Entry 8

Severance of External Jugular Vein

The external jugular vein (EJV) begins with the union of the retromandibular vein and the posterior auricular vein at the inferior angle of the mandible. After crossing the sternocleidomastoid muscle just deep to the platysma and then enters the lateral cervical region. The EJV terminates in the sublavian veins and is responsible for draining most of the scalp and side of the face. The EJV has 8 branches with 5 located in the neck; these include the ascending pharyngeal, superior thyroid, lingual, facial and occipital veins.

Severance of the EJV posterior to the border of the sternocleidomastoid muscle where it pierces the roof of the lateral cervical region where the lumen is held open by the tough investing layer of deep cervical fasica. The negative intrathoracic pressure will suck air into the vein causing a churning noise in the thorax and cyanosis. This could cause a venous air embolism filling the right side of the heart with froth, and nearly stopping blood flow. Application of firm pressure to the severed jugular vein will stop the bleeding and entry of air into the vessel until it can be sutured.
http://www.bartleby.com/107/144.html

Carotid Occlusion and Endarterectomy

The internal carotid arteries (ICA) are major arteries of the head and neck that are the continuations of the external carotid arteries. The distinction between the two vessels occurs at the level of the superior boarder of the thyroid cartilage. The ICA ascends to enter the cranium through the carotid canals in the petrous parts of the temporal bones and become the main blood suppliers of the brain and structures in the orbits.

Atherosclerotic, cholesterol deposits, thickening of the intima of the ICA, which may obstruct blood flow. Symptoms depend on a varying degree of obstruction; a partial occlusion may cause a transient ischemic attack (TIA). TIA is a sudden focal loss of neurological function, e.g. dizziness and vertigo,  that disappear within 24hrs. Arterial occlusion may cause a minor stroke, which is a loss of neurological function such as weakness or sensory loss on one side of the body that exceeds 24hrs. and is gone within 3 weeks. A noninvasive procedure to check for an occlusion is called a Doppler. Once located a procedure called carotid endartercetomy, which is stripping off of the plaque blocking the vessel. After the operation pharmaceutical aids are given to inhibit clot formation until the endothelium has regrown.
http://en.wikipedia.org/wiki/Endarterectomy

Injury to the Suprascapular nerve

The suprascapular nerve originates from the union formed by the 5^th and 6^th cervical nerves. It runs lateral beneath the trapezius and the omohyoideus muscles, and enters the supraspinatous fossa through the suprascapular notch, below the superior transverse scapular ligament. It then passes beneath the supraspinatus muscle and curves around the lateral border of the spine of the scapula to the infraspinatous fossa. The nerve innervates the supraspinatus and infraspinatus muscles.

            Trauma to the suprascapular nerve is usually caused by a fracture of the middle third of the clavicle. Injury of this nerve results in loss of lateral rotation of the humerus at the glenohumeral joint. The ability to initiate abduction of the limb is also affected. Nonsurgical treatment is accomplished by avoiding overhead activities, and the rehab of muscles; unfortunately the overall success is limited and inconclusive. Surgical treatment is the released from the tunnel that has trapped the nerve. Usually performed at the suprascapular notch and/or spinoglenoid notch. This treatment is usually associated with a high rate of pain relief and functional improvement.
http://en.wikipedia.org/wiki/Suprascapular_nerve

Entry 7

Anosmia

  The sense of smell is regulated by cranial nerve I, olfactory n. The cell bodies of olfactory receptor neurons are located in the olfactory organ; located in the roof of the nasal cavity and along the nasal septum and medial wall of the superior nasal concha. These neurons are both receptors and conductors, and the apical surfaces of the neurons are covered in fine olfactory cilia, bathed by a film of watery mucus secreted by the olfactory glands of the epithelium.

Anosmia is simply the loss of smell, just like hearing loss occurs with growing older, so does smell. Sometimes the loss of smell is associated with upper respiratory infections, sinus disease, and head trauma. A severe head trauma the olfactory bulbs may be torn away from the olfactory nerves or some olfactory nerve fibers may be torn as the pass through a fractured cribriform plate. If these bundles are torn a complete loss of smell will occur. Anosmia may also be a clue to a fracture of the cranial base and cerebrospinal fluid rhinorrhea. http://en.wikipedia.org/wiki/Anosmia

Acoustic Neuroma

 Cranial nerve VIII, vestibulocochlear nerve, regulates the special sensations of hearing and equilibrium and motion. CN VIII emerges from the junction of the medulla and pons continuing through the internal acoustic meatus and then separates into the vestibular nerve and cochlear nerves. The peripheral processes of the vestibular neurons extend to the utricle and saccule; to the cristae of the ampullae of the semicircular ducts. The peripheral processes of the cochlear neurons extend to the spiral organ for the sense of hearing.

