left sternocleidomastoid

In 4 atlases

paired muscle of the neck that traverses the neck between the manubrium sterni and the mastoid process

Description from Wikidata (https://www.wikidata.org/), available under CC0 1.0 (https://creativecommons.org/publicdomain/zero/1.0/).

Origin: left clavicle, manubrium
Insertion: mastoid process, superior nuchal line
Action: flexion of the neck, flexion of the head, lateral flexion of the neck, lateral flexion of the head and neck, rotation of the head, rotation of the neck
Innervation: Anterior ramus of sixth cervical nerve, spinal part of the accessory nerve, Anterior ramus of third cervical nerve, spinal accessory nerve
Arterial supply: sternocleidomastoid branches of occipital artery, left inferior thyroid artery, sternocleidomastoid branch of superior thyroid artery
Venous drainage: sternocleidomastoid vein

The 3D model shows 3 origin and insertion areas of this muscle.