Perhaps while sweating through a long Handstand or Forearm Balance you've had occasion to wonder what was supporting you. Obviously, your hands or forearms form the base of your pose where they contact the floor, but how is the weight of your torso transmitted to this base, and how do you lift your spine up out of your arms?
If you guessed that the major connection of the arm to the torso is the scapulae, or shoulder blades, and the muscles that support them, you would be right. It's important to understand that the scapulae form the foundation of the arms, just as the pelvis forms the foundation of the spine. In poses where you are bearing weight on your arms, whether on hands and knees in Marjaryasana (Cat Pose) or completely upside down in Headstand, the scapulae transmit your body weight from your spine and torso to the earth via your arms. The position and stabilization of the scapulae set the stage for the alignment and lift of your entire pose.
The scapulae are held in position by the collarbones and also by a number of important, if somewhat obscure, muscles. Actually, the only bony connection of the arm to your central skeleton is through the collarbone. Your humerus (upper arm bone) meets the scapula in the ball-and-socket shoulder joint. The scapula in turn connects to the collarbone, which connects to the breastbone, which connects to the rib cage, which connects to the spine. The collarbone is quite moveable, but it also guides and substantially limits movement: People that do not have collarbones, whether due to birth defect or trauma, can touch their shoulders together in front of their chests. The collarbones normally prevent this, acting like struts to hold the shoulder blades in their normal position on the back rib cage.
While the scapula meets with the humerus at the shoulder joint and also meets with the collarbone at the acromio-clavicular joint-the site of the injury commonly called "a separated shoulder"-the scapula does not have a true joint with the rib cage. Instead, it "floats" over the rib cage, separated from the ribs by a couple of layers of muscle. This mobility of the scapula allows it to move in several directions, including elevation (the shoulder blade lifting up toward your ear), depression (pulling down away from your ear), protraction (pulling around your side toward your chest), and retraction (pulling back toward the spine).
The scapulae also make another set of movements you use in many yoga poses. When your shoulders are flexed-that is, when your arms are overhead-your scapulae must be in a position called upward rotation. It's easiest to understand this position of the scapulae by looking at a friend's bare back. When the arms are by the sides, notice that the medial borders of the scapulae-the inner edges-are parallel to the spine and the inferior angles of the scapulae-the bottom tips-point straight down. As the person slowly raises the arms forward and then up overhead, notice that the scapulae begin to rotate; the inferior angles point out to the sides so that the medial borders are no longer parallel to the spine. In this position, the sockets of the shoulder joints, which are a part of the scapulae, point up, allowing the arms to move toward vertical.
Unlocking Your Shoulders
It's actually a kinesiological law that the scapula must rotate upward for the shoulder to flex. In fact, if scapular rotation is limited, the range of the shoulder flexion will also be limited. If you still can not fully open the shoulders in poses such as Adho Mukha Svanasana (Downward-
Facing Dog Pose) and Adho Mukha Vrksasana (Handstand), you might want to have the freedom of movement of the scapulae evaluated.
If the scapulae don't fully rotate up, the limitation is probably caused by tightness in the muscles that rotate the scapulae down. You can see downward rotation if you again look at your friend's bare back when he is standing with his arms at his sides. As he brings his arms straight back behind him into shoulder extension, you'll notice that the medial border and inferior angle of each scapula pull in closer to the spine. This is downward rotation. The primary muscle that performs this action is the rhomboid, which sits between the spine of the upper back and the medial border of the scapula. If the rhomboids are tight and short, they will limit the ability of the scapulae to rotate up.
A good pose for stretching the rhomboids is Garudasana (Eagle Pose). As you come into this pose, crossing your elbows in front of your chest and then intertwining your forearms, you should feel some stretch in the rhomboids. You can intensify the stretch by reaffirming the lift of your breastbone and then lifting the elbows and lengthening them away from your chest.
Even if you have full movement of the scapulae in upward rotation, you will also need strength in the muscles that will create this movement. The prime mover in upward rotation is a muscle called the serratus anterior. The serratus is a bit hard to see and feel because it originates on the sides of your rib cage, then angles back under the scapula and inserts along the medial border of the underside of the scapula. It's easiest to see on people who have done a lot of upper body strength work, like rowers and rock climbers. The serratus is assisted by the upper and lower trapezius. You might expect that the trapezius would be easier to see than the serratus, because it's just under the skin of the mid- and upper back, but it too can be hard to discern because on many people it's a thin, underdeveloped muscle.
