scalenus posterior muscle

The scalenus posterior (posterior scalene) is one of the three scalene muscles in the neck.

Summary

  • origin: transverse processes of lower two or three cervical vertebrae (C5-C7)
  • insertion: outer surface of second rib
  • action:
    • raises second rib (respiratory inspiration)
    • acting together: neck flexion
    • acting on one side: lateral neck flexion and rotation
  • nerve supply: ventral rami of cervical nerves C6-C8 from the cervical plexus

Gross anatomy

Relations
  • anteriorly: first rib
  • posteriorly: second rib
  • medially: pleural dome (at level of T1/T2)
  • laterally: upper digitation of serratus anterior muscle