THE DELTOID EXTENSION LAG SIGN FOR DIAGNOSIS AND GRADING OF AXILLARY NERVE PALSY

The deltoid extension lag sign has been developed to avoid the pitfall s confounding the diagnosis of an axillary nerve lesion. The physician elevates the arm into a position of near full extension. The patient is asked to attempt active maintenance of this position. If the deltoi d is week, the arm will drop. In five patients with traumatic axillary nerve palsy after anterior dislocation of the shoulder, the deltoid e xtension lag sign was used to evaluate the functional status of the de ltoid muscle. The magnitude of the angular drop, or lag, of the arm wa s a precise indicator of the functional status and recovery of the del toid. The sign proved to be objective and reproducible, allowing confi dent assessment of deltoid function and when repeated over time allowe d precise follow-up of deltoid recovery.