282.The answer is b.(Moore and Dalley, pp 911–913.)The superior oph-
thalmic vein drains the region of the paranasal sinuses and is directly con-
nected with the cavernous sinus although blood flow is normally away from
the brain. The pterygoid venous plexus (answer a)communicates with the
cavernous sinus via the ophthalmic veins. The frontal emissary vein (answer
c)communicates with the superior sagittal sinus via the foramen cecum. The
basilar venous plexus (answer d)communicates with the inferior petrosal
sinus. The parietal emissary vein (answer e)also communicates with the
superior sagittal sinus.
283.The answer is c.(Sander, pp 126–129.)Neural crest cells from cra-
nial regions of the neural tube migrate into the presumptive pharyngeal
arches and give rise to many structures of both the viscerocranium and
neurocrania. Intermediate mesoderm (answer a)never forms in the cranial
region. Also, somites never develop past the initial stage (somitomere), but
do give rise to some mesodermal derivatives of the head including the
bones at the base of the skull (visceral chondrocranium). Cervical somites
(answer b)only contribute minimally. In the cranial region, the lateral
plate mesoderm forms a solid core. It is notdivided into somatic (answer d)
and splanchnic (answer e)portions separated by a coelom.
284.The answer is a.(Moore and Dalley, pp 945–946.)The palpebral por-
tion of the orbicularis oculi muscle (innervated by the zygomatic branch of
the facial nerve) produces the blink, whereas the orbital portion (answer e)
is involved in “scrunching” the eye shut. The buccal branch of the facial
nerve innervates muscles of facial expression (including the buccinator
muscle) between the eye and the mouth, whereas the buccal branch of the
trigeminal nerve (answer b)is sensory. The levator palpebrae superioris
muscle(answer c),which elevates the upper eyelid, is innervated by the
oculomotor nerve, whereas the involuntary superior tarsal muscle (answer
d)is supplied by sympathetic nerves.
285.The answer is b.(Moore and Dalley, pp 919–920, 967.)The head CT
findings were consistent with subdural hematoma. This is the most likely
finding. Falls in older adults (while 62 many not be old for those young at
heart) that do notproduce skull fracture may still provide enough force to
cause the brain to move in relationship to the meningeal layers causing
Head and Neck Answers 439