Internal Rotators of the Hip
The primary internal rotators of the hip include the tensor fascia latae, gluteus minimus, gluteus medius (anterior fibers), and the anterior portion of gluteus maximus when the hip is flexed. 1, 2
Primary Internal Rotators
- Tensor fascia latae (TFL) is a significant internal rotator of the hip, showing approximately 90% increase in myoelectric activity during internal rotation torque application, particularly at 90° of hip flexion 2
- Gluteus minimus functions as an internal rotator of the hip across various hip positions 3
- Anterior fibers of gluteus medius contribute to internal rotation of the hip 1
- Superior fibers of gluteus maximus can function as internal rotators when the hip is flexed (showing approximately 7% increase in activity during internal rotation at extended position) 2, 3
Biomechanical Considerations
- Hip flexion angle significantly affects the rotational moment arms of hip muscles, with 15 of 18 muscle compartments showing a trend toward internal rotation capability as the hip is flexed 3
- During hip internal rotation exercises, gluteus medius, tensor fascia latae, and upper gluteus maximus show significantly larger activation compared to external rotation exercises regardless of hip flexion angle 1
- Lower fibers of gluteus maximus demonstrate increased activation during internal rotation when the hip is maintained at 90° of flexion 1
Clinical Implications
- Excessive hip flexion may exacerbate internal rotation of the hip due to the biomechanical changes in muscle moment arms 3
- In patients with cerebral palsy and other neurological conditions, internal rotation gait is multifactorial but significantly associated with hip flexor contracture 4
- For assessment of hip rotation, proper positioning is crucial - the hip should be placed in a flat position with limbs aligned to the body's midline to minimize the effects of rotation, adduction and abduction 5
- For hip examination, internal rotation of approximately 15-20° positions the femoral neck parallel to the scan table plane, which is important for proper assessment 5
Stretching Considerations
- When targeting the hip internal rotators, the most effective positions include 30° adduction from 90° of hip and knee flexion, and 45° external rotation with 90° hip and knee flexion 6
- The piriformis and superior gemellus (external rotators that can become tight and limit internal rotation) show larger length changes when adducting the hip from 90° of hip and knee flexion 6
Understanding the internal rotators of the hip is essential for proper diagnosis and management of hip-related pain, particularly in conditions affecting hip rotation and stability.