The pectineus muscle is a flat, quadrangular muscle situated at the upper part of the inner thigh. It is considered one of the muscles of the medial compartment of the thigh, but it also has a role in hip movement due to its anatomical positioning. The pectineus is involved in thigh adduction and flexion, contributing to the stability and movement of the hip joint.
Location
The pectineus muscle is located in the anterior (front) part of the upper thigh, just below the inguinal ligament. It originates from the superior ramus of the pubis bone and inserts into the pectineal line of the femur, near the lesser trochanter. It lies close to the adductor longus and the groin area, making it an integral muscle for movements involving the hip and upper leg.
Anatomy
Origin
The pectineus originates from the superior pubic ramus, specifically from the pecten pubis, which is the edge of the pubic bone extending from the pubic tubercle to the pubic symphysis.
Insertion
The muscle fibers extend obliquely downward and laterally from their origin to insert into the pectineal line of the femur, just below the lesser trochanter. This insertion point places the pectineus strategically for its role in moving the thigh and stabilizing the hip.
Structure
The pectineus is typically described as a flat, quadrangular muscle. It is located in the upper part of the inner thigh, nestled between the adductor longus and the iliopsoas muscles. Its size and shape can vary considerably among individuals. Despite being relatively small, it has a strong structure due to its short and thick muscle fibers.
Relations
- Superficially: It is covered by the fascia of the thigh and lies just beneath the inguinal ligament. The adductor longus and the femoral nerve lie lateral to it.
- Deeply: It rests on the capsule of the hip joint and the obturator externus muscle.
- Medially: The pectineus is adjacent to the adductor brevis and adductor longus muscles.
- Laterally: It borders the iliopsoas muscle.
Blood Supply
The blood supply to the pectineus comes primarily from the obturator artery, with contributions from the femoral artery. These vessels ensure the muscle receives the necessary nutrients and oxygen for its function.
Innervation
The innervation of the pectineus is unique in that it can receive nerve fibers from both the femoral nerve and the obturator nerve, making it a transitional muscle between the anterior and medial compartments of the thigh. This dual innervation varies among individuals.
Function
The pectineus muscle has several key functions related to the movements of the hip and upper thigh:
- Hip Flexion: The pectineus assists in flexing the hip joint, which involves bringing the thigh upward towards the torso. This action is crucial for many daily activities such as walking, running, or climbing stairs.
- Adduction of the Thigh: The muscle contributes to the adduction of the thigh, meaning it helps to move the thigh towards the midline of the body. This is important for stabilizing the leg during walking or standing.
- Medial Rotation of the Thigh: Though less pronounced, the pectineus can assist in the internal (medial) rotation of the thigh at the hip joint when the hip is flexed.
Clinical Significance
The pectineus muscle holds significant clinical relevance due to its role in hip and thigh movements and its involvement in various musculoskeletal conditions:
Groin Injuries: As a muscle located near the groin, the pectineus can be involved in groin strains or sports hernias, common in athletes or individuals engaged in activities requiring rapid changes in direction. Injuries to this muscle can lead to pain, swelling, and reduced mobility.
Hip Pain and Dysfunction: Dysfunction in the pectineus, whether due to strain, overuse, or muscle imbalance, can contribute to hip pain and impact overall lower limb function. It can also be involved in conditions like osteoarthritis or hip labral tears due to its proximity to the hip joint.
Pelvic Stability: The pectineus contributes to pelvic stability, especially during gait. Weakness or tightness in the muscle can affect gait mechanics and lead to compensatory issues in the lower back, hips, and knees.
Neurovascular Entrapment: Due to its anatomical location, an enlarged or spasmed pectineus muscle can potentially compress adjacent neurovascular structures, leading to conditions such as obturator neuropathy.
Rehabilitation and Physical Therapy: Understanding the anatomy and function of the pectineus is important for developing effective rehabilitation strategies for injuries affecting the hip and thigh. Strengthening and stretching exercises targeting the pectineus are often included in recovery protocols to improve mobility and prevent future injuries.
