Yoga Anatomy Lower Trapezius
The trapezius muscle has three distinct parts. There is a tendency for the upper trapezius to be overactive and the importance of the middle trapezius in improving posture and reducing risk of neck and shoulder pain. The lower trapezius is the largest of the three portions of the trapezius, yet many people demonstrate weakness in this muscle.
The lower trapezius originates along the center of the spine starting at the middle of the thoracic spine (the 6th thoracic vertebrae) to the bottom of the thoracic spine (the 12th thoracic vertebrae). (The thoracic spine is the part of your spine that has ribs attached to it. Since you have 12 ribs on either side, you have 12 thoracic vertebrae.) The fibers of the lower trapezius reach up and out to the shoulder blade. Specifically, the fibers insert onto the inside edge of the spine of the shoulder blade. The spine of the shoulder blade is a projection that runs horizontally along the top portion of the shoulder blade. It can be seen best on the left shoulder blade in the image above.
As a result of the muscles fibers running in a diagonal pattern (from the thoracic vertebrae to the spine of the shoulder blade), the action created with a simple concentric contraction is depression of the shoulder blade. When the muscle fibers shorten, the shoulder blade is pulled down towards the lower part of the thoracic spine. This is the opposite of the action of the upper trapezius (which is elevation of the shoulder blades). When you actively slide your shoulder blades down your back, you engage the lower trapezius. Because the fibers also run from the center of the spine and out to the shoulder blade, they also cause the shoulder blades to come in towards the spine. This movement is retraction of the shoulder blade. The fibers of the middle trapezius are better suited for shoulder blade retraction, but the lower trapezius is an important helper.
When you bring your arms over your head, your shoulder blades rotate. Rotation of the shoulder blade is complex and will be discussed in a future article. For now, consider that when something rotates, it's center point does not move. When you turn your steering wheel, the center of the wheel stays in the same place. For healthy shoulder movement, the center of your shoulder blade needs to remain fixed when your shoulder blades rotate. The three muscles that are primarily responsible for rotating your shoulder blade when you raise your arm over your head are the serratus anterior, upper trapezius, andlower trapezius. Each of the three muscles pulls in a different direction and the result of the three forces is rotation. When one of the muscles produces a stronger or weaker force than the others, pure rotation does not occur. Rather, the shoulder blade moves in the direction of the force of the strongest muscle.
As discussed, the upper trapezius is often overused while the lower trapezius is often weak. This combination results in poor rotation of the shoulder blade. It is common for the shoulder blade to elevate while rotating because of the strong upwards pull of the upper trapezius. Additionally, if the lower trapezius is weak, there is limited force in the downward direction. Elevation of the shoulder blade causes instability, poor bio-mechanics, and ultimately increased tension and possibly pain in the neck and shoulder region.
The key to healthy shoulder mechanics is balanced strength and flexibility in all of the muscles around the shoulder. I will show you some simple exercises to strengthen the lower trapezius. The first is to actively slide your shoulder blades down your back and hold them down. Avoid creating excess tension when drawing the shoulder blades down. Also, notice if you arch your back and lift your chest out in order to bring your shoulder blades down. Keep your spine long and still and let the movement of your shoulder blades be the only action in your upper body. Hold for 1 to 10 breaths, release and repeat 10 times. It is a good idea to do this exercise in Warrior II stance. Activate your strong legs and core to maintain good posture, and focus on your shoulder blades.
Another way to strengthen your lower trapezius. Lie on your stomach with your arms over your head and rested down on the mat. Wiggle your shoulders away from your ears. Inhale and lift your arms off the mat. As you exhale, lower your arms slowly to the mat. Keep your chest rested on the mat throughout this exercise. Repeat 10-15 times and rest before doing two more sets. If you are unable to do 10 of these, lie with your head at the corner of your bed and let your arms hang down off the edge of the bed (one arm on either side of the corner). Inhale, lift your arms up as high as you can bring them without struggling. Exhale, lower slowly. If 15 of these are easy for you, consider holding onto small water bottles as weights to add some resistance. The goal is to create a challenge in the lower trapezius muscle (which you will feel in the middle of your back) while still breathing with ease.
Another way to strengthen your lower trapezius. Lie on your stomach with your arms over your head and rested down on the mat. Wiggle your shoulders away from your ears. Inhale and lift your arms off the mat. As you exhale, lower your arms slowly to the mat. Keep your chest rested on the mat throughout this exercise. Repeat 10-15 times and rest before doing two more sets. If you are unable to do 10 of these, lie with your head at the corner of your bed and let your arms hang down off the edge of the bed (one arm on either side of the corner). Inhale, lift your arms up as high as you can bring them without struggling. Exhale, lower slowly. If 15 of these are easy for you, consider holding onto small water bottles as weights to add some resistance. The goal is to create a challenge in the lower trapezius muscle (which you will feel in the middle of your back) while still breathing with ease.