Differential diagnosis of nerve pathologies in the shoulder Sumit Bassi M.D. Sports Medicine Fellow Summa Health.

Disclosures Disclosure:- Financial — No relevant financial relationship exists. Nonfinancial — Member of American Medical Society of Sports Medicine. 2

Case 19 y/o right handed male baseball player, with right anterior shoulder pain. Shoulder Dislocation sensation while sliding head first into third base. ER work up - No fracture or any signs of dislocation on x-ray imaging. Numbness and tingling which lasted 24 hours after injury. After 2 weeks of rest, he noticed some weakness with bench press and deltoid flies. 3

Office visit Presents with complaints of on and off dull ache in shoulder Worsens with movement, overhead activities, and aggravated by sleeping on same side. No radiating pain, swelling, bruising, or tingling. Patient describes pain as an on and off dull ache. 4

Physical Exam 5

Another picture 6

7

Inspection from the back 8

Right shoulder Physical exam ROM: Active - Abduction-120 degrees. - Flexion degrees. - Internal Rotation- 70 degrees - External Rotation- 50 degrees : Passive- Normal ROM Strength testing against resistance: -:Supraspinatus- Decreases strength. -:External rotation- Decreased strength. -:Internal rotation - Normal strength.

Exam of the right shoulder Abduction- Decreased strength against resistance Subscapularis- Normal strength against resistance Biceps- Normal strength against resistance. Impingement tests:- Negative Sensory exam- grossly normal. Pulse- Normal 10

Further Testing 11

Imaging 12

Axial view 13

Differential Parsonage Turner Syndrome Long thoracic nerve injury C7 radiculopathy Spinal accessory nerve injury Fascioscapulohumeral dystrophy (FSHD) Scapulodysrythmia 14

Final diagnosis Traumatic long thoracic and spinal accessory nerve injury. 15

Common nerves affected around the shoulder Axillary Nerve - supplies the Deltoid muscle. Most commonly stretched with shoulder disclocations. Long Thoracic Nerve - supplies Serratus Anterior muscle and can cause Winging of the shoulder Suprascapular Nerve - supplies supraspinatus and infraspinatus muscles and can be entrapped or diseased. Musculocutaneous Nerve - supplies the Biceps muscle and can rarely be injured at surgery 16

Long thoracic nerve injury The long thoracic nerve is a pure motor nerve that arises from the fifth, sixth, and seventh cervical nerve roots The main causes of injury to the long thoracic nerve are the following ●Neuralgic amyotrophy ●Trauma or compression ●Stretch or traction from repetitive activities 17

Long Thoracic nerve innervating serratus anterior muscle 18

Treatment and Prognosis of Long Thoracic nerve injury Management and prognosis varies according to the mechanism of nerve injury Recovery from neuralgic amyotrophy occurs slowly over one to three years Most cases of long thoracic nerve injury caused by carrying or by repetitive activity are incomplete and resolve spontaneously within 6 to 24 months For those who do not experience functional recovery, surgical procedures may be an option, which is fascial grafts( transfer of sternal head of pectoralis major) 19

Medial and lateral winging of Scapula 20

Medial winging- Long thoracic nerve 21

Lateral winging- Spinal accessory nerve or dorsal scapular nerve 22

Medial and lateral winging medial winging usually seen in young athletic patient far more common lateral winging –history of neck surgery (lateral is usually iatrogenic) On physical exam:- medial winging medial spine of scapula moves upward and medial lateral winging medial spine of scapula moves downward and lateral 23

Spinal Accessory nerve injury The spinal accessory nerve is a cranial nerve that is derived from the upper cervical nerve roots and innervates the sternocleidomastoid and trapezius muscles, the latter of which primarily functions as a shoulder stabilizer. The most common causes of isolated spinal accessory neuropathy include biopsy of the cervical lymph nodes in the posterior triangle and local surgery, such as radical neck dissection Blunt injuries to the nerve are also common (eg, due to sports or combat). 24

Treatment and prognosis of Spinal accessory nerve injury Non operative care- observation and trapezius strengthening. Operative treatment includes- nerve explorations or muscle transfer ( lateralize levator scapulae and rhomboids, transfer from medial border to lateral border). The prognosis will vary by cause 25

Overview of the nerves innervating the shoulder 26

Suprascapular nerve entrapment at suprascapular notch. Compression can be from:- Ganglion cyst(often associated with labral tears) :- Transverse scapular ligament entrapment :- Callus formation after a fracture Presentation :-symptoms deep, diffuse, posterolateral shoulder pain :-physical exam pain with palpation of suprascapular notch 27

Ganglion cyst at the suprascapular notch 28

Suprascapular nerve entrapment at spinoglenoid notch Compression can be due to :- Posterior labral tears causing a cyst :- Spinoglenoid ligament :- Spinoglenoid notch ganglion :- Traction injury seen in volleyball players and rowers Presentation :-symptoms deep, diffuse, posterolateral shoulder pain 29

Spinoglenoid cyst 30

Upper extremity myotomes 31

Which nerve and site? 32

What nerve and which muscle? 33

What nerve and which muscle? 34

Work up When to get a MRI vs EMG? When to send for physical therapy? When to send for surgical intervention? 35