446 



THE MUSCLES AND FASCIA 



away at their insertion. The two layers are separated by a thin membrane, the deep plantar 

 fascia, on the removal of which is seen the tendon of the Flexor longus digitorum, the Flexor 

 accessorius, the tendon of the Flexor longus hallucis, and the Lumbricales. The long flexor 



tendons diverge from each other at an acute angle ; 

 the Flexor longus hallucis runs along the inner 

 side of the foot, on a plane superior to that of the 

 Flexor longus digitorum, the direction of which is 

 obliquely outward. 



Second Layer. 

 Flexor accessorius. Lumbricales. 



The Flexor accessorius arises by two 

 heads, which are separated from each other 

 by the long plantar ligament: the inner or 

 larger, which is muscular, being attached 

 to the inner concave surface of the os calcis 

 below the groove which lodges the tendon 

 of the Flexor longus hallucis ; the outer 

 head, flat and tendinous, to the outer surface 

 of the os calcis, in front of its lesser tubercle, 

 and to the long plantar ligament ; the two 

 portions join at an acute angle, and are 

 inserted into the outer margin and upper 

 and under surfaces of the tendon of the 

 Flexor longus digitorum, forming a kind of 

 groove in which the tendon is lodged. 1 



Relations. By its superficial surface, 

 with the muscles of the superficial layer, 

 from which it is separated by the external 

 plantar vessels and nerves ; by its deep 

 surface, with the os calcis and long 

 calcaneo-cuboid ligament. 



The Lumbricales are four small muscles 

 accessory to the tendons of the Flexor 

 longus digitorum : they arise from the 

 tendons of the long Flexor, as far back as 

 their angle of division, each arising from 

 two tendons, except the internal one. 

 Each muscle terminates in a tendon, 

 which passes forward on the inner side 

 of the .four lesser toes, and is inserted into 

 the expansion of the long Extensor tendon 

 on the dorsum of the first phalanx of the 

 corresponding toe. 



Dissection. The flexor tendons should be divided at the back part of the foot, and the 

 Flexor accessorius at its origin, and drawn forward, in order to expose the third layer. 



Third Layer. 



Flexor brevis hallucis. 

 Adductor obliquus hallucis. 

 Flexor brevis minimi digiti. 

 Adductor transversus hallucis. 



The Flexor brevis hallucis arises, by a pointed tendinous process, from the 

 inner part of the under surface of the cuboid bone, from the contiguous portion of 

 the external cuneiform, and from the prolongation of the tendon of the Tibialis 



1 According to Turner, the fibres of the Flexor accessorius end in aponeurotic bands, which con- 

 tribute slips to the second, third, and fourth digits. 



FIG. 262. Muscles of the sole of the 

 Second layer. 



foot. 



