THE BONES. 89 



year. The neck ossifies by extension from the body. The Tro- 

 chanter major ossifies in the fourth year, minor in the thirteenth 

 or fourteenth. Both are first united to the head towards the 

 twenty-eighth year, the other parts soon after puberty. 



103. II. Ossa cruris, Bones of the leg. 



1. Tibia, shin-bone. 



Position : below the thigh-bone, above the foot, on the inside 

 of the Fibula, on the same border as great toe, Tibial. 



Direction : vertical. 



Shape: three-sided, prismatic; above and below enlarged. 

 The strongest and longest bone next to the femur. 



Connection: with os femoris, Fibula (immoveable) ; Astraga- 

 lus ; the Patella by ligam. Patellae. 



a. Superior extremity, caput tibia, broad, much stronger than the inferior 

 extremity. 



1. Cavitas glenoidalis interna, longer and deeper than externa. Both oval, 

 concave, for Condyli femoris divided by 



2. Eminentia intermedia, pyramidal, rather posterior, for ligam. cruciata ; sup- 

 ported by 



3. Condylus internus, behind with a horizontal groove, for the Tendon of 

 Semimembranosus, and by Condylus extern., a slight enlargement with the small 

 external superficies peroncea, for the head of the fibula. Posteriorly between 

 the condyles a deeper notch, indsura poplitea; before a triangular surface 

 with several foramina, and under that, 



4. Spina tibice, rough, for tendo communis recti, crural., vasti, externally and 

 above a tubercle, for m. tibial. anticus. 



b. Central piece; three-sided, thick, weakest in the inferior third. 

 Internal surface, above, covered by an Aponeurosis, pes anserinus, below 



only by the external skin, above broad and oblique from before inwards, infe- 

 rior fourth narrow and directed directly inwards. 



External surface, for m. tibial. ant. et extens. digit, comm., above concave, 

 below directed forwards. 



Posterior surface, for m. tibialis posticus and flex, digit, comm., above broad ; 

 with Linea obliqua, for m. Soleus, and a triangular surface, for m. poplttaus ; 

 Foramen nutritium. 



Anterior border, Crista tibia, close under the skin, sharp, rounded in the 

 inferior fourth : continuation of Spina. 



External border, for ligam. inteross., divided below. 



Internal border, obtuse, for m. sartor., gracilis et semitendinosus. 



c. Inferior extremity, basis, almost four-sided, broad ; before convex, for the 

 Extensor tendons; behind, even with a slight fos&ce, for tendo m. flex, hallucis 

 long. ; externally, a triangular fossa, Indsura fibularis, for the Fibula ; inter- 

 nally, the thick four-sided Malkolus internus. springing strongly forwards. The 

 posterior border of the internal malleolus presents an oblique fossa descending 

 from without inwards, for the tendons of tibial. post, et flex, digit, long. The 

 external surface assists in forming the inferior articular surface. This last, 

 fossa glenoidalis, is four-sided, broader externally, divided by an elevation into 



two lateral halves, and it unites with the Astragalus. 



