OCR Text |
Show 1892.] MUSCULAR ANATOMY OF AULACODUS. 523 Gastrocnemius by a muscular insertion; it recalls the femoro-caudal of Birds. The Semitendinosus arises by two heads; its flat strap-shaped tendinous insertion on to the tibia commences just after that of the gracilis. The Gluteeus medius is a powerful muscle hardly to be distinguished at its origin from the Gluteeus minimus; it is inserted along the lower margin of the femur in front of the great trochanter for a distance of 30 mm.; the insertion is partly muscular and partly tendinous; the tendinous part of the insertion is divided up into a number of more or less distinct tendinous insertions. The Gluteeus minimus is a powerful muscle difficult to distinguish from the last at its origin; it arises from the greater part of the ilium ; it becomes quite separate from the Gluteeus medius a little before the insertion on to the great trochanter. There was no trace that I could discover of a Scansorius, whose presence is mentioned in several Rodents. The Adductor magnus is not by any means a large muscle ; it is quite distinct from the other adductors; it is long and thinnish, and arises from the symphysis pubis by a tendinous origin; the upper surface of the muscle is glistening for a considerable distance after the origin. The other two Adductors form a large fleshy mass and are not readily distinguishable from each other. The Iliacus is a large muscle divided into two portions; it is inserted together with the Psoas on to the lesser trochanter. The Psoas magnus is a large muscle, also divisible into two parts ; the part which arises most anteriorly becomes tendinous on one side a couple of inches from its insertion. The Pyriformis is present. Both Obturators were present. The Rectus femoris originates by two well-defined heads, which are tendinous, though overlaid by muscular fibres; the muscle is covered anteriorly by the Vastus externus. The Gastrocnemius has the usual two heads, which take origin from two sesamoids ; the inner head is the smaller of the two. The Plantaris arises in common with the outer head of the last, and is fused with it for some way; it splits into three tendons on the sole of the foot. The Soleus is fleshy with a tendinous origin from the head of the fibula; its exposed surface is glistening; it is inserted on to the os calcis. The tendons of the Flexores tibialis and fibularis join before the latter splits into its four tendons of insertion: the tendon of the Flexor tibialis seems to be mainly concerned with the supply of the inner of the four tendons; the fourth of the four tendons of the Flexor fibularis is very much smaller than the rest, which is of course in relation to the comparatively rudimentary fifth toe ; this tendon arises from the lower surface of the conjoined tendons and not from the outer edge. |