Block 5 Anat Temp Fossa Verteb Region Ta's W Expl

The lesser petrosal nerve is a branch of the glossopharyngeal nerve (CN IX). The lesser petrosal nerve carries presynaptic parasympathetic fibers to the otic ganglion. These fibers synapse in the otic ganglion, and the postsynaptic fibers travel on the auriculotemporal nerve to innervate the parotid gland. The geniculate ganglion is the sensory ganglion of the facial nerve--it holds the cell bodies of the neurons that carry taste sensations from the anterior 2/3 of the tongue.

A patient with Horner's syndrome will have a problem with his sympathetic nervous system. This will result in miosis (pupillary constriction), ptosis (drooping eyelid), and anhidrosis (decreased sweatng on face). Mydriasis is pupillary dilation, which will not be seen in Horner's syndrome.

The internal laryngeal nerve provides sensory innervation to the larynx above the vocal cords. This nerve punctures the thyrohyoid membrane and travels with the superior laryngeal artery(branch of external carotid artery). The internal laryngeal nerve travels through the piriform recess. The external laryngeal nerve supplies motor innervation to the cricothyroid muscle and some innervation to the inferior constrictors.

Remember general sensation and taste follow two different cranial nerves on the anterior 2/3 of the tongue. Taste is mediated via CN 7 while sensation follows the V3 of Trigeminal nerve. The posterior 1/3rd of the tongue is innervated through CN 9 for sensation and taste.

the lateral pterygoids are the only muscles of mastication that open the mouth.

The lingual nerve is a branch of V3 that conveys sensation to the anterior two-thirds of the tongue. It enters the oral cavity by passing just under the mandibular third molar between the medial pterygoid muscle and the mandibular ramus. Don't get this confused with the chorda tympani that does travel with the lingual, but carries taste from the anterior two-third of the tongue

the superior thyroid artery, superior thyroid vein, and external branch of the superior laryngeal nerve run together in a neurovascular triad that originates superior to the thyroid gland and lateral to the thyroid cartilage. Because the external branch of the superior laryngeal nerve courses just deep to the superior thyroid artery, it is at risk of injury during thyroidectomy. The cricothyroid muscle is the only muscle innervated by this nerve. The remaining laryngeal muscles are innervated by the recurrent laryngeal nerves, and also provide sensory innervation to the larynx below the vocal folds. a), b), c), and e) are all innervated by the recurrent laryngeal nerve.

The inferior thyroid artery supplies the posteroinferior portion of the thyroid gland and originates off of the thyrocervical trunk. The thyrocervical trunk is a branch of the subclavian artery which originates off of the aorta on the left side and off of the brachiocephalic trunk on the right side.

The vagus nerve (CN X), which exits the skull through the jugular foramen, is the motor nerve to the pharynx and allows for swallowing.

Drooping of the left side of her face. The facial nerve (VII) runs through the parotid gland and is easily injured in parotid gland surgery. The facial nerve is responsible for innervating the muscles of facial expression, and damage to this nerve results in drooping of the face, Bell’s palsy (left side in the case). (a) and (b) would result from damage to the trigeminal nerve. The trigeminal nerve branches before exiting the skull and neither branch runs through the parotid gland, and is not easily injured in surgery of the parotid gland. (d) would result from damage to the vagus nerve, which does is not run through the parotid gland. IT exits the skull via the jugular foramen and runs through the carotid sheath. (e) this presentation is consistent with damage to the spinal accessory nerve, which is not located near the parotid gland and highly unlikely to be damaged in parotid gland surgery.

The parotid gland is innervated by CN IX, via the Otic ganglion and the auriculotemporal nerve (V3). Once the gland is stimulated it secretes serous fluid through the Stensens duct. The submandibular and sublingual glands are innervated by CN VII and secrete mucinous fluid through the Whartons and sublingual ducts, respectively.

the internal laryngeal nerve (branch of the superior laryngeal) provides sensory innervation above the vocal cords while the inferior laryngeal nerve (branch of the recurrent laryngeal) provides sensory innervation below the vocal cords.

