Differential Diagnosis 6-9, 13-21

Axillary Neuropathy / “Unhappy Triad” / Quadrilateral Space Syndrome (QSS) / Combination Peripheral Nerve Dysfunction / Posterior Cord of the Brachial Plexus Injury / C5-6 Radiculopathy / Parsonage-Turner Syndrome (PTS)
Subjective History /
  • Pain to the deep or lateral shoulder
  • N/T of the lateral arm
  • Feeling of instability
  • History of trauma
  • Weakness & fatigue
/
  • Pain to the deep or lateral shoulder
  • N/T of the lateral arm
  • Feeling of instability
  • History of trauma
  • Weakness & fatigue
  • TTP at the insertion of the muscle involved
/
  • Pain to the deep or lateral shoulder
  • N/T in a non-dermatomal pattern
  • History of trauma OR overuse injury with overhead sports
  • Weakness & fatigue
  • TTP at the quadrilateral space
  • Symptoms present in overhead activities
/
  • Varies, depending on the peripheral nerve involvement, to include: axillary, suprascapular, musculocutaneous, & long thoracic nerves
/
  • Varies, depending on the site of the lesion, to include: radial, axillary, upper & lower subscapular, & thoracodorsal nerves
/
  • Insidious onset
  • Symptoms RELATED to neck movements
  • N/T of the lateral arm and webspace of the hand (dermatomal pattern)
/
  • Acute onset of intense pain
  • No MOI
  • Residual weakness/ paralysis
  • Symptoms NOT related to neck movements

Observation /
  • Atrophy of the deltoid & teres minor muscles
/
  • Atrophy of the deltoid, and any combination of the rotator cuff muscles
/
  • Atrophy of the deltoid & teres minor muscles
/
  • Atrophy to the muscles innervated by the nerves listed above
/ Atrophy of the muscles innervated by the nerves listed above /
  • Limited c-spine ROM
  • Atrophy to the muscles supplied by the C5 & C6 nerve roots
/
  • Limited c-spine ROM
  • Atrophy to the UE muscles supplied, usually those supplied by the C5 & C6 nerve roots

MMT /
  • Weakness of the deltoids & teres minor
/
  • Weakness of the deltoids, teres minor, & any combination of the rotator cuff muscles
/
  • Weakness of the deltoids & teres minor
/
  • Weakness to the muscles innervated by the nerves listed above
/ Weakness to the muscles innervated by the nerves listed above /
  • Myotomal weakness to the muscles supplied by C5 & C6
/
  • Weakness in the muscles innervated by the nerve involved
  • Commonly, weakness of C5-6 muscles

Neurologic Testing /
  • Reflexes: Intact
  • Myotomes: Weak deltoid & teres minor
  • Dermatomes: decreased sensation along the lateral shoulder
/
  • Reflexes: Intact
  • Myotomes: Weak deltoid teres minor
  • Dermatomes: decreased sensation along the lateral shoulder
/
  • Reflexes: Intact
  • Myotomes: Weak deltoid & teres minor
  • Dermatomes: decreased sensation along the lateral shoulder
/
  • Reflexes: Intact
  • Myotomes: Weak muscles innervated by the nerves listed above
  • Dermatomes: decreased sensation in the dermatomal pattern of the nerves listed above
/
  • Reflexes: diminished to biceps, brachioradialis, & triceps
  • Peripheral nerve weakness & sensation deficits:in the dermatomal pattern of the nerves listed above
/
  • Reflexes: diminished to biceps & brachioradialis
  • Myotomes: weakness- usually to the C5-6 muscles
  • Dermatomes: mild sensory deficits in the C5-6 dermatomal pattern
/
  • Reflexes: diminished to biceps & brachioradialis
  • Myotomes: weakness -usually to the C5-6 muscles
  • Dermatomes: mild sensory deficits in the C5-6 dermatomal pattern

Special Tests / (+) Deltoid Extension Lag / (+) Deltoid Extension Lag
(+) Painful Arc
(+) Infraspinatus test
(+) Drop arm sign / (+) Deltoid Extension Lag / (+) ULTT
(+) Spurling’s
(+) Rotation <60 degrees
(+) Distraction Test