Anatomy Exam 1 PDF

Head and Neck Central nervous system: 1. CNS: Brain and spinal cord 2. PNS: all other nervous tissue a. Somatic (walking, talking, and typing) b. Autonomic nervous system involuntary (automatic) functions. Autonomic NS 1. Parasympathetic (rest digest) a. Acetylcholine as main neurotransmitter b. Cel...

Head and Neck Central nervous system: 1. CNS: Brain and spinal cord 2. PNS: all other nervous tissue a. Somatic (walking, talking, and typing) b. Autonomic nervous system involuntary (automatic) functions. Autonomic NS 1. Parasympathetic (rest digest) a. Acetylcholine as main neurotransmitter b. Cell bodies are located in cranial and sacral site i. Cranial site: from gray matter of brainstem: ii. CN III, VII, IX, and X cranial parasympathetic outflow iii. Sacral site: from the gray matter of the sacral segments of the spinal cord (cauda equina) S2-S4 iv. These fibers leave through anterior roots of spinal nerves S2-S4 and pelvic splanchnic nerves that arise from their anterior rami v. Presynaptic fibers are long - run from CNS to effector organ (less CN III, Pterygopalatine, otic, and submandibular ganglia) vi. Postsynaptic neurons are shorter in those vii. Cranial outflow provides parasympathetic innervation to the head, while sacral outflow provides innervation to the pelvic viscera. viii. CN X is unique in that it provides parasympathetic innervation to all thoracic viscera and most of the GI tract 2. Sympathetic NS (fight flight): a. Catabolic system: uses norepinephrine as its predominant neurotransmitter b. Cell bodies (presynaptic) originate in the intermediolateral cell columns of the spinal cord. They run from T1 - L2 or 3 (mostly L3). c. Cell bodies of postsynaptic neurons of the sympathetic nervous system occur in two locations: paravertebral and prevertebral ganglia d. Paravertebral ganglia are known as sympathetic trunks or chains. i. This sympathetic chain ascends above T1 (cervical sympathetic ganglia) and descends below L3 to end in a ganglion impair inferiorly e. Prevertebral ganglia i. Located in plexuses that surround certain divisions of the abdominal aorta (celiac, aorticorenal, superior mesenteric, inferior mesenteric and aortic hypogastric and pelvic) ii. Presynaptic sympathetic neurons are shorter (as parasympathetic ones are long), but course varies - they can ascend or descend iii. They can synapse within the paravertebral ganglia or pass through this to form an abdominopelvic splanchnic nerve which will synapse within the prevertebral ganglia iv. The postsynaptic sympathetic fibers are generally longer than parasympathetic fibers v. They will ultimately synapse on a effector (target) visceral organ Anatomic orientation 1. Sagittal plane: right and left halves 2. Frontal (coronal) anterior (front) and posterior (back) 3. Transverse (horizontal or axial) - superior and inferior 4. Oblique: does not align with any of the above 5. Dorsal (back) ventral (front) 6. Anatomic position a. Back and buttock are dorsal (towards the back) 7. Medial (near the center) lateral (away from the center) 8. Proximal (close to the reference point) distal (further from the reference point) 9. Ipsilateral (same side) contralateral (opposite side) 10. Supine (laying on dorsal aspect) prone (ventral aspect) 11. Rostral (at or near the head) caudal (at or near the feet) 12. Superficial (top of the skin) intermediate (middle of the skin) deep (deep in the skin) 13. Flexion (decrease of angle between two reference points) extension (increase in angle) 14. Abduction (away from midline) adduction (closer to midline) 15. Internal rotation (medial) external rotation (lateral) 16. Elevation (elevating shoulders) depression (lowering the shoulders) 17. Retrusion (drawing something in) protrusion (sticking something out like your jaw) 18. Retraction (drawing shoulders in) protraction (sticking shoulders out) Scalp Anatomy: 1. Skin o Thin except in the occipital region o Contains sweat and sebaceous glands, hair follicles o Abundant arterial supply and good venous and lymphatic drainage 2. Dense Connective tissue (dense) o Thick, dense, richly vascular subcutaneous layer o Also has cutaneous nerves o Highly vascularized - application to locaration (it is a layer of the scalp that is susceptible to bleeding when lacerated) 3. Aponeurosis o Epicranial aponeurosis; thin, tendon-like structure, covers the calvaria (top of the skull) o Broad intermediate tendon of the frontal and occipital bellies of the occipitofrontalis muscle 4. Loose areolar connective tissue o Highly vascularized, emissary veins (which have potential for infection), o Spongy layer, high infection potential and potential spaces that may distend with fluid because of injury or infection 5. Pericranium