BQNES OF LOWER LIMB 47 



tuberosities to support the condyles of the femur. The outer 

 one somewhat overhangs the shaft. On the upper aspects 

 of these are two smooth semicircular surfaces for the articular 

 menisci, and between them in the centre a rough elevation, 

 the intercondyloid spine. Where the outer tuberosity over^ 

 hangs the shaft is a small articular facet for the head of the 

 fibula. On the posterior surface of the inner tuberosity is a 

 short horizontal groove for the semimembranosus muscle. In 

 front of the lower part of the two tuberosities is a large 

 tubercle, the upper half of which is smooth and covered 

 by a bursa ; the lower, rough, for the attachment of the 

 ligamentum patellae. 



The Shaft is triangular in shape, having an anterior, internal, 

 and external borders, and internal, external, and posterior 

 surfaces. The anterior border is sharp and subcutaneous, form- 

 ing what is known as the shin. The internal surface is also 

 subcutaneous, except in its upper fourth. On the posterior 

 .surface is seen the oblique, or popliteal, line, which runs from 

 the outer tuberosity to the internal border at T:he junction of 

 the upper and middle thirds. The posterior surface is divided 

 into two parts by a vertical line dropped from the middle of the 

 oblique line. 



The Lower Extremity is expanded and becomes quadrilateral. 

 The external surface has a large articular area for the lower 

 end of the fibula, and the internal surface is continued down- 

 wards into a triangular process, called the internal malleolus,. 

 whose outer surface is confluent with the inferior surface of 

 the shaft, and articulates with the astragalus. On the posterior 

 surface just external to the malleolus there are two grooves for 

 the passage of tendons. 



Ossification. At birth the shaft is almost completely ossified, 

 and a centre has appeared in the upper extremity. Very early 

 the centre appears for the lower extremity, and the whole bone 

 is fused together by the twenty-fourth year. 



The Fibula is a long, slender bone on the outer side of the 

 leg. It articulates above with the outer tuberosity of the tibia, 

 and below with the lower end of the tibia and the outer surface 

 of the astragalus. 



