by Kelly Gafner
I. Description of Motion:
Shoulder abduction of the glenohumeral (GH) joint can be described as the inferior roll/glide of the convex head of the humerus within the concave glenoid fossa of the scapula as the arm is raised away from mid-line in the frontal plane1.
Prime Movers:
- Supraspinatus: initiates abduction
- Deltoid
Normal ROM for abduction is 180 degrees; however only 120 degrees of abduction are produced through the GH joint. Proper movements of the sternoclavicular (SC) and scapulothoracic (ST) joints are necessary to achieve full abduction ROM. At the SC joint, the clavicle must glide inferiorly on the sternum. At the ST joint, the scapula must rotate upwardly on the thorax. It is proposed that for every 2 degrees of GH abduction, the ST joint contributes 1 degree of abduction. This relationship is termed the "scapulohumeral rhythm1." The video below further describes this relationship.
Source: http://www.physio-pedia.com/Scapulohumeral_Rhythm
Secondary Muscles:
- Serratus anterior
- Upper & Lower Trapezius
These secondary muscles help to achieve upward rotation of the scapula.
Nerve Root:
The C5 nerve root is typically tested for shoulder abduction integrity; however, contributions ranging from C3-7 are necessary for full shoulder abduction.
II. Mobilizing-Increasing Range of Motion:
The video below contains 3 exercises that can be used to increase shoulder abduction ROM.
Arm Across Chest Stretch:
Instruct patient to start in seating or standing and while reaching one arm across the chest, use the other arm to support around the elbow. Use the other arm to help pull until a stretch is felt in the shoulder/arm.
Perform this stretch 3 times for 30 seconds.
Arm Behind Back with Theraband Stretch:
Instruct patient to start in standing with the arm to be stretched facing away from the door. Secure a strap or Theraband around a doorknob or similar object. With the Theraband in hand, let the arm fall behind the back and begin to walk away from the door until a stretch is felt in the shoulder/arm. Be sure to keep both shoulders facing forward. Perform this stretch 3 times for 30 seconds.
Supraspinatus Stretch with Towel:
Instruct patient to start seated or in standing. Place a towel over the shoulder—with the other hand, reach behind the back to grab the other end of the towel. With the upper hand, pull up so that the other hand begins to rise up the back and a stretch is felt in the shoulder. Perform this stretch 3 times for 30 seconds.
III. Indications for Stretching:
Stretching of the shoulder abductors may be indicated in patients with adhesive capsulitis, impingement-like symptoms, and following any reconstructive shoulder surgery.
IV. Strengthening:
Below are 3 videos of exercises that can be used to increase shoulder abduction strength.
Isometric Shoulder Abductor Strengthening:
Instruct patient to place a pillow up against a wall and stand with the arm of involved side against the pillow. Elbow should be bent to 90 degrees. Patient should then push upper arm against wall and hold static contraction for 10 seconds. Perform 3 repetitions and increase repetitions as needed.
Shoulder Abductor Strengthening with Resistance Bands:
Instruct patient to start in standing with a Theraband under the shoe and the arms resting at the sides. With the thumb facing up and grasping the Theraband, raise the arm out to the side in a slow and controlled motion to end range or just before pain is felt. Return back to the starting position in a slow and controlled manner. Perform this exercise daily in 3 sets of 10 and increase resistance or repetitionss as needed.
Shoulder Abductor Strengthening with Free Weights:
Instruct patient to start in standing with free weights in hand and arms resting at the sides. With the thumbs facing up, raise the arms out to the sides in a slow and controlled motion to end range or just before pain is felt. Return back to starting position in a slow and controlled manner. Perform this exercise daily in 3 sets of 10 and increase weight or repetitions as needed.
V. Potential Clinical Syndromes or Etiologies:
To read more about potential clinical syndromes that these techniques may be appropriate for, please see the links listed below.
Eccentric Shoulder Abductor Strengthening for Shoulder Impingement:
http://www.ncbi.nlm.nih.gov/pubmed/22441232
Comparison of High-Grade and Low-Grade Mobilization Techniques in the Management of Adhesive Capsulitis of the Shoulder: Randomized Controlled Trial
http://ptjournal.apta.org/content/86/3/355.short
VI. Additional Web Based Resources:
This website provides further information about the anatomy, function, and common pathologies of the shoulder complex:
http://www.wheelessonline.com/ortho/shoulder_index
VII. References:
1. Neumann DA. Shoulder complex. In Neumann DA: Kinesiology of the musculoskeletal system: foundations for physical rehabilitation. Philadelphia, Pa: Mosby; 2002:5,91-132.
