532 



THE MUSCLES AND FASCIA. 



away at their insertion. The two layers are separated by a thin membrane, the d<< /> 

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



accessorius, the tendon of the Flexor longus hallu- 

 cis, and the Lumbricales. The long flexor tendons 

 cross each other at an acute angle, the Flexor 

 longus hallucis running along the inner side of 

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

 longus digitorum, the direction of which is ob- 

 liquely outward. 



Second Layer. 

 Flexor accessorius. Lumbricales. 



The Flexor accessorius arises by two 

 heads ; the inner or larger, which is mus- 

 cular, being attached to the inner concave 

 surface of the os calcis, and to the inferior 

 calcaneo-navicular ligament ; the outer head, 

 flat and tendinous, to the under surface of 

 the os calcis, in front of its outer 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 sur- 

 face, 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 each of the lesser toes, and is inserted 

 into the expansion of the long Extensor 

 second ia 3 y 3 er7 Muscles f the sole f the *** and base of the first phalanx of the cor- 

 responding 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 border of the cuboid bone, from the contiguous portion of the external 

 cuneiform, and from the prolongation of the tendon of the Tibialis posticus, which 



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. 



