheath and is not a content. CCA : Common Carotoid A., ICA : Internal carotid A., IJV : Internal jugular vein. Danger area in the neck Anterior Posterior This area extends from base of skull to mediastinum. Any infection might easily spread to base of skull or mediastinum. Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 3 03 29 Neurovascular structures & Lymph nodes in neck 00:32:13 ----- Active space ----- Arteries in the neck : 1. Subclavian A. and its branches : Scalenus muscle divides subclavian A. into 3 parts : mnemonic : VIT C-D Vertebral artery 1st part : Internal thoracic artery Thyrocervical trunk Suprascapular artery mnemonic : SIT Inferior thyroid artery Transverse cervical artery 2nd part: Costocervical trunk 3rd part: Dorsal scapular artery Inferior thyroid artery supplies a. Cervical esophagus b. Parathyroid gland. c. Thyroid gland. d.Thymus (Main supply : Int. thoracic A.) 2. Common carotid A. : Left common carotid artery arises from arch of aorta. Right common carotid artery arises from brachiocephalic trunk. Common carotid artery bifurcates into internal and external at the level of C3-C4 (C4>C3)/upper border of thyroid cartilage. A. Internal carotid artery has no branches in the neck. B. External carotid artery and its branches : Anteriorly : Superior thyroid, Lingual & Facial artery. Medially : Ascending pharyngeal (1st branch). Posteriorly : Occipital & Posterior auricular artery. Terminally : Superficial temporal & Maxillary artery. Anatomy Revision v1.0 Marrow 6.5 2023  30 03 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Nerves in the neck : Ansa cervicalis C1 : Superior root Ansa cervicalis C2, C3 : Inferior root C1 + CN X11 supplies geniohyoid & thyrohyoid Ms. Phrenic nerve Root value : C3, C4, C5 mixed nerve. Motor supply to diaphragm. Sensory supply to pleura, pericardium & diaphragm. Passes anterior to Scalenus anterior Enters thorax in between Subclavian vein in front and artery behind Note : In thorax, Phrenic nerve passes anterior to hilum of lung. Vagus passes posterior to hilum of lung. Lymph nodes in the neck : Upper jugular Sub mandibular Sub mental Mid jugular Anetrior nodes : present between hyoid to sternum Lower jugular Lymph nodes in post. triangle of neck (Va&b) Level V11 : Mediastinal nodes Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 3 03 31 Radical neck dissection : ----- Active space ----- Lymph node clearance + Sternocleidomastoid + IJV + Spinal accessory N. Modified radical neck dissection : Lymph node clearance + Preservation of non lymphatic structures. Infratemporal region 00:43:00 Muscles of mastication : Muscles Origin Insertion Action Outer surface of ramus of Masseter Zygomatic arch Strong elevator mandible Temporalis Temporal fossa Coronoid process of mandible Elevation > Retraction Lateral Infra temporal crest of spheoid Head of mandible, articular disc & Depression (only muscle) pterygoid & lateral pterygoid plate. capsule of TMJ > Protrusion. Medial Lateral pterygoid plate & Inner surface of ramus of Elevation > Protrusion pterygoid maxillary tuberosity mandible Upper & lower head of Lateral pterygoid TMJ Superficial & deep head of Medial pterygoid Masseter Temporalis Pterygoids Lateral pterygoid Head Coronoid process Medial pterygoid Temporalis Ramus Masseter Body Insertion of muscles Note : All masticatory muscles are supplied by Mandibular nerve. Best muscle for: Elevation : Masseter > Temporalis > Medial pterygoid. Depression : Lateral pterygoid. Protrusion : Lateral pterygoid muscle > Medial pterygoid. Retraction : Temporalis. Anatomy Revision v1.0 Marrow 6.5 2023  32 03 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Maxillary artery : 00:46:48 Terminal division of external carotid artery. Divided into 3 parts by lateral pterygoid muscle : 1st part/Mandibular part (MAIDA) : 3rd part/Pterygopalatine part (PIG PAS) : Middle meningeal a. Posterior superior alveolar a. Accessory middle meningeal a. Infraorbital a. (Inferior orbital fissure) Inferior alveloar a. Greater palatine a. Deep auricular a. Pharyngeal a. (Pharyngeal canal) Anterior tympanic a. rtery to pterygoid canal Sphenopalatine a. (Sphenopalatine foramen) 2nd part/pterygoid part : Muscular branches to muscles of mastication. Maxillary artery Mandibular nerve : Mixed nerve. 