396 



HUMAN ANATOMY. 



Sarcoma of the fibula attacks the upper end in the great majority of cases. 

 Osteophytes are not infrequent upon the median margin of the shaft above the lower 

 end. 



Landmarks. — In extension of the leg the position of the head of the fibula is 

 indicated by a depression on the posterior part of the outer surface of the leg a little 

 below the level of the tibial tubercle, corresponding to the interval between the 

 tendon of the biceps above and the peroneus longus below. The head is subcu- 

 taneous and may be distinctly felt there. In flexion it projects above the surround- 

 ing surfaces and may be seen. The insertion of the biceps may show as a rounded 

 prominence at the base of the styloid process. The synovial membrane of the knee 

 descends to a point just above the upper level of the head. The upper half of the 

 fibula is so covered by muscles that its outline cannot be recognized distinctly by 

 palpation. In the lower half it may be felt through the muscles. Its lower fifth lies 



between the tendons of the peroneus tertius and 

 Fig. 411. those of the peroneus longus and peroneus 



brevis, and is subcutaneous, as is the malleolus. 

 The relation of the plane of the shaft to that of 

 tlfe tibia should be remembered, as should the 

 plane of the external to that of the internal mal- 

 leolus (page 390 j. The tip of the external 

 malleolus is from twelve to eighteen millimetres 

 (one-half to three-quarters of an inch) nearer to 

 the heel than that of the internal malleolus. The 

 whole malleolus, viewed from without inward, 

 is in the mid-line (antero-posteriorly) of the 

 ankle-joint. It becomes abnormally prominent 

 in cases of atrophy of the peroneal muscles, 

 particularly of the peroneus longus. 



m 



%im 



Aiit. super, tibio-' 

 fibular ligaments 



/ 



Interosseous - 

 membrane 



Antero-internal 

 surface 



Anterior border- 



\l' 



CONNECTIONS OF THE TIBIA AND 

 FIBULA. 



,1 



These are the superior and inferior joints 

 and the interosseous membrane. 



The Superior Tibio-Fibular Articu- 

 lation ' (Fig. 411). — The cartilage-covered ar- 

 ticular surfaces already described vary greatly 

 both in direction and in the nature of their 

 curves. Perhaps the more ordinary arrange- 

 ment is for the tibial facet to be concave in a 

 horizontal and convex in a vertical plane ; but 

 the converse may occur, and there are many 

 intermediate forms. The synovia/ sac extends 

 upward behind and may communicate with the 

 knee-joint. The capsule is very strong, except 

 below, and especially so at the outer side where 

 the long external lateral ligament of the knee 

 is incorporated with it. The anterior and pos- 

 terior stiperior tibio-fibiilar ligaments "^ are strong 

 fibres, strengthening the capsule and passing 

 outward and slightly downward from the tibia 

 to the fibula. 



The interosseus membrane^ (Fig- 411) 

 extends from the head of the fibula down along 

 the interosseous ridges of both bones till these 

 split. Its fibres run in the main downward 



and outward, but in the upper part many run downward and inward. There is a 



large opening at the top above the membrane or through it. 



The Inferior Tibio-Fibular Articulation* (Fig. 411). — This joint is essen- 



' Articulatio tibiofibularis. " Ligg. capituli fibulae anterius et posterius ^ Memb. interossea cruris.  Syndesmosis 

 tiblofibulare. 



ftnt. infer, libio-fibular, 

 ligament 



Tibio-fibular ligaments from before. 



