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Clincal Correlations


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Lateral cervical cyst
When the cervical sinus persists in the neck. If it is open to the outside or inside (more rarely) it has a fistula. Would present with mucus discharge on the neck.

Always anterior to SCM.

May not become apparent until early adulthood as it slowly enlarges.

Can compress the carotid sheath (c.c. artery, IJV and Vagus nerve).
First Arch Syndrome
Not enough neural crest cells migrate into Arch 1.

Underdeveloped mandible
Defective cheek
Large mouth (lack of fusion between maxillary and mandibular processes)
Deformities of the auricul
Malleus and incus malformed
Loss of smell

Usually occurs with aging. Usually complain of loss of taste. Results from inflammation of nasal mucous membrane.

Can also result from injury to nerve itself. Clue to fracture of cranial base and leaking of csf through the nose. Can be one-sided.
Demyelinating Diseases and the Optic Nerve
Affect the nerve because the optic nerves are CNS tracts, surrounded by myelin sheaths.
Oculomotor Palsy (A complete lesion of CN III)
Could be cause by an aneurysm of posterior or cerebellar artery which would put pressure on CN III as it passes through them. Also caused by injuries, infections or tumors in the cavernous sinus.

Ptosis (drooping of superior eyelid) becuase levator palpebrae superioris is paralyzed.

Eyeball is down and out

No pupillary reflex to bright light because parasympathetic fibers to sphincters are interrupted.

Lens cannot adjust because ciliary muscles are paralyzed.
Compression of CN III (Oculmotor Nerve)
From extradural hematoma.

Compresses CN III against petrous part of temporal bone.

Autonomic fibers are affected first because they are superficial. Pupil dialates, slow pupillary response to light on injured side.
Injury to CN IV (Trochlear Nerve)
May be damaged by severe head injuries.

Double vision when looking down.

Cannot turn eyeball down and in. SO paralyzed. SO is the only muscle that depresses the eye during ADduction. Also inability to intorsion so eye is extorsion.

Person can compensate by turning head anteriorly and laterally toward side of normal eye.
Injury to CN V (Trigeminal Nerve)
Trauma, tumors, aneurysms, meningeal infections.

Paralysis of muscles of mastication with deviation of the mandible towards side of lesion.

Loss of soft, thermal, pain sensations on face.

Loss of corneal reflex (blinking when cornea is touched).

Loss of sneezing reflex.
Trigeminal Neuralgia
Affects the sensory root of CN V. Produces horrible eposodic pain, usually in maxillary and mandibular areas.
Injury to CN VI (Abducent Nerve)
Long intracranial course, stretched if intracranial pressure rises. Makes a sharp turn over petrous part of temporal bone. Brain tumor can compress.

Paralysis of lateral rectus, eye will be fully ADducted. Diplopia present in all eye positions except gazing to side opposite lesion.
Injury to CN VII (Facial Nerve)
Most frequently paralyzed CN.

Lesion near orgin/geniculate ganglion: Loss of motor, taste and autonomic functions.

Central lesion: Paralyisis of muscles inferiorly.

Between geniculate ganglion and origin of chorda tympani: Same as near ganglion but lacrimal secretion not affected.
Injury to CN VIII (Vestibulocochlear Nerve)
Tinnitus (ringing/buzzing of ears), Vertigo, loss of hearing.
Lesion of CN IX (Glossopharyngeal Nerve)
Uncommon. Infection or tumors. If in jugular foramen area, several nerves affected - jugular foramen syndrom.

Taste absent in posterior 1/3 of tongue. Gag reflex absent on side of lesion. Change in ability to swallow.
Lesion of CN X (Vagus Nerve)

Pharyngeal branches: Dysphagia (difficulty swallowing)

Superior Laryngeal nerve: Anesthesia of superior larynx, paralysis of cricothyroid muscle. Weak, tired voice.

Reccurrent laryngeal nerve: Hoarsness, dysphonia (difficulty speaking). If both sides affected: Loss of voice, harsh, high-pitched sound.

Lesions of left more common.
Injury to CN XI (Spinal Accessory Nerve)
Injury during surgical procedures because nearly subcutaneous in posterior cervical region.

