PELVIC GIRDLE. 79 



and forming the wrist, or carpus. Then come five cylindri- 

 cal bones which can be felt through the soft parts in the 

 palm of the hand; one for the thumb, and one for each of 

 the fingers. These are the metacarpal bones, and are dis- 

 tinguished as first, second, third, and so on, the first being 

 that of the thumb. In the thumb itself are two bones, and 

 in each finger three, arranged in rows one after the other; 

 these bones are all called phalanges. 



The Pelvic Girdle (Fig. 29). This consists of a large 

 bone, the os innominatum, Oc, on each side, which is 

 firmly fixed dorsally to the sacrum and meets its fellow in 

 the middle ventral line. In the child each os innominatum 

 consists of three bones, viz., the ilium, the ischium, and 

 pubis. Where these three bones meet and finally ankylose 

 there is a deep socket, the acetabulum, into which the head 

 of the thigh-bone fits (see Fig. 13). Between the pubic and 

 ischial bones is the largest foramen in the whole skeleton, 

 known as the doorlike or thyroid foramen. The pubic 

 bone lies above and the ischial below it. The ilium forms 

 the upper expanded portion of the os innominatum to 

 which the line drawn from Oc in Fig. 29 points. 



The Hind Limb. In this there are thirty bones, as in the 

 fore limb, bat not quite similarly arranged; there being one 

 less at the ankle than in the wrist, and one at the knee 

 not present at the elbow-joint. The thigh bone or femur 

 (a, Fig. 31) is the largest bone in the body and extends 

 from the hip to the knee-joint. It presents above a large 

 rounded head which fits into the acetabulum and, below, it 

 is also enlarged and presents smooth surfaces which meet 

 the bones of the leg. These latter are two in number, 

 known as the tibia, c, or shin-bone, and fibula, d; the tibia 

 being on the great-toe side. In front of the knee-joint is 

 the knee-cap, or patella, b. 



At the distal end of the leg-bones comes the foot, con- 

 sisting of tarsus, metatarsus, and. phalanges. The tarsus, 

 which answers to the carpus of the fore limb, is made up of 

 seven irregular bones, the largest being the heel-bone, or 

 calcaneum, h. The metatarsus consists of five bones lying 

 side by side, and each carries a toe at its distal end. In 



