This video shows the scalene muscles and describes their attachments and actions.
Scalenus Anterior
O: C3 – C6 Transverse processes, anterior side
I: First Rib
A: Raise first rib, flex neck
Scalenus Medius
O: C2 – C7 Transverse processes, posterior side
I: First Rib
A: Raise first rib, flex neck
Scalenus Posterior
O: C5 – C6 Transverse processes, posterior side
I: Second Rib
A: Raise second rib, flex neck
The scalenes raise the first two ribs, as in a forced inhalation, and they also help with neck flexion. They are frequently strained in whiplash accidents.
The brachial plexus originates form the nerve roots C5 – T1 and passes in between Scalenus Medius and Scalenus Anterior. Tightness in the scalene muscles can cause impingement on these nerves, causing symptoms of Thoracic Outlet Syndrome.
Symptoms of Thoracic Outlet Syndrome include parasthesia (pain, tingling, hypersensitivity or numbness) along the C-8 dermatome to the 4th and 5th fingers, arms going to sleep at night, and arms going to sleep when being held up or overhead.
Related Videos:
Thoracic Outlet Syndrome
Scalene Stretch
Scalenes – Sidelying Variation
Scalenes – Soft Tissue Release