Lesson 9: Rotator Cuff

This course describes the rotator cuff muscles, including the supraspinatus, infraspinatus, teres minor, and subscapularis. These muscles are likely most well known for their function as deep stabilizers of the shoulder joint (glenohumeral joint) and are commonly referred to when performing rotator cuff exercises during physical therapy for a rotator cuff injury. (Note, there is no such thing as a “rotator cup”, this is a mispronunciation of "rotator cuff".)

This course describes each of the rotator cuff muscles and their location, function, actions, and practical applications. For example, the infraspinatus muscle and teres minor muscle are the primary external rotators (lateral rotators) of the shoulder joint, and may be strengthened with corrective exercises like resisted external rotation (lateral rotation), which may be beneficial for individuals exhibiting rounded shoulder posture. The subscapularis muscle is a strong internal rotator (medial rotator) of the shoulder joint, and may be targeted with subscapularis activation, and this may be beneficial for individuals exhibiting shoulder instability. Last, the supraspinatus muscle is an abductor of the shoulder joint, and is often the muscle involved in rotator cuff tendonitis and rotator cuff tears, and over-activity in this muscle may be addressed with release techniques. Another important function of the rotator cuff is shoulder stability. This is accomplished via synergistic recruitment of all rotator cuff muscles during all shoulder movement to maintain alignment between the humeral head (upper arm bone) and the glenoid fossa of the scapula (shoulder blade). This occurs during all activities of daily living (e.g. putting a cup in a cupboard), commonly recommended exercises (e.g. bench press), and sports motions (e.g. baseball pitch).

Sports medicine professionals (personal trainers, fitness instructors, physical therapists, massage therapists, chiropractors, occupational therapists, athletic trainers, etc.) must be aware of the rotator cuff muscles for detailed analysis of human movement, and the development of sophisticated exercise programs and therapeutic (rehabilitation) interventions. Further, this course is essential knowledge for future courses discussing more complex topics including neural innervations of the rotator cuff (e.g. suprascapular nerve), the complex insertions of the rotator cuff tendons (e.g. lesser tubercle of the humerus and transverse ligament), its synergistic function with upper arm muscles (e.g. biceps brachii, pectoralis major), injury (e.g. shoulder muscle tendon dysfunction, shoulder injuries, shoulder pain, shoulder impingement syndrome, rotator cuff injuries, rotator cuff strain, rotator cuff tear - you don't always need rotator cuff repair or shoulder surgery), and rotator cuff exercises for rotator cuff weakness and sports performance (e.g. throwing, shooting, punching, lifting).

For more advanced anatomy check out our integrated functional anatomy courses:

• Supraspinatus
• Infraspinatus and Teres Minor
• Subscapularis

For rotator cuff specific exercises and techniques check out:

• Shoulder External Rotator Exercises (Activation)
• Scapula Muscle Release and Lengthening

Caption: The supraspinatus, infraspinatus, and teres minor muscle of the rotator cuff