00:46:46 Mandibular nerve Anterior division : Trunk of mandibular N. Posterior division : 1. Deep temporal n. ↓ 1. Auriculotemporal n. 2. Masseteric branch Motor Nerve to medial pterygoid 2. Lingual n. 3. Pterydoid branch Passes through otic ganglion 3. Inferior alveolar n. 4. Buccal branch (Sensory) : ↓ Pierces buccinator & Supplies : supplies cheek. 1. Medial pterygoid 2. Tensor palatini 3. Tensor tympani Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 3 03 33 ----- Active space ----- Course of Mandibular nerve Otic ganglion : Attached to mandibular nerve topographically. Attached to glossopharyngeal nerve functionally. Relation of otic ganglion (coronal view of infratemporal fossa) Anatomy Revision v1.0 Marrow 6.5 2023  34 03 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Pathway of otic ganglion Applied aspect : Frey syndrome : Injury to auriculotemporal n. (Parotidectomy) ↓ Regenrated auriculotemporal n. ↓ Innervates sweat glands (instead of parotid gland). Lingual nerve : Receives chorda tympani (branch of facial nerve). Crosses submandibular duct → M/C nerve affected during SM duct excision. Inferior alveolar nerve : Gives nerve to mylohyoid (supplies anterior belly of digastric & mylohyoid). Passes through mandibular foramen → Sensory supply to face. Dural Venous Sinuses 00:55:19 Cavernous sinus : Paired dural venous sinus located on either side of body of sphenoid bone. Relations : Medial : Sphenoidal sinus, pituitary gland. Lateral : Trigeminal ganglion. Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 3 03 35 Internal carotid artery ----- Active space ----- Occulomotor nerve Trochlear nerve Abducent nerve Ophthalmic div. of Trigeminal nerve (±) Maxillary div. of Trigeminal nerve Content Lateral wall Relations of cavernous sinus 1st nerve to get affected in cavernous sinus thrombosis : Abducent nerve. Tributaries (Inflow) : Superior ophthalmic vein Inferior ophthalmic vein Central vein of retina Superficial middle cerebral vein Inferior cerebral vein Sphenoparietal sinus Middle meningeal vein Communicating (out flow) channels : Dural venous sinuses Superior petrosal sinus : Cavernous sinus → Transverse sinus. Inferior petrosal sinus : Cavernous sinus → Internal jugular vein. Anterior & posterior inter cavernous sinus : Connect cavernous sinus of two sides. Hence, Cavernous sinus thrombosis always present bilaterally. Anatomy Revision v1.0 Marrow 6.5 2023  36 03 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Communication b/w cavernous sinus & facial vein : M/C communicating channel : Superior ophthalmic vein > Deep facial vein. Communication b/w cavernous sinus & facial vein Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.comAnatomy Revision 4 04 37 ANATOMY REVISION 4 ----- Active space ----- Orbit & extra ocular muscles 00:00:22 Bones forming orbit : Wall Structures Roof Frontal, lesser wing sphenoid. Floor (M/c to #) Maxilla, zygomatic, palatine. Zygomatic, greater wing of Lateral wall sphenoid. Medial wall Lacrimal, ethmoid, body of (thinnest) sphenoid, maxilla. Optic canal/foramen : In lesser wing of sphenoid. Superior orbital fissure (SOF) : B/w roof & lateral wall. Inferior orbital fissure : B/w floor & lateral wall. Structures passing through SOF Superolateral compartment Lacrimal, frontal and trochlear nerve, superior ophthalmic vein. Intermediate compartment/ Superior and inferior division of oculomotor common tendinous ring nerve, nasocilary and abducent nerve. Inferomedial compartment Inferior ophthalmic vein. Mnemonic : LFT for superolateral compartment. SONIA passes through intermediate compartment. Extraocular muscles : Levator palpebrae superioris : For elevation of eyelid. Muscle 10 action 20 action 30 action Superior rectus Elevation Intorsion Adduction Inferior rectus