MYOLOGY. 77 



Action. — Adductor, extensor and external rotator of thigh. 

 Nerve. — Obturator. 



QUADRATUS FEMORIS. 



Origin. — Tuber ischii. 



Insertion. — Posterior surface of femur, below trochanter. 



Action. — Extensor and adductor of femur. 



Nerve. — Great sciatic. 



EXTERNAL OBTURATOR. 



Origin. — Below margin of obturator foramen. 

 Ifisertion. — Trochanterian fossa. 

 Action. — Adductor ^and external rotator. 

 Nerve. — Obturator. 



INTERNAL OBTURATOR. 



Origin. — Above margin of obturator foramen. 

 Insertion. — Trochanterian fossa. 

 Action. — Abductor and external rotator. 

 Nerve. — Great sciatic. 



GEMELLL 



Origin. — Above and below tendon of obturator internus, from 

 ischium. 



Insertion. — Into tendon of internal obturator. 

 Action. — Like preceding. 

 Nerve. — Great sciatic. 



ANTERIOR EXTENSOR OF PHALANGES. 



Origin. — Digital fossa above external condyle of femur. 



Insei'tion. — Capsular ligament of metatarso-phalangeal articu- 

 lation, anterior surfaces of first two phalanges, and pyramidal emi- 

 nence of OS pedis. 



Action. — Extends digit. 



Nerve. — External popliteal. 



LATERAL EXTENSOR OF PHALANGES. 



Origin. — External femoro-tibial ligament and whole extent of 

 fibula. 



hisertion. — Terminates in tendon of anterior extensor. 

 Action. — As preceding. 

 Nerve. — External popliteal. 



