Which action is performed by the anterior scalene when the ribs are fixed?

• A. Elevate rib cage during inhalation
• B. Flex head and neck
• C. Laterally flex the head and neck to the same side
• D. Rotate head to opposite side

Answer: (B)

With the first rib anchored, the anterior scalene’s main action is to bring the head forward—neck flexion. The muscle connects from the cervical transverse processes to the first rib, so when the rib is fixed, its pull on the cervical vertebrae folds the neck toward the chest. That makes flexing the head and neck the best answer in this scenario.

Elevating the rib cage during inhalation is something the scalenes contribute when the ribs can move, but not when they’re fixed. Unilateral contraction can cause some lateral flexion to the same side (and minor rotation), but the primary action when the rib is fixed is to flex the neck.