scalenus anterior muscle

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 to 6 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

Siehe auch:

• Plexus brachialis
• scalenus posterior muscle
• Atemmuskulatur
• Halsmuskeln
• Musculus scalenus medius

und weiter:

• Arteria vertebralis
• Thoracic-outlet-Syndrom
• Musculi scaleni
• scalenus medius muscle