OCR Text |
Show 104 MESSRS. WATSON AND YOUNG ON THE [Jan. 14, to form a single broad tendon from which four slips are derived ; these, after perforating the superficial flexor-tendons, are inserted into the terminal phalanges of the toes. This fusion or junction of the tendons of the flexors hallucis and digitorum exists in H. striata, the Dog, and Cat, and also in the Civet. The flexor brevis digitorum (perforatus) in H. crocuta is confined to the sole of the foot, and is represented solely by tendon, a muscular belly being entirely wanting. This tendinous structure is attached posteriorly to the os calcis, and anteriorly divides into four slips, which, splitting for the passage of the corresponding deep flexor tendons, terminate on the sides of the second phalanges of their respective toes. Quite different is the arrangement in H. striata, in which the flexor brevis digitorum is described by Meckel as a prolongation of the tendon of the plantaris, receiving additional muscular fibres in the sole from the fourth metatarsal bone. The Civet presents a similar disposition, the additional muscular fibres being, however, derived from the os calcis. In the Cat a distinct muscular belly exists, springing from the tendon of the plantaris1. Museulus accessorius.-This muscle exists in H. crocuta, exceedingly small and slender. About one inch in length, it stretches from the front of the os calcis to join the tendon of the long flexor on its outer side. Meckel does not note its presence in H. striata, whilst Douglas avers its absence in the Dog. Chauveau, however, speaks of its existence as a small undeveloped muscle in both the D o g and Cat2. It exists well marked in Viverra. Lumbricales are three in number, as in the fore foot. They all spring from the tendons of the long flexor, and join those of the short. Their arrangement is as follows.-The first lumbrical arises from the superficial aspect of the deep tendon before its subdivision, and passes to the slip of the flexor brevis which is distributed to the third toe; the second arises below the first, but joins the same tendon of the flexor brevis; whilst the third arises from the point of bifurcation of the deep tendons going to the two outer toes, and is inserted into the tendon of the flexor brevis to the fourth toe. (Note.-In speaking numerically of the respective toes, we include the rudimentary hallux.) The interossei of the hind foot constitute a set of small muscular bundles, two to each toe, excluding the hallux. They all spring from the plantar aspect of the proximal extremities of the metatarsal bones, and pass upon either side of these bones to their distal ends, where they are inserted partly into the sesamoid bones and also into the extensor-tendons of the same toe; as pointed out by Meckel, they exercise principally the function of flexors. Extensor longus digitorum is, as usual, in Carnivores femoral in origin, springing from the outer surface of the external condyle. Its tendon passes, along with that of the tibialis anticus, beneath the annular ligament, and gives off three slips, which are distributed to the second, third, 1 Meckel, lo ca.n dc ifto,u rpt.h 45t1oe.s , none passing t2o Lt0hCIe cliitt%t pl>e 3o1r1 o uter |