hip dislocation

5.MC dislocation of hip joint
 a.anterior
b.posterior
c.posterolateral
d.central

ans:b 
posterior dislocation of hip joint is most commonly seen 
mech of injury: dash board injury
'vascular sign of narath ' seen due to head of femur impinges on femoral artery and absence of pulse.
complications:sciatic nerve injury
                       avascular necrosis of femoral head
                       osteoarthritis
                      myositis ossificans