Passive insufficiency can be exemplified by tight structures that cannot reach a position.

• A. Tight structures → cannot reach position
• B. Nerve damage
• C. Pain during movement
• D. Dehydration after exercise

Answer: (A)

Passive insufficiency occurs when a muscle that crosses more than one joint is so tight that it cannot lengthen enough to allow full passive range of motion at all the joints it crosses. When a structure is tight, it can’t reach the end position because the muscle can’t lengthen further to accommodate that position. A classic example is a two-joint muscle like the gastrocnemius, which crosses the knee and ankle: with the knee straight, the muscle is relatively short and can limit ankle dorsiflexion; bending the knee allows more dorsiflexion, illustrating how the muscle’s length across both joints prevents reaching the full end range. This is why the statement about tight structures that cannot reach a position fits passive insufficiency. Nerve damage would cause neurological deficits, pain during movement is a symptom rather than a limitation imposed by muscle length, and dehydration after exercise is unrelated to passive range of motion.