358 



MUSCLES OF THE FOOT. 



the first phalanx of the great toe, the others 

 are united to the outer edge of the long ten- 

 dons, with which they form the aponeurosis 

 which covers the dorsum of each toe. The 

 obliquity of this short muscle counteracts the 

 obliquity of the long extensor, ^nd it serves to 

 extend and to spread the toes, and to pull 

 them away from the great toe. 



2. Interossei dorsales vel externi. These are 

 four in number, and arise by double heads, 

 that is, they arise from both the contiguous 

 metatarsal bones, here occupying the whole of 

 the interosseal space, and thus concealing the 

 internal interossei, which are seen only in the 

 sole. Their flat tendon unites with that of the 

 long and short extensors, and is inserted into 

 the side of the bases of the first phalanges of 

 the toes in such a manner that, with internal 

 interossei, every toe has one of these little 

 muscles on each side of it, except the first toe, 

 which has two distinct muscles of its own for 

 the same action, and the little toe, which is 

 provided with a separate abductor. Their use 

 is to separate the toes, and perhaps to assist in 

 extending them. 



In the sole of the foot the inner side is 

 occupied by the muscles of the great toe, con- 

 stituting what some French writers call the 

 thenar eminence. These muscles are as fol- 

 lows: 



1. Abductor pollicis pedis. This commences, 

 by a tendinous and fleshy origin, from the tu- 

 bercle on the under and fore part of the os 

 calcis, from the ligament extending between 

 the os calcis and os naviculare, and from the 

 fascia plantaris. Its tendon unites with the 

 flexor brevis pollicis, and is inserted into the 

 internal sesamoid bone, and inner side of the 

 base of the first phalanx of the great toe. It 

 draws the great toe from the others. 



2. Flexor brevis pollicis. Lies between the 

 abductor and adductor, in contact with the me- 

 tatarsal bone. It arises, by two portions, from 

 the under and fore part of the os calcis, and 

 from the external cuneiform bone. It is united, 

 on each side, to the abductor and the adductor, 

 and is inserted with these, by a union of ten- 

 dons, into the two sesamoid bones and base of 

 the first phalanx of the great toe, having the 

 tendon of the long iiexor passing between the 

 two insertions. 



3. Adductor pollicis. This muscle, which is si- 

 tuated the most externally, or fibulad, of the mus- 

 cles of the great toe, commences by a tendinous 

 origin, from the calcaneo-cuboid ligament, and 

 from one or two of the metatarsal bones. It is 

 double at first, and then uniting, sends a tendon 

 to be fixed into the external sesamoid bone and 

 outer or fibular side of the base of the first pha- 

 lanx of the great toe, in close connexion with 

 the flexor brevis. It draws the toe towards the 

 others. The muscles of the little toe are situ- 

 ated on the outer edge of the foot, and form, in 

 that situation, a corresponding eminence, which 

 has been called the hypothenar eminence. 



1. Abductor minimi digiti. This arises from 

 the outer, under, and fore part of the os calcis, 

 and from the fascia plantaris. It forms a long 

 slender belly, and is fixed by its tendon into 



the base of the first phalanx of the little toe, 

 and head of its metatarsal bone. It flexes and 

 abducts the little toe, and, by its attachment 

 to the metatarsal bone, it strengthens the arch 

 of the foot, which indeed may be said of almost 

 all the muscles of the foot. 



2. flexor brevis minimi digiti commences 

 from the os cuboides and base of the metatarsal 

 bone of the little toe, and lying close to this 

 bone, it is inserted into the base of the first 

 phalanx. It is a very small muscle, and its 

 use is to flex the toe. 



The middle of the plantar region is occupied 

 by six muscles common to all the smaller toes. 



1. Flexor brevis digitorum, called also per- 

 Jbratus. This muscle arises, fleshy, from the 



anterior part of the protuberance of the os 

 calcis, also from the inner surface of the plantar 

 fascia, both from its central thick portion and 

 from the septa, which run between this muscle 

 and those of the great and little toes. Under 

 the metatarsus it sends off four small tendons, 

 which, entering the sheath on the under side 

 of the four outer toes, are inserted into their 

 second phalanx. Before these tendons arrive 

 at the point of insertion each of them splits, to 

 allow the passage of the tendon of the long 

 flexor, in a manner similar to what takes place 

 in the hand, and they thus have a double inser- 

 tion into the toe. The action of this muscle is 

 to flex the second joint of the four lesser toes. 



2. Flexor digitorum accessorius, or massa 

 carnca Jacobi Sylvii. This is a short muscle, 

 somewhat square in form, covered by the flexor 

 brevis digitorum. It arises, fleshy, from the 

 sinuosity of the os calcis, and tendinous from 

 the outer side of the same part; it is attached 

 anteriorly to the tendon of the flexor longus 

 digitorum, just before it divides. Its use is, evi- 

 dently, to assist the action of the long flexor. 



3. Lumbricales. These slender round mus- 

 cles are found between the tendons of the 

 long flexor of the toes ; they arise from these 

 tendons just after their division, and fix their 

 own tendon into the inner or tibial side of the 

 first phalanges of the four outer toes ; they act 

 by bending the first joint of these toes. 



4. Interossei plantar es vel interni. These 

 are three in number, smaller than the external, 

 and having their origin each from only one me- 

 tatarsal bone. Their insertion and action have 

 been mentioned when speaking of the external 

 interossei. 



5. Transversulis pedis. This little muscle 

 is situated across the heads of the metatarsal 

 bones, passing from the fibular side of the great 

 toe to the tibial side of the little one, and at- 

 tached to them all as it passes over them. It 

 goes under the tendons of the long flexors and 

 the lumbricales, or rather between them and 

 the bones. Its action is to draw the metatarsal 

 bones together, thus to consolidate, as it were, 

 and strengthen that an tero-posterior arch, which, 

 were its parallel portions allowed to spread out 

 unchecked, would be materially weakened, and 

 be less able to encounter the violent movements 

 to which the foot is liable in leaping, running, 

 &c. 



We shall now enumerate the muscles which 



