Muscle · Lower limb
Adductor longus: origin, insertion, action and innervation
The adductor longus arises from the body of the pubis, inserts on the middle third of the linea aspera, and adducts and flexes the thigh (obturator nerve).
Quick answer
- Latin name
- Musculus adductor longus
- Origin
- Body of the pubis, below the pubic crest (hip bone)
- Insertion
- Middle third of the linea aspera of the femur
- Action
- Adducts the thigh and helps flex it at the hip
- Innervation
- Obturator nerve, anterior division (L2–L4)
- Blood supply
- Deep femoral artery and its medial circumflex femoral branch, and the obturator artery
See it on the 3D body
The adductor longus lit on the 3D hip and thigh, as in the hip and thigh quiz. Turn the body, peel the layers, tap any structure for its name.
The adductor longus is a long, fan-shaped muscle on the inner side of the thigh, running from the body of the pubis to the middle of the linea aspera of the femur. It pulls the thigh toward the midline, helps flex the hip, and is supplied by the obturator nerve (L2–L4).
Where it is
The adductor longus belongs to the medial compartment of the thigh, the adductor group. Of the adductors, it is the most anterior: it lies in front of the adductor brevis and the adductor magnus, with the pectineus above and lateral to it and the gracilis along its inner side.
Its upper, rounded tendon makes a firm cord in the groin that you can feel when you squeeze your knees together. Its medial border also forms one side of the femoral triangle, a landmark at the top of the front of the thigh:
- Superior border: the inguinal ligament.
- Lateral border: the medial border of the sartorius.
- Medial border: the medial border of the adductor longus.
The femoral nerve, artery and vein pass through this triangle. See the whole adductor group on muscles of the thigh.
Origin and insertion
- Origin: a narrow, rounded tendon from the front of the body of the pubis, just below the pubic crest, in the angle between the crest and the pubic symphysis. The pubis is part of the hip bone.
- Insertion: the fibers spread out into a broad, thin sheet that attaches to the middle third of the linea aspera, the long ridge on the back of the femur, between the vastus medialis in front and the adductor magnus behind.
So the muscle starts as a small tendon at the pubis and widens into a triangle toward the femur.
What it does
- Adduction of the thigh: it brings the thigh toward the midline, as when you squeeze your knees together, cross your legs, or push off sideways in sports such as football, skating or horse riding.
- Hip flexion: because it passes in front of the hip joint, it helps flex the thigh, especially when the hip starts from an extended position.
- Stabilizing the pelvis: during walking and running, the adductors work with the abductors (the gluteus medius and minimus) to keep the pelvis and thigh steady.
Its role in rotation of the thigh is small and described differently from one textbook to another, so most exams focus on adduction and flexion.
Innervation and blood supply
The adductor longus is supplied by the anterior division of the obturator nerve (roots L2, L3 and L4). The obturator nerve leaves the pelvis through the obturator foramen and supplies most of the medial compartment of the thigh.
Blood comes from the deep femoral artery, its medial circumflex femoral branch, and the obturator artery.
How to remember it
- Adductor = brings the limb ad (toward) the midline. Longus = long, compared with the adductor brevis (short) behind it.
- The adductors are stacked from front to back: longus in front, brevis in the middle, magnus at the back.
- SAIL for the borders of the femoral triangle: Sartorius, Adductor longus, Inguinal Ligament.
- Medial compartment = obturator nerve. Front = femoral, back = sciatic.
Frequently asked questions
What is the main action of the adductor longus?
Adduction of the thigh, pulling it toward the midline. It also helps flex the hip.
Where does the adductor longus originate and insert?
It originates from the body of the pubis, just below the pubic crest, and inserts on the middle third of the linea aspera of the femur.
Which nerve supplies the adductor longus?
The anterior division of the obturator nerve, from roots L2 to L4.
What is the role of the adductor longus in the femoral triangle?
Its medial border forms the medial border of the femoral triangle. The sartorius forms the lateral border and the inguinal ligament forms the top.
Is the adductor longus a groin muscle?
Yes. The adductors are often called the groin muscles, and the adductor longus is the most prominent of them: its tendon is the cord you can feel at the top of the inner thigh, next to the pubis.
