THE FEMUR, OR THIGH BONE 225 



its upper part, where it is crossed by the femoral artery. It terminates, below, 

 at the summit of the internal condyle, in a small tubercle, the adductor tubercle, 

 which affords attachment to the tendon of the Adductor magnus. To the inner 

 lip of the linea aspera and its inner pro'ongation above and below arises the 

 Vastus internus, and to the outer lip and its outer prolongation above arises the 

 Vastus externus. The Adductor magnus is attached to the linea aspera, to its 

 outer prolongation above and its inner prolongation below r . Between the Vastus 

 externus and the Adductor magnus are attached two muscles viz., the Glutens 

 maximus above, and the short head of the Biceps femoris below. Between the 

 Adductor magnus and the Vastus internus four muscles are attached the Iliacus 

 and Pectineus above, the Adductor brevis and Adductor longus below. A little 

 below the centre of the linea aspera is the nutrient foramen, the orifice of the nutrient 

 canal, which is directed obliquely upward (proximally). 



The two lateral borders of the femur are only slightly marked, the outer one ex- 

 tending from the anterior inferior angle of the great trochanter to the anterior 

 extremity of the external condyle; the inner one from the spiral line at a point 

 opposite the lesser trochanter, to the anterior extremity of the internal condyle. 

 The internal border marks the limit of origin of the Crureus muscle internally. 



The anterior surface includes that portion of the shaft which is situated between 

 the two lateral borders. It is smooth, convex, broader above and below than in 

 the centre, slightly twisted, so that its upper part is directed forward and a little 

 outward, its lower part forward and a little inward. From the upper three-fourths 

 of this surface the Crureus takes origin; the lower fourth is separated from the 

 muscle by the intervention of the synovial membrane of the knee-joint and a bursa, 

 and affords origin to the Subcrureus to a small extent. 



The external surface includes the portion of bone between the external border 

 and the outer lip of the linea aspera; it is continuous above with the outer surface 

 of the great trochanter, below with the outer surface of the external condyle; 

 from its upper three fourths arises the outer portion of the Crureus muscle. 



The internal surface includes the portion of bone between the internal border 

 and the inner lip of the linea aspera; it is continuous above with the lower border 

 of the neck, below with the inner side of the internal condyle; it is covered by the 

 Vastus internus muscle. 



Lower or Distal Extremity. The lower extremity, larger than the upper, 

 is of a cuboidal form, flattened from before backward, and divided into two large 

 eminences, the condyles, by an interval which presents a smooth depression in 

 front called the trochlea (fades patellaris), and a notch of considerable size behind 

 the intercondyloid notch (fossa intercondyloidea). The external condyle (condylus 

 lateralis) is the more prominent anteriorly, and is the broader both in the antero- 

 posterior and transverse diameters. The internal condyle (condylus medialis) is 

 the longer, and more prominent inferiorly. This difference in the length of the 

 two condyles is only observed when the bone is perpendicular and depends upon 

 the obliquity of the thigh bones, in consequence of their separation above at the 

 articulation with the pelvis. If the femur is held obliquely, the surfaces of the 

 two condyles will be seen to be nearly horizontal. The two condyles are directly 

 continuous in front, and form a smooth, trochlear surface, the trochlea. The 

 trochlea and the inferior surface of the condyles constitute the articular surface 

 of the lower end of the femur, and are covered by hyaline cartilage in the recent 

 state. The trochlea articulates with the patella. It presents a median groove, 

 which extends downward and backward to the intercondyloid notch; and two 

 lateral convexities, of which the external is the broader, more prominent, and pro- 

 longed farther upward upon the front of the outer condyle. The external border 

 of this articular surface is also more prominent, and ascends higher than the 

 internal one. The inferior surfaces of the condyles are convex from side to side 



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