What innervates the iliocostalis muscle?

The iliocostalis muscle, part of the erector spinae group, is innervated by the lower cervical, thoracic, and upper lumbar spinal nerves. This innervation is crucial as it allows for the muscle's function in extending and laterally bending the vertebral column, which is essential for maintaining posture and facilitating movements such as bending and twisting.

The lower cervical spinal nerves contribute to the innervation by providing motor signals to the muscle fibers located in the cervical region. The thoracic spinal nerves are critical for innervating the segments of the iliocostalis that are responsible for movements in the thoracic region of the spine. Upper lumbar spinal nerves also play a role as they innervate the lower parts of this muscle, enabling proper functioning across a larger range of the spine.

This combination of innervation allows the iliocostalis muscle to effectively perform its role as a stabilizer and mover of the spine, highlighting the integrated function of multiple spinal nerves in controlling muscle action.