Explain proximal vs distal and superficial vs deep with an example.

• A. Proximal is closer to the trunk; distal is farther from the trunk. Superficial is closer to the surface; deep is farther from the surface. Example: elbow is proximal to wrist; skin is superficial to muscles.
• B. Proximal is farther from the trunk; distal is closer to the trunk. Superficial is deeper; deep is closer to the surface. Example: knee is distal to thigh; bones are deep to skin.
• C. Proximal means the part is larger; distal means smaller. Superficial means inside; deep means outside. Example: hand is proximal to shoulder; muscles are superficial to bones.
• D. Proximal and distal terms describe surface texture; superficial and deep describe temperature. Example: skin near arm is proximal; bone is deep.

Answer: (A)

Proximal and distal describe distance along a limb relative to the trunk. Proximal means closer to the trunk; distal means farther from the trunk. Superficial and deep describe depth from the body surface. Superficial is nearer the surface; deep is farther beneath the surface.

Using the arm as a guide: the elbow is closer to the trunk than the wrist, so the elbow is proximal to the wrist. The skin sits on the outside, so it is superficial to the muscles underneath, which are deeper.

Other options mix up these directions or depth, such as reversing proximal/distal or superficial/deep, which would not correctly describe the relationships.