lingual and chorda tympani nerves, which are much deeper and unlikely to
be at risk. The mandibular division of the mandible innervates the muscles
of mastication and exits the skull at the foramen ovale well deep to the
parotid and protected by the lateral pterygoid muscles, so losing the ability
to chew on the right side is unlikely (answer b).The hypoglossal nerve
innervates tongue muscle (answer d)from below the tongue, so is notin
jeopardy of being cut. The tensor tympani receives innervation from the
mandibular division of the trigeminal nerve as it exits the foramen ovale
which is well deep to the surgical area, thus in not in danger (answer e).
326.The answer is c.(Moore and Dalley, pp 1036, 1146.)Acoustic neu-
roma. An acoustic neuroma is a benign tumor of the Schwann cells that
myelinate the vestibular portion of the VIII cranial nerve. Even though the
tumor arises on the vestibular portion of the VIII cranial nerve, hearing loss
(answer a)is usually the first reported symptom. Tinnitus or ringing in the
ear and headaches are also frequently reported. Normally, while the
vestibular system may be disrupted (this patient reported a couple of days
of dizziness) since the vestibular system on the right side is functioning
normally and provides enough information once one is use to the loss. In
this case the tumor has started to also affect the VII cranial nerve which
controls the muscles of facial expression. Her symptoms go beyond con-
ductive hearing loss [she is also young (53) to be suffering from conductive
hearing loss]. Meniere’s disease (answer b)is an excess accumulation of
endolymph, which is usually associated with hearing loss, tinnitus and ver-
tigo (all reported in this woman), but would not be associated with any
facial paralysis. This is the second best answer. Tic douloureux (or trigem-
inal neuralgia) (answer d)is characterized by sudden pain along the dis-
tribution of the trigeminal nerve and is not a presenting problem.
327.The answer is b.(Moore and Dalley, p 1007.)You explain to the
mother that the problem could likely be corrected by cutting the lingual
frenulum. The boy is currently ”tongue-tied”. The frenulum of the tongue
limits its ability to protrude from the mouth. The inferior aspect of the
genioglossus and the geniohyoid muscles contract in order to pull the
hyoid bone forward allowing one to stick their tongue out of their mouth.
All the intrinsic and three quarters of the extrinsic muscles of the tongue
are innervated by the hypoglossal nerve (XII CN). It is very unlikely that the
XII cranial nerve never developed (answer a),since the child would then
Head and Neck Answers 457