Question

Upper segment to lower segment ratio in a 3 year old child is:

• A. 1.2
• B. 1.3
• C. 1.4
• D. 1.6

Hint:

US:LS falls with age: 1.7 at birth, 1.3 at 3 yr, 1.0 at 7 yr.

Answer 1

The Correct Option is B

Step 1: Recall the definition. The body is split at the pubic symphysis into an upper segment (head plus trunk) and a lower segment (the legs). Comparing their lengths gives the US to LS ratio.

Step 2: Picture the growth trend. A newborn is top-heavy with short legs, so the ratio is high at roughly 1.7 to 1. As the legs lengthen rapidly through childhood, the ratio declines toward 1 to 1 by about 7 years and then slightly inverts.

Step 3: Place a 3 year old on this curve. It sits between birth (1.7) and 7 years (1.0), and the accepted value at this age is about 1.3 to 1.

Step 4: So among the choices, 1.3 is correct. Higher figures like 1.4 or 1.6 belong to infancy, while 1.2 would be slightly older than three.

\[\boxed{1.3}\]