HIP JOINT DISTAL ARTICULATION (HIP JOINT COMPLEX BIOMECHANICS)Physiotherapy Tutorials

Summary

In this video, Adeb from Movement Science explains the digital articulation of the hip joint, focusing on its structure and two key angles: the angle of inclination and angle of torsion. He discusses the femoral head, neck, and acetabulum, along with related ligaments, particularly the teres ligament. Adeb elaborates on how these angles vary with age, sex, and health conditions, and their clinical relevance, such as in conditions like coxa valga and hip dysplasia. The video also covers the frog-leg position used in treating congenital hip dislocation, along with insights into articular congruence and how the hip joint functions in non-weight bearing positions.

Takeaways

• 😀 The hip joint consists of a femoral head (ball) that fits into the acetabulum (socket), with the fovea capitis being a key feature where the teres ligament attaches.
• 😀 The angle of inclination describes how much the femoral neck is tilted upward and typically ranges from 115° to 140°; it is generally smaller in women and decreases with age.
• 😀 A pathological increase in the angle of inclination is known as coxa valga, while a decrease is referred to as coxa vara.
• 😀 The angle of torsion refers to the twist of the femoral neck relative to the femoral condyles, with normal adult values ranging from 10° to 20°.
• 😀 Anteversion (excessive forward twisting) and retroversion (backward twisting) are conditions related to abnormal angles of femoral torsion.
• 😀 Hip dysplasia may be associated with an increased angle of torsion, typically around 42° ± 16°.
• 😀 Femoral torsion develops early in fetal life, starting at around 8 weeks when the lower limbs rotate into position.
• 😀 The frog-leg position, involving flexion, abduction, and lateral rotation, is important for maximizing femoral head contact with the acetabulum, particularly in cases of congenital hip dislocation.
• 😀 In non-weight bearing positions, the hip joint is incongruent due to the size mismatch between the femoral head and acetabulum, but this is compensated by a partial vacuum created in the acetabular fossa.
• 😀 The acetabular fossa’s partial vacuum is similar to the shoulder joint’s vacuum mechanism, helping stabilize the hip joint in certain positions.
• 😀 The development and changes in the angles of inclination and torsion are influenced by weight-bearing forces and anatomical differences, especially in children and adults.

Q & A

What is the digital articulation of the hip joint?

The digital articulation of the hip joint refers to the connection between the rounded head of the femur and the acetabulum, where two-thirds of the femoral head is covered by articular cartilage. The fovea capitis is a central area of the femoral head with no cartilage, where the ligament teres attaches.

What is the role of the ligament teres in the hip joint?

The ligament teres attaches from the fovea capitis of the femoral head to the acetabulum. It contains blood vessels that supply the head of the femur, contributing to the vascularization of the hip joint.

What is the angle of inclination of the femur?

The angle of inclination refers to how much the neck of the femur is inclined upwards relative to the shaft. The average value is around 126 degrees, but it can range from 115 to 140 degrees.

How does the angle of inclination vary between men and women?

Women typically have a smaller angle of inclination than men due to their wider pelvis, which affects the orientation of the femoral neck.

What happens to the angle of inclination with age?

As a person ages, the angle of inclination tends to decrease due to increased weight-bearing, which causes the femur to change its orientation over time.

What is coxa valga and coxa vara?

Coxa valga refers to an abnormally increased angle of inclination, while coxa vara refers to a decreased angle of inclination. These conditions can affect the mechanics of the hip joint.

What is the angle of torsion in the femur?

The angle of torsion refers to the amount of twist of the femoral neck relative to the femoral condyles. It is measured by the angle formed between the axis of the femoral head and neck and the axis of the femoral condyles.

What is the difference between anteversion and retroversion of the femur?

Anteversion refers to the femoral neck being twisted anteriorly, while retroversion refers to it being twisted posteriorly. These conditions can affect the alignment and function of the hip joint.

How does the angle of torsion change with age?

The angle of torsion decreases with age. In children, it is typically around 40 degrees, while in adults, it ranges from 10 to 20 degrees.

What is the frog leg position and its significance in hip joint congruence?

The frog leg position involves flexion, abduction, and lateral rotation of the hip joint. This position is important for achieving maximum contact between the femoral head and the acetabulum, particularly in the treatment of congenital hip dislocation.