Presentation on theme: "Clinical & Applied Anatomy Head & Neck Unit – Lecture 16 د. حيدر جليل الأعسم."— Presentation transcript:
Clinical & Applied Anatomy Head & Neck Unit – Lecture 16 د. حيدر جليل الأعسم
Lecture 1&2: Skull Fractures of the Skull Fractures of Pterion may lead to injury of anterior division of middle meningeal arteries, thus leading to epi-cranial or extradural haematoma. It usually affects level of consciousness then a re-gain of consciousness occur that called Lucid Period. Continuous increasing haematoma leads to deteriorating level of consciousness and may lead to cerebral compression, brain stem herniation and /or death. Fractures of cribriform plate of ethmoid bone may result in tearing of meninges. The patient will have bleeding from nose (epistaxis) and leakage of cerebrospinal fluid into the nose (CSF rhinorrhea). Fracture of the base of the skull results in passage of blood through superior and inferior orbital fissure to accumulate around the eyes. This lead to typical appearance of bilateral black eyes (Panda Eyes). Fracture of the floor of the orbit due to severe blow to the orbit may cause contents of orbital cavity to pass through floor of orbit into maxillary sinus, leading to damage to infraorbital nerve (altered sensation to skin of cheek, upper lip & gum) & lower rectus muscle may get entrapped in between fractured bones leading to squint.
Lecture 3: Meninges Intracranial Hemorrhage: result from trauma or cerebral vascular lesion. Extradural hemorrhage: results from injuries to meningeal arteries or veins. Most common artery to be damaged is middle meningeal artery by a minor blow to side of the head, resulting in fracture of Pterion. Subdural hemorrhage: results from tearing of superior cerebral veins at their point of entrance into superior sagittal sinus due to a blow on front or back of head. Blood under low pressure begins to accumulate in potential space between dura and arachnoid. Subarachnoid hemorrhage: results from leakage or rupture of a congenital aneurysm on circle of Willis or from an angioma. There will be sudden severe headache, stiffness of neck & loss of consciousness. Diagnosis is established by aspirating blood- stained CSF through a lumbar puncture (spinal tap). Cerebral hemorrhage: is generally caused by rupture of thin- walled branch of middle cerebral artery, thus involving a vital fibers in internal capsule and produces hemiplegia on opposite side of the body. Patient immediately loses consciousness, and paralysis is noted when consciousness is regained.
Lecture 4: Scalp Lacerations of the Scalp: Scalp has a profuse blood supply and arterial walls are attached to fibrous septa in subcutaneous tissue (unable to contract or retract after injury), thus a small laceration of scalp can cause severe blood loss and it is difficult to stop the bleeding of a scalp wound. Scalp Infections: Infections of scalp tend to remain localized and are usually painful because of abundant fibrous tissue in the subcutaneous layer. Occasionally, an infection of scalp spreads by emissary veins, which are valveless, to the skull bones, causing osteomyelitis or may travel farther into venous sinuses and produce venous sinus thrombosis.
Lecture 5: Face Facial Infections and Cavernous Sinus Thrombosis: Area of facial skin bounded by nose, eye, and upper lip is a dangerous zone for infection. A boil in this region can cause thrombosis of facial vein which my spread through inferior ophthalmic veins to cavernous sinus, resulting in cavernous sinus thrombosis that may be fatal. Facial Muscle Paralysis: Damage to facial nerve in internal acoustic meatus (by a tumor), in middle ear (by infection), in facial canal (perineuritis, Bell's palsy), or in parotid gland (by a tumor) will cause paralysis of facial muscles and distortion of face, with drooping of lower eyelid and mouth will deviated to normal side. This is essentially a lower motor neuron lesion. An upper motor neuron lesion will leave upper part of the face normal Testing the Integrity of the Facial Nerve Facial nerve supplies muscles of facial expression; anterior 2/3 of tongue with taste fibers; and is secretomotor to lacrimal, submandibular, and sublingual glands. To test motor facial nerve, patient is asked to show teeth by separating lips with teeth clenched, and then to close the eyes. Facial Artery pulsation: Pulsations of facial artery can be felt at lower margin of body of mandible at anterior border of masseter muscle.
Lecture 6: Temporal Region Dislocation of Temporomandibular Joint: It may occur when mandible is depressed because the joint is unstable. A minor blow on the chin or a sudden contraction of lateral pterygoid muscles (as in yawning) may be sufficient to pull head of mandible and articular disc beyond the summit of articular tubercle. In bilateral cases, mouth is fixed in an open position, and both heads of the mandible lie in front of the articular tubercles.
