foot rests on the balls of the toes. In
extreme cases, and especially when the extensors are completely
paralysed, the toes may be flexed towards the sole, and the weight is
borne on the dorsum of the foot (Fig. 146). The patient suffers from
painful corns and callosities, and from inflammation of bursae which
form over the points of pressure. When unilateral, the patient
compensates for the lengthening of the limb by flexing the knee and
throwing the limb outwards in walking. In severe cases, especially
when both limbs are affected, the patient may be dependent on
crutches.

The talus projects on the dorsum, the anterior part of its trochlear
surface escapes from the tibio-fibular socket, and the calcaneus is
drawn up so that it comes into contact with the bones of the leg (Fig.
147).

[Illustration: FIG. 147.--Skeleton of Foot from case of Pes Equinus
due to Poliomyelitis.]

Shortening of the soft parts affects chiefly the muscles inserted into
the tendo Achillis, the posterior ligament, and posterior parts of the
lateral ligaments of the ankle. The fasciae, ligaments, and muscles of
the sole of the foot are also shortened. The flexors of the toes, the
tibialis posterior, and the peroneus longus are shortened to a less
degree.

_Treatment._--Of all the deformities of the foot, pes equinus is that
most easily rectified. In recent cases a great deal may be done by
regular manipulations, and by the wearing of some corrective splint or
apparatus between times.

In well-marked cases it is necessary to lengthen the shortened
structures, and especially the tendo Achillis. When the equinus is
corrected, the excessive arching of the foot (pes cavus) and the
clawing of the toes usually disappear, but it may be necessary to
lengthen the flexor tendons, especially that of the great toe, and
also the plantar fascia.

Jones divides the tendo Achillis and the flexors of the toes
subcutaneously, and maintains the dorsiflexion by excising an oval
flap of skin from the front of the ankle.

In aggravated cases, the bones must be attacked, for example by
excising the talus. Arthrodesis of the ankle alone or along with the
mid-tarsal joint may be indicated when these joints are flail-like.
Amputation is reserved for cases which are otherwise hopeless, such as
that shown in Fig. 147.

When the deformity is compensatory to shortening of the limb, it is
usually said to be a mistake to correct the equinus. Experience shows,
howe