Movements of the Hip/The hip joint is a ball and socket joint that is the point of articulation between the head of the femur and the acetabulum of the pelvis. The joint is a diarthrodial joint with its inherent stability dictated primarily by its osseous components/articulations. The primary function of the hip joint is to provide dynamic support the weight of the body/trunk while facilitating force and load transmission from the axial skeleton to the lower extremities, allowing mobility.[rx][rx][rx]
Nerves
The hip joint receives innervations from the femoral, obturator, superior gluteal nerves.[rx]
Movements of the Hip
Muscles of the hip joint can be grouped based upon their functions relative to the movements of the hip.[rx]
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Flexion: Primarily accomplished via the psoas major and the iliacus, with some assistance from the pectineus, rectus femoris, and the sartorius.
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Extension: Primarily accomplished via the gluteus maximus as well as the hamstring muscles.
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Medial rotation: Primarily accomplished by the tensor fascia lata and fibers of the gluteus medius and minimus.
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Lateral rotation: Primarily accomplished by the obturator muscles, the quadratus femoris, and the Gemelli with assistance from the gluteus maximus, sartorius, and piriformis.
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Adduction: Primarily accomplished by the adductor longus, brevis, and Magnus with assistance from the gracilis and pectineus
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Abduction: Primarily accomplished by the gluteus medius and minimus with assistance from the tensor fascia latae and sartorius.
Structure and Function of Movements of the Hip
The hip joint connects the lower extremities with the axial skeleton. The hip joint allows for movement in three major axes, all of which are perpendicular to one another. The location of the center of the entire axis is at the femoral head. The transverse axis permits flexion and extension movement. The longitudinal axis, or vertically along the thigh, allows for internal and external rotation. The sagittal axis, or forward to backward, allows for abduction and adduction.[rx][rx]
In addition to movement, the hip joint facilitates weight-bearing. Hip stability arises from several factors. The shape of the acetabulum. Due to the depth of the acetabulum, it can encompass almost the entire head of the femur. There is an additional fibrocartilaginous collar surrounding the acetabulum, the acetabular labrum, which provides the following functions:
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Load transmission
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Negative pressure maintenance (i.e., the “vacuum seal”) to enhance hip joint stability
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Regulation of synovial fluid hydrodynamic properties