Depression Extorsion Adduction Medial rectus Adduction - - Lateral rectus Abduction - - Superior oblique Intorsion Depression Abduction Inferior oblique Extorsion Elevation Abduction Anatomy Revision v1.0 Marrow 6.5 2023  38 04 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Note : SIN → Superior muscles : Intorsion. RAD → Recti : Adductors. Oculomotor nerve palsy : Ptosis (LPS palsy). Dilated pupil (Sphincter pupillae muscle palsy). Down and out (SO4 and LR6 are spared). Loss of light & accommodation reflex. Left oculomotor nerve palsy Nose 00:09:30 Medial wall/nasal septum : Nasal spine of Perpendicular plate of ethmoid bone frontal bone Nasal bone Septal cartilage (Aka quadrilateral cartilage) Incisor crest Vomer bone Nasal crest of maxillary and palatine bones Red : Major contributors. Others are minor contributors. Schindylesis/sphenovomerian joint : B/w vomer & rostrum of sphenoid. Schindylesis joint Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 4 04 39 Little’s area : ----- Active space ----- Highly vascular area in anteroinferior aspect of nasal septum d/t Kiessel- bach plexus. Posterior ethmoidal artery does not contribute to plexus. Lateral wall of nasal cavity : Prominent elevations in lateral wall : Turbinates (3 in no.) Inferior turbinate is a separate bone (Not part of ethmoid bone). Little’s area Lateral wall of nasal cavity Osteomeatal complex/OMC : Comprise of : Bulla ethmoidalis : Most prominent anterior ethmoidal sinus. Uncinate process : Part of ethmoid bone. Hiatus semilunaris : Opening b/w uncinate process and ethmoid bulla. Receives opening of 3 sinuses : Maxillary Osteomeatal complex sinus, ant. ethmoidal sinus, frontal sinus. Block in OMC Sinusitis. Meatus Openings Sphenoethmoidal recess Sphenoid sinus Superior meatus Posterior ethmoidal sinus Middle meatus OMC Inferior meatus Nasolacrimal duct Anatomy Revision v1.0 Marrow 6.5 2023  40 04 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Tongue 00:17:45 Papillae : Have taste buds (Except filiform). Lined by stratified squamous non keratinised epithelium (Except filiform). Supplied by chorda tympani (Except circumvallate papillae which are supplied by glossopharyngeal nerve). Filiform papillae : Have no taste buds. Lined by keratinised stratified squamous epithelium. Holds food particles together. Posterior most part of tongue Lingual tonsil Posterior 1/3rd Sulcus terminalis Circumvallete papilla Foliate papilla Anterior 2/3 rd Filiform papilla Fungiform papilla Nerve supply of tongue Muscles of tongue : Styloglossus Nerve supply : Hypoglossal nerve (Except palatoglossus : Palatoglossus pharyngeal plexus). Genioglossus : Protrusion of tongue (Safety muscle of Hyoglossus tongue). Genioglossus Hypoglossal nerve palsy : Muscles of tongue Ipsilateral tongue atrophy. Tongue deviation to lesion side. Hypoglossal nerve palsy (I/L deviation) Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 4 04 41 Pharynx 00:23:40 ----- Active space ----- Extent : Base of skull → C6 (Continues as esophagus). Parts of pharynx : Nasopharynx, oropharynx, laryngopharynx. Structures seen in nasopharynx : Space of Rossenmuller Torus tubaris Eustachian tube opening Endoscopic view Pharyngeal isthmus Structures seen in Nasopharynx Pharyngeal isthmus : Gap b/w soft palate & posterior pharyngeal wall. Closed by Passavant’s ridge : Palatopharyngeus (PP) + Superior Constrictor (PP > SC). Structures seen in oropharynx : In it’s lateral wall : Tonsil. Tonsil : M/C source of bleeding post- tonsillectomy : Paratonsillar vein. Peritonsillar space infection : Quinsy. Bed of tonsil : Superior constrictor muscle. Glossopharyngeal nerve (CN 9) supplies tonsil and middle ear Peritonsillar space (Referred pain to middle ear). Relations of the tonsil. Anatomy Revision v1.0 Marrow 6.5 2023  42 04 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Blood supply of tonsil : 1. Principal artery : Facial artery. 2. Maxillary artery. 3. Tonsillar branches of ascending pharyngeal artery. 4. Ascending palatine artery. 5. Lingual artery. Blood supply of tonsil Hypopharynx : Piriform fossa : Boundaries : Medially → Aryepiglottic fold Laterally → thyroid cartilage. Significance : Internal laryngeal nerve (ILN) present → Site for ILN block. Foreign body entrapment. Piriform fossa Muscles of pharynx : 1. Constrictors : Superior, middle & inferior. 2. Palatopharyngeus. 3. Stylopharyngeus. 4. Salpingopharyngeus. Nerve supply : 1, 2, 4 (From above)→ Pharyngeal plexus. 3 → Glossopharyngeal nerve. Triangular gap b/w thyropharyngeus and cricopharyngeus is Killian’s dehiscence. Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 4 04 43 Larynx 00:33:25 ----- Active space ----- Cartilaginous tube extending from C3 to C6. Unpaired cartilage Paired cartilage Thyroid Arytenoid Cricoid Corniculate Epiglottis Cuneiform Hyaline cartilage Elastic cartilage Thyroid Epiglottis Cricoid Corniculate Arytenoid Cuneiform Apex of arytenoid Cartilages of larynx Coronal section of larynx : Vestibular ligament : Thickening of lower part of quadrangular membrane. Vocal ligament/true vocal cord : Thickening of Upper part of cricovocal membrane. Parts of larynx : Supraglottis : B/w laryngeal inlet & vestibular fold. Glottis : B/w vestibular ligament & vocal fold. Infraglottis/subglottis : Below vocal ligament. Carcinoma of larynx is m/c seen in glottis. Ca glottis : Good prognosis (No lymphatics & early presentation). Ca supra glottis & sub glottis : Lymphatic metastasis is common (Rich in lymphatics). Anatomy Revision v1.0 Marrow 6.5 2023  44 04 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Muscles of larynx : Muscle Action Transverse arytenoid Adductor of larynx. Lateral cricoarytenoid Only abductor of larynx Posterior cricoarytenoid (Safety muscle of larynx). Cricothyroid Tensor of larynx > adductor. Thyroarytenoid Relaxer. Thyroepiglotticus Opens the inlet. Aryepiglotticus Closes the inlet. Nerve supply of larynx : Sensory : Above vocal cord : Internal laryngeal nerve. Below vocal cord : Recurrent laryngeal nerve (RLN). Motor : All muscle except cricothyroid : RLN. Cricothyroid : External laryngeal Muscles of larynx nerve (ELN). ELN : Accompanies superior thyroid artery. Recurrent laryngeal nerve (RLN) : Right RLN : Arises at the level of right subclavian artery. Left RLN : Arises at the level of arch of aorta. Longest course. More commonly injured. Accompanies inferior thyroid artery (Affected in tracheoesophageal groove). Nerve supply of larynx Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.comAnatomy Revision 5 05 45 ANATOMY REVISION 5 ----- Active space ----- Brachial plexus 00:00:14 Branches Roots C5, C6, C7, C8, T1 Dorsal scapular nerve (C5) : Rhomboid minor, Rhomboid major, Levator scapulae. Long thoracic nerve (C5, C6 ,C7) : Serratus anterior Trunk Upper trunk : C5, C6 Nerve to subclavius (C5, C6). Middle trunk : C7 Supra scapular nerve (C5, C6) : Supraspinatus & Infraspinatus muscle. Lower trunk : C8, T1 Divisions Each trunk is divided into Do not give any branches. anterior & posterior division Cord Lateral cord : Musculocutaneous nerve : Anterior Anterior division of upper & compartment of arm. middle trunk Lateral pectoral nerve : Pectoralis major, pectoralis minor. Lateral root of median nerve. Medial cord : Medial pectoral nerve. Anterior division of lower trunk Medial cutaneous nerve of arm. Medial cutaneous nerve of forearm. Ulnar nerve. Medial root of median nerve. Posterior cord : Upper subscapular nerve : Upper part of Posterior division of all trunks subscapularis. Lower subscapular nerve : Lower part of subscapularis, Teres major. Nerve to latissimus dorsi. Axillary nerve : Deltoid, Teres minor. Radial nerve. Anatomy Revision v1.0 Marrow 6.5 2023  46 05 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Musculocutaneous & Axillary Nerve Injuries : Musculocutaneous N. Injury : Axillary N. Injury : Loss of Causes : Fracture of surgical neck of 1. Elbow flexion humerus, dislocation of shoulder joint, palsy (Biceps brachii, brachialis). of deltoid, teres minor. 