the peronei, for example, may be attached to the tubercle of
the navicular. We have not found it necessary to employ this
procedure.

In _cases of the fourth degree_, in which the displacement and
alterations in shape of the bones constitute an insuperable bar to
correction, operative treatment may be considered, either resection of
a wedge including the talo-navicular joint or forward displacement of
the tuberosity of the calcaneus.

#Spasmodic Flat-foot.#--There are cases of flat-foot in which pain and
spasm of the peronei muscles are the predominant features. If the
spasm is not allayed by rest in bed and hot fomentations, the foot
should be inverted under an anaesthetic; and in this position it is
encased in plaster-of-Paris. Jones resects an inch of each of the
peroneal tendons about 2-1/2 inches above the tip of the lateral
malleolus; Armour and Dunn claim to have obtained better results from
crushing the peroneal nerve in the substance of the peroneus longus.

#Paralytic Flat-foot# (Fig. 155).--In typical cases this results from
poliomyelitis affecting the tibial muscles. When other groups of
muscles are affected at the same time, compound deformities, such as
pes calcaneo-valgus, are more likely to result.

[Illustration: FIG. 155.--Bilateral Pes Valgus and Hallux Valgus in a
girl aet. 15, the result of Anterior Poliomyelitis.]

In paralytic valgus the medial border of the foot is depressed and
convex towards the sole, and although the foot can readily be restored
to the normal position by manipulation, it at once resumes the valgus
attitude. The leg is wasted, the skin is cold and livid, and the ankle
is flail-like. The treatment consists in reinforcing the paralysed
tibial muscles by attaching the peronei, or a strip of the tendo
Achillis, to the scaphoid, or in bringing about an ankylosis of the
joints above and in front of the talus.

#Traumatic flat-foot# is that form which results directly from injury.
It is most often due to a fall from a height on to the feet; the
ligaments supporting the arch are ruptured, and the bones are
displaced, either at the time of the injury or later when the patient
gets out of bed. The arch can only be restored by a wedge-resection of
the tarsus. Loss of the arch may follow as a result of walking on the
everted foot after injuries about the ankle, especially a badly united
Pott's fracture; the foot may be displaced laterally and pronated, the
sole looking laterally. T