288 THE SKELETON. 



directed forward and a little outward, its lower part forward, and a little inward. 

 To the upper three-fourths of this surface the Crureus is attached ; the lower 

 fourth is separated from the muscle by the intervention of the synovia! 

 membrane of the knee-joint and a bursa, and affords attachment 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 ; to its upper three-fourths is attached 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 Yastus internus muscle. 



The Lower Extremity, larger than the upper, is of a cuboid form, flattened from 

 before backward, and divided into two large eminences, the condyles (xovoy/oc, 

 a knuckle), by an interval which presents a smooth depression in front called the 

 trochlea, and a notch of considerable size behind the inter condyloid notch. The 

 external condyle is the more prominent anteriorly, and is the broader both in the 

 antero-posterior and transverse diameters. The internal condyle is the narrower, 

 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, which articulates with 

 the patella. It presents a median groove, which extends downward and back- 

 ward to the intercondyloid notch ; and two lateral convexities, of which the 

 external is the broader, more prominent, and prolonged farther upward upon the 

 front of the outer condyle. The external border is also more prominent, and ascends 

 higher than the internal one. The intercondyloid notch lodges the crucial liga- 

 ments ; it is bounded laterally by the opposed surfaces of the two condyles, and in 

 front by the lower end of the shaft. 



Outer Condyle. The outer surface of the external condyle presents, a little 

 behind its centre, an eminence, the outer tuberosity ; it is less prominent than the 

 inner tuberosity, and gives attachment to the external lateral ligaments of the 

 knee. Immediately beneath it is a groove which commences at a depression a 

 little behind the centre of the lower border of this surface : the front part of this 

 depression gives origin to the Popliteus muscle, the tendon of which is lodged in 

 the groove during flexion of the knee. The groove is smooth, lined with synovia! 

 membrane in the recent state, and runs to the posterior extremity of the condyle. 

 The inner surface of the outer condyle forms one of the lateral boundaries of the 

 intercondyloid notch, and gives attachment, by its posterior part, to the anterior 

 crucial ligament. The inferior surface is convex, smooth, and broader than that 

 of the internal condyle. The posterior extremity is convex and smooth : just 

 above the articular surface is a depression for the tendon of the outer head of the 

 Gastrocnemius, above which is the origin of the Plantaris. 



Inner Condyle. The inner surface of the inner condyle presents a convex 

 eminence, the inner tuberosity, rough for the attachment of the internal lateral 

 ligament. The outer side of the inner condyle forms one of the lateral boundaries 

 of the intercondyloid notch, and gives attachment, somewhat posteriorly, to the 

 posterior crucial ligament. Its inferior or articular surface is convex, and 

 presents a less extensive surface than the external condyle. Just above the articular 

 surface of the condyle, behind, is a depression for the tendon of origin of the inner 

 head of the Gastrocnemius. 



Structure. The shaft of the femur is a cylinder of compact tissue, holloAved 

 by a large medullary canal. The cylinder is of great thickness and density in the 

 middle third of the shaft, where the bone is narrowest and the medullary canal 

 well formed ; but above and below this the cylinder gradually becomes thinner, 



