Lateralflexion

Lateralflexion, also known as lateral flexion or lateroflexion, is the movement of bending the spine or torso sideways toward the right or left. This motion can occur in the cervical, thoracic, or lumbar regions and is often accompanied by some rotation of the trunk, though it can occur in isolation.

Anatomy and mechanics: Lateral flexion is produced by several muscle groups acting on the spine. In the lumbar region, the quadratus lumborum, erector spinae (including the iliocostalis and longissimus), and the oblique abdominal muscles contribute to side bending. Intertransversarii between the vertebrae assist in guiding motion. In the cervical region, deep neck muscles such as the intertransversarii, along with the sternocleidomastoid and portions of the splenius muscles, help produce lateral flexion. The thoracic cage and rib attachments limit the degree of flexion in that region.

Range of motion and assessment: Normal ranges vary by region; cervical lateral flexion is typically about 40 to 50 degrees per side in healthy individuals, while lumbar lateral flexion is commonly around 20 to 40 degrees per side. Clinically, lateroflexion is evaluated during spinal range-of-motion testing with goniometers or inclinometers, and pain or restricted movement during the test can indicate facet joint pathology, disc involvement, or nerve irritation. Severe, asymmetric lateral flexion may relate to scoliosis or muscular imbalance.

Function and contexts: Lateral bending is integral to many daily activities and athletic movements, such as reaching the side, bending to pick up objects, or performing side stretches in exercise and physical therapy. It is a fundamental component of several postural and conditioning programs.