and the vagus nerve. Answers aandbare notcorrect because the carotid
sheath contains the vagus, notthe sympathetic chain, northe phrenic nerve
(answers c and d).The internal carotid artery (which has a palpable pulse)
is medial and the internal jugular vein, into which you insert your cardiac
catheter, is just lateral within the carotid sheath.
323.The answer is d.(Moore and Dalley, pp 1095–1096.)The food is
most likely stuck in the laryngeal pharynx, so you must produce an alter-
native airway below the glottis, which reflexly closes. Locations around the
hyoid bone (answers a and b)and above the laryngeal notch (answer c)are
above the blockage and would notget air into the lungs. The isthmus of the
thyroid gland generally lies in front of the second and third tracheal ring
(answer e),and because it is so highly vascular, it is notan ideal location
for an emergency airway. An additional alternative location for an emer-
gency airway would be the jugular notch, but is notpreferred because of
the occurrence of a thyroid ima artery below the isthmus, in a small per-
centage of the population.
324.The answers is b.(Sadler, pp 262–264.)A, C, E, G, and I denote the
first, second, third, fourth, and sixth branchial arches, respectively. B, D, F,
H, and J denote the first, second, dorsal third, ventral third, and fourth
branchial pouches, respectively. See the following table.
Head and Neck Answers 455