Muscle
Anterior scalene
Key neck landmark
High-yield
Phrenic nerve lies on its anterior surface; subclavian artery and brachial plexus pass between anterior and middle scalenes (interscalene triangle).
Overview
A deep lateral neck muscle that elevates the first rib and flexes the neck; the phrenic nerve descends on its surface and the brachial plexus/subclavian artery pass behind it.
Reference facts
- Origin
Transverse processes of C3–C6
- Insertion
Scalene tubercle of the first rib
- Action
Elevates the first rib in inspiration; laterally flexes and rotates the neck
- Innervation
Anterior rami of C4–C6
- Blood supply
Ascending cervical / inferior thyroid arteries
Clinical correlation
Compression in the interscalene triangle underlies thoracic outlet syndrome.