Is the trapezius muscle located in the abdomen, back, head, neck, or thorax?

The correct answer will be options neck and back.

Explanation:

The trapezius muscle is a broad and flat muscle which is named for its "trapezoid" shape. This triangular muscle is one of the widest back muscles beneath the skin which work to stabilize the scapula, turn and tilt the head and neck and twist the arms.

This muscle covers the upper back of the shoulders and neck extending from the occipital bone (base of the skull) to middle of the back which is divided into three parts:

1. Upper part: at the back of the neck.

2. Middle part:  in the shoulders and upper back.

3. Lower part:  in the middle of the back.

Thus, the neck and back are the correct options.