The longus colli (also longus colli muscle, latin: musculus longus colli) is a prevertebral muscle of the neck extending between the atlas and the thoracic vertebrae, involved in flexion of the head and neck.
The longus colli originates from the transverse processes of the 2nd to 5th cervical vertebrae (C2 - C5), from the bodies of the 5th to 7th cervical vertebrae (C5 - C7) and bodies of the 1st to 3rd thoracic vertebrae (T1 - T3).
The longus colli muscle inserts onto the anterior tubercle of the atlas (C1), the bodies of the 2nd to 4th cervical vertebrae (C2 - C4) and the transverse process of the 6th cervical vertebra (C6).
By contracting on both sides the longus colli flexes the head and neck. By contracting on one side it carries out lateral flexion of the head and neck.
The longus colli is innervated by branches of the anterior rami of the 2nd to 6th cervical spinal nerves (C2 - C6).