Muscle
Anterior scalene
First-rib elevator beside the brachial plexus
High-yield
The phrenic nerve crosses the front of anterior scalene. The brachial plexus and subclavian artery pass behind it, between anterior and middle scalene; the subclavian vein passes in front.
Overview
Anterior scalene links the cervical transverse processes to the first rib. It helps bend the neck and can lift the rib during inspiration. Its surfaces are useful landmarks for the nerves and vessels entering the upper limb.
Learning this group? Read How to learn the brachial plexus.
Reference facts
- Origin
- Anterior tubercles of the transverse processes of C3–C6
- Insertion
- Scalene tubercle on the first rib
- Action
- Raises the first rib; bends the neck toward the same side and assists neck flexion and rotation
- Innervation
- Anterior rami of cervical spinal nerves, commonly described as C4–C6
- Blood supply
- Ascending cervical artery, usually arising from the inferior thyroid artery
Clinical correlation
The interscalene interval is one possible site of brachial plexus or subclavian artery compression in thoracic outlet syndrome. Other compression sites also occur; the subclavian vein does not traverse this interval.
Frequently asked questions
What does the anterior scalene do?
Raises the first rib; bends the neck toward the same side and assists neck flexion and rotation.
What nerve innervates the anterior scalene?
Anterior rami of cervical spinal nerves, commonly described as C4–C6.
Where does the anterior scalene attach?
Origin: Anterior tubercles of the transverse processes of C3–C6. Insertion: Scalene tubercle on the first rib.
What is the blood supply of the anterior scalene?
The anterior scalene is supplied by the ascending cervical artery, usually arising from the inferior thyroid artery.