The sternocleidomastoid muscle is a paired muscle.
Anatomy
Origin
The sternocleidomastoid muscle originates by one head from the sternum and by the other head from the clavicle.
Insertion
The sternocleidomastoid muscle inserts on the Processus mastoideus
Function
With unilateral innervation, the sternocleidomastoid muscle rotates the head to the contralateral side and tilts it toward the ipsilateral side. With bilateral innervation, the head is elevated[^1].
Innervation
The sternocleidomastoid muscle is innervated by the Nervus accessorius
Clinical relevance
During the surgical approach for ACDF surgery, the sternocleidomastoid muscle serves as an important landmark, as the approach is performed directly medial to the course of the muscle.
