MUSCULAR SYSTEM. 149 



Structure. — Composed of a fleshy belly, having its superior 

 border tendinous ; which border, after the muscTe has passed 

 through the sciatic notch, gives origin to a slender tendon 

 that insinuates itself between the geniini to gain the tro- 

 chanter. 



Actio?i. — To assist in the extension of the haunch. 



OBTURATOR EXTERN US. — Subpubio-trocliauterius Externus. 



Situation. — Deep-seated, in the supero-internal part of the 

 thigh. 



Form. — Quadrilateral, and putting on the appearance of a 

 double muscle. 



Attachments. — Internally, to the external border of the obtu- 

 rator foramen, and to the external surface of tlie obturator liga- 

 ment : externally, to the cavity behind the trochanter major, 

 and to the upper portion of the ridge extending from the larger 

 to the lesser trochanter. 



Relations. — Posteriorly, with the biceps abductor; superiorly, 

 with the gemini and obturator internus ; internally, with the 

 adductor niagnus. 



Direction. — Outward. 



Structure. — Attachments, both tendinous and fleshy ; surfaces, 

 striped with aponeurotic tendon. 



Action. — To assist in the extension of the haunch ; and at the 

 same time to rotate it outwards. 



OBTURATOR INTERNUS. — Subpubio-trochanterius Internus. 



Situation. — Upon the lower side of the pelvic cavity. 



Form. — Circular border, having radiating fibres converging 

 towards one common centre. 



Attachments. — Internally, to the internal border of the ob- 

 turator foramen, and to the inner surface of the obturator liga- 

 ment : externally, to the root of the trochanter major. 



Relations. — Superiorly, with the peritoneum ; inferiorly, with 

 the obturator ligament. 



Structure. — From the foramen the fleshy fibres converge 

 and form a belly which passes between the tuberosity and 

 spine of the ischium, and then makes its appearance without the 

 pelvis, in the vicinity of the hip joint. 



Action. — To approach the trochanter to the pelvis ; the eftbct 

 of which will be to turn the haunch outwards. 



G E jM 1 N I . — Ischio-trochanterius . 

 Situation. — Without the pelvis, at its postero-inferior part. 

 Form. — Thin; flat; quadrilateral. 



