What nerves provide innervation to the Semispinalis muscle?

The Semispinalis muscle is part of the deep layer of the back muscles, specifically within the transversospinalis group. This muscle is primarily responsible for extending and rotating the vertebral column and is innervated by the dorsal rami of spinal nerves.

The correct answer indicates that both cervical and thoracic spinal nerves provide the necessary innervation for the Semispinalis muscle. This is consistent with the anatomical position of the Semispinalis muscle, as it spans multiple vertebral levels in the cervical and thoracic regions. The cervical innervation enables the muscle to contribute to the movement of the neck, while the thoracic innervation affects the upper back region, allowing for coordination in trunk and neck movements.

In contrast, options suggesting that only lumbar or only specific spinal nerve regions (either cervical or thoracic) provide innervation fail to account for the full anatomical distribution and functional requirements of the muscle, thus leading to an incomplete understanding of how this muscle is activated during movement.