Which statement about muscle origin and insertion is true?

• A. The origin is distal and stable; the insertion is proximal and movable
• B. The origin is proximal, medial and stable
• C. The origin is distal and movable; the insertion is proximal and stable
• D. The origin is proximal and movable; the insertion is distal and stable

Answer: (B)

The key idea is how attachments behave during contraction: the origin is the fixed, anchor attachment, while the insertion is the end that moves toward the origin when the muscle shortens. In most bodies, that anchor end is closer to the trunk (proximal) and toward the midline (medial) compared with the moving end, and it stays relatively stable during the contraction.

So saying the origin is proximal, medial and stable fits that pattern: it identifies the origin as the end near the trunk and towards the midline, which acts as the stable point the muscle pulls from. The other statements imply the origin moves or isn’t near the trunk or midline, which goes against how origins are understood in relation to movement.