Lecture 7: Orbit & Eye Pupillary Reflexes: are reactions of pupils to light & accommodation. Direct light reflex: normal pupil reflexly contracts when a light is shone into patient's eye. Nerve impulses pass through Retina - optic nerve - optic chiasma - optic tract - lateral geniculate body where fibers concerned with this reflex leave and pass to oculomotor nuclei on both sides. Then efferent fibers leave midbrain in oculomotor nerve and reach ciliary ganglion via nerve to inferior oblique. Postganglionic fibers pass to constrictor pupillae muscles via short ciliary nerves. Indirect (consensual) light reflex: is contraction of pupil in one eye in response to shining light in opposite eye. This reflex is possible because afferent pathway travels to nuclei of both oculomotor nerves. Accommodation reflex is the contraction of pupil that occurs when a person suddenly focuses on a near object after having focused on a distant object. Nerve impulses pass through Retina - optic nerve - optic chiasma - optic tract - lateral geniculate body - optic radiation - cerebral cortex. Visual cortex is connected to the eye field of frontal cortex which send efferent impulses to oculomotor nucleus that reach constrictor pupillae via oculomotor nerve, ciliary ganglion, and short ciliary nerves.
Lecture 8: Ear Otitis Media & Complications: Pathogenic organisms can gain entrance to middle ear by ascending through auditory tube from naopharynx. Otitis Media is the acute infection of middle ear and produces bulging and redness of tympanic membrane. Inadequate treatment of otitis media can result in spread of infection into mastoid antrum and mastoid air cells (acute mastoiditis). Acute mastoiditis may be followed by further spread of organisms beyond boundaries of middle ear. Spread of infection in superior direction could produce meningitis & cerebral abscess in temporal lobe. Spread of infection in medial direction can cause a facial nerve palsy & labyrinthitis with vertigo. If infection spreads in posterior direction, Thrombosis in sigmoid sinus may occur.
Lecture 9: Nose & Paranasal sinuses Infection of the Nasal Cavity: Infection of nasal cavity can spread in a variety of directions. Paranasal sinuses are especially prone to infection (Sinusitis). Organisms may spread via nasopharynx & auditory tube to middle ear. It may ascend to meninges of anterior cranial fossa along sheaths of olfactory nerves through cribriform plate & produce meningitis. Nose Bleeding (Epistaxis): Epistaxis, or bleeding from nose, is a frequent condition caused most commonly by nose picking. Bleeding may be arterial or venous, and most episodes occur on anteroinferior portion of septum and involve septal branches of sphenopalatine and facial vessels.
Lecture 10: Oral cavity & Salivary Glands Parotid Salivary Gland and Lesions of Facial Nerve: Facial nerve lies in interval between superficial & deep parts of parotid gland. Malignant tumour usually involves facial nerve, causing unilateral facial paralysis while benign tumours rarely cause facial palsy. Parotid Gland Infections: Parotid gland may become acutely inflamed as a result of retrograde bacterial infection from mouth via parotid duct or via bloodstream, as in Mumps. In both, gland is swollen and painful because capsule is strong and limits swelling of the gland. Swollen glenoid process, which extends medially behind TMJ, causes pain when eating. Submandibular Salivary Gland: Calculus Formation: Submandibular gland is a common site of calculus formation which is rare in other salivary glands. Tense swelling below the mandible before or during meals and absence of swelling between meals, is diagnostic of this condition. Frequently, stone can be palpated in the duct, which lies below mucous membrane of the floor of mouth. Sublingual Salivary Gland and Cyst Formation: Sublingual salivary gland, which lies beneath sublingual fold of floor of mouth, opens into mouth by numerous small ducts. Blockage of one of these ducts is believed to be cause of cysts under the tongue.
Lecture 11&12: Neck Triangles Congenital Torticollis Congenital torticollis is a result of excessive stretching of sternocleidomastoid muscle during a difficult labour. Hemorrhage occurs into the muscle and may be detected as a small, rounded tumour during early weeks after birth. Later, it is replaced by fibrous tissue, which contracts and shortens the muscle pulling mastoid process down toward sternoclavicular joint. Thus, cervical spine is flexed and face looks upward to opposite side. If left untreated, asymmetrical growth changes occur in face, and cervical vertebrae may become wedge shaped. Spasmodic Torticollis: Spasmodic torticollis results from repeated chronic contractions of sternocleidomastoid and trapezius muscles and is usually psychogenic. Section of spinal part of accessory nerve may be needed in severe cases. External Jugular Vein Catheterization: External jugular vein is superficial valved vein that can be used for venous catheterization because it is in most direct line with superior vena cava. It is catheterized about halfway between level of cricoid cartilage and clavicle. Catheter should be inserted during inspiration?
