REIDER PART 2
12

272 Chaptkr 7_Lower Leg, Foot, and Anklc

B

Figurę 7-36. A, Active ankle dorsiflexion. B, Passive ankle dorsiflexion.

Plantar Flexion. To assess active plantar flexion, the

patient is asked to point the foot downward as far as pos-sible (Fig. 7-37A). Passive plantar flexion may be assessed by again grasping the hindfoot, inverting the forefoot, then plantar flexing the ankle as far as possible (Fig. 7-37B). Normal plantar flexion is about 50°. An ankle that cannot even plantar flex to neutral is said to be in calcaneus.

Causes of Lost Plantar Flexion. Limited plantar flexion may be due to anterior capsular contracture following trauma or posterior joint impingement. Capsular contracture may be a nonspecific seąuela of a major ankle injury such as a fracture. Posterior impingement may be associated with chronic ankle instability or trauma to a prominent processus trigonum or os trigonum. The processus trigonum is a normal bony prominence of the posterior talus, and the os trigonum is a smali ossicle that occurs at the same location. If posterior impingement is suspccted, the examincr may test for it by quickly and sharply plantar flexing the ankle passively (Fig. 7-37B). Posterior ankle pain in response to such a maneuvcr sug-gcsts the possibility of posterior impingement.

Subtalar Joint

lnversion and Eversion. The principal motions of the subtalar joint are inversion and eversion. Active inver-sion and eversion may be roughly assessed in the seated patient (Fig. 7-38), although the motion of the heel may be morę precisely assessed with the patient lying prone.

Figurę 7-37. A, Active ankle plantar flexion. B, Passive ankle plantar flexion.

A    B