lateral regions of the face including the forehead, eyelids, and middle ear.
Superficial and deep cervical nodes (answer c)receive lymph from other
nodes including the parotid and retroauricular. Buccal lymph nodes
(answer e)drain the cheeks and sides of the nose.
277.The answer is c.(Moore and Dalley, pp 919, 923–925.)Cerebrospinal
fluid formed in the choroid plexus circulates in the subarachnoid space
and is absorbed by the venous sinuses through the arachnoid villi, some of
which project into the superior sagittal sinus. Cerebrospinal fluid protects
the nervous system from concussions and mechanical injuries and is
important for metabolism. It circulates slowly through the ventricles of the
brain and through the meshes of the subarachnoid space.
278.The answer is b.(Moore and Dalley, pp 979–980.)The infratemporal
fossa communicates directly with the orbit via the inferior orbital fissure
and the pterygopalatine fossa. The fissure normally carries branches of the
maxillary nerve (V 2 ) and branches of the infraorbital vessels. The optic
canal(answer a)and superior orbital fissure (answer e)open into the
middle cranial fossa and carry the optic nerve (CN II) and the oculomotor
(CN III), trochlear (CN IV), and abducent (CN VI) nerves, respectively. The
pterygoid canal (answer c)connects the middle cranial fossa with the
pterygopalatine fossa. The Vidian nerve traverses the pterygold canal on its
way to the pterygopalatine ganglion. The ethmoidal sinuses (answer d)are
mucosa-lined cavities within the ethmoid and adjacent bones. They drain
into the nasal cavity.
279.The answer is a.(Moore and Dalley, pp 906–907.)A mnemonic
device for remembering the order in which the soft tissues overlie the cra-
nium is SCALP: Skin, Connective tissue, Aponeurosis, Loose connective
tissue, and Periosteum (answer d).The scalp proper is composed of the
outer three layers, of which the connective tissue contains one of the rich-
est cutaneous blood supplies of the body. The occipitofrontal muscle com-
plex inserts into the epicranial aponeurosis, which forms the intermediate
tendon of this digastric muscle (answer e).This structure, along with the
underlying layer of loose connective tissue, accounts for the high degree of
mobility of the scalp over the pericranium. If the aponeurosis is lacerated
transversely, traction from the muscle bellies will cause considerable gaping of
the wound. Secondary to trauma or infection, blood or pus may accumulate
Head and Neck Answers 437