We have all heard the term "shoulder blade," and we probably even have a pretty good idea where our shoulder blades are. But, did you know how important your shoulder blades are to movement in your entire arm, neck, and even face? Well, read on to find out why these triangular shaped bones are so important to movement in our body.
Basic Scapula Anatomy and Movement
The scapulae (singular scapula), commonly referred to as the "shoulder blades," are flat, triangular shaped bones found on the posterior, thoracic rib cage (i.e. upper back). The scapulae are not directly attached to the posterior thoracic ribs; rather, they are held in place (i.e. stabilized) by the surrounding musculature.
While many muscles help to stabilize the scapulae, the main stabilizers are:
Serratus Anterior
Pectoralis Minor
Rhomboid Major and Minor
Levator Scapulae
Trapezius
Scapular Muscle Locations and Functions
The Serratus Anterior is a multi-headed muscle that forms the lateral part of the chest wall, giving it a "serrated" appearance. Contracting this muscle draws the scapula forward and away from midline (i.e. protraction). Relaxing this muscle allows the scapula to be drawn toward midline, opening the chest.
The Pectoralis Minor is a small, three-headed muscle lying deep to the Pectoralis Major (chest muscle). The Pectoralis Minor draws the scapula downward and forward (i.e. protraction), assisting the Serratus Anterior. This muscle also assists with lifting the rib cage during respiration (i.e. breathing).
The Rhomboid Major and Minor (collectively referred to as the "Rhomboids") are flat, rectangular muscles in between the scapulae. Contraction of the Rhomboids draws the scapula toward the midline of the body and opens the chest. The Rhomboids are an anatogonist to the Serratus Anterior muscle.
The Levator Scapulae is located at the side and back of the neck. Its primary function is to lift (i.e. elevation) the scapula.
The Trapezius is a large, broad, triangular-shaped muscle, extending from the lower thoracic spine to the base of the skull. Contraction of the lower fibers draws the scapula downward (i.e. depression). Contraction of the upper fibers elevates and rotates the scapula upward. This helps to secure the head of the arm bone (i.e. humerus) in the shoulder socket more firmly in overhead movements. Contraction of the middle fibers draws the scapulae toward the midline of the body (i.e. retraction), assisting the Rhomboids.
Why Should I Care About My Scapulae?
The motion of the scapula is coordinated with the motion of the arm (called scapulohumeral rhythm).
Weakness or tightness in any one of the muscles attaching to the shoulder blade, particularly the larger scapular muscles (e.g. serratus anterior, rhomboids, etc. - see section above), can affect the resting position of the scapula on the upper back and/or the way that the scapula move.
Poor movement patterns, deficits in muscle strength, and/or excessive tightness in the muscles at the scapula can lead to:
Uncoordinated movement in the arm (shoulder, elbow, wrist, hands), neck, and/or facial muscles (jaw, cheeks, tongue)
Instability in the arm, neck, and/or facial muscles
Pain/injury in the arm, neck, and/or facial muscles
Overuse of the smaller muscles in the extremities
In fact, injuries in the shoulder, elbow, wrist, neck, or even face can often be traced back to poor functioning, a lack of strength, and/or excessive tightness in the muscles of the scapulae. Also, exercises aimed at strengthening, stabilizing, and opening the muscles of the scapulae have been shown to improve posture (especially at the neck) and reduce injury or pain in the arm or neck.
Conclusion
Your arm and neck rely heavily on the scapular stabilizers to maintain optimal scapular position throughout movement. When your scapulae do not rest or move in the proper way, it can decrease function in your arm and neck, increasing your risk for injury or pain. Luckily, careful attention to the scapulae muscles in your workout routine can help prevent and correct issues with your shoulder blades. Stay tuned for a future blog post outlining some different yoga poses that work to strengthen and open the scapular stabilizers.
Side note: I want to give a special shout-out to my wonderful husband, Matt Allen, who drew the amazing images of the scapular muscles.
~Namaste, Jackie Allen, M.S., M.Ed., CCC-SLP, RYT-200, RCYT
References:
Kang, J-I, et al., (2018). “Effect of Scapular Stabilization Exercise on Neck Alignment and Muscle Activity in Patients with Forward Head Posture.” Journal of Physical Therapy Science. 30: 804 – 808.
Long, R. (2006). The Key Muscles of yoga. Scientific Keys, Volume 1. Bandha Yoga Publications.
Paine, R., et al., (2013). “The Role of the Scapula.” International Journal of Sports Physical Therapy. 8(5): 617 – 629.
Pompa, Lizette (2019). “Essential Body Parts: Scapula and Yoga.” https://www.yogateket.com/blog/scapula-and-yoga
West Coast Sci Active Physiotherapy (2018). “Importance of Scapular Stability.” https://westcoastsci.com/general-blog/2018/8/13/importance-of-scapular-stability
West, Thomas (2017). “Shoulder Function: Enhancing Scapular Stabilization.” https://blog.nasm.org/fitness/shoulder-function-enhancing-scapular-stabilization