The Scalene muscle group consists of 3 separate muscles:
The Anterior Scalene
The Middle Scalene
The Posterior Scalene
All three muscles attach superiorly from the transverse processes of the cervical vertebrae and extend downward to attach to the first and second ribs. Bilateral contraction of the Scalene muscles can elevate the ribs to aid in inhalation, and also flex the neck to the same side if contracting unilaterally.
A neuro-vasular bundle exits the neck region and passes through the space between the middle and anterior scalene muscles, above the first rib and below the clavicle.
Behind these muscles is the Subclavian Artery, whos branches include the vertebral artery, the internal thoracic artery, the thyrocervical trunk, the costocervical trunk, and the dorsal scapular artery.
Vertebral artery Internal thoracic artery Thyrocervical trunk Costocervical trunk Dorsal scapular artery Mnemonic: 'VIT C and D'
Once the subclavian artery reaches the axilla, it becomes known as the axillary artery.