2. Supination C/F : Regimental badge area anaesthesia (Biceps brachii). (Sensory loss in upper lateral aspect of arm). 3. Sensation in lateral Lateral Medial aspect of forearm. Coracoid process Coracobrachialis Brachial plexus Biceps brachii Brachialis Cutaneous innervation Musculocutaneous nerve Axillary nerve Erbs palsy Vs Klumpke’s palsy : Erb’s palsy Klumke’s palsy Upper trunk injury (C5, C6). Lower trunk injury (C8, T1). D/t injury at erb’s point : Falling on their D/t hyperabduction injury. shoulder. Nerves affected : Nerves affected : Musculocutaneous nerve. C8, T1 of ulnar & median nerve affected Axillary nerve. (supply small muscles of hand). Suprascapular nerve. Deformity : Policemen’s tip deformity. Deformity : Shoulder joint : Adducted & Complete claw hand > Horner’s medially rotated. syndrome. Elbow : Extended. Forearm : Pronated. Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 5 05 47 Note : Cutaneous branches of brachial plexus. ----- Active space ----- Nerve Branch of Medial cutaneous nerve of arm Medial cord of brachial plexus Medial cutaneous nerve of forearm Upper lateral cutaneous nerve of arm Axillary nerve Lower lateral cutaneous nerve of arm Radial nerve Posterior cutaneous nerve of arm Radial nerve Lateral cutaneous nerve of forearm Musculocutaneous nerve Radial Nerve : 00:08:31 Course : Mixed nerve + Largest nerve of brachial plexus. Axilla Axilla Post. Cutaneous N. Spiral groove of arm Lower triangular interval Triceps (Long head) Upper arm Triceps (Medial head) Post. compartment of arm Lower lateral Triceps (Lateral head) Cutaneous N. of arm Triceps (Medial head) & Anconeus Spiral groove (shaft of humerus) Lower arm Brachialis Brachioradialis Lower lat. aspect of arm Extensor carpi radialis longus Elbow joint Below elbow joint Forearm Superficial Extensor carpi radialis brevis branch of Superficial branch Deep branch Supinator Radial N. Extensor digitorum Sensory nerve Motor Nerve Extensor digiti minimi Also called as Post. Extensor carpi ulnaris Abductor pollicis longus Interosseus N. (PIN) Skin of lateral Extensor pollicis longus 2½ > 3½ Post. Cutaneous N. Extensor pollicis brevis fingers in of forearm Extensor Indicis dorsum of hand. Applied aspect : 1. Holstein Lewis # : # shaft of humerus with radial nerve involvement. 2. Crutch palsy : Compression of radial nerve in the axilla. 3. PIN palsy : a. Extension of elbow intact as triceps (Radial N) is unaffected. b. Extension of wrist intact as ECRL (Radial N) is unaffected. c. Finger drop d/t loss of extension of MCP. d. No sensory loss (PIN is pure motor nerve). Anatomy Revision v1.0 Marrow 6.5 2023  48 05 Anatomy Www.Medicalstudyzone.com ----- Active space ----- Median N. Median N. Radial N. Ulnar N. Radial N. Sensory supply of hand Extensor retinaculum : 6 compartments (Lateral to medial) : 1st Abductor pollicis longus, Extensor pollicis brevis. 2nd ECRL, ECRB. 3rd Extensor pollicis longus. 4th Extensor digitorum, Extensor indices, Posterior interosseous nerve. 5th Extensor digiti minimi. 6th Extensor carpi ulnaris. Extensor retinaculum Applied aspect : De Quervain’s tendinitis Synovitis of 1st compartment tendon (AbPL, EPB). Anatomical snuff box : Present b/w 1st & 3rd compartment. Boundaries : Laterally : AbPL, EPB. Medially : EPL. Roof : Cephalic vein, Superficial branch of Radial N. Floor : Lower end of radius, Scaphoid, Trapezium, Base of 1st metacarpal & 2nd compartment tendons (ECRL, ECRB). Content : Radial artery. # scaphoid : Pain in anatomical snuff box. M/c fractured carpal bone. Anatomy Revision v1.0 Marrow 6.5 2023  Www.Medicalstudyzone.com Anatomy Revision 5 05 49 Median Nerve : 00:22:09 ----- Active space ----- Mixed nerve, Root value : C5-C8, T1. Formed by union of medial root of median N. + lateral root of median N. Supplies mainly long flexors of forearm → Labourer’s nerve. Median nerve in Cubital fossa : Lateral Medial Boundaries Contents Imaginary line joining two epicondyles of humerus Superficial branch of Radial N. Median nerve in forearm : In flexor compartment of forearm, muscles are arranged