The multifidus muscle plays a significant role in the body’s core system and overall spinal health. It is a deep muscle that contributes to spinal stability and movement, making it important for maintaining a healthy back and preventing discomfort.
Understanding Its Anatomy
The multifidus is a group of short, triangular muscles located deep within the back, running along both sides of the spine. These muscles extend from the sacrum at the base of the spine up to the cervical (neck) region, filling the groove between the spinous and transverse processes of the vertebrae. They are part of a larger group known as the transversospinales.
Each individual multifidus muscle segment spans across two to five vertebral levels, connecting one vertebra to another. In the lumbar (lower back) region, fibers originate from the sacrum and lumbar vertebrae, inserting into the spinous processes of vertebrae several levels above. The multifidus is the deepest and most medial of the paraspinal muscles, positioned close to the facet joints of the spine.
Key Functions of the Multifidus
The multifidus muscle performs several important functions for spinal health and movement. Its primary roles include contributing to spinal stability, enabling precise segmental control of individual vertebrae, and providing proprioceptive feedback. This muscle is continuously active, even during quiet standing, providing ongoing support to the spine. This activity helps maintain proper posture and prepares the spine for movement.
The multifidus allows for fine-tuned control of spinal segments, making small, precise adjustments between individual vertebrae. This segmental control is important for smooth and coordinated movements, preventing excessive motion that could lead to injury. When both sides of the multifidus contract, they help extend the vertebral column, allowing the back to bend backward. Unilateral contraction assists in lateral flexion (bending sideways) and rotation of the spine to the opposite side.
Beyond movement, the multifidus also plays a significant role in proprioception, the body’s ability to sense its position and movement in space. This muscle contains specialized sensory receptors called muscle spindles, which send information to the brain about the spine’s position and the degree of muscle stretch. This feedback loop allows the central nervous system to regulate muscle activation and control spinal movement, contributing to neuromuscular control and stability.
Contribution to Spinal Stability
The multifidus muscle is a significant stabilizer of the spine, particularly in the lumbar region. It works as a “local stabilizer,” meaning its actions primarily influence individual segments of the spine rather than producing large movements. This deep muscle group provides continuous, subtle support to the vertebral column, helping to maintain its alignment and integrity during both static postures and dynamic activities.
This muscle contributes to spinal stiffness by exerting a compressive force over small movements, which helps secure spinal segments. This ability to compress each segment enhances stability, resisting forces that might otherwise cause excessive shear or rotation between vertebrae. The multifidus collaborates with other core muscles, such as the transversus abdominis and pelvic floor muscles, to create a coordinated support system that stabilizes the torso and protects the spine.
Continuous activation of the multifidus helps maintain stiffness and stability in the lumbar spine, which is important for preventing injury and supporting the spine under load. Its role in stabilizing the vertebrae before and during limb movements highlights its importance in functional stability. This preemptive engagement ensures that the spine is adequately supported as the body moves, reducing the risk of strain or injury.