In anatomy, what does the term lumen refer to?

• A. The fibrous connective tissue covering the surface of a bone
• B. The hollow interior space within a tubular structure (such as a blood vessel or intestine)
• C. A deep depression on a bone where another bone articulates
• D. The outermost layer of the skin composed primarily of keratinized cells

Answer: (B)

Verified step by step guidance

1. Step 1: Understand that the term 'lumen' is used in anatomy to describe a specific part of tubular structures in the body.
2. Step 2: Recognize that many organs and vessels, such as blood vessels, intestines, and other hollow organs, have a central hollow space through which substances pass.
3. Step 3: Identify that this central hollow space inside these tubular structures is called the 'lumen'.
4. Step 4: Differentiate the lumen from other anatomical terms such as the fibrous connective tissue covering bones, bone depressions, or skin layers, which refer to different structures.
5. Step 5: Conclude that the lumen specifically refers to the hollow interior space within a tubular structure, allowing passage of fluids or other contents.