Gluteus minimus muscle
The gluteus minimus is the smallest and deepest of the three gluteal muscles. It plays a crucial role in stabilizing the pelvis and facilitating movements of the hip joint. Understanding its anatomy and function is essential for clinicians, physiotherapists, and anatomists.
Anatomy
Location and Boundaries
The gluteus minimus is located in the posterior-lateral region of the hip, lying immediately beneath the gluteus medius. It covers the outer surface of the ilium and contributes to the contour of the lateral hip.
- Anterior Boundary: Iliac crest and iliac fossa
- Posterior Boundary: Gluteus medius and greater sciatic notch
- Superior Boundary: Iliac crest
- Inferior Boundary: Hip joint capsule and tensor fasciae latae
Origin
The gluteus minimus originates from the outer surface of the ilium, between the anterior and inferior gluteal lines. It arises from the external surface of the ilium, medial to the origin of the gluteus medius, providing a broad attachment for its muscle fibers.
Insertion
The tendon of the gluteus minimus inserts onto the anterior surface of the greater trochanter of the femur. This attachment allows the muscle to exert its primary actions on the hip joint, including abduction and medial rotation. The insertion lies deep to the gluteus medius tendon.
Structure
The gluteus minimus has a fan-shaped structure, with fibers converging from a broad origin to a narrow insertion. Its muscle belly is short and thick, giving way to a strong tendon that blends with the hip joint capsule and the gluteus medius tendon. The orientation of its fibers is primarily horizontal, which optimizes its role in lateral stabilization of the pelvis.
Innervation and Blood Supply
Nerve Supply
The gluteus minimus is innervated by the superior gluteal nerve, which originates from the L4, L5, and S1 nerve roots. This nerve enters the muscle on its deep surface and is critical for initiating abduction and medial rotation of the hip. Damage to this nerve can lead to weakness in hip abduction and an abnormal gait pattern.
Blood Supply
The primary arterial supply to the gluteus minimus comes from the superior gluteal artery. This artery runs in close association with the superior gluteal nerve and provides oxygenated blood to both the muscle belly and its tendon. Secondary contributions may come from small branches of the inferior gluteal and lateral circumflex femoral arteries.
Function
The gluteus minimus is a key muscle in maintaining pelvic stability and controlling movements of the hip joint. Its actions are essential for proper gait and balance during standing and locomotion.
- Hip Abduction: The gluteus minimus abducts the thigh at the hip joint, moving the leg away from the midline of the body.
- Medial Rotation: It assists in medially rotating the femur, which is important for the alignment of the lower limb during walking and running.
- Pelvic Stabilization: During single-leg stance, such as in walking or running, the gluteus minimus helps stabilize the pelvis, preventing it from dropping on the opposite side.
Clinical Significance
Injuries and Pathologies
Injuries to the gluteus minimus are less common than those of the gluteus medius but can still occur, particularly in athletes or individuals involved in repetitive hip movements.
- Strains or Tears: Overstretching or sudden contraction can lead to partial or complete muscle tears.
- Tendinopathy: Degenerative changes in the tendon can cause chronic pain and weakness in hip abduction.
Impingement Syndromes
The gluteus minimus tendon can be involved in lateral hip pain syndromes, particularly trochanteric pain syndrome. Inflammation or compression of the tendon may result in pain over the greater trochanter, which worsens with activity or lying on the affected side.
Rehabilitation and Strengthening
Rehabilitation focuses on restoring strength, flexibility, and neuromuscular control. Strengthening exercises target hip abduction and pelvic stabilization to prevent recurrent injuries.
- Side-lying hip abduction exercises
- Clamshell exercises for lateral hip strengthening
- Resistance band exercises targeting abductor muscles
- Functional gait training and balance exercises
Comparative Anatomy
The gluteus minimus is the smallest and deepest of the three gluteal muscles, lying beneath the gluteus medius and gluteus maximus. Its structure and function can be compared to these neighboring muscles to better understand its unique role in hip mechanics.
| Muscle | Size | Location | Primary Function |
|---|---|---|---|
| Gluteus Maximus | Largest | Superficial posterior hip | Hip extension, lateral rotation, abduction |
| Gluteus Medius | Intermediate | Between gluteus maximus and minimus | Hip abduction, medial rotation, pelvic stabilization |
| Gluteus Minimus | Smallest | Deepest, beneath gluteus medius | Hip abduction, medial rotation, pelvic stabilization |
Evolutionarily, the gluteus minimus contributes to bipedal locomotion by providing fine control of hip movements and stabilization, which is crucial for upright walking.
References
- Standring S. Gray’s Anatomy: The Anatomical Basis of Clinical Practice. 42nd ed. London: Elsevier; 2020.
- Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy. 9th ed. Philadelphia: Wolters Kluwer; 2021.
- Drake RL, Vogl W, Mitchell AWM. Gray’s Atlas of Anatomy. 2nd ed. Philadelphia: Elsevier; 2019.
- Neumann DA. Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. 4th ed. St. Louis: Elsevier; 2020.
- Hopkins A, et al. Functional anatomy of the gluteus minimus and its relevance to hip stability. J Anat. 2019;234(5):678-690.
- Gajdosik RL, et al. Hip abductor muscle function: clinical implications for rehabilitation. Phys Ther. 2018;98(3):213-222.
- Fukuda T, et al. Anatomy and biomechanics of the gluteus minimus muscle. Clin Anat. 2017;30(4):501-510.
