Anatomy of joints
Structure and components of a joint
What is a joint?
To understand how arthritis affects your joints, you must know how your joints are made up.
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The joint is the point of contact of two or more bones. |
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The bone ends of the joint are covered with cartilage, which provides a smooth surface for movement. (Articular disk, the plate like end of certain bones in movable joints.) |
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The synovium is a membrane that surrounds the joint and secretes a fluid that lubricates the cartilage and the joint. |
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The whole joint is enclosed in the tough, protective joint capsule. This is the articular capsule, an envelope of tissue that surrounds a joint. It is made up of an outer layer of white fiber like tissue and an inner synovial membrane. |
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Ligaments connect the bones and keep the joints stable. |
Types of joints.
Skull Spine Knee
Fibrous joints Cartilaginous joints Synovial joints
Types of joints.
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Each is classified according to structure and movability as fibrous, cartilaginous, or synovial.
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Fibrous joints or sutures are immovable; |
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Cartilaginous joints are slightly movable; and |
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Synovial joints are freely movable. |
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Typical immovable joints connect most of the bones of the skull with a sutural ligament. |
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Typical slightly movable joints connect the vertebrae and the pubic bones. |
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Most of the joints in the body are freely movable. |
Skeleton
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The supporting frame for the body, it has 206 bones that protect delicate structures, provide attachments for muscles, allow body movement, serve as major reservoirs of blood, and produce red blood cells. |
Vertebral column.
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Vertebra include 33 bones of the spinal column. |
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There are 7 in the neck, 12 in the back, 5 in the lower back, 5 in the pelvic area, and 4 in the tailbone. |
Bones
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The dense, hard, and slightly stretchy connective tissue that makes up the 206 bones of the human skeleton. |
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It is made up of dense bone tissue (osseous) surrounding spongy tissue that contains many blood vessels and nerves. |
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Covering the bone is a membrane called the periosteum. |
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Long bones contain yellow marrow in the long spaces and red marrow in the ends near the joints. |
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Red marrow also fills the spaces of the flat and the short bones, the backbones (vertebrae), the skull, the breastbone (sternum), and the ribs. |
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Blood cells are made in active red marrow. 2. any single element of the skeleton, as a rib, the sternum, or the femur. |