The semispinalis capitis (complexus) is situated at the upper and back part of the neck, deep to the splenius, and medial to the longissimus cervicis and capitis.
It arises by a series of tendons from the tips of the transverse processes of the upper six or seven thoracic and the seventh cervical vertebrae, and from the articular processes of the three cervical vertebrae above this (C4-C6).
The tendons, uniting, form a broad muscle, which passes upward, and is inserted between the superior and inferior nuchal lines of the occipital bone.
The medial part, usually more or less distinct from the remainder of the muscle, is frequently termed the spinalis capitis; it is also named the Biventer cervicis since it is traversed by an imperfect tendinous inscription.
It lies deep to the trapezius muscle.
The semispinalis muscles are innervated by the dorsal rami of the cervical spinal nerves.
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