o Outer layer of skull bone o Continuous with the fibrous tissue uniting the sutures, fontanelles (structure that allows for the passage of a fetus skull during childbirth, and allow for growth of head of an infant) Meningeal Layers: ● Dura Mater – fibrous connective tissue that divides into two layers o The sagittal sinus is contained within the dura mater o Layers that form the dural venous sinuses ▪ Periosteal layer (outer) ● Attaches to/surrounds the skull ● Formed by the periosteum ▪ Meningeal layer (inner) ● Surrounds brain, continues inferiorly to form the spinal dura ● Extends inward to form falx cerebri o Largest dural infolding, continuous with the tentorium cerebelli o Falx cerebelli is a vertical dural infolding inferior to the tentorium cerebelli o 4 dural infoldings: falx cerebri, tentorium cerebelli, falx cerebelli, diaphragma sellae o Consequences of injury to the meningeal layer will cause intracranial hemorrhage ● Arachnoid Mater – composed of collagen and elastic tissue o Space between arachnoid and dura mater forms in danger ▪ The separation of arachnoid and dura mater is caused from trauma o Subarachnoid space ▪ Beneath the arachnoid mater ▪ filled with CSF, high levels of vascularity (cerebral arteries) o Arachnoid granulations ▪ contains excess CSF, extend up through meningeal dura sublayer ▪ transfer CSF to the venous (blood) system ● Pia Mater – delicate connective tissue o Highly vascularized with fine blood vessels o Clings to the brain like plastic wrap o Where the cerebral arteries penetrate the cerebral cortex, the pia follows for short-distance, forming a pial coat and a peri-arterial space o Meningitis ▪ Inflammation of the pia and arachnoid mater ▪ Can be caused by viruses or bacteria Brain Anatomy ● Cerebral Hemisphere arrangement o 2 cerebral hemispheres form the largest part of the brain o Hemispheres are separated by a longitudinal fissure into which the falx cerebri extends o 4 lobes in each hemisphere o Diencephalon: central core of the brain ▪ epithalamus, thalamus, hypothalamus o Midbrain: rostral part of the brainstem ● Lobes of the brain o Frontal lobe ▪ Occupy the anterior cranial fossa o o o ▪ Executive function Parietal lobe ▪ Sensory (skin) Temporal lobe ▪ Occupy the lateral parts of the middle cranial fossae ▪ Primary auditory cortex (hearing process) Occipital lobe ▪ Extends posteriorly over the tentorium cerebelli ▪ Primary visual cort ● Other brain structures o Corpus callosum ▪ Located at the base of the cerebrum, connects the two hemispheres o Third ventricle ▪ Deep to the callosum ▪ Continuous with the cerebral aqueduct ▪ Contains the septum pellucidum and lateral ventricles ▪ Contains choroid plexus ● Wall of ventricles ● Where CSF is made o Thalamus ▪ Encloses the third ventricle ▪ Relay system for incoming sensory information o Pineal Gland ▪ Posterior to thalamus ▪ Secretes melatonin ▪ Regulates circadian rhythm o Hypothalamus ▪ Inferior to thalamus ▪ o o Neuroendocrine organ that regulates survival processes (life sustaining behaviors) ▪ Relationship with pituitary gland – secretes and releases hormones into pituitary gland Pituitary Gland Basal Ganglia – subcortical nuclei; promotes desired motor action and inhibits undesired functions ▪ Lateral to the thalamus ▪ Contains a white matter track serving motor function ▪ Ramshorn shape, contains ● Caudate ● Putamen ● Globus pallidus ● Substantia nigra ● Subthalamic nucleus ▪ Site of movement disorders, Huntington’s (causes degeneration of the cells in the brain) ▪ Conduit between cerebral cortex and thalamus ▪ Significant disease states include: problems controlling movements, speech, and posture. ● Midbrain o Superior colliculi – visual reflexes, following moving objects o Inferior colliculi – relay for auditory info, startle reflex o Deep to both colliculi ▪ Red nucleus ● highly vascularized ● Relay station for descending motor pathways ▪ Pons ● Beneath the red nucleus ● Bulging area of brainstem ● Site for several branching cranial nerves ● Contains reticular activating system – wakefulness, attention ● Conduit from motor cortex to cerebellum ● Associated with CN V (trigeminal nerve) ▪ Medulla Oblongata ● Contains “decussation of the pyramids” o Where the motor fibers cross midline ● Regulation center for vital functions, cardiovascular center, respiratory center ● Regulation of primitive reflexes: coughing, sneezing, swallowing, vomiting ▪ Cerebellum ● Location: below the temporal and occipital lobes (in the back of the head behind the pons and medulla) Smooths out gross motor movements ● Contains fourth ventricle ● Arbor vitae: myelinated tracts within cerebellum Arterial supply to brain ● Carotid arteries o Internal carotid arteries arise in the neck from the common carotid arteries o Right and left common carotid arteries branch off aortic arch o further branches off the internal carotid arteries ● Ophthalmic arteries ● Cerebral arterial circle (of Willis) o Anterior cerebral a. 