The splenius cervicis (/ˈspliːniəs sərˈvaɪsɪs/) (also known as the splenius colli, /- ˈkɒlaɪ/) is a muscle in the back of the neck. It arises by a narrow tendinous band from the spinous processes of the third to the sixth thoracic vertebrae; it is inserted, by tendinous fasciculi, into the posterior tubercles of the transverse processes of the upper two or three cervical vertebrae.

Splenius cervicis muscle
Muscles connecting the upper extremity to the vertebral column. (Splenius capitis et cervicis labeled at upper right, at neck.)
Details
Origin	Spinous processes of T3-T6
Insertion	Transverse processes of C1-C3
Artery	Transverse cervical artery and occipital artery
Nerve	Posterior rami of the lower Cervical spinal nerves
Actions	Bilaterally: Extend the head and neck, Unilaterally: Lateral flexion to the same side, Rotation to the same side.
Identifiers
Latin	musculus splenius cervicis
TA98	A04.3.02.104
TA2	2274
FMA	22681
Anatomical terms of muscle [edit on Wikidata]

Its name is based on the Greek word σπληνίον, splenion (meaning a bandage) and the Latin word cervix (meaning a neck).^[1] The word collum also refers to the neck in Latin.^[1]

The function of the splenius cervicis muscle is extension of the cervical spine, rotation to the ipsilateral side and lateral flexion to the ipsilateral side.^[2]