The Adductor Longus is a long, flat, triangular skeletal muscle located high in the medial compartment of the thigh. As its name suggests, this muscle belongs to a group responsible for movement toward the body’s midline. Its specific placement and attachments provide the leverage necessary to perform functions integral to both standing balance and dynamic movement.
Precise Anatomical Location
The Adductor Longus is housed in the medial compartment of the thigh, the innermost section of the upper leg. It is one of the most superficial members of the adductor group, lying near the skin surface relative to its neighbors, the Adductor Brevis and Adductor Magnus. Its broad, triangular structure begins near the pelvis and runs diagonally downward toward the back of the thigh bone.
It sits lateral to the Gracilis muscle and medial to the Pectineus muscle at its upper end. The muscle’s superior border helps define the femoral triangle, a depression in the upper thigh where major blood vessels and nerves pass through. The Adductor Longus forms the medial boundary of this triangular region, making it a significant topographical landmark.
The muscle lies anterior to the deeper Adductor Brevis and Adductor Magnus muscles. Near its insertion point, the muscle fibers extend toward the back of the leg, closely associated with the neurovascular bundle, including the femoral artery and vein.
Origin and Insertion Points
The Adductor Longus attaches to the bones of the pelvis and the thigh. Its origin is found on the anterior surface of the body of the pubis, the lower, front part of the hip bone. This attachment point is situated just lateral to the pubic symphysis, the joint connecting the two halves of the pelvis.
From this small, tendon-like origin near the groin, the muscle fibers expand into a wider, fleshy belly that travels downward and slightly backward. The muscle’s insertion is located on the posterior aspect of the thigh bone, known as the femur. It anchors specifically onto the middle third of the medial lip of the linea aspera.
The linea aspera is a prominent ridge that runs vertically down the length of the femur’s shaft, serving as a common attachment site for many thigh muscles. The Adductor Longus extends across the hip joint from the front of the pelvis to the back of the femur.
Role in Lower Body Movement
The primary function of the Adductor Longus is adduction of the thigh, which is the action of moving the leg inward toward the midline of the body. This movement occurs at the hip joint and is necessary for activities like crossing one leg over the other, standing with the feet together, and maintaining balance while walking. The muscle’s attachments on the pelvis and the femur provide the mechanical advantage needed to pull the entire thigh inward.
The Adductor Longus also contributes to other movements at the hip joint. It assists in hip flexion, helping to lift the leg forward, especially when the thigh is already extended. It also plays a part in the rotation of the thigh, contributing to both medial (inward) and lateral (outward) rotation, depending on the leg’s position.
For the muscle to contract, it must receive a signal from the nervous system. The Adductor Longus is primarily innervated by the anterior division of the Obturator Nerve, which originates from the lumbar spinal segments L2 through L4. This nerve relays the command to the muscle fibers, facilitating movement and helping stabilize the pelvis during locomotion.