When you lift your thumb, there is a temporary white or blanched area where your thumbprint was, but it vanishes in a second. The thumbprint leaves no depression. If your feet are swollen, you can repeat the procedure but sometimes the thumbprint area remains indented after the white color vanishes. What is the most likely explanation for these two phenomena?
*A. Pressing the skin alters the melanocyte distribution and damages and indents the underlying subcutaneous tissues.
*B. Pressing on the skin forces blood from surface capillaries; the impression on the foot is from failure of the blood to return.
*C. Pressing on the skin forces blood from surface capillaries; the impression on the foot is from fluid in the tissues or edema, and that does not rapidly return.
*D. Pressing on the skin forces lymph from lymphatics; the color changes are due to bruising or blood cells lost to interstitial regions.
*E. Pressing on the skin forces blood and plasma out of surface capillaries; the liquid lymph returns to the vessels but the thick albumins clog the tissues.
Can you explain why the answer is C?
*A. Pressing the skin alters the melanocyte distribution and damages and indents the underlying subcutaneous tissues.
*B. Pressing on the skin forces blood from surface capillaries; the impression on the foot is from failure of the blood to return.
*C. Pressing on the skin forces blood from surface capillaries; the impression on the foot is from fluid in the tissues or edema, and that does not rapidly return.
*D. Pressing on the skin forces lymph from lymphatics; the color changes are due to bruising or blood cells lost to interstitial regions.
*E. Pressing on the skin forces blood and plasma out of surface capillaries; the liquid lymph returns to the vessels but the thick albumins clog the tissues.
Can you explain why the answer is C?