TIII: rusri-:i;n>i; /./v/;s. U7 



Hi lot ion*. -The glutcal aponeurosiH is prolonged over tho external 



sin face of the long vastus, becomes increased in thickness, and is more or less 



cla>tic; it strongly adheres to this muscle, and superiorly gives attachment 



to a great number of its muscular fasciculi. Inwards, tho long vastus 



mis: To the aponeurosis of the superficial glutens, which separates it, 



lor the most part, from the principal gluteus and the trochantt r ; to tin-deep 



of the fascia lata, which isolates it from tho external vastus; to the 



.r face of the patella, over which it glides by means of a small 



synovial bursa, before becoming inserted ; to tho external muscles of the 



to tho sciatic nerves; to the great adductor of tho thigh, and to the 



seiiiinieiulirano.sus. Inferiorly, the semiteiidinosus is related to its internal 



and more superiorly, it is in contact with the posterior border of this 



muscle, whose sacro-ischiatic insertions it covers by its upper extremity. 



.1.7,'..;;. Tho two portions of the long vastus do not act in the same 

 manner, and in this respect they are essentially distinct. The principal 

 division, pulling the patella oiitwards and the femur backwards, is an 

 abductor of the entire limb, and an extensor of the thigh ; while the posterior 

 portion merely determines the flexion of the leg and the tension of the tibial 

 aponeurosis. 1 



If the leg be the fixed point, this muscle, in contracting, causes the 

 pelvis to swing on the head of the femur, and in this way it plays an 

 important port in rearing. 



2. Semitendinosus. (Figs. 129, 10 ; 130, 14.) 



mi/ing. Ischio-tibialis medius or posticus Girard. (Posterior sacro-itchio- 

 Leyh. Percivall describes this and the next muscle by the name of adductor 



Situation Extent Direction. This muscle is situated behind the pre- 

 ceding, and, like it, extends from the sacral spine to the leg, describing a 

 curve whose convexity is posterior. 



Vhm FI mi Structure. Less considerable than the long vastus, it 

 is elongated from above to below, bifid at its superior extremity, thick and 

 pri.-mutie, but nevertheless compressed on both sides. Its muscular fibres 

 I a pal.-red colour, ore parallel to each other, and follow the general 

 direction of the muscle ; they terminate, iuferiorly, on an aponeurosis and on 

 a tlattened tendon. 



Atfn< -/nut uts. This muscle arises, above, by one of its branches from the 

 sacral spine and the sacro ischiatic ligament, in common with tho long vastus; 

 hv the other branch, which is tho shortest, from the ischiatic tuberosity. 

 Its inferior aponeurosis is confounded with that of the tibia ; tho tendon 

 glides over tho internal surface of the tibia, and is inserted into its anterior 



/,',/,(/;,. ;;x. Its sacro-ischiatic branch is covered by tho gluteal aponeurosis, 



and c..v.-i> the long vastus. For the remainder of its extent, it responds: 



riorly,to that aponourosis ; anteriorly, to the sciatic nerv. s ; externally. 



t.. the ].,ng vastus and gastrocnemius ; internally, to the semimembranosus 



and the long adductor of the thigh. 



.1 ./;,. It is a flexor of tho leg, and tensor of the tibial apoueurosis, 



1 It" it \\i-ri- \vi.-ln-.l to r.-tabliah a compnriann between tlio nature of tin- :i.-ii..n ..f tli.- 

 \\\'< ("'in >n- of tlit- l"ii^ vu>tii.-. im.1 tlicir relations ami uttm-liun-nts, tlii-ir mmlo^ii. - in 



i-ily <1. t. rniiii. .1. The untcrinr is mi<l<>iil>tr<lly H r.nixi.lrruM.- portion of 



-. tin 



luttiM iii.ixiiniis, prolonged to the patella; tin- i>o.-tii"r r-pr> >. .1!-. tin- i 



