Scalenus anterior muscle

Changed by Frank Gaillard, 29 Oct 2019

Updates to Article Attributes

Body was changed:

Show markup changes

The scalenus anterior (also known as anterior scalene) is a neck muscle and known as the "key" structure for the thoracic inlet as it is an important anatomical landmark.

Summary

origin: transverse processes of 3^rd to 6^th cervical vertebrae
insertion: inner border of first rib (scalene tubercle)
blood supply: ascending cervical artery
innervation: ventral rami of cervical nerves (C4, C5 and C6) from the cervical plexus and occasionally C3
action
- raises first rib (inspiration)
- adjunct: neck rotation/flexion
note: this muscle is covered by prevertebral fascia

Gross anatomy

Relations

anteriorly
- phrenic nerve, vagus nerve
- ascending cervical artery, transverse cervical artery, suprascapular artery
- internal jugular vein, subclavian vein
- sternocleidomastoid muscle, omohyoid muscle
- clavicle
posteriorly
- second portion of subclavian artery (which is divided in three parts by the muscle)
- scalenus medius muscle: the space between them is the scalene triangle
- anterior rami of C3-T1
medially
- common carotid artery, first portion of subclavian artery, thyrocervical trunk, vertebral artery and vein
- stellate ganglion
- thoracic duct (left) or right lymphatic duct (right)
laterally
- trunks of brachial plexus
- third portion of the subclavian artery

~~-<li><a href="/articles/scalenus-medius-muscle">scalenus medius muscle</a></li>~~
+<li>
+<a href="/articles/scalenus-medius-muscle">scalenus medius muscle</a>: the space between them is the <a title="Scalene triangle" href="/articles/scalene-triangle">scalene triangle</a>
+</li>
~~-<li>third portion of subclavian artery</li>~~
+<li>third portion of the <a title="Subclavian artery" href="/articles/subclavian-artery">subclavian artery</a>
+</li>