Rotator Cuff Denervation Syndromes is caused by variety of causes, most important are:
- Viral neuritis: Parsonage-Turner syndrome
- Fibrous bands
- Paralabral cyst
- Nerve injury (stretching/traction injury)
In this case, the distribution of muscles affected doesn't follow the anatomical muscle innervation, which favors Parsonage-Turner syndrome.
Typical anatomical nerve distributions are:
- suprascapular nerve
- supraspinatus muscle
- infraspinatus muscle
- axillary nerve
- teres minor muscle (5th cervical nerve)
- deltoid muscle (5th & 6th cervical nerves)
- subscapular nerve
Please note that the chronic stage differs in MRI appearance.