4/6 DR. R. W. SHUFELDT ON [NoV. 16, 



The patella is found encased in front in this great tendinous sheath 

 of the knee-joint, and below the apex of this sesamoid we find the 

 enveloped track of the tendon of the ambiens muscles, as it passes 

 round in front of the femoro-tibial articulation. The combined 

 tendon of the extensor femoris is finally inserted into the cnemial 

 crest of the tibial and the lateral boundaries of the summit of that 

 bone. Some of the superficial muscles on the outer side of the leg 

 are so extended as to take a certain amount of their origin from this 

 great tendinous expansion. 



In Plate XLIV. fig. 2 I have very thoroughly divided these two sub- 

 divisions of the extensor femoris, in order to show their relative size, 

 as well as their relation to each other and the surrounding structures. 



The biceps flexor cruris (Plate XLIV. fig. 1 ; fig. 2, Bi) arises by 

 carneous fibres upon quite an extensive portion of the under surface of 

 the over-curled part of the ilium behind the acetabulum, and by a long 

 tendinous slip which comes off from the free an'erior margin of this 

 part of the ilium. The fibres converge as they pass downwards, and 

 unite to form a somewhat flattened muscle. Opposite the head of the 

 tibia, the biceps terminates in a round tendon, of cord-like dimen- 

 sions, which passes through a special loop to make its way between 

 some of the muscles at the back of the leg, to become inserted on the 

 tubercle intended for it on the outer side of the superior moiety of 

 the shaft of the fibula. The loop of the biceps (Plate XLV. fig. 1,/) 

 is flat and fashioned like a delicate tendinous ribbon. Its upper end 

 arises from the side of the shaft of the femur above the external 

 condyle, while the lower end comes off from this protuberance just 

 below the insertion of the outer slip of the external head of the 

 gastrocnemius muscle. A branch of the sciatic nerve also passes 

 through this loop in companv with the tendon of the biceps. 



The seinitendinosus (Plate XLIV. figs. 1, 2, St ; Plate XLV. fig. 1, 

 St) is a marvellously well-developed muscle in this form, as is also its 

 accessory head. Its origin fills about three fourths of the nether 

 cavity formed by the posterior overarching portion of the ilium, 

 under which it arises. 



Posteriorly, the fibres forming its free margin are so arranged as 

 to create a rounded border ; the lower end of its arc terminating 

 about opposite the post-pubis of the pelvis. From this origin the 

 fibres of the semitendinosus pass downwards and forwards as a great, 

 though somewhat compressed muscle. When within rather more 

 than a centimetre's length of the shaft of the femur, they terminate 

 in an obhque tendinous raphe, which latter forms the bounding-line 

 between this muscle and the next. 



The accessory semitendinosus (Plate XLV. fig. 1, a.s.t) is com- 

 posed of coarser fibres than the muscle just described. It springs 

 from a longitudinal line occupjdng the distal half of the shaft of 

 the femur, and from the upper surface of the hinder aspect of the 

 external condyle of that bone. The fibres pass backwards and a 

 little upwards to become inserted into the tendinous raphe just 

 alluded to. 



The lower extremity of this tendinous raphe terminates, in 

 Oeococcyx, in a thin, flat, and delicate tendon, which continues down- 



