Clinical Director, Duke University School of Medicine
Vagus nerve (C) lies inside the carotid sheath sandwiched between common carotid artery medially and internal jugular vein laterally cholesterol ratio calculator buy cheap vytorin 20 mg line. A - Sympathetic trunk lies postero-medial to the carotid sheath in the carotid triangle of neck cholesterol ratio australia vytorin 30mg low cost. B - Phrenic nerve cholesterol test las vegas order vytorin 30mg overnight delivery, lies anterior to scalenus anterior muscle lowering cholesterol foods eat discount 30mg vytorin amex, covered by pre-vertebral fascia, in the posterior triangle of neck. D - Recurrent laryngeal nerve, branch of vagus running in the tracheo-oesophageal groove. Phrenic descends anterior of the muscle from the lateral to the medial side (but nerve fibres may pierce the muscle occasionally). Scalenus anterior muscle is sandwiched between subclavian artery from subclavian vein, and separates the two vessels. Transverse cervical artery passes anterior to the scalenus anterior muscle (may be found running posterior as a variation). Scalenus anterior muscle is considered to be an important surgical landmark in the neck region. Oral Vestibule is bounded by lips and cheeks externally and teeth and gums internally and receives opening of parotid Oral Cavity Proper is bounded anteriorly and laterally by teeth and gums; its roof is formed by the palate, and its floor is It communicates posteriorly with the oropharynx. Tongue Tongue is attached by muscles to the hyoid bone, mandible, styloid process, palate, and pharynx. It has a V-shaped sulcus terminalis which divides it into anterior two-thirds and a posterior one-third, which differ Foramen cecum is located at the apex of the V and indicates the embryologic site of origin of the embryonic thyroglossal Lingual Papillae are small, nipple-shaped projections on the anterior two-thirds of the dorsum of the tongue. They are Circumvallate Papillae are arranged in the form of a V in front of the sulcus terminalis, are studded with numerous taste Fungiform Papillae are mushroom-shaped projections with red heads and are scattered on the sides and the apex of the Filiform Papillae are numerous, slender, conical projections that are arranged in rows parallel to the sulcus terminalis. Lingual Tonsil is the collection of nodular masses of lymphoid follicles on the posterior one-third of the dorsum of the tongue. It passes deep to the hyoglossus and lies on the middle pharyngeal constrictor muscle. It gives suprahyoid, dorsal lingual, and sublingual arteries and terminates as the deep lingual artery, which ascends between the genioglossus and inferior longitudinal muscles. Venous Drainage: Deep lingual vein is the principal vein of the tongue, visible on the inferior surface of the tongue near the median plane. Venae comitantes accompanying the lingual artery and are joined by dorsal lingual veins and venae comitantes accompanying the hypoglossal nerve. These veins unite at the posterior border of the hyoglossus to form the lingual vein, which drains into either common facial vein or internal jugular vein. Lymphatic Drainage: the lymphatics of tongue are grouped into four groups: Apical vessels drain the tip and inferior surface of the tongue into submental lymph nodes after piercing the mylohyoid muscle. Their efferents go to the submandibular nodes mainly, some cross the hyoid bone to reach the jugulo-omohyoid nodes. Marginal vessels drain the marginal portions of the anterior two-third of the tongue unilaterally into submandibular lymph nodes and then to the lower deep cervical lymph nodes, including jugulo-omohyoid. Central vessels drain the central portion of the anterior two-third of the tongue. They pass vertically downwards in the midline of the tongue between the genioglossus muscles and then drain bilaterally into the deep cervical lymph nodes. Basal vessels drain the root of the tongue and posterior one-third of the tongue bilaterally into upper deep cervical lymph nodes, including jugulodigastric. Figure in the inset shows areas (in red) having bilateral lymphatic drainage Head and Neck Nerve supply; Motor nerve supply to the muscles (extrinsic and intrinsic) of the tongue is hypoglossal nerve (except palatoglossus, which is supplied via the pharyngeal plexus, innervated by the cranial accessory nerve fibres carried by vagal branches). Proprioception is carried by the lingual, glossopharyngeal or hypoglossal nerves, and the cervical spinal nerves. Sensory supply reflects its embryological