Muscles de la hanche et leur fonction

Muscle Groups for Hip Motion

• Two muscle groups involved: gluteal muscles and hamstrings.
• The gluteus maximus is the strongest and thickest in the hip region, aided by posterior fibers of the gluteus medius and minimus.
• Hamstrings' effectiveness in hip movement is dependent on knee position; knee locking enhances hip extension, acting against the quadriceps.
• The adductor magnus also functions as a hip extensor.

Hip Extensors and Their Actions

• Extensors vary in function based on their position relative to the anteroposterior axis.
• Above the axis: combined abduction and extension by posterior fibers of gluteal muscles.
• Below the axis: extension and adduction primarily by gluteus maximus, hamstrings, and posterior adductors.
• Hip extensors stabilize the pelvis in the anteroposterior direction.

Pelvic Tilt and Center of Gravity

• Retroversion of the pelvis moves the center of gravity (CG) behind the hip line, stabilized by the iliofemoral ligament.
• CG position over the hip center indicates unstable equilibrium; anterior pelvic tilt moves the CG forward, requiring contraction of hamstrings to realign the pelvis.
• Retroversion: ligament tension; Anterior version: muscle tension from the hamstrings.

Ligamentary Considerations in Hip Extension

• Extension wraps ligaments around the femoral neck, creating tension when the femur is stationary.
• Close-packed position reinforces stability through ligament tension.

Adduction Mechanics

• Adduction brings the lower limb inward towards the body's midline.
• Engaged muscles include pelvi-trochanteric groups and various adductors.
• Adduction causes tension in the horizontal ligament fibers, especially in iliofemoral and pubofemoral ligaments, while ischiofemoral is relaxed.

Internal Rotation (IR)

• Internal rotation shifts the foot outward with a range of 30 to 40 degrees, involving specific muscle groups like the anterior gluteal, sartorius, and tensor fascia latae (TFL).
• In moderate internal rotation, obturator externus and pectineus lose their external rotation capacity.
• Internal rotation leads to tension variations in ligaments around the hip joint.

Muscle Action Inversion

• Muscles have primary or secondary actions that change depending on joint position.
• Movements at the knee involve anterior and posterior drawer actions, limited by anterior and posterior cruciate ligaments.

Physiological Movement Amplitudes

• Extension pulls the back of the leg away from the thigh by 5 to 10 degrees; no true absolute extension exists in anatomical position.
• Active extension depends on hip positioning; the rectus femoris is more effective during extension.

Knee Flexion Dynamics

• Knee flexion brings the leg closer to the thigh, dependent on hip position (flexed or extended).
• Absolute and relative flexion definitions varying based on the reference position.

Dorsiflexion and Plantarflexion

• Dorsiflexion reduces the angle between foot and shin; ranges from 70° to 80° of total flexion-extension.
• Factors limiting dorsiflexion include bony structures and capsular tension.
• Plantarflexion is the opposite movement, creating an angle between the foot and the leg.

Stability in the Subtalar Joint

• Articulation congruence in the subtalar joint is critical, with the neutral foot position providing stability against gravity.
• The alignment of the talus and calcaneus facilitates dynamic and static balance in standing positions.

Découvrez les différents groupes musculaires associés à la hanche, y compris le grand fessier et les ischio-jambiers. Ce quiz explore leur efficacité et rôle dans l'extension de la hanche, ainsi que l'impact de la position du genou. Testez vos connaissances sur l'anatomie musculaire et leur fonctionnement.