What are the joints of the human body?

The connecting devices between bones are called joints. The relatively large joints of the human body include shoulder joints, elbow joints, hip joints, knee joints, ankle joints, etc.

Joints generally consist of articular surfaces, joint capsule, and joint cavities.

Articular surfaces are the contact surfaces between bones. The protruding spherical surface is called the joint head, the opposite concave surface is called the joint fossa, and the joint surface is covered with a relatively thin layer of transparent cartilage, which is called the joint cartilage. This layer of cartilage is very smooth and elastic, it is sandwiched between the concave and convex surface, when the person moves, it can reduce the friction of the adjacent two bones and the vibration and impact during movement, and play a cushioning role.

The joint capsule is a tough connective tissue that attaches to the periphery of the articular surface and wraps around the entire joint, firmly connecting the two adjacent bones. The inner surface of the cyst wall secretes synovial fluid, reducing friction on the articular surface.

The articular cavity is a cavity surrounded by the joint capsule and the articular surface, and there is a small amount of synovial fluid in it, which acts as a lubricating agent and can reduce the friction between bones. Joints are the hub of the body's movements. But not every joint can do all kinds of movement.

For example, knuckles can only be flexed and extended; The wrist joint can not only flex and extend, but also adduct and abduct. The shoulder joint can do multi-directional, wide-range movements. This is mainly due to the different shape of the articular surfaces of the joints, and therefore, the range and direction of motion of different joints are also different.

A person's joints are not the same in childhood, adolescence and adulthood. In childhood and adolescence, the articular cartilage is thicker, and the articular capsule and ligament are more extensible, so the range of motion of the joint is much larger than that of adults, but the firmness is poor. As for adults, the amplitude of joint movement is also different.

If the joints do not move for a long time, they are prone to become stiff and even lose the ability to move.

People who exercise regularly can thicken the joint capsule and ligaments, which increases the firmness, flexibility and flexibility of the joints.

It is mainly composed of three parts: joint head, joint capsule and joint socket, and the joint head and joint socket are covered with articular cartilage to play the role of vibration damping.

Joints are one of the components of the human locomotor system, which is found in everyone, so do you know its components, let's take a look.

01 The basic structure is the articular surface, that is, the surface that is in direct contact between the joints, which is generally made up of bone surface or cartilage surface, which can slide against each other.

02 Joint capsule. The joint capsule is also one of the basic structures of the joint, which is a dense connective tissue attached to the joint, which wraps and strengthens the joint, which is of great significance for the stability of the joint.

03 Ligaments. This should be common in all kinds of advertisements, ligaments are made up of dense connective tissue, which plays an important role in stabilizing joints.

04 Articular discs and labials. Probably you haven't heard of these two structures, these two structures are very similar, both belong to the fibrocartilage disk, and only exist in the synovial joints.

There are many joints in the human body, mainly distributed in the limbs, such as the shoulder joints, elbow joints, wrist joints and knuckles of the upper limbs, and the hip joints, knee joints, ankle joints and so on of the lower limbs

Therefore, the answer is: such as the shoulder joint, elbow joint, wrist joint and knuckle joint of the upper limbs, and the hip joint, knee joint, ankle joint of the lower limb

Although the joints of the human body are diverse, their basic structure is no less than the joint surface, joint capsule, and joint cavity.

1. Articular surface: The smooth surface where each bone touches each other is called the articular surface. The articular surface is covered by a layer of cartilage called articular cartilage.

2. Joint capsule: It is composed of connective tissue, which attaches to the bone surface around the articular surface. It can be divided into two layers, the outer layer is the fiber layer, which is composed of dense connective tissue; The inner layer is the synovial layer, which is composed of a thin layer of loose connective tissue, which secretes synovial fluid and plays a lubricating role.

3. Joint cavity: It is the closed space between the articular cartilage and the joint capsule.

4. Articular cartilage: reduce friction between bones.

5. Joint head: Closely linked with the joint socket for exercise.

6. Joint socket: Tightly connect with the joint head and carry out exercise. Basic lesions of the joints.

According to the shape of the articular surface, it can be divided into:

1. Ball-and-socket joint.

The articular head is globous, and the articular surface of the other bone is fossa that wraps a portion of the articular head. Therefore, the joint head and the socket are only loosely connected, and can flexion, extension, adduction, abduction, circumferential rotation and rotational movements, which is the most mobile joint structure. Typical: hip.