development: Anterior two-thirds (presulcal part) is derived from first arch mesenchyme and the posterior third (postsulcal part) from third arch mesenchyme. General sensations from the anterior two-thirds of the tongue are carried by the lingual nerve (mandibular, trigeminal) and taste sensation by the chorda tympani (facial nerve). Both general sensation and taste sensation from the posterior one-third are carried by glossopharyngeal nerve. The taste area is located in the inferior part of the postcentral gyrus (primary sensory cortex). Taste sensation from the epiglottis is carried by the internal laryngeal branch of the superior laryngeal nerve (branch of the vagus). It is also called safety muscle of tongue as it prevents backward fall of tongue into the oral cavity, especially if the patient is unconscious. Taste sensation from anterior 2/3rd of tongue is carried by chorda tympani (branch of facial nerve), towards the facial nerve and geniculate ganglion. Apical vessels drain the tip and inferior surface of the tongue into submental lymph nodes after piercing the mylohyoid muscle. Sulcus terminalis V shape structure which divides the tongue into anterior two-thirds (oral part) and posterior one-third (pharyngeal part). The two parts differ in their developmental origin and accordingly mucosa, innervation and lymphatic drainage as well. Sulcus terminalis Teeth Development Teeth are derived from neural crest cells and the surface ectoderm.
Results of possible fetal abnormalities are available earlier in the pregnancy than with amniocentesis cholesterol levels tester vytorin 20mg overnight delivery. Ultrasonography is important in the assessment of fetal age cholesterol test large small buy generic vytorin pills, fetal sex fasting cholesterol test green tea vytorin 30mg online, multiple pregnancies cholesterol definition in spanish buy discount vytorin 30 mg on line, fetal viability, and for detection of possible fetal morphologic abnormalities. Unconjugated estriol (uE3) (1) Estriol is an excellent marker of fetal, placental, and maternal dysfunction (see Chapter 22). Cross-linking theory (1) Definition: Suggests that increased cross-linking of proteins in the extracellular matrix. Example: Glycosylation of collagen and the eye lens protein crystallin is associated with cataracts in older people. Free radical theory (see Chapter 2) (1) Definition: Suggests that most aging changes are due to free radical damage of cell membranes and nuclear proteins (2) High levels of free radical metabolizing enzymes. Definition: Proposes that the process of aging is part of a genetically programmed continuum of development and maturation b. Supported by the similarity of attained age in identical versus nonidentical twins, increased longevity in certain families, and the presence of genetic defects in people with premature aging. Excretion from the body is at a slower rate, which increases half-life and extends pharmacologic effects. Reflectsdecreasedappetite(senseofsmellandtasteisreduced) and decreased interest in food, particularly if there is a recent loss of a partner or close friend. VitaminB12 deficiency may lead to dementia and demyelination syndromes in the spinal cord (subacute combined degeneration; see Chapter 12) and macrocytic anemia with pancytopenia (see Chapter 12). Lack of adequate amounts of folic acid may also lead to macrocytic anemia (see Chapter 12). Impairmentsinvasomotorfunction,skeletalmuscleresponse, and sweating mean that older people will react more slowly to changes in temperature. Problems with thermoregulation are more likely in the presence of atherosclerosis and hypothyroidism as well as with medications such as sedatives and hypnotics. Hypothermia commonly complicates other acute illnesses such as pneumonia, stroke, and fractures. Financial pressures and old or nonfunctional heating systems may result in inadequate heating during cold weather. Thisincludessystolic hypertension, which commonly occurs due to loss of aortic elasticity. Treatment of the hypertension is essential to prevent myocardial infarction, heart failure, and stroke. Atrial fibrillation increases the risk for developing embolic strokes, due to stasis of blood in the left atrium leading to thrombus formation (see Chapters 11 and 26). Direct thrombin inhibitors and factor Xa inhibitors are often used rather than warfarin. Lackof appetite (anorexia), generalized weakness or fatigue rather than bouts of chest pain may be the presentation rather than chest pain with radiation into the left arm. Common causative