Scalenus medius (Musculus scalenus medius)
Educational content only — not medical advice.
Anatomy
The largest scalene extending to the second rib; the gap between it and the anterior — through which the plexus roots and artery pass — is the "gateway" diagnosed in thoracic outlet syndromes.
Origin & insertion
Transverse processes of C2–C7.
Action
Elevates ribs 1–2 in inspiration and steadies the neck in lateral flexion.
Innervation
Anterior rami of C3–C8.
Clinical notes
Hypertrophy in carriers and athletes narrows the thoracic outlet producing lower-plexus symptoms; must be distinguished from C7–T1 disc compression by neuroimaging.
Related structures
Educational references
FAQ
What is the role of the Scalenus medius?
The largest scalene extending to the second rib; the gap between it and the anterior — through which the plexus roots and artery pass — is the "gateway" diagnosed in thoracic outlet syndromes.
Why is the Scalenus medius clinically important?
Hypertrophy in carriers and athletes narrows the thoracic outlet producing lower-plexus symptoms; must be distinguished from C7–T1 disc compression by neuroimaging.
Source & license
BodyParts3D, © The Database Center for Life Science licensed under CC Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/). license details