American Academy of Professional Coders (AAPC) Practice Exam

Which type of membrane lines joint cavities?

1. Mucous Membrane

2. Serous Membrane

3. Synovial Membrane

4. Meninges

The correct answer is: Synovial Membrane

The synovial membrane is specifically designed to line the cavities of joints, also known as synovial joints. This type of membrane produces synovial fluid, which serves several important functions, such as lubricating the joint to reduce friction during movement, providing nutrients to the cartilage, and acting as a shock absorber for the joint. The synovial membrane is crucial for maintaining joint health and facilitating smooth motion between bones. In contrast, mucous membranes line various body cavities that open to the exterior, such as the respiratory or gastrointestinal tracts, and are involved in secretion and absorption but do not line joint cavities. Serous membranes, on the other hand, are found lining body cavities that do not open directly to the exterior and cover the organs within these cavities—examples include the pleura surrounding the lungs and the peritoneum covering the abdominal organs. Meninges are protective membranes that encase the brain and spinal cord rather than joint spaces. Understanding these distinctions is key to recognizing the specific roles and locations of different membrane types in the body.