agents for endocarditis are enterococci from the urinary tract (particularly if the patient has a urinary catheter) and Streptococcus bovis from the gastrointestinal tract (see Chapter 11). As expected, morbidity and mortality are much higher in the older than in the younger population. Precipitating factors include intercurrent illness (cardiac problems), surgery (hip replacement), change of environment, medications, sensory deprivation (no visitors), volume depletion (loss of insensible water from fever), pain, hypoxia, fever, acute urinary retention (more likely in older males), or alcohol withdrawal. Continued Female reproductive 186 Rapid Review Pathology Age-Related Changes (See. Pseudomembranous colitis from Clostridium difficile is more common, especially in hospitalized patients or those in nursing homes, owing to the loss of protective bacteria. Olderpatientsaremorelikelytohaveconfusion, anorexia, or lack of pain to palpation. Cancer is more likely to be a cause of pain in older compared with younger people. As expected, reduced volume of blood has its greatest effect on the central nervous system (dizziness, apathy) and the cardiovascular system (dyspnea, edema). Iron deficiency is more likely due to blood loss from the gastrointestinal system (serum ferritin is the best screening test). Anemia of chronic disease is likely to accompany chronic lung disease, rheumatologic disease, and malignancy. Macrocytic anemias are more likely to beduetovitaminB12 (pernicious anemia from chronic gastritis) and/or folic acid deficiency (related to poor diet). Renal tubular function declines with old age, leading to a decline in urinary concentration ability. Examplesincludeprostatehyperplasiawithurinary tract obstruction, renovascular hypertension due to atherosclerosis of the renal arteries, heart failure with a reduced cardiac output leading to decreased renal artery blood flow. This is usually not a major problem in older adults unless there is underlying respiratory disease. Recurrent pneumonia is often due to aspiration of gastric contents and gastroesophageal reflux disease. Signs of atrophy include a thin epidermis and a gradual loss in blood vessels, dermal collagen, fat, and the number of elastic fibers (normally give skin elasticity and resilience [skin turgor when pinched]). Hair follicles, sweat ducts, and sebaceous glands are reduced, resulting in a decrease in perspiration and sebum production.
Vagus Accessory Complex Nucleus ambiguus (in medulla oblongata) gives axons to form cranial part of accessory nerve which are carried by the Vagus nerve gives pharyngeal branches to pharyngeal plexus (which carry axons of cranial accessory nerve and the plexus itself sends these axons to muscles of palate and pharynx cholesterol chart nz discount vytorin 20mg with amex. Spinal accessory nerve roots arise from spinal cord C1-5 cholesterol facts order vytorin 30 mg fast delivery, form a trunk that ascends in the vertebral canal list of ldl cholesterol lowering foods vytorin 30 mg without prescription, enter foramen magnum and join the cranial part cholesterol ratio berekenen order cheap vytorin line. Both pass through the jugular foramen, cranial accessory fibres join the vagus nerve (vagus accessory complex) whereas, the spinal accessory nerve supplies sternocleidomastoid muscle and trapezius. Cranial accessory nerve (neuron bodies in nucleus ambigus) fibres are carried by vagal branches to supply muscles of palate, pharynx and larynx. Stylopharyngeus muscle is supplied by the glossopharyngeal nerve, fibres arising from nucleus ambigus. Receives contributions from vagus nerve carrying cranial accessory nerve component b. All the other muscles are supplied by the vago-accessory complex / pharyngeal plexus. The pharyngeal branch of the vagus supplies all the muscles of the pharynx (excluding stylopharyngeus, which is supplied by the glossopharyngeal nerve) and of the soft palate (excluding tensor veli palatini, which is supplied by the mandibular division of the trigeminal via the nerve to medial pterygoid). It emerges from the upper part of the inferior vagal ganglion and consists mainly of filaments derived from the cranial accessory nerve: almost all the neuronal cell bodies are in the nucleus ambiguus. Stylopharyngeus muscle is the only muscle developing in the third pharyngeal arch and the only muscle to be supplied by the glossopharyngeal nerve. Most of the muscles of the palate and pharynx develop in the fourth pharyngeal arch and are supplied by the cranial part of accessory nerve, whose