The multifidus is a deep, small muscle positioned along the spine, playing an important role in maintaining spinal health. Its continuous activity helps support the vertebral column. Understanding this muscle’s function is important for everyday movement and physical well-being.
Understanding the Multifidus
The multifidus muscle is part of the transversospinales group, deep muscles located along the back. It lies beneath more superficial back muscles, nestled within the groove on either side of the spinal processes. This muscle extends along the entire vertebral column, from the sacrum at the base to the axis in the neck, though it is most developed in the lumbar region.
Composed of numerous short, fleshy and tendinous fasciculi, the multifidus connects various vertebral segments. Each segment of the muscle typically spans between two to five vertebral levels, attaching from the transverse processes of one vertebra to the spinous processes of vertebrae above it. This deep and segmented arrangement allows it to exert precise control over individual spinal segments.
Its Core Function
The primary action of the multifidus muscle is the segmental stabilization of the spine. It provides control over individual vertebrae, which is important for maintaining spinal integrity during movement and static postures. This muscle is continuously active, even in upright positions, contributing to stability for anti-gravity activities.
Beyond stabilization, the multifidus also contributes to spinal movements. When both sides contract, they facilitate extension of the vertebral column. Unilateral contraction aids in ipsilateral lateral flexion (bending to the same side) and contralateral rotation (twisting to the opposite side). It stabilizes vertebrae as the spine moves, acting like extensible ligaments to maintain alignment.
Beyond Primary Action
The multifidus muscle also plays a role in proprioception, the body’s sense of its position and movement. This function is supported by a high density of muscle spindles within the multifidus. These sensory receptors provide constant feedback to the brain about the precise position and changes in length of the spinal segments.
This continuous feedback is important for coordinating movements and maintaining balance. The information from the multifidus helps the central nervous system make subtle adjustments, ensuring smooth and controlled spinal motion. This sensory contribution is distinct from its mechanical actions but important for overall spinal function and movement efficiency.
When the Multifidus is Compromised
When the multifidus muscle does not function optimally, it can affect spinal stability. Dysfunction or weakness can lead to decreased control over individual vertebral segments and altered movement patterns. This is often linked to low back pain, with weakness or atrophy associated with chronic cases.
The muscle may become inhibited or lose function following injury, inactivity, or poor posture. This can create a cycle where instability contributes to discomfort.