This is a description of Frey’s Syndrome, where fibers of the auriculotemporal branch of the trigeminal nerve regenerate incorrectly; there is crossover between the sympathetic fibers supplying sweat glands of the scalp and parasympathetic fibers supplying parotid gland salivation, causing sweating over the parotid while eating. Lesions of the remainder of these nerves would not create this clinical picture.

The internal laryngeal nerve branches directly off the superior laryngeal nerve to supply sensory sensation to the larynx above the vocal cords. The second branch of the superior laryngeal nerve is the external laryngeal nerve, which provides motor innervation to the cricothyroid muscle. Below the vocal cords, sensation is provided by the recurrent laryngeal nerve. ‬‬‬‬

from the medulla, fibers from CN IX hitch hike onto the tympanic nerve to the tympanic plexus, then becomes lesser petrosal nerve to the Otic ganglion. After the otic ganglion, post-ganglionic fibers hitch hike onto auriculotemporal to the parotid gland.

The Auriculotemporal nerve is commonly damaged in fractures of the neck of the mandible, which carries parasympathetic fibers to supply the partoid gland from the Lesser petrosal branch of cranial nerve IX.

The temporalis muscle is responsible for elevating and retracting the mandible. This means that it helps in closing the jaw and pulling it backward.

The inferior thyroid artery and vein run in close proximity with the recurrent laryngeal nerve. The patient is presenting with hoarseness of voice. This should be a clear indication that the nerve which the surgeon most likely cut was a branch of the vagus nerve; more specifically the recurrent laryngeal nerve. Remember, be able to trace back your nerve roots to the original source. It's not enough to memorize the endings. This is a fair option some professors may choose when providing answer choices for mini questions (i.e., vagus n. ----> superior laryngeal n.-----> external and internal laryngeal n. etc.) The parathyroid gland is responsible for maintaining normal calcium levels in the body. These glands are small and may sometimes be mistaken for parts of the thyroid. In other words, it was a red herring in the question and you should learn to filter this type of information in question stems.

Several of the answers have incorrect pairs, while others are correct pairings but do not branch in the infratemporal region. Answer A is incorrect because chorda tympani does not branch from the lingual nerve. Rather, it joins a branch of V3 to form the lingual nerve. Chorda tympani is actually a branch of the facial nerve, but the process branching occurs will in the middle ear, not infratemporal fossa. Therefore, answer B is incorrect. The nerve to the mylohyoid does branch in the infratemporal fossa, but not from the lingual or facial nerves. It is a branch of V3 (trigeminal). Therefore, answers C and D are incorrect. The middle meningeal artery is a branch of the maxillary artery and this occurs in the infratemporal fossa. Therefore answer F is correct and E is incorrect. Lastly, the lingual artery is a branch of the external carotid artery, but this occurs more caudally (in the neck), making both G and H incorrect.

The patient is showing signs and symptoms of Reynaud's disease, which is described by overstimulation of sympathetic nerve fibers leading to a widened pupil and increase activation of sweat glands. Treatment of this disease often involves surgically induced paralysis of the stellate ganglion in order to reduce the unpleasant symptoms. Trigeminal neuralgia (A) is mostly a sensory deficit involving increase sensitivity to touch stimuli. Horner's syndrome (B) is characterized by a lack of sweating and a miotic (constricted) pupil. Answer C is incorrect because you do not want to further stimulate the sympthathetic chain for Reynaud's. Early stage Pancoast tumors (E) effects the lung in its early stages.

Cranial nerve IX, glossopharyngeal innervates the parotid gland not V3 mandibular branch of the trigeminal nerve. Yes CN IX does "hand" over the signal/fibers to V3 to reach the parotid gland, but CN IX still gets credit

The woman is complaining of pain due to thoracic outline syndrome involving her anterior scalene muscle.

The angular and ophthalmic arteries provide the primary anastamosis for the ICA on the anterior head; posteriorly, this anastamosis may be provided by the occipital and meningeal arteries. None of the remainder of the answer choices provide any anastamosis with the as regarding blood supply to the brain.‬