by Amber McKinney
I. Description of Motion
Adduction can be defined as the motion that occurs in the frontal plane by way of the humerus rotating around an axis that is oriented in an anterior-posterior direction.1 In most instances, shoulder adduction occurs as the arm is returned to the side from a raised position. However, the mechanics of shoulder adduction are not only produced by the glenohumeral joint. In order for someone to carry out proper shoulder adduction, the scapula must simultaneously downwardly rotate while the shoulder is adducting. From an arthrokinematics standpoint at the glenohumeral joint, shoulder adduction occurs by way of the convex head of the humerus rolling inferiorly while simultaneously sliding superiorly on a concave glenoid fossa.1 From an arthrokinematics standpoint at the scapulothoracic ‘joint’, the clavicle must depress at the sternoclavicular (SC) joint while downward rotation occurs at the acromioclavicular (AC) joint.1 The nerve roots responsible for innervating the muscles involved in shoulder adduction range from C5-T1.
- Latissimus Dorsi
- Pectoralis Major
- Teres Major
- Triceps Brachii Long head (resists dislocation during adduction)
Downward Rotation of Scapula
- Rhomboid Major/Minor
- Levator Scapula
- Pectoralis Minor
- Latissimus Dorsi
II. Mobilizing - Increasing Range of Motion
Serratus Anterior Self Stretch:
Have patient seated sideways in a chair. Affected arm is placed behind back of chair, with elbow flexed and relaxed. Have the patient rotate the torso toward the uninvolved direction. The patient should feel a stretch under the scapula. Hold for 30 seconds. Repeat 10x.
Crescent Side Bend:
Instruct the patient to stand up tall with a straight spine. Have the patient extend the arms toward the ceiling and place the palms together. Have the patient slide the scapula downward, bringing the shoulders away from the ears. Have the patient bend to the left, while pressing the hips out to the right. Cue the patient that they should be trying to create a ‘C’ shape with their spine. This will provide a stretch to the right serratus anterior. The stretch can be modified by having the patient oscillate for a count of 10 after they feel the stretch. Hold for 30 seconds. Repeat 10x.
Upper Trapezius Stretch:
Place arm of involved side behind back. Instruct the patient to reach up with the opposite arm, and place hand on top of head. Patient should then apply gradual pressure to pull the ear toward the shoulder. The patient should feel a stretch, or ‘pull’ in the involved trapezius. Hold for 30 seconds. Repeat 10x.
III. Indications for Stretching
Deficits in shoulder adduction ROM are very infrequent, and are rarely treated. However, it is not uncommon to see a patient who has altered scapular mechanics. While full adduction may be present, the patient’s scapular mechanics may be faulty, or incorrect. In order for proper adduction to occur, downward rotation of the scapula must also be present as part of the motion. If a patient is lacking scapular downward rotation, the above stretches may be effective in helping to restore proper motion.
Shoulder Isotonic Adduction with Theraband:
Before beginning the exercise, be sure that the patients scapula is in a good position. Have the patient hold an elastic band away from their side, pull the band towards your side. Keep your elbow straight. Be sure to instruct the patient to use control during both directions of the exercise. If the patient can complete 10 reps without fatigue, have the pt do 3 sets of 10 reps. To progress the exercise, increase the resistance of the theraband.
Shoulder Isometric Adduction with Theraband:
Place a strap on a fixed location. Instruct the patient to grab the end of the strap with the involved arm. Instruct the patient to pull the band until their arm is fixed by the side. Instruct the patient to step away from the band while keeping the arm stationary. This exercise will require isometric activation of the shoulder adductors. If the patient can complete 10 reps without fatigue, have the patient do 3 sets of 10 reps. To progress the exercise, increase the resistance of the theraband.
Isometric Towel Squeezes:
First, have the patient gently squeeze / set shoulder blades. Have the patient pull the elbow into their side to ‘squeeze’ the towel. To progress this exercise, increase the difficulty by adding an object that provides increased resistance, such as a ball. Hold for 30 seconds. Repeat 10x.
V. Potential Clinical Syndromes or Etiologies
The adduction strengthening exercises described above may be appropriate for use in patients with certain types of scapular dyskinesis. You can read more about scapulohumeral rhythm and associated muscular weakness here:
1. Neumann DA. Shoulder complex. In: Falk K, ed. Kinesiology of the musculoskeletal system: foundations for rehabilitation. 2nd ed. St. Louis, Mo: Mosby/Elsevier; 2010:120-172