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. 



Insertion. — 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 la)^er of fascia, l^efore 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 plantae (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. 



Insertion. — 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 



