Scalenus anterior muscle

Last revised by Daniel J Bell on 22 Jul 2022

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


  • origin: transverse processes of 3rd to 6th 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


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