Long thoracic nerve palsy is a medical condition involving the damage of the long thoracic nerve, due to an acute injury to the nerve itself, or other circumstances not related to traumatization.
The long thoracic nerve is responsible for supplying the serratus anterior muscle, whose function is to maintain the scapula in a balanced position while upper extremity movements are performed . A case of long thoracic nerve palsy (LTNP) corresponds to a weakened serratus anterior muscle  . The most easily observed manifestation related to the long thoracic nerve palsy is winging of the scapula (a protrusion of the scapula from the back)  .
Patients are mainly adults which are between 20 and 60 years old. They present with marked scapular winging and inability to elevate the arm or push efficiently . Loss of normal shoulder mobility is the primary complaint of the affected patients, that can also be followed by a feeling of instability. Athletes experience a restriction in their exercising potential, whereas non-athletic patients report a significant difficulty in performing everyday tasks, such as getting dressed or pushing. Pain in the shoulder region is also experienced when the back is resting upon a firm surface.
Long thoracic nerve palsy and subsequent paralysis of the serratus anterior muscle is a medical condition encountered frequently which, in general, leads to a considerable disability in everyday activities  . Tendonitis may also arise in the affected shoulder joint, and so may brachial plexus radiculitis, adhesive capsulitis, and subacromial impingement . Paresthesia of the shoulder girdle is another possible symptom .
Long thoracic nerve palsy is typically diagnosed clinically; even though electromyography can provide a clear confirmation of the diagnosis, it brings desired results only after 6 weeks from the initial symptomatology.
The following clinical findings constitute sufficient evidence for the existence of LTNP:
Radiographs are not expected to illustrate abnormalities in a case of LTNP, except for an occasional, slight discrepancy in the positioning of the scapulae. They are obtained in order to exclude the possibility of a scapular mass. Electromyography is carried out at least six weeks after the symptoms have developed and offers the final confirmation of LTNP.