Middle scalene

The middle scalene (Latin: musculus scalenus medius) is a neck muscle situated between the anterior and posterior scalene muscles. It is classified as the scalene muscle and one of the lateral neck muscles. The middle scalene is the largest and longest of the scalene group.

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Middle scalene muscle by Anatomy Next
Middle scalene muscle
OriginPosterior tubercles of the transverse processes of the C2 - C7 vertebrae
Insertion Upper surface of the first rib between the anterior scalene tubercle and subclavian groove
Action

Unilateral contractions - neck lateral flexion (ipsilateral), neck rotation (contralateral), elevation of the first rib

Bilateral contractions - neck flexion

   Innervation Anterior rami of the 3rd to 8th cervical spinal nerves (C3 - C8)
Blood supplyAscending cervical artery

 

Origin

The middle scalene muscle originates from the posterior tubercles of the transverse processes of the 2nd to 7th cervical vertebrae (C2 - C7).

 

Insertion

The middle scalene inserts on the upper surface of the first rib between the anterior scalene tubercle and subclavian groove.

 

Action

By contracting on both sides, the anterior scalene muscle flexes the neck. By contracting on one side, it bends the neck laterally to the same side (ipsilateral). Also, unilateral contractions provide contralateral neck rotation and elevation of the first rib.

 

Innervation

The middle scalene is innervated by the anterior rami of the 3rd to 8th cervical spinal nerves (C3 - C8).

 

Blood supply

The middle scalene muscle receives arterial blood supply from the ascending cervical branch of the inferior thyroid artery.