Flexion and extension are performed around the frontal axis, abduction and adduction are performed around the sagittal axis, and rotation is done around the vertical axis.

2. Plane joints.

The occurrence of this joint activity is secondary to other activities. For example, when you flex and extend the elbow joint.

, no other joint movement is caused. However, the carpal bones.

Movement cannot be run by just one activity. The wrist joint is required for the movement of the carpal bones.

Performed under the premise of flexion and extension or abduction and adduction.

3. Ellipse joint.

It is composed of two oval articular surfaces, convex and concave, which can be used for anterior-backward and left-right movements. Typical example: wrists. The wrist is centered on the frontal axis to produce flexion and extension movements, and the sagittal axis is used as the center for ulnar and radial deviation.

4. Saddle joint.

The articular surface of each bone is both the joint head and the joint socket, which can be flexed, extended, adducted, abducted and circumferential, and has greater mobility than the elliptical joint.

Typical: thumb joint. Although the thumb can flex, extend, adduct, abduct, and rotate, it is similar to carpal movement in that it is secondary to other joint movements.

If, without flexion and abduction, you try to turn your thumb and you find that you can't do it.

When the thumb is adducted, pay attention to the direction of the lower thumb; When the thumb is abducted and flexed, the direction of the pointing changes approximately 90 degrees. This rotational action is not active, but is caused by the shape of the joint. Although the thumb joint is not a true biaxial joint because of the limitation of rotation, it is still homing because the active movement occurs around both axes.

5. Trochlear (flexion) joint.

The protruding part of one bone is embedded in the concave part of the other bone, and can only be flexed and extended in a single plane, as in the operation of a door hinge. The humeral-ulnar joint in the elbow joint is a good example.

6. an axle joint.

The radial-ulnar joint shows another type of uniaxial movement—the axle joint. When the forearm is supinated anteriorly and supination, the ulna.

Without moving, the radial head moves around the ulna. Axle motion is actually a movement on a horizontal plane centered on the longitudinal axis.

Human joints can be roughly divided into eight types: flexion joints (such as interphalangeal joints of the hand), snail-like joints (such as ankle joints), axle joints (such as proximal radial-ulnar joints), elliptical joints (such as radial-wrist joints and occipital atlantal joints), saddle joints (such as the wrist-metacarpal joint on the thumb side), ball-and-socket joints (such as shoulder joints), clubbed joints (such as hip joints), and planar joints (such as joints between tarsal bones).

Interphalangeal joints. Ankle and radial carpal joints.

Metacarpal joint. Shoulder, hip.

The surface of the joint is cartilage, which has a certain elasticity and toughness, and can withstand greater pressure and impact. On the surface of the articular cartilage, there is a thin layer of fluid called synovial fluid. The function of synovial fluid is mainly to reduce joint softness.

The friction on the surface of the bone lubricates, cushions and absorbs heat. At the same time, synovial fluid is the main nutrient of articular cartilage**, which plays an important role in maintaining the integrity and function of articular cartilage.

2) Joint capsule: The joint capsule is a closed structure, which is used to wrap the bones that make up the joint and connect it into a whole to keep the joint stable during movement.

3) Joint cavity: The space in the joint capsule is the joint cavity, and one of the important structures is the joint disc (also called the cartilage plate). The disc acts like a cushion washer between two bones, reducing shock and vibration between the bones of the joint.

The disc in the knee joint is called the meniscus, and it makes the knee joint more stable and flexible.

In short, when the body signs age or suffers from disease, it inevitably affects all parts of the joints and causes changes in the bones.

The joint is composed of three parts: the articular surface, the joint capsule and the joint cavity. ]

Clinical Core Test Points01 Anatomy 01 Osteology and Arthrology 02 Basic Structure of Joints: Articular Surface, Joint Capsule, Joint Cavity; Auxiliary structures.

Belch. I forgot, but it should be like the above].

Head: temporomandibular joint, neck:

Atlantoaxial joints, intervertebral joints between the vertebrae, sternoclavicular joints, shoulders:

Acromioclavicular joint, shoulder joint.

Elbow: elbow joint, proximal ulnar joint,

Wrist: deflex ulnar distal joint, wrist joint,

Metacarpal joints, interphalangeal joints, waist of the hand:

Lumbosacral joint, pelvis:

The sacroiliac joint and pubic symphysis are semi-joints.

Lower limbs: hip joint, knee joint, proximal tibia and fibular joint, distal tibia and fibular joint, ankle joint, foot: metatarsophalangeal joint, interphalangeal joint.