258 



MUSCLES OF THE LOWER LIMB. 



JRdations. — Tlie tendon of the flexor longus poUicLs iiins in the hiterval 

 between the heads of the short flexor. A sesamoid bone is developed in connec- 

 tion with each tendon of the short flexor. 



Fig. 199. Fig. 199. — Tjiird Layer op Plantar Muscles. 



1 , flexor Lrevis polHcls ; 2, adductor polliciE ; 3, transvei-sus 

 pedis ; 4, flexor brevis minimi digiti ; 5, .'>, part of the third 

 aud fourth dorsal interossei ; 6, C, the second and third plantar 

 interossei ; 7, tendon of the peroneus longus passing round 

 the cuboid bone to enter its groove ; 8, long plantar ligament 

 passing forwards to the ridge of the cuboid bones and spreading 

 over the groove of the peroneus tendon. 



The adductor pollicis pedis, placed obliquely 

 in the sole of the foot, and forming a thick fleshy 

 mass, arises fi'ora the tarsal extremities of the 

 third and fourth metatarsal bones, and from the 

 sheath of the peroneus longus muscle ; narrowing 

 as it passes forwards, it is inserted, conjointly 

 with the external head of the flexor brevis pollicis, 

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



Helatlon.f. — At its inner side it is connected with the 

 flexor brevis pollicis ; its deep surface rests upon the 

 second, third, and fourth metatarsal bones and the inter- 

 vening interosseous muscles. The external plantar artery 

 and nerve pass inwards beneath its outer border. 



Ydrlcfi/. — The ojyjwticm hallucls is a muscle frequently 

 found. It usually comes off as a slip from the adductor, and is inserted into the 

 metatarsal bone of the gi-eat toe. It occurs in some apes. (Macalister.) 



The ti-aixsversus pedis consists of narrow fasciculi of flesliy fibres, 

 placed transversely under cover of the flexor tendons, and arising from 

 the inner lateral raetatarso-phalangeal ligaments of the four outer toes. 

 The fibres of the muscle pass transversely inwards, and are inserted in 

 union with the adductor pollicis into the first phalanx of the great toe. 



Kchitionx. — Superficially it is crossed by the flexor tendons and by the digital 

 nerves ; its deep surface rests upon the heads of the second, thii-d, and fourth 

 metatarsal bones, the interossei muscles and the digital vessels. 



Yarhti/. — The slip from the little toe is frequently absent : absence of other 

 slips or of the entire muscle has also been recorded. (Boehmer.) 



The flexor brevis ininimi digiti arises by tendinous fibres from 

 the base of the fifth metatarsal bone, and from the sheath of the pero- 

 neus longus, and terminates in a tendon which is inserted into the base 

 and external border of the first phalanx of the little toe. 



BrJtitionx. — It is covered partly hy the abductor minimi digiti, partly by the 

 plantar fascia. It rests upon the fifth metatarsal bone, and its tendon blends at 

 its insertion with the inferior metatarso-phalangeal ligament. 



Yarirti/. — The opjwncn.t minimi dh/itl is a small additional muscle frequently 

 found at the inner border of the flexor brevis, of which, indeed, it would seem 

 to be a slip. It is always united to the flexor brevis for some distance from its 

 origin, but is inserted separately into the inner side of the anterior half of the 

 fifth metatarsal bone. 



The Fourth Layer of Muscles. — The interosseous muscles of 



tlie foot, like those of the hand, arc seven in number, tlirce plantar and 

 four dorsal ; the plantar interossei are visible only from the under side : 



