The muscles in the medial compartment of the thigh are collectively known as the hip adductors. There are five muscles in this group; gracilis, obturator externus, adductor brevis, adductor longus and adductor magnus. All the medial thigh muscles are innervated by the obturator nerve, which arises from the lumbar plexus. Arterial supply is through the obturator artery. In this article, we shall examine the anatomy of the muscles of the medial thigh – their attachments, actions and clinical correlations.
The adductor magnus is the largest muscle in the medial compartment of the thigh. It is comprised of two parts – an adductor component and a hamstring component.
The adductor longus is a large, flat muscle. It partially covers the adductor brevis and magnus. The muscle forms the medial border of the femoral triangle.
The adductor brevis is a short muscle, lying underneath the adductor longus. It separates the anterior and posterior branches of the obturator nerve and is an important anatomical landmark within the medial thigh.
The obturator externus is one of the smaller muscles of the medial thigh and it is located superiorly within the compartment.
The gracilis is the most superficial and medial of the muscles in this compartment. It crosses at both the hip and knee joints.
Strain of the adductor muscles is the underlying cause of what is colloquially known as a ‘groin strain‘. The proximal part of the muscle is most commonly affected, tearing near their bony attachments in the pelvis. Groin injuries usually occur in sports that require explosive movements or extreme stretching. Treatment of any muscle strain should utilise the RICE protocol – rest, ice, compression and elevation.
The adductor muscles play an important role in medial thigh function and injury to these muscles can lead to decreased movement and pain. It is important to understand the anatomy, attachments, actions and innervation of these muscles in order to diagnose and treat strain or injury in this area of the body.
The muscles located in the medial compartment of the thigh are known as the hip adductors. This includes the adductor brevis, adductor longus, adductor magnus, gracilis, and pectineus muscles. Among these, the adductor muscles have many bony attachments, including the pubis, femur, and proximal tibia. Other than adduction, these muscles are also involved in medial and lateral rotation of the thigh, depending on the action and innervation.
The adductor longus is a large and flat muscle which covers the adductor brevis and magnus partially. It creates the medial border of the femoral triangle, and originates from the pubis bone and expands into a fan shape on the linea aspera of the femur. Its role in the body is to aid adduction of the thigh, and its innervation is provided by the obturator nerve (L2-L4).
The adductor brevis lies underneath the adductor longus, and is a short muscle. It seperates the anterior and posterior branches of the obturator nerve, and is an important anatomical landmark in the medial thigh. It originates from the body of pubis and inferior pubic rami, and attaches to the linea aspera on the posterior surface of the femur. It is involved in adduction of the thigh, and is innervated by the obturator nerve (L2-L4).
The obturator externus is one of the smaller muscles in the medial thigh, and is located superiorly within the compartment. It originates from the membrane of the obturator foramen, and runs underneath the neck of femur and attaches to the posterior aspect of the greater trochanter. The functions of this muscle are adduction and lateral rotation of the thigh, and it is innervated by the obturator nerve (L2-L4).
The gracilis is the most superficial and medial of the muscles present in this compartment. It crosses the hip and knee joint, and originates from the inferior rami of the pubis and the body of the pubis. Along the medial aspect of the thigh it descends and attaches to the medial surface of the tibial shaft. Its actions are adduction of the thigh at the hip and flexion of the leg at the knee, and it is innervated by the obturator nerve (L2-L4).
Strains of the adductor muscles are a common cause of what is colloquially known as a 'groin strain'. The proximal part of the muscle is usually affected, tearing near its bony attachments in the pelvis. Groin injuries are usually seen in sports which require explosive movements or extreme stretching. The RICE protocol – rest, ice, compression and elevation – is recommended for treatment of any muscle strain.