🡪 anterior communicating a 🡪 internal carotid a. 🡪 posterior communicating a. 🡪 basilar a. 🡪 vertebral a. ● Vertebral arteries o Begin in the root of the neck as branches of the first part of the subclavian arteries The Orbit: the socket that holds the eye ● Composed of frontal bone, zygomatic bone, sphenoid bone, maxilla, lacrimal bone, ethmoid ● Fractures 🡪 loss of vision, fractures, leakage of fluid, inflammation ● Eyelids ▪ Thin layer of skin/CT tissue ▪ Inner eyelid is very important in lubrication and protection of eye ▪ Superior and inferior tarsus – dense CT of eyelid o Muscles and soft tissues (see Moore’s table 8.6) ▪ Orbicularis oculi muscles ● Orbital part ● Palpebral part – over the eyelid proper ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ o ● Innervated by CN VII (facial nerve) ● Action: Closes the eyes Medial, lateral ligaments Orbital septum Action: Opening the eye o Levator palpebrae superioris m. o Superior tarsal muscle m. o Both innervated by CN III (oculomotor) ● Horner’s syndrome: CN III damage and cervical sympathetic ganglia – ptosis, miosis (constricted pupil), anhidrosis (no sweating) ● Dysfunction o Conjuctivitis: inflammation of conjunctiva/inner eyelid Superior rectus m. CN III Lateral rectus m. ● CN VI (abducens) – moves eye away from midline Medial rectus m. CN III Inferior rectus. M. CN III Superior oblique m. ● CN IV (trochlear) – abduction and down Inferior oblique m. CN III Ciliary glands and tarsal glands – lubricate the eye ● Stye: blockage of sweat glands of eyelashes ● Chalazion - blockage in the eye Vessels of the orbit ▪ Internal carotid gives rise to most of the orbital vessels ● ● ● ● ● ● ● o o Supratrochlear A., V Supra-orbital A., V. Superficial temporal A., V. Angular A., V Lacrimal A. Transverse facial A. Infra-orbital A. Lacrimal apparatus ▪ Function: produces tears to lubricate and protect eye ● Content of tears: lipids, enzymes, saline ▪ Lacrimal gland ● Gland in the upper outer corner of eye ● Innervated by CN VII (facial nerve) ▪ Lacrimal sac collects tears ▪ Nasal cavity collects tears from lacrimal sac Sensation to the outer eye is testing corneal reflex ▪ Innervated by CN V The Eye ● Sclera o Whites of the eye ● Cornea o Clear protruding part, allows light into eye ● Iris o Smooth muscle on either side of the pupil o Colored part of the eye ● Pupil o Opening of the eye o Reflex is controlled by CNIII (oculomotor) ● Lens o Reflects light that enters the pupil to the retina ● Retina o Outermost portion of the inner part of the eye o CN II (optic) nerve – goes back into optic chiasm 🡪 superior colliculi 🡪 occipital lobe o Fovea ● Optic chiasm - allow for the crossing of fibers from the nasal retina to the optic tract on the other side. The Ear – The auricle ● Outer structures o Helix o Antihelix o Fossa o Conchae o Tragus o Antitragus o Lobule o External auditory meatus/canal o o ● ● ● ● ● Tympanic membrane Dysfunction ▪ otitis externa: swimmer’s ear, infection in external auditory canal Middle ear structures o Ossicles ▪ Malleus ▪ Incus ▪ Stapes ▪ Pharyngotympanic tube ● equalizes pressure between atmosphere and middle/inner ear ● drains and is connected to nasal sinuses ● Dysfunction o otitis media: mucus blockage of pharyngotympanic tube, more common in children due to angle of tube being straighter o Conductive hearing loss: natural aging process of fusion of ossicles, less vibration Inner ear structures o The cochlea ▪ Snail shaped; fluid filled ▪ Inner membrane with hair cells ▪ CN VIII (vestibulocochlear nerve) 🡪 primary auditory cortex of temporal lobe ▪ Semicircular canals ● Vestibular sense – acceleration and tilt of head ▪ Dysfunction ● Meniere’s disease (fluid build up in the inner ear) – tinnitus (ear ringing) ● Otitis interna (infection of nerves that connect inner ear to the brain) ● Sensorineural hearing loss: CNVIII damage Sound wave stimulation: travels from external auditory meatus 🡪vibrates tympanic membrane 🡪 vibrates the ossicles 🡪 vibrates the hair cells on the inner membrane of the cochlea Conductive hearing - through the external ear, mid ear or both Sensorineural hearing loss - problem with the cochlea or neural pathway to the auditory cortex Question from the quiz: What is the structure between the stapes and cochlea? - Oval window. The Nose ● Bones of the nose: nasal portion of the frontal bone, nasal bone of the maxilla, bony portion of nasal septum ● Hyaline cartilage forms the shape of the external nose ● Nasal vestibule: beginning of the nostril o Lined with skin