Lecture 11&12: Thyroid Gland Swellings of Thyroid Gland and Movement on Swallowing: Thyroid gland is invested in a sheath derived from pretracheal fascia. This tethers gland to larynx & trachea and explains why thyroid gland follows movements of larynx in swallowing. Any thyroid swelling will move upward when the patient is asked to swallow. Retrosternal Goiter: Sternothyroid muscles to thyroid cartilage limits upward expansion of thyroid gland; thus sometimes enlarged thyroid gland extend downward behind sternum (Retrosternal goiter). It can compress trachea & causes dangerous dyspnea; it can also cause severe venous compression. Thyroid Arteries and Important Nerves: The two main arteries supplying thyroid gland are closely related to important nerves that can be damaged during thyroid operations. Superior thyroid artery on each side is related to external laryngeal nerve, which supplies cricothyroid muscle. Terminal branches of inferior thyroid artery on each side are related to recurrent laryngeal nerve. External laryngeal nerve damage results in hoarseness of voice because? Thyroidectomy and the Parathyroid Glands: Parathyroid glands are usually 4 in number & closely related to posterior surface of thyroid gland. In partial thyroidectomy, posterior part of thyroid gland is left undisturbed, so parathyroid glands are not damaged
Lecture 13: Pharynx Quinsy: It is peritonsillar abscess caused by spread of infection from palatine tonsil to loose connective tissue outside capsule of the tonsil. Adenoids: is excessive hypertrophy of pharyngeal tonsils usually associated with infection. They blocks the posterior nasal openings and causes the patient to snore loudly at night and to breathe through open mouth. It may cause recurrent otitis media and deafness because of the close relationship of infected lymphoid tissue to auditory tube. Adenoidectomy is treatment for hypertrophied adenoids with infection. Piriform Fossa and Foreign Bodies Piriform fossa is a common site for lodging of sharp ingested bodies such as fish bones. This causes the patient to gag violently. It sometimes needs physician's assistance when the object has become jammed.
Lecture 14: Larynx Lesions of the Laryngeal Nerves: Muscles of larynx are innervated by recurrent laryngeal nerves except cricothyroid which is supplied by external laryngeal nerve. Both these nerves are vulnerable during thyroid operations. Left recurrent laryngeal nerve may be involved in a bronchial or esophageal carcinoma or in secondary metastatic deposits in mediastinal lymph nodes. Section of external laryngeal nerve causes weakness of voice because vocal fold can’t be tensed as cricothyroid muscle is paralyzed. Unilateral complete section of recurrent laryngeal nerve results in vocal fold on affected side assuming position midway between abduction and adduction. It lies lateral to midline but speech is not greatly affected because other vocal fold compensates to some extent and moves toward affected vocal fold. Bilateral complete section of recurrent laryngeal nerve results in both vocal folds assuming position midway between abduction and adduction. Breathing is impaired because rima glottidis is partially closed & speech is lost. Unilateral partial section of recurrent laryngeal nerve results in a greater degree of paralysis of abductor muscles than of adductor muscles. Affected vocal fold assumes adducted midline position. Bilateral partial section of recurrent laryngeal nerve results in bilateral paralysis of abductor muscles and drawing together of vocal folds. Acute breathlessness (dyspnea) and stridor follow and tracheostomy is necessary.
Lecture 15: Root of the Neck Supraclavicular Approach of Subclavian vein catheterisation: Preffered 1. Site of penetration of vein wall is larger. 2. Needle is pointed downward & medially toward mediastinum. 3. Catheter is inserted along more direct course into brachiocephalic v. With patient in supine position with head tilted downward or simple supine position and head turned to opposite side. Needle is inserted through skin at site where posterior border of clavicular origin of sternocleidomastoid is attached to upper border of clavicle. At this point, needle lies lateral to lateral border of scalenus anterior muscle and above first rib. Needle is directed downward in direction of opposite nipple and pierces the following structures: 1. Skin 2. Superficial fascia and platysma 3. Investing layer of deep cervical fascia 4. Wall of the subclavian vein Possible Complications: 1. Paralysis of diaphragm: if injury to phrenic nerve occurs. 2. Pneumothorax or hemothorax: 3. Brachial plexus injury: if injured by needle passing posteriorly into the roots or trunks of the plexus.