352 



MUSCLES AXD FASCIAE. 



Relations. By its superficial surface, with, the plantar fascia. By its deep 

 surface, with the Flexor accessorius, the Flexor brevis minimi digiti, the long 

 plantar ligament, and Peroneus longus. On its inner side are the external plantar 

 vessels and nerve, and it is separated from the Flexor brevis digitorum by a ver- 

 tical septum of fascia. 



Fig. 195. Muscles of the Sole of the Foot. 

 Second Layer. 



Dissection. The muscles of the superficial layer should be divided at their origin, by inserting 

 the knife beneath each, and cutting obliquely backwards, so as to detach them from the bone ; 



. they should then be drawn forwards, in order 

 to expose the second layer, but not separated 

 at their insertion. The two layers are sepa- 

 rated by a thin membrane, the deep plantar 

 fascia, on the removal of which are seen the 

 tendon of the Flexor longus digitorum, with 

 its accessory muscle, the Flexor longus pol- 

 licis, and the Lumbricales. The long flexor 

 tendons cross each other at an acute angle, 

 the Flexor longus pollicis running along the 

 inner side of the foot, on a plane superior to 

 that of the Flexor longus digitorum. the di- 

 rection of which is obliquely outwards. 



Second Layer. 



Flexor Accessorius. 

 Lumbricales. 



TJie .Flexor Accessorius arises by two 

 heads: the inner or larger, which is 

 muscular, being attached 'to the inner 

 concave surface of the os calcis, and 

 to the calcaneo-scaphoid ligament; the 

 outer head, flat and tendinous, to the 

 under surface of the os calcis, in front 

 of its outer tuberosity, and to the long 

 plantar ligament. The two portions 

 become united at an acute angle, and 

 are inserted into the outer margin and 

 upper and under surfaces of the tendon 

 of the Flexor longus digitorum, form- 

 ing a kind of groove, in which the 

 tendon is lodged. 



Relations. By its superficial surf ace, 

 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 forwards on the inner side of each of the lesser toes, and is 

 inserted into the expansion of the long Extensor and base of the second 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 forwards, in order to expose the third layer. 



