torn labrum

the labrum is a ring around the hip socket that help hold the femur in place. the labrum may tear for varying reasons. a tear may be due to femoroacetabuar impingement, excessive trauma to the socket, etc. when a tear occurs it inflames the area, causes immense pain and much irritation to the iliac and anterior femoral region.

http://www.bryankellymd.com/hip_kelly_new.html  
  
http://www.bryankellymd.com/hip_kelly_new.html

here are a few resources to understand a torn labrum:

hip info
torn labrum-mayo clinic
acetabular labrum tears-sports injury bulletin
hip labral tear-hiplabraltear.com
tear-understandingfai.com