Which of the following is a core muscle of the Inner Unit?

• A. Pelvic Floor
• B. Transverse Abdominis
• C. Diaphragm
• D. Quadratus Lumborum

Answer: (A)

The Inner Unit stabilizes the spine with a coordinated set of deep muscles that brace from inside. The pelvic floor forms the bottom of this stabilizing system, working with the diaphragm at the top and the transverse abdominis in front to maintain internal pressure and spinal stiffness during movement. Because it directly contributes to this internal brace and pelvic stability, the pelvic floor is a core muscle of the Inner Unit. The diaphragm and transverse abdominis are also part of that inner group, while the quadratus lumborum serves more as a broader back stabilizer rather than a primary inner-unit member.