292 TSE MUSCLES. 



extremity of tlie latter muscle, and is separated from tie sciatic nerves and 

 the long vastus by an aponeurotic lamina. The crural vessels pass 

 between its two branches, one of which, the internal, responds anteriorly and 

 near its insertion to the internal vastus muscle. 



Action. This muscle is an adductor and extensor, as well as a rotator 



outwards of the femoral ray. 



6. Square Crural. (Figs. 90, U; 131, 10.) 



Sijnomjms.—The gracilis internus of Sourgelaf, and the ischio-femoral gracilis of 

 Gimrd. (Not described by Percivall. Small iscUo-femoralis of Leyh, The quadratus 

 femoris of Man.) 



Situation — Direction — Form — Structure. — Situated on the posterior face 

 of the femur, between the great adductor and external obturator, and oblique 

 downwards and outwards, the quadratus cruralis is a small band flattened 

 from before to behind, and formed of parallel muscular fibres, slightly tendi- 

 nous at their inferior extremity. 



Attachments.— AhoYe, to the inferior surface of the ischium, in front of 

 the ischiatic tuberosity— (»%to ; terminating, below, on the linear imprint 

 on the posterior face of the femur, a little below the trochanter. 



Relations. — In front with the posterior face of the femur and external 

 obturator. Behind, and inwardly, with the great adductor of the thigh. 

 Outwards, with the sciatic nerves and the posterior gemellus of the pelvis. 



Action. — It is an extensor and adductor of the femur. In our opinion, 

 its mode of attachment will not permit it to rotate this bone either inwards 

 or outwards — at least in Solipeds. 



7. External Obturator. (Fig. 90, 13.) 

 Synonym. — Subpubio-troohanterius externus — Girard. 



Form — Structure — Situation — Direction. — A short, thick muscle, 

 flattened on both sides, triangular, fasciculated, fleshy and aponeurotic, 

 very delicate in texture, and placed almost horizontally beneath the pelvis, 

 at the margin of the oval foramen, which it appears destined to close, and 

 from which it derives its name of obturator. 



Attachments. — 1. To the inferior surface of the pubis and ischium, by 

 the internal extremities of its fasciculi — fixed insertion ; 2. To the 

 trochanterian fossa, by the external extremities of these fasciculi — movable 

 insertion. 



Melations. — Its inferior face is covered by the pectineus, the two 

 adductors of the thigh, and the square crural ; the superior covers the 

 capsule of the hip-joint, and is related to the internal obturator. 



Action. — An adductor and rotator outwards of the thigh. 



8. Internal Obturator. (Figs. 90 ; 131.) 

 Synonym. — Subpubio-troclianterius internus — Girard. 



Situation. — This muscle is situated in the pelvic cavity, above the oval 

 foramen, and is, consequently, opposite the external obturator. 



Form — Structure — Attachments. — It is formed of two portions. One is 

 very thin, and composed of slightly tendinous divergent muscular fasciculi, 

 which arise from around the oval foramen, are directed outwards, and 

 terminate in a tendon belonging to the other portion. The latter, elongated 

 and penniform, is situated in the pelvis, and extends from the anterior angle 



