Adductor Magnus Muscle – Origin, Nerve Supply, Function

Adductor Magnus Muscle/Adductor Magnus is a large triangular muscle, situated on the medial side of the thigh. It consists of two parts. The portion which arises from the ischiopubic ramus (a small part of the inferior ramus of the pubis, and the inferior ramus of the ischium) is called the pubofemoral portion, adductor portion, or adductor minimus, and the portion arising from the tuberosity of the ischium is called the ischiocondylar portion, extensor portion, or “hamstring portion”. Due to its common embryonic origin, innervation, and action the ischiocondylar portion (or hamstring portion) is often considered part of the hamstring group of muscles. The ischiocondylar portion of the adductor Magnus is considered a muscle of the posterior compartment of the thigh while the pubofemoral portion of the adductor Magnus is considered a muscle of the medial compartment.

Origin of Adductor Magnus

Origin (proximal attachment)

• Oblique head – inferior ramus of pubis & ischial ramus.
• Vertical head – ischial tuberosity.
• The adductor part –  arises from the outer surface of the inferior pubic ramus and the ischial ramus, and is considered a muscle of the medial compartment of the thigh.

Insertion (distal attachment)

• Oblique head – gluteal tuberosity, linea aspera, and proximal supracondylar line of femur.
• Vertical head – adductor tubercle of femur.
• The hamstring part – originates from the inferolateral side of the ischial tuberosity and is considered a muscle of the posterior compartment of the thigh. Due to their common embryologic origin, innervation and function, the hamstring part is also often considered a part of the hamstring group of muscles.

Nerve Supply of Adductor Magnus

• It is a composite muscle as the adductor and hamstring portions of the muscle are innervated by two different nerves. The adductor portion is innervated by the posterior division of the obturator nerve while the hamstring portion is innervated by the sciatic nerve.^[rx][rx]
• Obturator nerve – L2,3,4 and
• Sciatic nerve – L4,5,S1.

Blood Supply of Adductor Magnus

• The adductor Magnus muscle gets its main arterial blood supply from the perforating branches of the deep femoral artery, passing through its use-aponeurotic openings. In addition, the superior portion of the muscle is supplied by the medial femoral circumflex artery, and the inferior portion receives blood from the femoral, popliteal, and genicular arteries.

Functions

• The adductor Magnus is a powerful adductor of the thigh, made especially active when the legs are moved from a widespread position to one in which the legs parallel each other.
• The part attached to the linea aspera acts as a lateral rotator. The part which reaches the medial epicondyle acts as a medial rotator when the leg is rotated outwards and flexed, and also acts to extend the hip joint.^[rx]

References

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