External obturator muscle

The external obturator muscle is a pelvic muscle located on the ventral side of the coxal bone, closing the obturator foramen ventrally. It is located caudally to the hip joint.

Conformation: It is composed of several thick branches that are easily separable. It has a more or less conical shape and is slightly flattened dorsoventrally. It ends in a strong, short tendon.

Origin: The various branches originate around the obturator foramen, on the ventral surface of the pubic and ischial bones.

Insertion: It is located in the trochanteric fossa of the femur.

Relations: Ventro-caudally, it is in contact with the adductors muscles of the thigh and the quadratus femoris. Through the obturator foramen, it touches the obturator membrane and the obturator internus muscle.

Action: Adduction and rotation of the femoral radius.

Vascularization: Obturator artery and obturator vein, or the medial circumflex femoral artery.

Innervation: Obturator nerve.

Description: The external obturator muscle is located caudally to the hip joint. It originates on the ventral edge of the obturator foramen, on the pubis and ischium bones. It is composed of several separable branches that gradually join together to give the muscle a flattened cone shape towards its insertion. It is attached by a short tendon that inserts into the trochanteric fossa of the femur near those of the gemelli or obturator internus muscles, with which it sometimes shares a common insertion. Dorsally, it is in contact with the obturator membrane and the obturator internus muscle through the obturator foramen. Along its path, it is surrounded by the femur cranially and by the adductor muscles of the thigh and quadratus femoris muscle ventrocaudally. The activation of this muscle causes the adduction and rotation of the femoral radius. It is activated by the obturator nerve. Blood supply is provided by the obturator artery and vein or, when these are absent, by the medial femoral circumflex artery.