What are the symptoms of a prosterior labrum tear?

Posterior labrum. Posterior labrum tears can occur in posterior shoulder dislocation, or when the numeral head (ball) is forced backwards on the socket. Symptoms include pain referred into the upper arm with overhead activities. Patients also commonly complain of mechanical popping, catching, or grinding in the shoulder.
Instability & pain. Posterior shoulder instability often results from a tear of the posterior labrum. The posterior shoulder capsule attaches via the labrum to the glenoid (inner shoulder joint bone). Posterior instability often causes posterior shoulder pain and a sensation that the shoulder is slipping out the back, especially when a posteriorly directed load is placed along the long axis of a forward elevated arm.