o Hair follicles o Has two cavities: ▪ Opens into respiratory region ● Largest region ● Ciliated respiratory epithelial lining ● Mucous cells ▪ Olfactory region ● Small area in apex (superior and posterior location) ● Lined with olfactory epithelium and olfactory receptors ● Paranasal sinuses o Lined with respiratory mucosa, ciliated o Function: secrete mucus o Open into nasal cavities o CN I (olfactory) carried out olfactory sense ▪ General sensation to nasal regions is from CN V, anterior region by ophthalmic branch V1, posterior from maxillary branch V2. o CN 5 (trigeminal) V1 carries out general sensation of the nasal area ● Blood supply o External carotid gives rise to ▪ Facial a. ▪ Maxillary a. o Internal carotid ▪ Ophthalmic A. – ethmoidal branches The Face ● Musculature o Almost all innervated by CN VII (facial nerve) o Glandular influence of CN VII and also its branches - temporal, zygomatic, buccal, marginal, mandibular, and cervical. ● Arterial supply to the face o External carotid gives rise to the facial artery ▪ Branches into superior and inferior labial branches, lateral nasal a. ▪ Transverse facial a. branching off superficial temporal a. ▪ Maxillary A. and its branches (look at the picture) ▪ Opthalmic a. And its branches (follow the picture) o External and internal jugular veins ▪ Veins run parallel, similar to arteries ● Lymphatics of the face o Parotid gland ▪ Innvervated by CN IX (glossopharyngeal) ▪ CN VII travels through but does not innervate o Skin sensation: CN V o Muscles of the face: CNVII The oral cavity ● Boundaries ● Degree of separation from mandible/maxilla established by elevating and depressing lower jaw at the temporomandibular joint ● Temporomandibular joint - TMJ ○ Features: hinge type of joint - facilitates movements of the jaw ○ Clinical significance - can cause pain in your jaw and jaw muscles (trouble chewing) ● The tongue - overall structure with regard to papillae variations ○ Function of the tongue: assist in chewing, taste, deglutition (swallowing), articulation, and oral cleansing. ○ Structure: ■ Root ■ Body ■ Apex ■ Curved dorsal surface ■ Inferior surface ○ Associated muscles and their innervations: ■ Intrinsic muscles: superior and inferior longitudinal, transverse, and vertical muscle. ■ Extrinsic muscles: genioglossus, hyoglossus, styloglossus, and palatoglossus ○ All muscles of the tongue are innervated by CN XII - the hypoglossal nerve, except for the palatoglossus which is innervated by CN X - vagus nerve ● Sensation of taste, touch, pain and temperature ○ General sensation (touch and temperature) is innervated by cranial nerve 5 trigeminal nerve - which is the anterior two thirds of the tongue. ○ Taste is supplied through chorda tympani nerve which is the CN VII the facial nerve. ○ The mucus membrane of the posterior third of the tongue along with vallate papillae is supplied by glossopharyngeal nerve CN IX Deglutition ● Stage I - voluntary, tongue and soft palate push food from mouth to oropharynx ● Stage II - involuntary and rapid - utilize pharyngeal muscles ○ Soft palate is elevated, sealing off the nasopharynx from the oropharynx and laryngopharynx (pharyngeal muscles) ● Stage III - involuntary - utilize pharyngeal muscles ● External circular constrictors - move food bolus through pharynx into esophagus ● Internal longitudinal elevators - elevate the pharyngeal wall ● Pharynx - the superior expanded part of the alimentary system posterior to the nasal, oral, and laryngeal cavities. ● Divisions of pharynx: ○ Nasopharynx - posterior to the nose and superior to the soft palate ○ Oropharynx - posterior to the mouth ○ Laryngopharynx - posterior to the larynx Gag reflex - CN IX (glossopharyngeal) and CN X (vagus) are responsible for contraction of each side of oropharynx. And Glossopharyngeal branches (CN IX) provide the afferent limb of the gag reflex. The neck: ● Anterior and posterior triangles ● Fascia layers: ○ Superficial cervical fascia ○ Deep cervical fascia - consists of three fascial layers ■ Investing ■ Pretracheal ■ Prevertebral ○ Function: provide the slipperiness that allows structures in the neck to move and pass over one another without difficulty ○ They also form natural cleavage planes - allowing the separation of spaces during surgery ● Neck muscles ○ Superficial to deep ● Posterior neck muscles: ○ Trapezius ○ Semispinalis capitis ○ Splenius capitis ● Intricate relationship with hyoid bone(anterior muscle) ● Innervation from CN VII, CN V, CN III,CN XII, and C1-C3 ● Vessels of the neck ● Lymphatics of the neck - most superficial tissues of the neck are drained by lymphatic vessels. ● Structure: ○ Lymphatic vessels start in → superficial cervical lymph nodes near the external jugular vein (EJV) and drain