30 ELEMENTARY PHYSIOLOGY 



The phalanges (Gr. phalanx, a line of soldiers ; a rank) of the 

 fingers are united to the metacarpal bones. There are three of 

 these in each finger and two in the thumb, making a total of 

 fourteen for each hand. 



The bones of the lower extremities are : 



Pelvic or hip bones. 



Femur or thigh-bone. 



Patella or knee-cap. 



Tibia or shin-bone j h fe f fa , 



Fibula or splint-bone. \ 



Tarsal or ankle-tones. 



Metatarsal or instep- bone?. 



Phalanges or toe-bones. 



The pelvic or hip-bones are also called the ossa innominata 

 or innominate bones (Lat. in, not : and nomen, a name). If we 



Fig. 33. Pelvis and Sacrum, seen from before. 



i, sacrum ; 2, ilium ; 3, ischium ; 4, pubis ; 5, acetabulum. 



examine these in the skeleton of a young child, we find that each 

 os innominatum is composed of three distinct parts, which meet at 

 a deep cup-like depression called the acetabulum (Lat., a cup for 

 holding vinegar). The broad upper portion is called the ilium 

 (Gr. eileo, I twist) ; the lower part, the ischium (Gr. ischion, the 

 hip) ; and that portion which is joined to the other innominate 

 bone, the pubis. 



The acetabulum receives the rounded head of the thigh bone. 

 The bones of the pelvis are supported like a bridge on the legs as 

 pillars, and serve in turn as a support for the internal organs of 

 the abdomen or lower part of the trunk. 



