Gluteus Muscles: Anatomical and Functional Overview
Gluteus Maximus
The gluteus maximus is primarily a powerful hip extensor, with its superior three-fourths inserting predominantly into the gluteal tuberosity of the femur rather than the iliotibial tract as traditionally described. 1
Origin
- External surface of the ilium posterior to the posterior gluteal line
- Posterior surface of the sacrum and coccyx
- Sacrotuberous ligament 1
Insertion
- Superior three-fourths: Forms a strong plate-like distal tendon inserting primarily into the gluteal tuberosity of the femur, with only partial adhesions to the iliotibial tract 1
- Inferior one-fourth: Terminates at a complex involving the lateral femoral intermuscular septum, the plate-like distal tendon of the superior portion, and the proximal tendon of vastus lateralis 1
Innervation
- Inferior gluteal nerve 1
Primary Actions
- Hip extension: The dominant function, particularly through the superior portion's direct femoral insertion 1
- Hip external rotation: Secondary action 1
- The larger superior portion contributes directly to hip joint movement, while the smaller inferior portion provides supporting function 1
Gluteus Medius
The gluteus medius consists of three distinct anatomical parts, each with separate innervation, functioning primarily to stabilize the hip joint during the initial phase of gait and initiate pelvic rotation. 2, 3
Origin
- External surface of the ilium between the anterior and posterior gluteal lines 3
Insertion
- Lateral and superior surfaces of the greater trochanter 3
Innervation
- Superior gluteal nerve, with each of the three parts receiving separate nerve branches 3
Primary Actions by Segment
- Anterior and middle parts: Vertical fiber orientation suggests these segments initiate hip abduction through vertical pull 3
- Posterior part: Fibers run parallel to the femoral neck, functioning to stabilize the femoral head in the acetabulum during different stages of the gait cycle 3
- Overall function: Responsible for hip joint stabilization during the initial phase of the gait cycle and initiating pelvic rotation as a major gait determinant 2
- Clinical relevance: The sacral plexus terminal branches supply motor innervation to the gluteal region muscles 4
Gluteus Minimus
The gluteus minimus functions as the primary hip stabilizer during the mid- and late phases of the gait cycle, with distinct anterior and posterior segments serving different biomechanical roles. 2, 5
Origin
- External surface of the ilium between the anterior and inferior gluteal lines 3, 5
- Sciatic notch region on the internal pelvic surface, where it protects the superior gluteal nerve and artery 5
Insertion
- Anterosuperior aspect of the hip joint capsule (capsular insertion) 5
- Greater trochanter (main insertion site) 5
Innervation
- Superior gluteal nerve, with the anterior and posterior parts each receiving separate nerve branches 3
Primary Actions
- Hip stabilization: Primary function during mid- and late phases of the gait cycle 2
- Capsular tightening: Stabilizes the femoral head in the acetabulum by tightening the joint capsule and applying pressure on the femoral head 5
- Position-dependent actions: Functions as a flexor, abductor, and internal or external rotator depending on femoral position and which muscle segment is active 5
- Anterior segment: Vertical fiber orientation suggests initiation of hip abduction, which is then completed by tensor fasciae latae 3
- Posterior segment: Fibers parallel to the femoral neck provide femoral head stabilization 3
Clinical Implications
Surgical Considerations
- Preservation of gluteus minimus tendon during hip surgery is strongly recommended due to its critical role in hip stability and capsular integrity 5
- The three-part structure of gluteus medius and two-part structure of gluteus minimus, each with separate innervation, means that selective denervation or injury can produce partial rather than complete muscle dysfunction 3