III!-. SKELETON 43 



Bones of the Limbs 



The- skc-k-ton of the arm and that of the leg are arranged on 

 the same plan, namely, with long and narrow bones, called 

 "long" bones, in each segment of the limb, small irregular 

 bones at the wrist and in the foot, and small " long " bones in 

 the fingers and toes. 



Arm. Humerus. Thigh. Femur. 



(Knee-cap Patella. ) 

 Forearm. Radius and ulna. Leg. Tibia and fibula. 



Ankle and \ _ 

 \\nst.-8 carpal bones. nce j , 7 tarsal bones. 



Hand. 5 metacarpal bones. Foot. 5 metatarsal bones. 



Fi ngcrs. Phalanges Toes. Phalanges 



3 in each finger. 3 in each toe 



2 In thumb. (except big toe which 



has 2 only). 



The long bones consist of an upper end or head, a shaft, 

 and a lower end. The ends are variously shaped according to 

 the kind of joint into which they fit. These will be best 

 described with the joints. 



Bones of the Head 



All tin- hones of the skull, except that of the lower jaw, are 

 united firmly together by the interlocking of their toothed edges 

 with one another. The skull consists of the cranium or brain 

 case and the bones of the face. 



The Cranium. The cranium consists of irregular bones 

 at the base, and of flat bones arching up forming the sides, 

 roof, back, and front. There are six of these flat bones ; 

 namely, two temporal at the temples, two parietal at the 

 sides, passing up to meet each other in the middle of the 

 roof, the frontal in front, and the occipital behind. The 

 occipital hone forms also part of the base of the skull and 

 lia- a I.UIM- hole through which the spinal cord becomes 

 continuous with the brain. On each side of this hole is a 

 smooth surface by which the bone articulates with the atlas, 



