Shoulder Safety Part 3: rotator cuff anatomy

Anders Hendricks, Aurora Sports Medicine Institute

Anders is a licensed athletic traininer at the Aurora Sports Medicine Institute in Burlington and at Badger High School in Lake Geneva.

This blog entry will focus on the rotator cuff anatomy, a part of the body one might hear a lot about, but is frequently misunderstood.  By reading this entry, one will understand the function and anatomy of the rotator cuff, and will learn how to improve the efficiency of the rotator cuff through scapular exercises.

The rotator cuff is comprised of four muscles, each starting on the shoulder blade (scapula) and ending on the shoulder (humerus).  While the ligaments and labrum in the shoulder provide static stability, the rotator cuff works to provide dynamic stability, meaning stability to the shoulder when it is in motion.  When the shoulder is moving, the rotator cuff muscles work to keep the head of the humerus stabile in the glenohumeral joint, reducing the chance of injury or dislocation.  Commonly referred to as the SITS (an acronym using the first letter of the four muscles) muscles, the rotator cuff is made up of the supraspinatus, infraspinatus, teres minor and subscapularis.

One excellent way to improve rotator cuff function is to improve the stability of the scapula.  Since the muscles of the rotator cuff originate on the scapula, increasing the stability of the scapula allows for the rotator cuff muscles to work from a solid base.  This is very similar to the idea of strengthening ones core muscles in order to make their leg muscles more efficient.  An easy way to personify this is to compare this example to moving a heavy load on flat ground compared to an unstable surface like a trampoline or foam pit.  Since the base is stable, one would find it easier to move a heavy load while standing on flat, solid ground, than compared to moving the same load on an unstable surface.  All of the energy can be transferred to the load instead of using energy to help stabilize oneself, which is exactly the case when discussing the rotator cuff.

The best way to work on scapular stability is to exercise the rhomboid muscles.  These muscles originate off of the spine, and insert on the inside boarder of the scapula.  They work to retract the scapula, or squeeze them towards the spine.  An excellent introductory exercise is simply working to retract the shoulder blades by standing tall with ones core tight, and pulling the shoulder straight back and squeezing for two seconds, then relaxing for two.  To start, attempt to do this 10 times in a row, increasing the reps as the exercise becomes more comfortable.  It is important to remember to move the shoulders straight back, and avoid any shrugging of the shoulders.  By moving the shoulders straight back, one is able to isolate the rhomboids and exercise that muscle group efficiently.  To add difficulty to this exercise, one can practice doing rows, which are explained in the Perfect Posture #6 – Upper Body Posture blog entry.

As always, if readers have any questions or comments about this topic, or past and future topics, please feel free to email me at  Thanks a bunch!

Follow the new Shoulder Series with weekly updates here at our fitness blog!

Part 1: Shoulders: An Introduction

Part 2: Bone Shoulder Anatomy

Don’t give up the sport — give up the pain! Visit the Aurora Sports Medicine Institute at 13 Wisconsin locations, visit our website, follow us on Facebook, browse our YouTube channel, or call our hotline at 1-800-219-7776.


About Anders Hendricks

Anders Hendricks is a Licensed Athletic Trainer for the Aurora Sports Medicine Institute in Burlington and at Badger High School in Lake Geneva. Anders studied Kinesiology and Athletic Training at the University of Wisconsin-Eau Claire, and has worked as an athletic trainer at the University of Wisconsin at Parkside. In the summer and fall, he enjoys following the Green Bay Packers and Milwaukee Brewers, and ice hockey and downhill skiing in the winter. Anders started blogging to give people a better understanding of what athletic training is, and how licensed athletic trainers help the patients of Aurora Health Care live well.
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