Freeze. Are you jutting your head forward to read this text? If so, are you also slouching, a position that collapses the front of your rib cage and forces you into a belly breathing pattern? If so, your scalenes aren’t terribly happy with you.
The scalenes are a group of three muscles, three on the right and three on the left. Their primary job is to move your head and neck but they also help with inhalation. Scalenus anterior originates on the transverse processes of C3-C6 and inserts on the first rib. Scalenus medius originates on the transverse processes of C2-C7 and inserts on the first rib behind its anterior brother. Scalenus posterior originates on the transverse processes of C5-C7 and inserts on the second rib.
As mentioned, the scalenes’ primary function is to move the head and neck. On unilateral contraction they laterally flex the cervical spine ipsilaterally and contralaterally rotate the cervical spine. In other words, the right scalenes tip your right ear toward your right shoulder and turn your head to the left. The scalenes get a workout in any yoga pose where the trunk inclines or curves to the side. So when you practice trikonasana, triangle pose, on the right side, your left scalenes prevent your head from drooping toward the floor and your right scalenes help turn your head to look at the ceiling. On bilateral contraction, the scalenes flex the cervical spine, bowing your chin into your chest. They function in this capacity, for example, when you initiate a traditional abdominal curl-up by nodding your chin toward your neck. Here’s what many anatomy books don’t mention: on bilateral contraction the anterior and medial scalenes also extend the cervical spine—not by tilting your head back, but by translating forward the vertebrae on which they originate, à la jutting your head forward to see a computer screen. Given the prevalence of computing in contemporary society, the scalenes work overtime in this role.
If the neck remains fixed, the scalenes help to elevate the first two ribs, making them accessory muscles of inhalation. Let’s say you’re slumped forward reading this article. (And I’ll confess that this is my posture as I write—exacerbated by the fact that my computer is sitting on a knee-height café table.) When you stoop, movement of your rib cage is constrained by the closure across the front of the chest. Because the big strong diaphragm now can’t effectively expand the rib cage on inhalation, the accessories—including the scalenes—start jumping up and down shouting, “I’ll do it! I’ll do it!” like a bunch of excited eight-year-olds volunteering to bang the erasers. (Do classrooms still use chalkboards?) But since the scalenes’ insertion points on the rib cage are largely immobilized by your slouch, the scalenes here are about as effective in assisting respiration as the aforementioned eight-year-olds would be in trying to tug the chalkboard off the wall. In this scenario, the scalenes (and other accessories of inhalation) become hypertonic.
A lot of neck pain is breath- and posture-related. If a student complains of neck pain, it’s worth asking how they spend their day outside of the asana room. Activities like computing or cradling a phone between shoulder and ear ask a lot of the scalenes (and other neck muscles). Sometimes we can best serve students by attuning their awareness to how they hold themselves while going about their day-to-day activities. And, of course, honing sustained attentiveness is one of the primary skills to be derived from a yoga practice.