Synovial bursa

Synovial bursa refers to a small fluid-filled sac lined by synovial membrane with an inner capillary layer of viscous fluid (synovial fluid). It is found in areas where tissues such as skin, muscle, ligaments, and tendons rub over bone. The primary function of a synovial bursa is to reduce friction between these moving tissues and the bone underneath, thereby facilitating smooth movement of the joints.

Structure

A synovial bursa is a closed sac that provides a gliding surface to reduce friction. It is composed of an outer fibrous layer known as the membrane and an inner synovial layer. The synovial layer produces the synovial fluid, which is rich in hyaluronic acid, making it viscous and elastic. This fluid acts as a lubricant to minimize friction and wear between the tissues.

Function

The main function of the synovial bursa is to cushion and reduce friction between moving parts of the body, such as where muscles and tendons slide across bone and joints. This is crucial for the smooth movement of joints and for protecting the underlying bone from wear and tear.

Types

There are over 150 synovial bursae in the human body, and they are typically classified by their location. Some of the most well-known include:

• Prepatellar bursa: Located in front of the kneecap.
• Olecranon bursa: Found at the tip of the elbow.
• Subacromial bursa: Situated under the acromion of the shoulder.
• Trochanteric bursa: Located at the side of the hip.
• Ischial bursa: Found in the buttock area, near the ischial tuberosity.

Clinical Significance

Bursae can become inflamed, a condition known as bursitis, which can cause pain, swelling, and restricted movement. Bursitis can be caused by repetitive motion, trauma, infection, or conditions such as rheumatoid arthritis. Treatment typically involves rest, ice, and anti-inflammatory medications. In severe cases, corticosteroid injections or surgery may be necessary.

Prevention

Preventing bursitis involves avoiding repetitive motions or positions that put excessive pressure on the bursae. Regular stretching and strengthening exercises can also help maintain joint health and prevent bursitis.

See Also

• Joint
• Ligament
• Tendon
• Muscle
• Bone
• Rheumatoid arthritis
• Osteoarthritis