Pectineus Muscle

Original Editor -Abdallah Ahmed Mohamed Top Contributors - Abdallah Ahmed Mohamed, Lucinda hampton, Kim Jackson, Vidya Acharya and Alexandra Stead  

Introduction

The Pectineus muscle assists in hip adduction and flexion, and is one of the muscles located on the medial thigh, alongside a group of four primary large muscles. These primary muscles include the Adductor Longus, Adductor Brevis, Adductor Magnus, and Gracilis muscles, which primarily function in hip adduction..

Activities that use this muscle include: running, skating, kicking a soccer ball, playing basketball.

An adductor strain can occur in this muscle during sporting activities or in a fatigues muscle. Treatment often includes physiotherapy.

Image 1: Pectineus, red outline

Anatomy

Pectineus can be classified in the medial compartment of thigh (when the function is emphasised) or the anterior compartment of thigh (when the nerve is emphasised).

Origin: pectineal line (pecten pubis) and adjacent bone of pelvis

Insertion: oblique line extending from base of lesser trochanter to linea aspera on posterior surface of femur

Image 2: Pectineus of right side - outline and attachment-areas.

Action: adducts and flexes thigh at hip joint

Arterial supply: superficial part by medial circumflex femoral artery and deep part by the anterior branch of obturator artery.

Nerve supply: The pectineus is considered a transitional muscle between the anterior thigh and medial thigh; this is due to innervation mainly from the femoral nerve and also sometimes from the obturator nerve.

Relation

The muscle lies in the frontal plane:

• Medial to adductor longus.
• Laterally, it is related to the psoas major muscle and the medial circumflex femoral artery and vein.
• The anterior surface of pectineus forms the medial part of the floor of femoral triangle together with adductor longus.
• This surface of pectineus is covered with the deep layer of fascia that separates it from the femoral artery, femoral vein and great saphenous vein that course through the femoral triangle. 
• Posterior to pectineus are the adductor magnus, adductor brevis and obturator externus muscles, and the anterior branch of obturator nerve.

Image 3: Pectineus muscle. human anatomy

Action

Due to the course of its fibres, pectineus both flexes and adducts the thigh at the hip joint when it contracts. When the lower limb is in the anatomical position, contraction of the muscle first causes flexion to occur at the hip joint. This flexion can go as far as the thigh being at a 45 degree angle to the hip joint.

At that point, the angulation of the fibres is such that the contracted muscle fibres now pull the thigh towards the midline, producing thigh adduction.

Injury

The pectineus muscle can become injured by overstretching; specifically, by stretching a leg or legs too far out to the side or front of the body. Pectineus injuries can also be caused by rapid movements like kicking or sprinting, changing directions too quickly while running, or even by sitting with a leg crossed for too long.

See Groin Strain and Assessment of Athletes with Groin Pain

Symptoms of the injury

The most common symptom of an injured pectineus muscle is pain. Other may include bruising, swelling, tenderness and stiffness.

Treatment

Treatment of pectineus muscle injury involves initially resting from key aggravating factors that might cause further injury and modify activities that use the pectineus muscle, such as walking and running, to allow the muscle time to heal. The rehab professional may recommend to follow PEACE and LOVE principles, and gradually return to activity and sports once key progression indicators have been achieved.