There are actually three scalene muscles on each side of the neck that function together.
They are: scalenus anterior, scalenus medius, and scalenus posterior.
Sometimes there is also a scalenus minimus but it’s not especially common.
What does scalene mean?
The name “scalene” is related to the Greek word skalenos which was used to refer to a triangle of unequal sides.
The name refers to the shape that is formed when the three scalene muscles come together on each side of the neck to form a scalene triangle.
Where do the scalene muscles attach?
Specifically, the three scalene muscles originate together on the transverse processes of the vertebrae from the third to the sixth cervical vertebrae (C3 to C6). Remember that the transverse processes are the bony projections that stick out on the sides of each vertebrae.
The anterior and middle scalene muscles insert on the first rib, while the posterior scalene inserts on the second rib.
What actions do the scalene muscles do?
They function unilaterally, to assist in lateral flexion of the neck to the same side.
The scalenes as a group also assist as secondary respiratory muscles. If we are in a situation where we need more air to get into the lungs, these muscles will kick in and lift the ribs that they attach to. They work to assist in forced inspiration or inhalation, for example, when we are running or hiking up a steep hill.
Poses where the scalene muscles contract:
Poses where the scalene muscles are lengthened: