266 



THE MUSCLES OF THE LOWER LIMB. 



the accessorius. It has also been seen replacing the latter muscle. It rarely sends a slip 

 to the flexor hallucis tendon. Gries describes an accessory slip from the tibialis anticus, which 

 joined the flexor digitorum at the ankle. 



Intimately connected with the tendon of the flexor longus digitorum are the 

 flexor accessorius and the lumbricales muscles, which, although they are situated 

 in the foot, may be most conveniently described in this place. 



The flexor accessorius arises by two heads, the internal and larger of which is 

 fleshy, and is attached to the inner surface of the calcaneum, while the external, flat, 

 narrow, and tendinous, is attached to the outer surface of the calcaneum a little in 



Fig. 259. SECOND LAYER OF MUSCLES OP THE SOLE. J 



b, tendon of flexor longus digitorum ; c, tendon of flexor longus 

 hallucis ; e, long plantar ligament ; 2, tendon of flexor brevis digi- 

 torum to second toe, cut short ; 4, flexor accessorius ; 5, first lum- 

 bricalis ; 6, 6, flexor brevis hallucis ; 9, flexor brevis minimi digiti ; 

 10, third plantar interosseous muscle. 



front of the external tubercle, and to the long plantar 

 ligament. These origins united form a muscular mass 

 which is inserted into the external border and upper 

 surface of the tendon of the flexor longus digitorum. 



Varieties. The outer head of the muscle is often want- 

 ing : absence of the whole muscle is recorded. The number 

 of digital tendons to which the fibres of the accessorius 

 can be followed is subject to considerable variation. Most 

 frequently offsets are sent to the second, third and fourth 

 toes ; in many cases however to the fifth as well ; occasion- 

 ally to two toes only. More rarely a slip joins the tendon of 

 the flexor hallucis, and the muscle has been seen to end 

 entirely on that tendon. 



The lumbricales muscles, four in number, arise 

 from the tendons of the flexor longus digitorum at 

 their point of division, each being, with the exception 

 of the most internal, attached to two tendons. They 

 pass forwards to the inner sides of the four outer 

 toes, each muscle ending in a tendon, which is inserted 



into the expansion of the extensor tendon on the dorsum of the first phalanx of 



the toe. 



Varieties. Absence of one or more of the lumbricales has been observed ; also doubling 

 of the third and fourth. The insertion of these muscles frequently takes place, partly or 

 wholly, into the first phalanges. There are sometimes small bursse between the tendons and the 

 bases of the first phalanges. 



Relations. In the sole of the foot the tendons of the flexor longus digitorum, together 

 with the flexor accessorius and the lumbricales, are covered by the abductor hallucis and 

 flexor brevis digitorum, the hinder part of the external plantar vessels and nerve being placed 

 between. They lie over the tendon of the flexor longus hallucis, the adductor obliquus and 

 adductor transversus hallucis, the interosseous muscles, and the plantar arterial arch. 



The flexor longus hallucis muscle (fl. long, pollicis pedis) arises from the 

 lower two-thirds of the posterior surface of the fibula, from the intermuscular septum 

 between it and the peronei, and from the aponeurosis common to it and the flexor 

 longus digitorum, which covers the tibialis posticus. The muscular fibres, passing 

 obliquely backwards and downwards, end in a tendon on the posterior surface of the 

 muscle. This tendon traverses a groove on the lower end of the tibia, on the back 



