90 SPECIAL ANATOMY. 



Structure. The spongy mass of the Extremities is perforated by numerous 

 vascular foramina. 



Development. Three osseous points. In the body the first 

 appears between the thirty-fifth and fortieth days ; in the superior 

 extremity with the conclusion of the first year ; in the inferior 

 extremity in the course of the second. The union of the three 

 portions commences at the inferior extremity, and is only perfect 

 when the growth is complete, between the eighteenth and the 

 twenty-fifth year. 



104. 2. Fibula s. Per one. 



Position: upon the outer, as well as above, upon the posterior 

 side of the shin bone, on the same side as the little toe of the foot, 

 Fibula border. 



Direction : vertical, below a little external. 



Figure : thin, long, like the tibia, twisted. 



Connection : with the tibia, the astragalus ; and with the os 

 femoris by the ligam. lateralia. 



a. Superior extremity, capitulum with : superficies tibialis superior, the con- 

 cave articular surface of the Tibia ; externally, flat fossae for ligam. lateralia 

 extern, et m. biceps ; behind 5 and above the point, apex seu proc. styloideus, for 

 m. biceps. 



b. Central piece, three-sided, prismatic. External surface, grooved, for m. 

 perorueus long, et brevis, inferiorly one-fifth directed backwards. 



Internal surface, divided by a Crista, for lig. interosseum into two halves, for 

 Tibial postic., peronceus tertius, and extens. hallucis longus; below turned for- 

 wards. 



Posterior surface, above narrow, below broad and directed inwards, with 

 Foram. nutritium. Muscles: soleus, flex, hallucis longus. The borders are 

 sharp 5 the internal, for ligam. interosseum inclines forwards, the anterior out- 

 wards, the external backwards. 



c. Inferior extremity, projects beyond the articular surface of the Tibia, is 

 longer and thicker than the inferior extremity of the last. Malleolus externus : 

 external surface convex, lies close beneath the skin 5 internal surface forms 

 the articular fossa for the astragalus and unites with the Tibia ; with Tuber- 

 culum anticum et posticwn, for the ligam. tibio-Jibularia ; posterior surface, 

 grooved for the tendons of the two peroncri, with fossa malleoli externa, for ligam. 

 fibulare tali post. 



Structure. The medullary canal in the centre is very narrow ; the extre- 

 mities are spongy. 



Development. Three osseous nuclei ; the first, in the centre 

 piece, appears between the fortieth and fiftieth days, foetal; the 

 second, in the inferior extremity only, in the second year ; the 

 third, at the superior extremity, in the fifth year. The inferior 

 extremity first unites with the body, between the twentieth and 

 the twenty-fifth year. 



