66 ANATOMY AND PHYSIOLOGY 



junction of the neck and shaft are the two trochanters the 

 trochanter major on the lateral side, and the Irochanter minor on 

 the medial and posterior side. The lower extremity presents two 

 condyles projecting downward, the medial and the lateral. The 

 medial is slightly longer, the lateral slightly broader of the two; 

 the deep notch between them is called the intercondyloid notch or 

 fossa. There is a projection from the side of each condyle called 

 the medial and the lateral epicondyle. 



The shaft has a prominent posterior border called the linea 

 aspera. This divides lower down into two lines running to the 

 condyles and enclosing a smooth triangular space called the pop- 

 liteal space, or plane of the femur. The other borders are not plainly 

 seen. 



THE LEG (FIG. 60) 



Tibia. A long bone in the medial side of the leg. Its upper 

 extremity is the head, which presents two condyles, medial and 

 lateral, having shallow depressions on the top to bear the 

 condyles of the femur. Between these depressions is the inter- 

 condyloid eminence, or spine of the tibia. The tuberosity of the 

 tibia is a large elevation in front, just below the head. The lower 

 extremity has a projection downward from its medial surface called 

 the medial malleolus, which helps to form the ankle-joint. 



The shaft has a prominent anterior border called the crest 

 or shin, which is plainly felt under the skin. This border and the 

 medial surface are both called subcutaneous because no muscles 

 cover them. 



Fibula. A long bone, in the lateral side of the leg, slender and 

 easily broken. Its upper extremity is the head, which has a short 

 styloid process pointing upward. The lower extremity is the lateral 

 malleolus, which helps to form the ankle-joint. 



Note. The space between the tibia and fibula is called the interosseous 

 space, and is occupied by interosseous membrane. 



The lower extremities of these two bones form the prominences 

 at the side of the ankle known as the ankle-bones; they are the 

 medial and the lateral malleoli, which, being subcutaneous, are 

 especially exposed to blows. 



Special notes. Observe that the heads of all three bones are proximal; 

 that the fibula does not form any part of the knee-joint ; that the nutrient 

 foramina all run from the knee. 



