THE FK.Vrff, OR THIGH-BONE. 



285 



OBTURATOR INTERNUS 



nn i GEMCLLI. 



PYRIFCHMI5. 



Fi<;. J13. Right femur. Anterior surface. 



half is increased by the thicken- 

 ing of the lower edge, which slopes 

 downward to join the shaft at the 

 lesser trochanter, so that the outer 

 half of the neck is flattened from 

 before backward, and its vertical 

 diameter measures one-third more 

 than the antero-posterior. The inner half is 

 smaller and of a more circular shape. The 

 anterior surface of the neck is perforated by 

 numerous vascular foramina. The posterior 

 x/i /-face is smooth, and is broader and more 

 concave than the anterior ; it gives attachment 

 to the posterior part of the capsular ligament 

 of the hip-joint, about half an inch above the 

 posterior intertrochanteric line. The superior 

 border is short and thick, and terminates exter- 

 nally at the great trochanter ; its surface is per- 

 forated by large foramina. The inferior border, 

 long and narrow, curves a little backward, to 

 terminate at the lesser trochanter. 



The Trochanters (-ooydto. to run or roll) are 

 prominent processes of bone which afford lever- 

 age to the muscles which rotate the thigh on its 

 axis. They are two in number, the great and 

 the lesser. 



The Great Trochanter is a large, irregular, 

 quadrilateral eminence, situated at the outer 

 side of the neck, at its junction with the upper 

 part of the shaft. It is directed a little out- 

 ward and backward, and in the adult is about 

 three-quarters of an inch lower than the head. 

 It presents for examination two surfaces and 

 four borders. The external surface, quadri- 

 lateral in form, is broad, rough, convex, and 

 marked by a prominent diagonal line, which 

 extends from the posterior superior to the 

 anterior inferior angle ; this line serves for the 

 attachment of the tendon of the Gluteus medius. 

 Above the line is a triangular surface, some- 

 times rough for part of the tendon of the same 

 muscle, sometimes smooth for the interposition 

 of a bursa between that tendon and the bone. 

 Below and behind the diagonal line is a smooth, 

 triangular surface, over which the tendon of the 

 Gluteus maximus muscle plays, a bursa being 

 interposed. The internal surface is of much 

 less extent than the external, and presents at 

 its base a deep depression, the digital or tro- 

 chanteric fossa, for the attachment of the tendon 

 of the Obturator externus muscle, and in front 

 of this an impression for the attachment of the 

 Obturator internus and Gemelli. The superior 

 border is free; it is thick and irregular, and 

 marked near the centre by an impression for 

 the attachment of the Pyrifoi mis. The inferior 

 border corresponds to the point of junction of 