axons are carried by the vagus nerve through the pharyngeal plexus to the muscles. Tensor tympani muscle develops in first pharyngeal arch and is supplied by the mandibular nerve (trigeminal). Vagus nerve carry axons of cranial accessory nerve (vagus accessory complex) and gives pharyngeal branches to pharyngeal plexus and the plexus itself sends these axons to muscles of palate and pharynx. Cranial part of accessory nerve supplies most of the pharyngeal muscles with few exceptions. Stylopharyngeus develops in third pharyngeal arch and supplied by glossopharyngeal nerve. Most of the muscle of palate are supplied by cranial accessory nerve (via vagus accessory complex) except few exceptions. Tensor veli palate develops in first pharyngeal arch and supplied by mandibular branch of trigeminal nerve. Tensor veli palati 382 Head and Neck Hypoglossal nerve Hypoglossal Nerve is given by the medulla oblongata ventrally in the preolivary sulcus and passes through the hypoglossal It loops around the occipital artery and the carotid bifurcation (in carotid triangle) to pass between the carotids and It runs deep to the digastric posterior belly and stylohyoid muscles to enter the submandibular triangle. It enters the mouth by passing above the greater horn of the hyoid bone between the middle pharyngeal constrictor and After crossing the loop of the lingual artery a little above the tip of the greater cornu of the hyoid, it inclines upwards and Between mylohyoid and hyoglossus, the hypoglossal nerve lies below the deep part of the submandibular gland, the It then passes on to the lateral aspect of genioglossus, continuing forwards in its substance as far as the tip of the tongue. It supplies motor fibers to all of the intrinsic and extrinsic muscles of the tongue except the palatoglossus (which is supplied It carries sensory fibers from C1 to supply the cranial dura mater through the meningeal branch to supply the upper root of the ansa cervicalis and the nerve to both the thyrohyoid and geniohyoid muscles. Corticobulbar fibers project predominantly to the contralateral hypoglossal nucleus. Bilateral contraction of genioglossus help in protrusion and depression of tongue in midline, since the vector of medial pull is balanced and cancelled. Palsy of right genioglossus muscle deviates the tongue to the right side, due to unopposed medial pull of the left genioglossus. Tactile sensation of tongue is not carried by the hypoglossal nerve, hence there will be no loss of tactile sensation on the tongue. It also carries the C-1 fibres to supply the two muscles of hyoid bone: Geniohyoid and thyrohyoid. Lesion of the hypoglossal nerve causes unilateral lingual paralysis and eventual hemiatrophy. The protruded tongue deviates to the paralysed side and the larynx may deviate towards the active side during swallowing. Sympathetic chain gives gray rami communicantes but receives no white rami communicantes in the cervical region. Cervical sympathetic chain has 3 cervical ganglia: Superior, middle, and inferior. They are formed by the fusion of eight Superior Cervical Ganglion (the largest) lies in front of the transverse processes of vertebrae C1 to C2, posterior to the internal carotid artery and anterior to the longus capitis. It is formed by the fusion of four primitive cervical ganglia and contains cell bodies of postganglionic sympathetic fibers that pass to the visceral structures of the head and neck. It gives the internal carotid nerve to form the internal carotid plexus (and supply superior tarsal muscle and dilator pupillae muscles). It also gives the external carotid nerve to form the external carotid plexus; the pharyngeal branches to the pharyngeal plexus; and the superior cervical cardiac nerve to the heart. Middle Cervical Ganglion lies at the level of the cricoid cartilage (vertebra C6), just above the inferior thyroid artery. It is formed by the fusion of the 5th and 6th primitive cervical ganglia and gives middle cervical cardiac nerve, which is the largest of the three cervical sympathetic cardiac nerves. Inferior Cervical Ganglion is formed by the fusion of the 7th and 8th primitive cervical ganglia. It gets fused with the first thoracic ganglion to become the cervicothoracic (stellate) ganglion. It lies in front of the neck of the first rib and the transverse process of vertebra C7 and behind the dome of the pleura and the vertebral artery.
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Diseases
Craniofacial deafness hand syndrome
Macules hereditary congenital hypopigmented and hyperpigmented
