M. opponens digiti quinti.
Origin by a flat tendon from the middle of the ligament which covers the peroneal canal. It passes obliquely outward parallel to the last.
Insertion on the inner side of the shaft of the fifth metatarsal.
The two remaining muscles of the fifth digit take origin from the outer part of the ligament covering the peroneal canal. They cover the ventral surface of the shaft.
Insertion.—The lateral one is inserted into the lateral sesamoid and is therefore an abductor brevis. The medial one is inserted into the extensor tendon and is therefore an adductor longus.
C. Muscles of the Tarsus.
—M. calcaneometatarsalis (part of M. adductor minimi digiti?).—A weak muscle made up largely of tendon-fibres, some of which pass directly from origin to insertion. It may be regarded as a ligament.
Origin, the lateral and ventral surface of the calcaneus near the proximal end. It passes distad and slightly laterad outside of the quadratus plantæ.
Insertion, the lateral side of the base of the fifth metatarsal, and the adjacent surfaces of the cuboid and calcaneus.
Action.—Probably causes slight motion of the cuboid on the head of the calcaneus.