She uses a Nordic Track for exercise, which now also reproduces her symptoms. She denies constitutional symptoms. Prior to continuing, please develop a differential diagnosis and list each possible diagnosis in order of likelihood. Commentary I Rotator cuff tendinitis is probably the most common cause of anterolateral shoulder pain subsequent to reaching and lifting activities. The tendinitis is usually secondary to subacromial impingement of the supraspinatus, and is frequently accompanied by subacromial and subdeltoid bursitis.
Biceps tendinitis can also develop after repetitive reaching and lifting activities.
Musculoligamentous strain or sprain of any of the shoulder girdle muscles can also contribute to regional pain symptoms. Cervical disc disease and C5 or C6 radiculopathies can present with pain in the shoulder region. Shoulder instability is a common cause of secondary rotator cuff tendinitis, especially in teen-age and young adult populations. Thoracic outlet syndrome usually presents with neck and shoulder region pains, often accompanied by C8 and T1 distribution parasthesias with extremes of neck rotation or overhead reaching activities. Peripheral neuropathy involving either the suprascapular, long thoracic, or axillary nerves can contribute to shoulder region pains and dysfunction.