into ○ → inferior cervical cervical lymph nodes that descend across the lateral cervical region with spinal accessory nerve (CN XI). ○ Lymph from the 6th and 5th nodes drain into the supraclavicular lymph nodes (near transverse cervical artery) ○ Group of deep cervical nodes form a chain along the internal jugular vein (IJV) ○ Jugular lymphatic trunks - efferent lymphatic vessels from the deep cervical lymph join and form jugular lymphatic trunks (present on the left side of the thorax) ○ Other cervical nodes include the prelaryngeal, pretracheal, paratracheal, and retropharyngeal nodes. ● Function - removal of interstitial fluid and help immune response (fight infection) Larynx ● Area/contents ● Vocal folds - true vocal cords ○ Ligament of thickened elastic tissue ● Voice production - coordination of laryngeal muscle contraction/respiration ● Gender differences ○ Females have shorter vocal cords Mastication: the act of chewing ● Masseter muscle ○ Innervation: cranial nerve V - trigeminal nerve ○ Function: elevates mandible (opens the jaw) ● Temporalis ○ Innervation: cranial nerve V - trigeminal nerve ○ Function: closes the jaw ● Lateral and medial pterygoids - serve movement of the temporomandibular joint (TMJ) ○ Medial pterygoid ■ Innervation: medial pterygoid nerve ■ Function: causes jaw closure and protrusion. ○ Lateral pterygoid ■ Innervation: lateral pterygoid nerve ■ Function: opens the jaw ● Testing for damage - ??? Dysphagia: ● Trouble swallowing ○ Various causes from damage/compression to a number of cranial nerves ○ Esophageal strictures/obstructions ○ Stricture - abnormal narrowing of the esophageal lumen ○ Severe consequences ranging from malnutrition to increased portals for infection from parenteral nutrition ○ Aspiration pneumonia ■ Common complication of neurodegenerative diseases Swelling/infection of the lungs due to the food obstruction (food is breathed into the lungs instead of swallowed) Thyroid gland ● Shape: butterfly shaped ● Location: deep to the sternothyroid and sternohyoid muscles at the level of C5-T1 vertebrae. On the sides of the trachea, inferior to the larynx. ● Blood supply ○ Paired superior and inferior thyroid arteries ● Innervation ○ Vagus nerve (CN X) ● Accessory thyroid tissue ○ May develop in the neck lateral to thyrohyoid muscle ● Parathyroid glands ○ Location: lie external to the fibrous capsule on the medial half of the posterior surface of each lobe of the thyroid gland ○ Number: most people have four, only 5% have more, and some have two glands. ○ Function: to make parathyroid hormone (PTH) ■ It regulates the amount of calcium, phosphorus, and magnesium in bones. ● Clinical issues related to both thyroid and parathyroid function ● Physiology of TSH - thyroid stimulating hormone: ○ Hypothalamus releases TRH → Pituitary gland releases TSH (thyroid stimulating hormone) ■ Stimulates: T4 (thyroid hormone), T3 (active thyroid hormone), Calcitonin (places calcium in the bone) ○ Hyperthyroidism - high amount of T3 and T4 hormones ■ Causes: too much iodine, grave’s disease. ○ Hypothyroidism - low amount of T3 and T4 hormones ■ Causes: low iodine in diet, pituitary tumor, thyroidectomy. ● Parathyroid physiology and pathophysiology: ○ Main function of parathyroid glands is to keep calcium levels stable ○ There are 4 parathyroid glands ● Hypoparathyroidism: ○ Low calcium levels and high phosphate levels ○ Will cause an increase in parathyroid hormone (PTH) ■ Acts to raise calcium levels by increasing the absorption of calcium in the intestines, and increasing reabsorption of of calcium in kidneys, and increasing the osteoclast (bone break down) activity in the bones (vitamin D acts to help to do those tasks) ● Hyperparathyroidism: ○ Uncontrolled parathyroid hormone being produced by a tumor (as an example) ○ Leads to high calcium levels (hypercalcemia) BEWARE OF THE CONTENTS OF the carotid sheath Sample Clinical Scenario Ques for Anatomy: A 63 year old man presents with a thrombosis that is occluding his right external carotid artery. He displays symptoms of decreased blood flow to his right face with absent facial artery pulse in his right occipital region, the area behind his right ear, his right temporal region and the deep structures of the right face normally supplied by the maxillary artery. Based on the structures and vessels receiving decreased blood flow, where is the occlusion on the external carotid artery? A. B. C. D. Superior to the maxillary artery At the level of the occipital artery Just below the facial artery At the level of the transverse facial artery Ans C An experienced surgeon is delicately removing an adenocarcinoma in the submandibular triangle. She dissects away the subcutaneous fat and identifies the cancerous