Adductor magnus muscleThe adductor magnus muscle is a large triangular muscle of the lower limb, with its apex situated on the hip bone, and its base on the linea aspera of the femur. It is situated both in the posterior and medial fascial compartments of the thigh. The distribution of this muscle in two compartments is reflected in the fact that it receives dual nerve supply. Regardless of its position, the adductor magnus muscle is classified as a muscle of the medial compartment of the thigh.
The adductor magnus is the largest and strongest muscle of the medial compartment of the thigh, which also consists of adductor longus, adductor brevis, pectineus, and gracilis muscles. In respect to their function, these 5 muscles are collectively called the adductors of the thigh, even though their actions are a bit more complex than that.
|Origin||Adductor part: Inferior pubic ramus, ischial ramus
Ischiocondylar part: Ischial tuberosity
|Insertion||Adductor part: Gluteal tuberosity, linea aspera (medial lip), medial supracondylar line Ischiocondylar part: Adductor tubercle of femur|
Hip joint - Thigh flexion, thigh adduction, thigh external rotation
Hip joint - Thigh extension, thigh internal rotation
Entire muscle: Pelvis stabilization
Adductor part: Obturator nerve (L2-L4) Ischiocondylar part: Tibial division of sciatic nerve (L4)
Mnemonic: African Mouse Sneaks Out (refers to Adductor Magnus Sciatic Obturator)
|Blood supply|| Deep femoral artery;
Femoral, popliteal and genicular arteries
This article will teach you everything you need to know about the attachments, relations, neurovascular supply and functions of the adductor magnus muscle!
Origin and insertion
The adductor magnus muscle is a massive triangular muscle that extends over the entire medial side of the thigh. It is a composite muscle consisting of two parts, the adductor part and the hamstring part, also called the ischiocondylar part.
- 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.
- 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.
The adductor part can be divided into two portions. The superior portion, that arises from the pubic ramus and the inferior portion that arises from the ischial ramus. The superior portion of the adductor part passes obliquely and almost horizontally to insert at the upper part of the linea aspera. It then continues slightly superior and inserts at the medial margin of the gluteal tuberosity, almost reaching the greater trochanter of the femur medially to the attachment of gluteus maximus. This part of the muscle, comprised of short horizontal fibers, lies more anterior to the rest of the adductor magnus muscle and is sometimes considered a separate muscle, called adductor minimus. This part of the muscle also lies adjacent to the quadratus femoris muscle. Sometimes they can be fused together, whereas sometimes there’s a gap between them that allows the passage of the circumflex artery.
The larger, inferior portion of the adductor part fibers that originate from the ischial ramus fan out inferolaterally to insert in a linear fashion along the entire length of the linea aspera and the upper part of the medial supracondylar line. These fibers insert indirectly via a broad aponeurosis, which contains 4-5 oseo-aponeurotic openings, maintained by tendinous arches attached to the bone. These openings serve as a passage for perforating branches of the deep femoral artery. The most caudal opening is the largest, called the adductor hiatus, which transmits the terminal femoral artery and vein to the popliteal fossa, which then become the popliteal artery and vein.
At its distal attachment on the linea aspera, the adductor portion blends with the fibers from the proximal attachment of the short head of biceps femoris muscle. This allows these two muscles to work in unison to stabilize the femur and pelvis.
The most medial part of the muscle, the hamstring part, stemming from the ischial tuberosity, forms the thick medial margin of the muscle that descents almost vertically towards the lower end of the thigh. It ends in a rounded tendon and inserts at the adductor tubercle on the medial femoral condyle.
The adductor magnus occupies the majority of the medial portion of the thigh. Anteriorly to the adductor magnus muscle are the pectineus, adductor longus and adductor brevis. Neurovascular structures in relation to the anterior surface of the adductor magnus are the femoral artery and vein, the deep femoral artery and vein and the posterior branches of obturator artery, nerve and vein.
On the posterior aspect, the adductor magnus muscle is in relation with the gluteus maximus, semimembranosus, semitendinosus and the sciatic nerve. The medial border of the adductor magnus muscle is related to the gracilis and sartorius muscles, whereas its superior border is related to the obturator externus and quadratus femoris muscle. The adductor part of the muscle runs parallel with the quadratus femoris muscle, leaving a gap through which the femoral circumflex artery passes. At times, these muscles can be fused with no gap present.
The adductor magnus muscle takes part in creating the boundaries of the adductor canal also called the Hunter's canal. The adductor canal is a narrow passageway in the middle third of the thigh, transmitting the descending genicular and muscular branches of the femoral artery and their corresponding veins, the saphenous nerve, and the nerve to vastus medialis. The adductor canal ends by going through the adductor hiatus and into the popliteal fossa. The adductor canal is bounded by:
- Anteriolaterally: Vastus medialis muscle
- Posterimedially: Adductor magnus and longus muscles
- Anteriomedially (also called roof): Subsartorial fascia and the sartorius muscle
The adductor canal has a lot of clinical significance, one of which is to provide access for anesthesia for the leg and foot procedures. This can be achieved by a saphenous nerve block at the level of the adductor canal.
The nerve supply of the adductor magnus muscle is reflected by its position in both the medial and the posterior compartment. Like other muscles of the medial compartment, the adductor part is innervated by the posterior division of the obturator nerve (L2, L4). The hamstring part, sometimes considered a part of the hamstring group of muscles, is also innervated accordingly by the tibial component of the sciatic nerve (L4).
In order to remember the innervation of the adductor magnus muscle you can use the mnemonic African Mouse Sneaks Out which stands for; Adductor Magnus Sciatic Obturator.
The adductor magnus muscle gets its main arterial blood supply from the perforating branches of the deep femoral artery, passing through its oseo-aponeurotic openings. In addition, the superior 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.
The adductor magnus muscle is a powerful adductor of the thigh, working in a coordinated fashion with the adductor longus and brevis and pectineus muscles. In addition to thigh adduction, all of these muscles serve as important stabilizers of the pelvis on the lower limb during walking.
The two parts of the adductor magnus muscle, the adductor and hamstring part, have some similar but also some different functions. Besides adducting the thigh, the adductor part also contributes to the flexion of the thigh, especially the superior horizontal portion of the adductor part. The hamstring part adducts the thigh as well, but also cooperates with the hamstring group of muscles and assists the extension of the thigh.
The adductor magnus does not partake in the adduction of the abducted thigh when standing because gravity alone is enough for that action. The adductor magnus is most active during adduction of the flexed thigh when standing, for example when kicking with the medial side of the foot in soocer, or during supine positions. The fibers of the adductor part of the muscle that attach to the linea aspera can also act as lateral rotators due to their oblique attachment. It is also believed that, together with the adductor longus, this muscle acts as a medial rotator of the thigh, however these actions of medial and lateral rotation depend on the position of the thigh and the mechanical axis of the femur.
To wrap your head around these functions of the adductor magnus muscle as well as other adductors of the thigh, check out our learning materials.