MUSCLES OF THE PELVIC LIMBS. 213 
band to the medial surface of the scaphoid and the medial 
cuneiform. It divides into four slips which diverge to the four 
toes, each ending in-a flat tendon. The slips decrease in size 
from the lateral to the medial side. The three lateral ones 
overlap one another proximally. 
fusertion.—Each tendon expands at the distal end of the 
metatarsal and is wrapped about the tendon of the deep flexor 
which perforates it. The two halves unite beneath the perforat- 
ing tendon and pass together with the perforating tendon 
through fibrous rings, the annular ligaments. One of these is 
attached to the sesamoids at the base of the phalanx. The 
other is attached to the head of the first phalanx. The tendons 
are finally inserted into the bases of the second phalanges. 
The two annular ligaments are connected by fascia so as 
.to form a continuous canal for the tendons. This canal is lined 
by a synovial membrane. Covering this canal is a more super- 
ficial layer of fascia. Before passing into the proximal annular 
ligament the two middle tendons unite each with the tendon 
of the corresponding lumbrical muscle. Each also gives off 
a branch, the lateral one on its lateral side and the medial one 
on its medial side. These branches, like those of the two 
middle ones, are inserted into the common phalangeal fascia. 
Action.—Flexor of the second phalanges of the digits. 
M. quadratus plante (called also the plantar head of the 
flexor longus digitorum) is a thin flat muscle which takes 
origin from the dorsal part of the lateral surface of the cal- 
caneus and the cuboid. Its fibres converge to a flat tendon 
which passes transversely across the flexor longus digitorum 
and beneath the flexor brevis digitorum and calcaneometatar- 
sal. 
Iusertion.—Into the medial part of the outer surface of the 
tendon of the flexor longus digitorum. 
Action.—It holds the flexor longus tendon in place. 
Mm. lumbricales.—These are six. 
Origin. —The three larger ones have origin from the outer 
surface of the expanded portion of the flexor longus digitorum 
on its distal half. Each ends in a slender tendon. 
Insertions. —The tendons unite with the divisions of the 