tissue, and then identifies the local neurovascular structures that she wants to preserve in the surrounding area. The surgeon finds the facial vein and facial artery but has trouble finding the nerve that also passes near the submandibular gland. Which of the following nerves is the surgeon likely trying to identify? A. B. C. D. Accessory Ophthalmic Maxillary Hypoglossal Ans D TBL #1 1. Discuss the anatomy of the central nervous system, peripheral nervous system, and somatic nervous system. Cranial Nerves that synapse with CNS - CNS- Brain/ Spinal cord (white (Myelinated) and gray matter (unmyelinated)) - Brain (White matter internal, Gray external) - Dura, arachnoid, subarachnoid, pia mater - Spinal Cord (White matter external, Gray matter Internal) - - Dura, arachnoid, pia mater - Epidural space - separates dura from spinal cord PNS- Nerves that branch from the brain and spinal cord. Allows communication between CNS and the rest of the body. Peripheral nerves are cranial nerves or spinal nerves - SNS - Sensory and motor functions - Somatic sensory fibers = touch / pain / temp/ position - Somatic motor fibers - stimulate skeletal muscles - Fibers relate to dermatomes and myotomes - Voluntary actions 2. Discuss the anatomy of the Autonomic Nervous System, and the difference between sympathetic and parasympathetic innervation. - Involuntary Visceral actions Regulation of homeostasis - Sympathetic (thoracolumbar division) - Has similar anatomy as parasympathetic, however, it releases a different neurotransmitter called norepinephrine. fight or flight response - The cell bodies of presynaptic neurons are located in the intermediolateral cell column or nuclei of the spinal cord - They subdivide into left and right IMl which extend between the 1st thoracic and the 2nd or third lumbar segments of the spinal cord.a - Parasympathetic (craniosacral division) Releases acetylcholine conserve & restore energy - The presynaptic neuron cell bodies are located in the cranial and sacral site inside the CNS, and their fibers exit by two routes. - Cranial site comes from the gray matter of the brainstem and fibers exit CNS from CN 3, CN 7, CN 9, and CN 10 - The sacral site comes from the gray matter of the sacral segments of the spinal cord and their fibers exit the CNS through the anterior roots of spinal nerves in S2-S4. 3. Discuss the differences between damage to CNS and peripheral nerves. - - CNS axons do not regenerate after injury PNS axons can regenerate slowly overtime CNS- Above C4/5 death due to phrenic nerve - TBI or TSI - Auto accidents, stroke, ruptured brain aneurysm, lack of O2 PNS- Decreased voluntary mobility and sensation - Relates to dermatomes and myotomes - Clinician must understand dermatome / myotome mapping to identify with testing which spinal nerve is not functioning proper TBL #2 1. Why are fractures to the pterion life threatening? (Moore’s p. 502) - Pterion fractures can be life threatening because it overlies the frontal branches of the middle meningeal vessels, which lie in grooves on the internal lateral wall of the calvaria. The thin bones forming the pterion can rupture the frontal branches (deep to pterion) when the head is damaged. This results in an epidural hematoma which exerts pressure on the underlying cerebral cortex. An untreated middle meningeal artery hemorrhage may cause death within a few hours. 2. Discuss the clinical significance of the emissary veins of the skull and discuss the general anatomy of the dural venous sinuses. (Moore’s pp. 507-509) - - Emissary vein is located in the loose areolar connective tissue and protrude through the periosteum of the skull. This layer is considered the danger area of the scalp. The emissary vein serves as a passageway for infection. An infection in the loose connective tissue can pass through the calvaria and enter the meninges Dural venous sinuses are located between the periosteal and meningeal layers of the dura. Large veins enter into these sinuses. Emissary vein is a passageway into these sinuses. It can carry with it infection. 3. How do the sources of extravasated blood differ with an epidural hematoma, subdural hematoma, and a subarachnoid hemorrhage? (Moore’s p. 514) - Arterial Bleeds can be more severe due to increased risk of bleeding out - Epidural hematoma - blood from torn branches of middle meningeal artery collect between external periosteal layer of the dura and calvaria - Subdural hematoma- blood does not collect within preexisting space but creates a space at dura-arachnoid junction, venous in origin and commonly results from tearing of superior cerebral vein. - Subarachnoid hemorrhage - usually an arterial escape of blood into the subarachnoid space. They result from rupture of a saccular aneurysm, and are associated with head trauma such as cranial fractures and cerebral lacerations. 