The deltoid is the main muscle in the glenohumeral joint (shoulder).It is innervated by the axillary nerve which also innervates the teres minor (external rotator) and contributes to the sensitivity of the shoulder tip.
Isolated paralysis of this nerve occurs following glenohumeral dislocations or shoulder surgery.
The sign of paralysis is severe shoulder weakness with functional impairment, sometimes associated with pain.
Early signs of recovery can be detected through close monitoring over a period of several months.If no sign of recovery is visible 5 months from injury, explorative surgery will be required.
Depending on the findings of the intra-operative assessment, a simple release, nerve graft or neurotisation of the axillary nerve by the nerve of the long triceps muscle will be carried out.
For injuries diagnosed late (over one year), when impairment is severe, palliative tendon transfers are possible but palliative surgery will often lean towards glenohumeral arthrodesis (joint fusion).