MUSCLES OF TEE FOOT. 257 



digiti. and is covered by the plantar fascia, wliicli adheres veiy closely to the 

 posterior part of its surface, and gives origin there to some of its fibres ; it 

 conceals the flexor accessorius, -with the tendons of the flexor longus digitorum, 

 the lumbricales, and the plantar vessels and nerves. 



Varicfii's. — This muscle has been seen with only thi-ee tendons, that for the 

 little toe being absent ; or with five tendons, two to the second toe. The slip to 

 the little toe frequently arises as a small fusifonn muscle from the side of the 

 long flexor tendon, or from the flexor accessorius ; or it may arise by two heads, 

 one from the long flexor, the other from the inner tubercle of the os calcis. 



The abductor pollicis pedis muscle arises from the inner part of 

 the larger protuberance of the calcaneum, from the internal annular 

 ligament and the tendinous and fibrous structures on the inner border 

 of the foot as far forwards as the internal cuneiform bone, from the 

 septum between it and the flexor brevis digitorum, and from the plantar 

 fascia covering it. The fleshy fibres end in a tendon, which, after 

 uniting with the internal head of the flexor brevis pollicis, is inserted 

 into the inner border of the base of the first phalanx of the great toe. 



liiiations. — It is covered by the thin internal division of the plantar fascia. 

 Its deep surface is in contact with the tendons of the tibialis anticus and pos- 

 ticus, and of the long flexor muscles, with the flexor brevis pollicis. and with the 

 plantar vessels and nerves. 



Varieties. — Tlie abductor pollicis sometimes sends a slip to the base of the 

 first i^halanx of the second toe. Another slip is occasionally given to the skin of 

 the ball of the great toe. 



The abductor minimi digiti muscle has a wide origin behind, 

 from the front of both tubercles on the under surface of the os calcis, 

 from the external intermuscular septum, and from the deep surface of 

 the process of the j^lantar fascia which extends from the external 

 tubercle to the base of the fifth metatarsal bone. The fleshy fibres 

 end in a tendon, which after sliding along a smooth impression on the 

 inferior surface of the base of the fifth metatarsal bone, is inserted 

 into the external surface of the base of the first phalanx of the little toe. 



Helation.-i. — This muscle is covered by the plantar fascia. Its deep surface is 

 in contact with the external head of the flexor accessorius, the ligamentiun 

 longum plantce. the peroneus longus, and the flexor brevis minimi digiti. 



J'tj?-iet>/. — The ahductor ossis mrtafarsi mini/>ii diz/ifi is an occasional muscle 

 which arises from the external tubercle of the os calcis, and is inserted into the 

 spur-like jarocess of the fifth metatarsal bone beneath the outer margin of 

 the plantar fascia. It may be adherent to the abductor minimi digiti, and it lias 

 been seen inserted into the middle or even the anterior part of the metatarsal 

 bone. It was fii-st described as a human muscle by Wood, and it occurs nearly 

 once in every two subjects. (Wood, Macalister.) 



The Second Layer of Muscles. — The flexor accessorius and the 

 lumbricales muscles composing this layer, have been already described 

 (p. 253) with the tendons of the long flexor muscles, with which they 

 are intimately associated. 



The Third Layer of Muscles. — The flexor brevis pollicis pedis 

 arises by a fiat tendinous process from the inner border of the cuboid 

 bone and from the fibrous band sent to the cuneiform bones from tlie 

 tendon of the tibialis posticus. The muscle is single and pointed 

 behind, but ni front it divides so as to form two muscular bellies 

 which are inserted by tendons one into the inner border of the base of 

 the first phalanx in union with the abductor pollicis, the other into the 

 outer border ni union with the adductor. 