4. Distinguish between an ischemic stroke, a hemorrhagic stroke, and a TIA. Discuss brain vasculature in general. (Moore’s pp. 518-520) - - Middle cerebral artery is where most ischemic strokes take place Ischemic stroke - lack of oxygenated blood supply due to a clot/ thrombosis - Clot busting drugs can be administered Hemorrhagic– Brain bleed of sacs (most dangerous due to having to wait for clotting factors to take place) if patient has low PTT time clotting can take to long - Can lead to subdural hematoma TIA- Transient Ischemic attack (mini stroke) - Subsides in minutes to hours - Symptoms similar to stroke due to momentary lack of oxygen - Can return back to baseline after - High risk for stroke in coming days to weeks Brain vasculature - Dense connective tissue is highly vascular Loose areolar connective tissue is highly vascularized- susceptible to bleeds - Subarachnoid Spaces Highly vascular cerebral arteries Carotid Arteries- Right and left branches off of the aortic arch - - Further branches off of the internal and external carotid arteries Cerebral arterial circle (of Willis) - Vertebral arteries- Branching off of right and left subclavian, fusing superiorly to form basilar artery TBL #3 1. What are the three main branches of the Trigeminal Nerve and their functions? What are some consequences of injury to these? (Moore’s P. 530) 1. Ophthalmic branch a. sensation from the cornea , skin of forehead, scalp, eyelids, nose, mucosa of nasal cavity, paranasal sinus b. Consequences of injury: loss of sensation to the areas innervated - loss of general sensation of the face, loss of corneal reflex 2. Maxillary branch a. sensation from skin of face over maxilla, including upper lip, maxillary teeth, mucosa of nose maxillary sinus, palate b. Consequences of injury: trouble chewing or speaking, and whistling, Trigeminal neuralgia (episodes of pain in the areas supplied), inability to clench teeth 3. Mandibular branch a. sensation from skin over mandible, including lower lip, side of head, mandibular teeth, temporomandibular joint, mucosa of mouth, anterior ⅔ of tongue b. Motor to muscles of mastication c. Consequences of injury: paralysis of muscles of mastication - the mandible would deviate to the side of the lesion, (episodes of pain in the areas supplied) 2. What is Bell Palsy and why do afflicted individuals frequently dab the affected eye and corner of the mouth and have troubles eating/chewing? (Moore’s p. 530) - - It is an injury to the 7th cranial nerve (CN VII) - the branches will paralyze some or all facial muscles on the side that is affected. The side of the face will be distorted and have a sag. - The lacrimal fluid will not be spread over the cornea which causes inadequate lubrication, hydration and flushing of the cornea. - If it paralyzes the buccinator the food will get stuck in the oral vestibule during mastication. - Affected sphincters or dilators will displace the mouth which will cause food and saliva to drip out of the corner of the mouth. - Will not properly be able to whistle or blow. - Speech will be affected by weakened lips. - The affected individuals frequently dab the affected eye and corner of the eye due to the to wipe the fluid of tears and saliva from the eye and mouth. If you can move your forehead, it’s a stroke. If not, it’s Bell palsy. 3. Describe the pupillary light reflex and the result of oculomotor and abducens nerve palsy. (Moore’s p. 550) - Tested using penlight during neurological examination, test the reflex involving CN II and CN III - Bright light causes constriction of the pupils, when light enters one eye both pupils constrict because each retina sends fibers into the optic tracts of both sides - Interruption of these fibers causes dilation of the pupil because of unopposed action of the dilator pupillae muscle - First sign of compression of the oculomotor nerve is ipsilateral slowness of the pupilary response to light - Cranial 6 (VI) nerve palsy can be caused by strokes, bleeds, masses, diabetes (have it more often) , inflammation of the nerve. Diabetes can affect nerves, eyes and kidneys. - Oculomotor nerve palsy affects most of the ocular muscles including the levator palpebrae and the sphincter pupillae - The superior eyelid droops and cannot be raised voluntarily because of the unopposed activity of the orbicularis oculi - Pupil is also fully dilated and non reactive because of unopposed dilator pupillae - Pupil is fully abducted and depressed (down and out) because of unopposed activity of the lateral rectus and superior oblique - In abducens nerve palsy the lateral rectus is paralyzed - Individual cannot abduct the