lesser trochanter of femur

2 min read 19-03-2025

The lesser trochanter is a bony prominence located on the medial proximal femur. Understanding its anatomy, function, and clinical relevance is crucial for medical professionals and students alike. This comprehensive article explores these aspects in detail.

Anatomy of the Lesser Trochanter

The lesser trochanter is a smaller, conical projection found on the posteromedial aspect of the femur's proximal end. It's located inferior and slightly posterior to the greater trochanter. Unlike the greater trochanter, which serves as an attachment point for multiple muscles, the lesser trochanter's primary function is to provide a robust attachment site for a single major muscle:

Musculotendinous Attachments

Iliopsoas muscle: This powerful hip flexor attaches to the lesser trochanter via its tendon. The iliopsoas is composed of two muscles, the iliacus and psoas major, which converge to form a single tendon inserting on the lesser trochanter. This attachment is vital for its role in hip flexion and external rotation.

Function of the Lesser Trochanter

The lesser trochanter’s primary function is to serve as the insertion point of the iliopsoas muscle. This muscle is crucial for several lower limb movements:

Hip Flexion: The iliopsoas is a primary hip flexor, bringing the thigh towards the abdomen. This action is essential for activities like walking, running, and climbing stairs.
Hip Internal Rotation: While the iliopsoas's primary action is flexion, it also contributes to internal rotation of the hip joint.
Trunk Stabilization: The iliopsoas also plays a role in stabilizing the trunk and pelvis, especially during activities requiring core strength.

Clinical Significance of the Lesser Trochanter

Injuries involving the lesser trochanter are less common than those affecting the greater trochanter, but they can occur. Specific issues related to the lesser trochanter include:

Avulsion Fractures

Mechanism: A forceful contraction of the iliopsoas muscle can, in certain circumstances, result in an avulsion fracture of the lesser trochanter. This typically occurs during high-impact activities or sudden, powerful movements.
Symptoms: Pain in the medial proximal thigh, often worsened by hip flexion, is a common symptom. Swelling and bruising may also be present.
Diagnosis: Imaging techniques such as X-rays are crucial for diagnosing avulsion fractures. Sometimes, more sophisticated imaging such as MRI may be necessary for a more complete assessment of the injury.
Treatment: Treatment options vary depending on the severity of the fracture. Less severe fractures might only require conservative management, including rest, ice, and pain medication. More significant fractures might necessitate surgical intervention.

Lesser Trochanteric Bursitis

Description: Inflammation of the bursa located near the lesser trochanter can cause pain. This bursitis is less common than greater trochanteric bursitis.
Causes: Repetitive strain, trauma, or underlying medical conditions can contribute to lesser trochanteric bursitis.
Symptoms: Pain is usually localized to the medial aspect of the proximal thigh. The pain may be aggravated by hip flexion and internal rotation.
Treatment: Treatment typically involves conservative measures like rest, ice, anti-inflammatory medications, and physical therapy.

Other Clinical Considerations

The lesser trochanter's proximity to major blood vessels and nerves makes it clinically important. Surgical procedures in the region must consider potential damage to these structures. Furthermore, imaging of the lesser trochanter can aid in the assessment of other hip pathologies.

Conclusion

The lesser trochanter, while less prominent than its greater counterpart, plays a vital role in hip function. Its primary function is providing attachment for the iliopsoas muscle, a crucial muscle for hip flexion, internal rotation, and overall lower limb movement. Understanding its anatomy and its susceptibility to injury, like avulsion fractures and bursitis, is crucial for accurate diagnosis and effective treatment strategies. Further research into the lesser trochanter's role in various pathological conditions continues to expand our understanding of its clinical significance.