Fat pads are masses of closely packed fat cells, also known as adipocytes, surrounded by fibrous tissue septa. Think of them as pockets of fat cushioned within other tissues. These pads are often extensively supplied with capillaries and nerve endings. In some cases, like intra-articular fat pads, they are also covered by a layer of synovial cells.
Key Characteristics of Fat Pads:
- Composition: Primarily composed of adipocytes (fat cells).
- Structure: Enclosed by fibrous connective tissue.
- Vascularization: Rich in blood vessels (capillaries).
- Innervation: Supplied with nerve endings.
- Location: Found in various locations throughout the body, often near joints.
Functions of Fat Pads:
The primary functions of fat pads relate to:
- Cushioning and Protection: They act as shock absorbers, protecting underlying structures like bones, tendons, and nerves from impact and pressure.
- Space Filling: They fill in empty spaces around joints, aiding in proper joint mechanics.
- Nutrient Storage: Adipocytes store energy in the form of triglycerides.
- Potential Role in Inflammation: While primarily cushioning, they can sometimes become inflamed themselves.
Examples of Fat Pads:
- Infrapatellar fat pad (Hoffa's fat pad): Located below the kneecap, this is one of the most well-known fat pads and is susceptible to injury and inflammation (Hoffa's syndrome).
- Suprapatellar fat pad: Situated above the kneecap, contributing to the cushioning within the knee joint.
- Retrocalcaneal fat pad: Located behind the heel bone, providing cushioning between the Achilles tendon and the calcaneus.
- Buccal fat pad: Located in the cheek.
Clinical Significance:
Fat pads can be affected by:
- Inflammation: Inflammation of a fat pad, often due to injury or overuse, can cause pain and swelling.
- Impingement: The fat pad can become trapped or impinged between other structures, leading to pain.
- Degeneration: Age and wear and tear can cause changes in the fat pad.
Fat pads play a crucial role in the biomechanics and health of joints. Understanding their structure and function is important in diagnosing and treating various musculoskeletal conditions.
