The abductor pollicis longus (APL) is located in which planes of the forearm?

The abductor pollicis longus (APL) is located in which planes of the forearm?

• A. Frontal
• B. Sagittal
• C. Coronal
• D. Frontal and Sagittal

Answer: (D)

Anatomical planes describe how structures sit in three-dimensional space, and many forearm muscles don’t stay confined to a single flat plane because their fibers run obliquely as they reach the hand. The abductor pollicis longus starts on the posterior surfaces of the radius and ulna (and the interosseous membrane) and sweeps laterally toward the base of the first metacarpal. Its tendon travels in an oblique path around the radius to insert at the thumb, so parts of its course lie in different planes: some portions align more with the sagittal (left–right) orientation, while others align with the frontal (anterior–posterior) orientation. Because of this oblique trajectory, it’s accurate to say the muscle is located in both the frontal and sagittal planes. This reflects how forearm muscles often span multiple planes to enable complex thumb movement.

Anatomical planes describe how structures sit in three-dimensional space, and many forearm muscles don’t stay confined to a single flat plane because their fibers run obliquely as they reach the hand. The abductor pollicis longus starts on the posterior surfaces of the radius and ulna (and the interosseous membrane) and sweeps laterally toward the base of the first metacarpal. Its tendon travels in an oblique path around the radius to insert at the thumb, so parts of its course lie in different planes: some portions align more with the sagittal (left–right) orientation, while others align with the frontal (anterior–posterior) orientation. Because of this oblique trajectory, it’s accurate to say the muscle is located in both the frontal and sagittal planes. This reflects how forearm muscles often span multiple planes to enable complex thumb movement.