<prompt> Monteggia fracture isFracture upper ulna Dislocation of upper radio ulnar jointFracture upper radius Radioulnar joint dislocationLower ulnar fracture Lower radio-ulnar joint dis- locationLower radius fracture Lower radio-ulnar joint dislocation  <response>: A Fracture upper ulna Dislocation of upper radio ulnar joint MONTEGGIA FRACTURE DISLOCATION: This is a fracture of the upper-third of the ulna with dislocation of the head of the radius. It is caused by a fall on an outstretched hand with the forearm forced into excessive pronation hyperpronation injury It may also result from a direct blow on the back of the upper forearm. Posterior interosseous nerve may be injured Posterior interosseus nerve is also injured in operations on head of radius. In this nerve injury wrist drop does not occur since extensor carpi radialis long us and ECR brevis are spared which are supplied by radial nerve. Sensory deficit also does not occur since posterior cutaneous nerve of forearm supplies forearm skin. PO nerve is a branch of tadial nerve in cubital fossa, so it can be inured in Monteggia fracture. Bartons fracture: Distal radius, intra-articular fracture Chauffeurs fracture: Radial styloid fracture Colies fracture: Distal radius, extra-articular 12 of the radius with dislocation of distal radio-ulnar joint Night-stick fracture: Isolated fracture shaft of the ulna Smiths fracture: distal radius fracture, extra-articular with volar tilt of the distal fragment. REMEMBER! Mnemonic MUSS stands for Monteggia ; Ulna; Superior 13rd ; Supination injury GRIP stands for Galeazzi ; Radius; Inferior 13rd ; Pronation injury 