Nepedia
Back to Discover
Advanced Reader
🧬

Hip

life science Maturity 11-13 Next article →

The hip is a vital anatomical region and joint in the vertebrate body. It serves as the primary connection between the lower limbs and the axial skeleton of the trunk. In medical terminology, the hip refers to an anatomical region or a joint on the lateral side of the pelvis. The hip joint is scientifically known as the acetabulofemoral joint or the coxofemoral joint. Its primary function is to support the weight of the torso during both static and dynamic postures. This means it holds you up while standing still and manages forces while walking or running. It also plays a critical role in maintaining balance and pelvic inclination angles.

Hueftgelenk-gesund
Hueftgelenk-gesund

The mechanics of the hip rely on a ball-and-socket synovial joint structure. This joint is formed by the articulation of the rounded femoral head and the cup-like acetabulum of the pelvis. The femoral head is the top portion of the femur, which is the thigh bone. The acetabulum is a socket that faces downwards and anterolaterally. To ensure smooth movement, both joint surfaces are covered with articular hyaline cartilage. This is a strong, lubricated layer of tissue. The acetabulum itself is formed at the union of three pelvic bones: the ilium, the ischium, and the pubis. In adults, these three bones have fused into a single hip bone.

Canova-Dancer with her hands on her hips 45degree view
Canova-Dancer with her hands on her hips 45degree view

Several specific structures deepen the stability of this joint. The acetabulum grasps almost half of the femoral ball. This grip is strengthened by the acetabular labrum, which is a horse-shoe shaped ring of fibrocartilage. The labrum extends the joint beyond its equator to hold the bone in place. The femoral head has an average radius of curvature of 2.5 cm. Inside the acetabulum, the center is called the fovea. The fovea does not articulate with anything; instead, it is lined with a fat pad and attached to the ligamentum teres. This intracapsular ligament can be a vital conduit for a small artery supplying the femoral head.

Coxa-valga-norma-vara-000
Coxa-valga-norma-vara-000

The hip is reinforced by a strong fibrous capsule and four key ligaments. The capsule has two sets of fibers: longitudinal and circular. The circular fibers form a collar around the narrowest part of the femoral neck called the zona orbicularis. This acts like a buttonhole to help maintain joint contact. Three of the ligaments are extracapsular: the iliofemoral, ischiofemoral, and pubofemoral ligaments. The iliofemoral ligament is the strongest ligament in the human body, with a tensile strength of 350 kg. It is a Y-shaped, twisted structure that prevents the trunk from falling backward when standing. This allows you to remain upright without constant muscular activity.

Specific angles define the health and shape of the hip. The acetabular angle, or Sharp's angle, changes significantly during growth. It measures 35 degrees at birth but drops to less than 10 degrees by age 15. In adults, this angle typically ranges from 33 to 38 degrees. Another measurement is the caput-collum-diaphyseal angle, or CCD angle. This is the angle between the axes of the femoral neck and the shaft. In newborns, this angle is approximately 150 degrees, but it decreases to about 126 degrees in adults. If this angle is too small, it is called coxa vara; if it is too large, it is called coxa valga.

Changes in these angles can affect the rest of the body. For example, coxa valga is often associated with genu varum, or bow-leggedness. Conversely, coxa vara can lead to genu valgum, which is known as knock-knees. These changes occur because the shape of the femur affects the alignment of the knee. Such shifts in shape also change the stress patterns applied to the bone. These stress patterns influence the trabecular patterns, which are the internal structures of the bone. Dislocation or other injuries can cause these internal patterns to shift as well.

Blood supply is essential for maintaining the health of the hip joint. The joint receives blood from the medial and lateral circumflex femoral arteries. These are usually branches of the profunda femoris, the deep artery of the thigh. There are also important connections called anastomoses, such as the cruciate and trochanteric anastomoses. The trochanteric anastomosis provides most of the blood to the femoral head. Maintaining this blood supply is vital to avoid avascular necrosis, a condition where bone tissue dies due to lack of blood. This is especially important if the neck of the femur is fractured.

738 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (3)
File:Hueftgelenk-gesund.jpg
Hueftgelenk-gesund.jpg
File:Coxa-valga-norma-vara-000.svg
Coxa-valga-norma-vara-000.svg
File:Canova-Dancer with her hands on her hips 45degree view.jpg
Canova-Dancer with her hands on her hips...
More to explore

✨ What else?

Related topics you might enjoy

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.