at the base of the fifth metatarsal. Inversion of the foot is a common means
of avulsing this tendon from the tuberosity of the fifth metatarsal and is
calledJones fracturefor the doctor that causes his own fracture while dancing
around a pole. It is normally treated by placing the patient in a short walking
cast. The fibularis (peroneus)longus(answer c)passes under the tarsal arch
to insert onto the plantar aspect of the first metatarsal. The tibialis posterior
(answer e)inserts onto the navicular bone, whereas the tibialis anterior
(answer d)inserts into the first cuneiform and first metatarsal. The abduc-
tor digiti minimi (answer a)inserts onto the proximal phalanx of the fifth
toe.
489.The answer is b.(Moore and Dalley, pp 572, 711, 719.)Navicular.
The navicular bone (B)articulates with both the talus and the three
cuneiforms, which are distal. Other labeled structures are as follows: A,
talus;C,calcaneus;D,cuboid; and E,fifth metatarsal.
490.The answer is c. (Moore and Dalley, pp 514–515.)Kyphosis is an
excessive anterior curvature of the spine, usually in the upper thoracic and
lower cervical regions. Often this abnormal curvature is due to osteoporo-
sis, especially in women, but also may be due to weakening of musculature
and decrease height of the intervertebral discs. Lordosis (answer a)is an
abnormal secondary curvature of the lumbar region of the spine and often
occurs with pregnancy. Scoliosis (answer b)is abnormal lateral curvature
of the spine that often appears during adolescence. Neither rheumatoid
arthritis(answer e)nor osteoarthritis (answer d)is generally associated
with height loss in the elderly.
491.The answer is d.(Moore and Dalley, pp 586–587, 642.)The common
fibular (peroneal) nerve is the lateral terminal branch of the sciatic nerve.
After arising near the apex of the popliteal fossa, it descends on the popli-
teus muscle and winds superficially around the fibular neck. It is extremely
vulnerable in this position and is the most often injured nerve in the lower
extremity. The common fibular nerve innervates all muscles in the anterior
and lateral compartments of the leg. In addition, it provides sensory inner-
vation to the dorsum of the foot and the anterolateral surface of the legs via
the superficial and sural (answer c)/lateral sural cutaneous nerves, respec-
tively. The tibial nerve innervates plantar flexors of the posterior compartment.
The sciatic nerve (answer a)generally divides into the tibial (answer e)and
600 Anatomy, Histology, and Cell Biology