Which of the following statements correctly characterizes articular cartilage?

• A. It is composed primarily of elastic fibers.
• B. It is highly vascularized and contains many nerves.
• C. It covers the diaphysis of long bones.
• D. It is avascular and lacks a perichondrium.

Answer: (D)

Verified step by step guidance

1. Understand the definition of articular cartilage: Articular cartilage is a type of hyaline cartilage found at the ends of long bones within synovial joints. Its primary function is to reduce friction and absorb shock during joint movement.
2. Analyze the composition of articular cartilage: Articular cartilage is primarily composed of collagen fibers (specifically type II collagen) and proteoglycans, not elastic fibers. This rules out the option stating it is composed primarily of elastic fibers.
3. Evaluate the vascularization and innervation: Articular cartilage is avascular (lacks blood vessels) and aneural (lacks nerves). Nutrients are supplied through diffusion from synovial fluid. This eliminates the option stating it is highly vascularized and contains many nerves.
4. Consider the location of articular cartilage: Articular cartilage covers the epiphysis (ends) of long bones, not the diaphysis (shaft). This eliminates the option stating it covers the diaphysis of long bones.
5. Confirm the correct characterization: Articular cartilage is avascular, lacks a perichondrium (a dense connective tissue layer found in other types of cartilage), and relies on synovial fluid for nutrient exchange. This matches the correct answer provided in the problem.