The mystery of the femoral head: location, pressure and pathology

Author: Xiao He, attending physician at Nanfang Hospital, Southern Medical University

Reviewer: Wang Jian, Chief Physician, Nanfang Hospital, Southern Medical University

The femoral head plays a vital role in the complex and delicate skeletal system of the human body. However, do you really understand the location of the femoral head and the key role it plays? Do you know what kind of pressure the femoral head is under in daily life? More importantly, when the femoral head has a disease, such as femoral head necrosis, what is the mechanism and pathological process behind it? Today, let us unveil the mysterious veil of the femoral head.

Where is the femoral head located? What are its functions?

Location of the femoral head: The femoral head is located on the surface of the body at the midpoint of the groin of the hip joint, that is, the middle of the thigh root. From an anatomical point of view, the femoral head is in the hip joint. The hip joint is what people often call the "hip bone."

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2. The role of the femoral head: The hip joint is an important structure of the human body, connecting the trunk and lower limbs, and has the important function of sharing the weight of the upper body and carrying the activities of the lower limbs. The hip joint is one of the larger joints in the human body, responsible for connecting the upper and lower body, and supporting the weight of the upper body. The hip joint is both stable and flexible. It can not only move forward and backward, left and right, but also rotate inward and outward. It is a joint with a very high degree of freedom. It is precisely because the hip joint can rotate freely in a wide range of directions that people can enjoy the fun of various sports. At the same time, there are many ligaments and muscles wrapped around the hip joint, and its stability is relatively high.

The femoral head is an important part of the hip joint. Generally speaking, the hip joint is mainly composed of two parts: a "mortise" and a "head". The "mortise" refers to the acetabulum of the hip bone, and the "head" refers to the femoral head. The femoral head is located below the hip joint and bears the weight of the trunk.

How much pressure does the femoral head bear?

1. When a person is standing still, the femoral heads on both sides bear 50% of the pressure of the upper body weight.

2. Walk slowly. The moment one leg leaves the ground, the other leg will bear a pressure of 1.5 to 2.0 times the weight of the upper body.

3. When walking quickly and bearing weight on one leg, the femoral head on the weight-bearing side will bear a pressure that is more than twice the weight of the upper body.

4. When going up and down stairs with one leg bearing weight, the femoral head on the weight-bearing side will bear a pressure of 3 to 4 times the weight of the upper body.

The femoral head is under tremendous pressure every day. Once there is a problem with the femoral head, it will cause hip pain, which will limit movement. The patient will feel pain when walking and cannot enjoy a free and active life, which will inevitably make him feel unhappy.

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In daily life, we need to learn about maintaining hip joints, exercise properly, quit smoking and drinking, control weight, and develop good living habits.

What are the mechanisms and pathological processes of femoral head necrosis?

1. Mechanism of femoral head necrosis: The blood flow to the femoral head is blocked due to various reasons, which will prevent it from getting enough nutrients. Ischemia and hypoxia may occur in the femoral head, and edema may occur, leading to increased pressure. At this time, the patient will feel obvious hip pain, and then the femoral head will collapse because it cannot support the body weight load, resulting in hip deformation and dysfunction. Femoral head necrosis can lead to loss of hip joint function and may cause disability. If not treated correctly, the patient may be "confined" to a wheelchair for life.

2. Pathological process of femoral head necrosis: If we use an apple to represent the femoral head, a normal femoral head is round and smooth like a good apple. However, a necrotic femoral head is like a rotten apple. If the rotten area is the bearing point, it will collapse over time and then gradually rot to the deep part.

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