Anatomy 101: Understand Your Pectoralis Minor

This minor muscle is a major player in backbends. Expand it—and its web of connective tissue—for greater range of motion in your chest and back.
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This minor muscle is a major player in backbends. Expand it—and its web of connective tissue—for greater range of motion in your chest and back.
locust pose, salambasana

This minor muscle is a major player in backbends. Expand it—and its web of connective tissue—for greater range of motion in your chest and back.

Let’s face it—we are a society of sitters and slouchers. And there’s one little-known and small but very important muscle that helps create that slouch: the pectoralis minor, which is located on the front of the chest and connects your ribs to your shoulders. To find it, put your hand in the little depression under your collarbone in the front of your shoulder—now you’re touching pec minor under the larger pectoralis major.

This short yet powerful muscle is the main contracting muscle of a web of tissue (the clavipectoral fascia) that weaves through a large part of the front of the torso. It originates at the coracoid process of the shoulder blade, a bony protrusion that pokes its head anteriorly toward the uppermost corner of the chest. It then inserts on ribs 3–5, more or less under the nipple. When it’s flexible, pec minor can allow for that “open heart space” you’re always hearing about in yoga class, enabling you to reach your shoulders back to backbend successfully or sit in meditation without rounding forward. But a tight pec minor nearly guarantees that you will be stuck with a rounded upper back, hunched shoulders, and forward head placement—all too common, perhaps due to the many hours we spend with pec minor in a contracted position, while sitting at the computer or behind the wheel (though not all specialists agree on the cause). For yogis, a tight pec minor can make it impossible to backbend without pain. This is because of the muscle’s role in the larger area of clavipectoral fascia.

Fascia is the stuff that connects muscles, bones, ligaments, and tissues into a whole being; it’s a weblike biological fabric that takes up every nook and cranny in your body and holds your shape in various postures. You’ve likely heard the term “connective tissue,” which can represent anything from bones to blood vessels and includes the unique subcategory of fascia. As Tom Myers, fascia specialist and author of Anatomy Trains, explains in his book, “[Fascia] is very aptly named. Although its walls of fabric do act to direct fluids, and create discrete pockets and tubes, its uniting functions far outweigh its separating ones. It binds every cell in the body to its neighbors and even connects the inner network of each cell to the mechanical state of the entire body.” So, the network of fascia accounts for how all aspects of the body interrelate beyond the origin and insertion points where muscles start and stop.

See alsoDump the Slump: Yoga Lessons for Better Posture

skeleton, muscles, shoulder, collarbone, lungs

It is helpful to think of the pectoralis minor not as a single muscle that begins and ends somewhere in our chest, but as a contractile mover of the much larger bag of clavipectoral fascia. If the pec minor is contracted, it will shorten the entire bag of clavipectoral fascia, which takes up nearly half the anterior torso! This shortening will in turn contribute to a collapsed chest and a slouching of the upper back and shoulders. Imagine walking up to a spider’s web and using your fingers to scrunch the webbing together—a tight pec minor is like your fingers in the web, causing the clavipectoral fascia to scrunch, which will in turn pull your shoulders forward and sink in the chest. Over time, the tight fascia may adhere to surrounding tissues. This severely limits movement and makes it exceptionally difficult to achieve enough openness and length for backbending asanas, because contraction across the chest inhibits extension and elevation in the mid- to upper back.

When you’re on your yoga mat, stretching this area when prepping for a backbend will help give you the needed room to first lift up through the sternum (breastbone) and then to curve backward. The common cue of “Widen your collarbones and lift your chest” for backbending poses is fantastic, but often impossible if the pec minor and clavipectoral fascia are tight. If you solely focus on bending backward, without expanding horizontally and vertically across the chest and shoulders, you aren’t giving your spine the length it needs to curve in a spacious way. This forces your backbend into your lower back, creating a risk for painful compression of the lumbar discs and facet joints between the vertebrae. But by first lengthening the pectoralis minor and its fascial bag in the front of your body with stretches like the one below, you will set yourself up for successful extension of the spine and expansive backbends.

See also Too Much Desk Time? Here’s How Yoga Helps Muscular Imbalances

wall supported shoulder stretch

How To Stretch the Pectoralis Minor + Clavipectoral Fascia

Modify this common stretch for the chest to target the pectoralis minor specifically. Standing with your right side close to a wall, extend your right arm up and out behind your body, with your palm on the wall at a 45-degree angle. Turn your breastbone away from the wall and toward the center of the room to feel a stretch deep in the chest. Hold for 7–10 breaths; release, and repeat on the other side.

Tips

  • Don’t let the head of the humerus bone round forward in the shoulder. This will undo a lot of the opening you are trying to achieve. Draw the scapula toward the spine and down the back.
  • Keep your head back and in line with your torso.
  • Combine your chest stretches with upper- and mid-back strengthening poses like Salabhasana (Locust Pose). Lie on your belly with your arms extended back alongside your outer hips. The palms can either face the floor or you can externally rotate the arms so that the inner wrists face out toward the walls. Lift the shoulders off the floor and hug them in to allow maximum width across the collarbones and chest. Draw your shoulder blades toward the spine and down the back.

TRY 3 More Foolproof Chest and Shoulder Openers

ABOUT OUR PROS 
Teacher Lauren Haythe is a certified advanced KMI (Kinesis Myofascial Integration) practitioner and registered yoga teacher in New York City who studies with Kula Yoga Project directors Nikki Vilella and Schuyler Grant (laurenhaythe.com). Model Alec Vishal Rouben teaches in Boulder and Denver, Colorado, and completed Richard Freeman’s Teacher Intensive at the Yoga Workshop (aleclovelifeyoga.com).