pupil on affected side - Pupil is is fully adducted by the unopposed pull of the medial rectus 4. Define and distinguish between otitis externa and otitis media. Discuss the role of the pharyngotympanic tube and which one of the above conditions it has an impact on. (Moore’s pp. 588-589). Otitis Externa- outer ear infection, “swimmers ear” from inner ear to outer ear. Swelling of external acoustic meatus. Typically due to build up on bacteria that is often in water remaining after swimming that also allows for an environment for bacteria to grow. Causes increased pain in the outer lobe of the ear. Can be treated with antibiotic ear drops. Has no effect on pharyngotympanic. Otitis Media - (middle ear infection) bulge of red tympanic membrane. Inflammation “or swelling of the mucous membrane lining the tympanic cavity can block the pharyngotympanic tube. If untreated, impaired hearing is the result. - The role of the pharyngotympanic tube is to drain into the nasal sinus. more common in children because the pharyngotympanic tube is straighter which allows for easier transport of mucous to the middle ear. As our ears develop, the tube forms a slight curvature which prevents the mucous from traveling further into the ear, which is why adults tend to have less middle ear infections. Therefore, pharyngotympanic tube has an impact on otitis media. TBL #4 1. Discuss congenital torticollis Vs. cervical dystonia. (Moore’s p. 509) Torticollis = contraction of cervical muscles , leads to a twisting of the neck and slanting of the head Congenital torticollis = results from a fibrous tissue tumor in SCM (sternocleidomastoid) before or shortly after birth - - Can be a due to pulling the baby’s head excessively during a difficult birth and tearing the fibers of the SCM leading to a hematoma that can develop into a fibrous mass that entraps part of the spinal accessory nerve (CN XI) and denervating the SCM Surgical release may be necessary of SCM from its distal attachment to manubrium and clavicle Cervical dystonia - (spasmodic torticollis) - abnormal tonicity of the cervical muscles - begins in adulthood - Involves bilateral combination of neck muscles (sternocleidomastoid and trapezius) neck muscles contract involuntarily causing your head to twist to one side - An example of neck stiffness. 2. Discuss the significance of a subclavian vein puncture and the importance of the external jugular vein. (Moore’s p. 605) - - Subclavian vein provides a point of entry into the venous system for the central line placement. The subclavian vein puncture is significant since the central line placement will provide passageway to administer parenteral fluids and medications, as well as measure the central venous pressure. - Risk of puncture to the subclavian artery, therefore, alternative site of central venous line placement are IJV and femoral vein. External jugular vein serves as an internal barometer. The distance of it will indicate whether the venous pressure is normal or not. Short distance of the external jugular vein which is visible superior to the clavicle means that the venous pressure is in normal range. When the venous pressure is elevated the vein will go throughout the side of the neck. - The abnormal venous pressure may suggest signs of heart failure, obstruction of the superior vena cava vein, enlarged supraclavicular lymph nodes, or increased intrathoracic pressure. 3. What are the symptoms and treatment of carotid artery occlusion? (Moore’s p. 611) - Artherosclerotic thickening (build up of fats, cholesterol, on the artery walls) of the internal carotid artery can obstruct blood flow - Symptoms depend on the degree of obstruction and the amount of collateral blood flow to the brain from other arteries - Can cause TIA, sudden loss of neurological function (dizziness and disorientation) that disappear within 24 hours - Can also cause a stroke - Stenosis relieved by opening the artery at its origin and stripping of the artherosclerotic plaque within the intima (carotid endarterectomy) - Risk to CN IX, X, XI, XII - - Carotid angioplasty and stenting (for blockages to hard to reach with endarterectomy or for people with other health conditions that make surgery to risky) Arterial blood clots more serious 4. Discuss some indications and potential adverse effects of a thyroidectomy. (Moore’s p. 621) - Thyroidectomy is removal of part of the thyroid or parathyroid gland, typically due to malignancy, enlargements (goiter), or hyperthyroidism (overactivity). Removal of one can cause damage to the other. Tetany can adversely happen due to rapid decrease in blood calcium levels. Hormone levels can be affected as well, most importantly thyroxine or tetraiodothyronine (T4) and triiodothyronine (T3).