Weakness, atrophy of trapezius, SCM. Weakness rotary movements of head, shrugging shoulders.
Injury to CN XII (Hypoglossal Nerve)
Paralyzes same side of tongue, which will atrophy. Deviates towards paralyzed side because of unopposed genioglossus muscle.
Thyroglossal duct cyst
Always in the midline of the neck. Parts of the thyroglossal duct will persist and become cystic and fills with cell debris and fluid. They can occur in the tongue itself, but most frequently just below the hyoid bone. Thyroglossal duct cysts can accumulate with fluid and sometimes can secondarily rupture on the surface of the thyroglossal duct sinus or fistula.
Tentorial Herniation
Incisura – medial edge of tentorium cerebelli, wraps around posterior and lateral aspects of brain stem. Separates posterior and middle cranial fossas. Space between brain stem and incisura can be a place of herniation, pinching off nerves and arteries
Carotid cavernous fistula
ICA traverses the carotid canal in the skull and into the cavernous sinus. In the case of a basilar skull fraction, where the base of the skull is sheared, the ICA can be lacerated. This introduces high pressure arterial blood which reverses the flow of venous blood (pressure is reversed and sinuses are dilated). Clinical presentation can show a “pulsing eyeball”.
Blowout fracture
If a person receives a blow to the eye, the increased pressure will cause the floor of the orbit to fracture causing the eyeball to sink into the maxillary sinus which interferes with proper movement of the eye; this causes double vision (diplopia).
Infection danger to orbit from a sinus
Infections from the maxillary sinus can spread through the floor of orbit and involve orbital contents.

Medially are the ethmoidal air cells, or tiny spaces in the ethmoid bone. Infections may arise in the ethmoidal labyrinth.

1. There is potential danger to the optic nerve in trying to clean or irrigate these air cells due to the very thin medial wall, and accidentally hitting the nerve. People have been blinded in this way.
Detachment of Retina
May result from a blow to the eye.

Can cause flashes of light or floating specks.
Edema of the retina. Caused by increased CFS pressure which slows venous return from the retina. Can be seen as a swelling of the optic disc.

Could be caused by a brain tumor.
Injury to masseteric nerve (V3)
Ipsilateral deviation of the chin via the muscle attachment of primarily the pterygoid muscles. The jaw will swing toward the side. Deviation of the jaw to the right means that V3 on the right is injured.

Atrophy of the temporal fossa and laterally, near the cheek (due to lack of innervation to the masseter).
Chronic epistaxis
Chronic nosebleeds.

Sphenopalatine- main blood supply of the nasal cavity; terminal branch off maxillary artery.

Patients will have their maxillary artery ligated to fix.

Good collateral blood supply allows this.
How can infection travel from the skin of the nose or cavernous sinus to the pterygoid venous plexus?
Via deep facial vein from facial vein.

Via inferior opthalmic vein from cavernous sinus.
Jefferson (burst) fracture of the atlas
Fracture of one or both of the bony arches of the atlas.

Results from compressive forces passed through the occipital condyles into the atlas (example, diving accidents where the head hits the bottom of a pool, or dropping heavy object onto head). The lateral masses are somewhat wedge-shaped with the medial aspect narrower and the lateral aspect wider. When this happens, the lateral masses tend to be displaced laterally.

Sometimes if the force is great enough, the transverse ligament of the atlas will rupture. If the ligament doesn’t rupture, there may not be damage to the spinal cord, because of increased diameter of the ring. If it does rupture, then the dens may impinge on the spinal cord and cause serious injury or death.
Hangman's fracture of the atlas
The neck is hyper extended by the noose. When the person is hanged the pars interarticularis of the axis (between the superior and inferior articular processes) is fractured. The dens can be fractured as, usually at its base. About 40% of [axial] fractures involve the dens.

If base is fractured, its blood supply is cut off and you get avascular necrosis; not good in terms of healing.

Fractures of the body heal better because the 2 fragments still have their own blood supply.
What happens if the transverse ligament of the atlas is ruptured?
The atlas can be displaced anteriorly. The posterior arch of the atlas traps the spinal cord between it and the dens.

There is some leeway for anterior displacement of the atlas because about a third of the diameter of the ring of the atlas is occupied by dens, a third by the spinal cord, and the remaining third by the soft connective tissues, meninges, and fluids (CSF).

This principle is Steele’s Rule of Thirds.

You can get displacement of the atlas of up to one third of the diameter of the ring and the patient may still be relatively asymptomatic, but once it exceeds one third, you get compression of the spinal cord.
Where can infections of the teeth, tonsils and base of the tongue travel to?
First to the lateral pharyngeal space then to the retropharyngeal space to the heart.
Horner's Syndrome
Caused by lesions on the sympathetic trunk which cut off the sympathetic innervation of the head.

Ptosis and miosis involve the internal carotid plexus because this is the way that the dilator pupillae and superior tarsal muscle are innervated.

Vasodilation and anhydorsis in the face mainly involves the plexus along the external carotid artery.

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