The serratus and the upper and lower trapezius work together to rotate the scapula up: The upper trapezius pulls in and up on the outer corner of the scapula, while the lower trapezius fibers pull down on the upper inner corner. And the serratus is ideally situated for positioning the scapula when we bear weight on the arms, since its fibers pull the inner border and the bottom tip of the bone forward along the rib cage, away from the spine. The serratus also helps hold the medial border
of the scapula down on the rib cage, helping to prevent the "winging" of the scapulae that creates a big valley between the shoulder blades.
While commonly known muscles, like the pectorals on the chest and the triceps on the back of the upper arm, are important in poses where you bear weight on your arms, the lesser-known serratus and trapezius are just as important. Remember, your scapulae must be held in upward rotation for you to sustain an arms-overhead position. If you're in Handstand, for example, your serratus muscles must bear nearly your full body weight, minus only the weight of your arms, as they transmit the weight of your legs and torso from your rib cage to your scapulae. Unfortunately, many students come to yoga weak in the trapezius and serratus. Even people who have worked on upper-body weight training are likely to have focused on the triceps, pectorals, and latissimus dorsi (which extend from the lower spine to the upper arm bone) and to have done much less work on the upward rotators.
Because the upward rotators are essential in positioning the scapulae when the arms are overhead, it's vitally important that they be strong before you begin work on inversions. If they cannot stabilize the scapulae, Urdhva Mukha Vrksasana (Handstand), Sirsasana (Headstand), and Pincha Mayurasana (Forearm Balance) are likely to be wobbly and unstable, and so you will not be able to get the necessary strong vertical lift up through the center of these poses. Headstand is likely to suffer the most, as the weak foundation through the arms, shoulders, and shoulder blades will probably add up to compression and poor alignment of the head and neck.
Teachers should be on the lookout for the telltale "winging" of students' scapulae in Headstand; this is a sure sign that the serratus muscles are too weak to properly support and stabilize the scapulae in this particular pose.
Give Yourself a Lift
Fortunately, it's simple to include some serratus and trapezius strengthening poses in your practice well before you begin work on inversions. Beginning on hands and knees, let your chest sag down between your arms. In this position an observer can see, and you should be able to feel, the valley that forms between your shoulder blades. Now lift your chest up so the valley disappears and the space between the scapulae flattens (but don't lift so high that you round the spine up toward the ceiling, making a "cat back"). This lifting and broadening of the space between the shoulder blades is the work of the serratus muscles, though most people can't actually feel them contracting.
To put more challenge on the serratus, maintain the broad, flat space between the scapulae while you lift the right arm in front of you, parallel to the ground or higher. This action increases the work of both the left and right serratus. The left one now works harder because it's supporting more of your weight, while the right one works harder as it attempts to completely rotate the scapula up so the shoulder can fully flex.
Once you place the hand back on the ground, you can also work the serratus by lifting both knees and then coming into Plank Pose, making sure to keep the space between the shoulder blades broad and flat. From Plank Pose you can crank out a few push-ups, which have long been recognized as wonderful serratus-strengthening exercises. If you can't perform push-ups with straight legs, then you can still strengthen your serratus anterior muscle by doing the exercise with your knees touching the floor.
Anytime you practice poses that require shoulder flexion-in other words, those that require you to hold your arms overhead-you are working your upward rotators. Since these muscles are so crucial when you bear weight in your arms in inversions and in backbends like Urdhva Dhanurasana (Upward-Facing Bow Pose), be sure to build and maintain upward rotator strength by regularly practicing poses like Virabhadrasana I (Warrior Pose I), Vrksasana (Tree Pose), and Adho Mukha Svanasana (Downward-Facing Dog Pose). To build endurance, use a timer and hold the standing poses for one full minute and Downward Dog for two to three minutes. Then when you begin work on inversions like Handstand and Headstand, your upward rotators will have the strength to support you in a stable, vertical, and beautiful pose.
A licensed physical therapist and certified Iyengar Yoga teacher, Julie Gudmestad runs a private physical therapy practice and yoga studio in Portland, Oregon. She regrets that she cannot respond to letters or calls requesting personal advice.