Beevor's Sign is associated with paraspinal muscles innervated by which spinal levels?

• A. Abdominal muscles
• B. Latissimus dorsi
• C. Intercostal muscles
• D. Paraspinal muscles innervated by T5-T12

Answer: (D)

Beevor's sign reflects weakness of the trunk muscles controlled by the thoracic spinal segments, particularly the paraspinal muscles along the spine. When a person with this weakness performs trunk flexion, the upper abdominal muscles can drive the movement more than the lower ones, causing a characteristic shift of the umbilicus upward. The paraspinal (erector spinae) muscles that stabilize the trunk are innervated by the dorsal rami of the thoracic nerves, mainly from levels T5 through T12. So Beevor's sign points to involvement of paraspinal muscles innervated by T5–T12. The other muscle groups listed are innervated by different nerves and do not align with this thoracic-segment pattern.