            Acoustic neuroma is a slow growing benign tumor of the Schwann cells. These cells wrap around neurons creating a myelin shealth, a conductive platform for impulses to travel down. The tumor begins in the vestibular nerve while it is in the internal acoustic meatus. The early symptom is usually hearing loss; Dysequilibrium and tinnitus can also occur but only in 70% of patients. Treatment options range from simple observation to surgery and possibly stereotactic radiosurgery.
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001782/

Olfactory Hallucinations

            Cranial nerve I, olfactory nerve, as stated previously in this entry, regulates the sense of smell. CN I emerges from the forebrain, but unlike the other cranial nerves, it consists of a collection of many sensory nerve fibers that extend to the olfactory bulb; passing through the many openings of the Cribriform plate of the Ethmoid bone. These tracts divide into the lateral and medial olfactory striae. The lateral olfactory stria terminates in the piriform cortex of the anterior part of the temporal lobe. The medial stria prjects through the anterior commissure to olfactory structures.

Olfactory hallucinations might be the result of lesions in the temporal lobe of the cerebral hemisphere. These lesions could cause irritation to the lateral olfactory area, which could cause temporal lobe epilepsy, or “uncinate fits”. Characterized by imaginary disagreeable odors and involuntary movements of the lips and tongue. This disorder was one of the symptoms of the patient on the latest House episode. Treatment of these lesions is still in the infancy stages.
http://en.wikipedia.org/wiki/Phantosmia

Entry 6

Foreign Bodies in Laryngopharynx

The laryngopharynx, as called hypopharynx,is one of three sections of the pharynx. The other two are the oropharynx (mesopharynx) and nasopharynx (epipharynx). The laryngopharynx is the section of pharynx that connects the throat to the esophagus; lying inferior to the epiglottis. The superior boundary of the laryngopharynx is the hyoid bone and is the pathway for both air entering the larynx and food & drink entering the esophagus. When the two battle over which one will have the right away, the food & drink wins most of the time. The laryngopharynx is innervated by the pharyngeal plexus and is lined with stratified squamous epithelium.

The laryngopharynx is the location of halting foreign objects in the throat due to the piriform sinus. The piriform sinus is a recess located on either side of the laryngopharynx, and just deep to the mucous membrane of this fossa lie the the internal laryngeal nerve a branch of the superior laryngeal nerve. When objects like chicken bones or fish bones get caught in the piriform sinus there is a risk of puncturing through the mucous membrane and causing damage to the internal and superior laryngeal nerves. Injury to these nerves could cause anesthesia of the laryngeal mucous membrane as far inferiorly as the vocal folds; causing lose of the ability to speak. Until recently this trauma would be permanent but through medical advancements doctors are able to repair the laryngeal nerves.

http://en.wikipedia.org/wiki/Human_pharynx#Laryngopharynx

Enlargement of Thyroid Gland

            The thyroid gland is located in the anterior neck at the same level of C5-T1 vertebrae and the second & third tracheal rings.  The thyroid gland is one of the largest endocrine glands in the body, and controls how quickly the body uses energy, makes proteins and controls how sensitive the body should be to other hormones. The gland produces several hormones: triiodothyronine (T3) and thyroxine (T4) both of these hormones regulate the rate of metabolism, and are synthesized by both iodine and tyrosine. The thyroid also produces calcitonin which plays a role in calcium homeostasis.

            The non-neoplastic and noninflammatory enlargment of the thyroid gland is called a goiter. This is a result of a lack of iodine in the diet. It is common in certain parts of the world where the soil and water are deficient in iodine. The goiter can compress the trachea, esophagus, and recurrent laryngeal nerves. Depending on the size of the goiter determines the treatment. Small goiters are usually monitored but most of the time left alone. Large goiters, compressing the trachea and/or esophagus, need surgical intervention.

http://en.wikipedia.org/wiki/Thyroid

Trauma to the Recurrent Laryngeal Nerves

            The recurrent laryngeal nerves (RLN) branch from cranial nerve X, vagus nerve. The RLN branches into the right and left RLN each following its own distinctive path. The right RLN loops inferior to the right subclavian artery at approximately the T1-T2 level. The left RLN loops inferior to the arch of the aorta at approximately the T4-T5 vertebral level. Both nerves ascend to the thyroid gland, traveling through the tracheo-esophageal groove, innervating the trachea, esophagus, and all the intrinsic muscles of the larynx except the cricothyroid.

Trauma of the recurrent laryngeal nerves can be a result from a surgical procedure, pressure from associated blood vessels, or from blunt force trauma to the neck. The right RLN is intimately related to the inferior thyroid artery and its branches. The nerve can cross this vessel from different directions in different people causing a possible problem during surgery. The left RLN is a little more distinctive during surgical procedures because of its more vertical ascent from the superior mediastinum, and blood vessels. The closer to the inferior aspect of the thyroid gland, the more convoluted the left RLN becomes. Hoarseness is the most common result of trauma; usually pointing toward unilateral RLN injury. Temporary aphonia or disturbance of phonation and laryngeal spasms may also occur. Vocal rest is the usually treatment for unilateral trauma to the RLN.  

http://en.wikipedia.org/wiki/Recurrent_laryngeal_nerve