THE FEMUR 



99 



^■.W 



of the gastrocnemius. The external border is i:)roininent in its upper part, and 

 hears at the junction of its proximal and middle thirds the external or third tro- 

 chanter (Trochanter tertius) ; this process is curved forward, and furnishes in- 

 sertion to the tendon of the superficial gluteus muscle. At the lower part is found 

 the supracondyloid or plantar fossa (P'ossa plant aris), in which the superficial 

 flexor arises; it is bounded externally by a thick 

 rough margin, to which the outer head of the gastroc- 

 nemius muscle is attached. 



The proximal extremity (Extremitas proximalis) 

 is large and consists of the head, neck, and great tro- 

 chanter. The head (Caput femoris) is placed at the 

 inner side and is directed inward, upward, and some- 

 what forward. It is approximately hemispherical 

 and articulates with the acetabulum. It is cut into 

 internally by a deep notch, the fovea capitis, in which 

 the i:)ub()-femoral and round ligaments are attached. 

 The articular surface is surrounded b\' a distinct mar- 

 gin. The neck (CoUum femoris) is most distinct in 

 front and internally. The great trochanter (Tro- 

 chanter major) is situated externally; it presents 

 three features. The anterior part or convexity is 

 situated opposite to the head and rises little above 

 the level of the latter; it gives attachment to the 

 deep gluteus muscle, and in the fresh state its outer 

 surface is coated with cartilag(% over which a tendon 

 of the middle gluteus passes, to be inserted into the 

 crest, which is placed below and behind the convex- 

 ity. The posterior part or summit is separated from 

 the convexity by a notch; it is situated behind the 

 plane of the head and rises to a much greater height. 

 It furnishes insertion to part of the middle gluteus 

 muscle. Its posterior border is continued downward 

 as the trochanteric ridge, which forms the outer wall 

 of the trochanteric fossa. A number of foramina are 

 found in the concave area internal to the con- 

 vexity. 



The distal extremity (Extremitas distalis) is 

 large in both directions and comprises the trochlea 

 in front and two condyles behind. The trochlea 

 consists of two ridges separated by a groove, and 

 forms an extensive surface (Facies patellaris) for 

 articulation with the patella. It is very unsym- 

 metrical; the inner ridge or lip is much wider, 

 more prominent, and extends up higher than the ex- 

 ternal one, and the two converge below. The con- 

 dyles, internal and external (Condylus medialis, 

 lateralis), are separated by the deep intercondyloid 



fossa (Fossa intercondyloidea), and articulate with the condyles of the tibia and the 

 semilunar cartilages of the stifle joint. A ridge connects each condyle with the lower 

 part of the corresponding lip of the trochlea. The intercondyloid fossa lodges the 

 spine of the tibia and the crucial ligaments of the stifle joint, which are attached here. 



The condyles are obliquely placed, with their long axes directed downward, forward, and 

 inward. The articular surface of the external condyle is more strongly convex from side to side 

 than that of the inner one, and the ridge which connects it with the trochlea is much narrower. 



Fig. 66. — Frontal Section of Left 

 Femur of Horse, Anterior 

 View. 



The figure .shows that the me- 

 dullary cavity is traversed for the most 

 part by fine bony trabecular. 



