206 



relations : 



Insertion 

 of tendon 

 of flexor 

 hallucis ; 



relations ; 



use on first 



and other 

 toes. 



Dissect 

 third layer 

 of muscles. 



Muscles of 

 third layer. 



Flexor 

 brevis 

 hallucis : 



origin ; 



insertion ; 



DISSECTION OF THE FOOT. 



foot, and contribute slips to the pieces of that tendon going to th 

 second, third and fourth digits. 



The muscle may be bifurcated behind, and the heads of origii 

 separated by the long plantar ligament. On it lie the extema 

 plantar vessels and nerve; and the muscles of the first layei 

 conceal it. 



Action. By means of its offsets to the tendons of certain digit* 

 the muscle helps to bend the toes ; and from its position on the 

 outer side of, and behind the long flexor to which it is united, it 

 will oppose the inward pull of that muscle, and enable it to bend 

 the toes more directly backwards. 



The tendon of the FLEXOR LONGUS HALLUCIS (fig. 77, c) is 

 deeper in the sole of the foot than the flexor longus digitorum : 

 taking a straight course to the root of the great toe, it enters the 

 digital sheath, to be inserted into the base of the last phalanx. 

 It is united to the long flexor tendon by a strong tendinous process, 

 which, joined by bands of the accessorius, is continued into the 

 pieces of that tendon belonging to the second and third toes. 



Beneath the internal annular ligament this tendon lies in a groove 

 on the back of the astragalus : in the foot it first occupies a similar 

 groove on the under-surface of the sustentaculum tali, and then lies 

 over the flexor brevis hallucis. 



Action. For the action of this muscle on the great toe, see 

 p. 193. Through the slip that it gives to the tendons of the common 

 flexor going to the second and third toes, it will help to bend those 

 digits with the great toe. 



Dissection (fig. 78, p. 208). For the dissection of the third 

 layer of muscles, the accessorius and the tendons of the long flexors 

 are to be cut through near the calcaneum, and turned towards the 

 toes. While raising the tendons, the external plantar nerve and 

 artery are not to be interfered with ; and small nerves and vessels 

 to the outer three lumbricales are to be looked for. Afterwards the 

 areolar tissue is to be taken from the muscles now brought into view. 



THIRD LAYER OF MUSCLES (fig. 78). Only the short muscles 

 of the great and little toes enter into this layer. On the metatarsal 

 bone of the great toe the flexor brevis hallucis lies, and external to 

 this is the adductor obliquus hallucis ; on the metatarsal bone of 

 the little toe is placed the flexor brevis minimi digiti. Crossing 

 the heads of the metatarsal bones is the adductor transversus 

 hallucis. 



The fleshy masses between the adductor obliq_uus and the short 

 flexor of the little toe consists of the interosseous muscles of the 

 next layer. 



The FLEXOR BREVIS HALLUCIS (flexor brevis pollicis pedis, 

 fig. 78, A) arises behind by two tendinous slips, one of which is 

 fixed to the inner side of the cuboid bone (fig. 76, p. 201), while 

 the other is prolonged from the tendon of the tibialis posticus. 

 Near the front of the first metatarsal bone the fleshy belly divides 

 into two heads, which are inserted into the sides of the base of 

 the metatarsal phalanx. 



