Which muscle is a stabilization muscle of the core?

• A. Internal obliques
• B. Psoas major
• C. External obliques
• D. Diaphragm

Answer: (C)

Stability in the core comes from muscles that brace the trunk and resist unwanted movement, rather than those whose main job is to create big motions. The external obliques help with that bracing by forming part of the abdominal wall on the sides. They work with the internal obliques and other deep stabilizers to keep the spine aligned and to control rotation and lateral bending during dynamic activities. This stabilizing action—supporting the ribcage and pelvis and helping transfer forces between the upper and lower body—makes them a key stabilization muscle of the core. Psoas major is mainly a hip flexor, the diaphragm is primarily a breathing muscle (though it does contribute to intra-abdominal pressure), and while internal obliques also aid stability, the external obliques are the best match for a stabilization role in many functional movements.