title: Anatomic Characteristics of Pronator Quadratus Muscle: A Cadaver Study.
abstract: OBJECTIVE
  To identify the anatomic characteristics of the pronator quadratus (PQ) muscle and the entry zone (EZ) of the anterior interosseous nerve (AIN) to this muscle by means of cadaver dissection.
  
  
  METHODS
  We examined the PQ muscle and AIN in 20 forearms from 10 fresh cadavers. After identifying the PQ muscle and the EZ of the AIN, we measured the distances from the midpoint (MidP) of the PQ muscle and EZ to the vertical line passing the tip of the ulnar styloid process (MidP_X and EZ_X, respectively) and to the medial border of the ulna (MidP_Y and EZ_Y, respectively). Forearm length (FL) and wrist width (WW) were also measured, and the ratios of MidP and EZ to FL and of MidP and EZ to WW were calculated.
  
  
  RESULTS
  The MidP was found to be 3.0 cm proximal to the ulnar styloid process or distal 13% of the FL and 2.0 cm lateral to the medial border of the ulna or ulnar 40% side of the WW, which was similar to the location of EZ. The results reveal a more distal site than was reported in previous studies.
  
  
  CONCLUSIONS
  We suggest that the proper site for needle insertion and motor point block of the PQ muscle is 3 cm proximal to the ulnar styloid process or distal 13% of the FL and 2 cm lateral to the medial border of the ulna or ulnar 40% side of the WW.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Korea University College of Medicine, Seoul, Korea.
authors.forename: Phil Woo
authors.identifier: 0000-0003-0252-226X
authors.initials: PW
authors.lastname: Choung
authors.affiliation: Department of Physical Medicine and Rehabilitation, Korea University College of Medicine, Seoul, Korea.
authors.forename: Min Young
authors.identifier: 0000-0003-4188-8213
authors.initials: MY
authors.lastname: Kim
authors.affiliation: Department of Physical Medicine and Rehabilitation, Korea University College of Medicine, Seoul, Korea.
authors.forename: Hyung Soon
authors.identifier: 0000-0003-0732-7690
authors.initials: HS
authors.lastname: Im
authors.affiliation: Department of Physical Medicine and Rehabilitation, Korea University College of Medicine, Seoul, Korea.
authors.forename: Ki Hoon
authors.identifier: 0000-0002-7257-3858
authors.initials: KH
authors.lastname: Kim
authors.affiliation: Department of Anatomy, Korea University College of Medicine, Seoul, Korea.; Practical Anatomy Center, Korea University College of Medicine, Seoul, Korea.
authors.forename: Im Joo
authors.identifier: 0000-0002-5558-6278
authors.initials: IJ
authors.lastname: Rhyu
authors.affiliation: Department of Physical Medicine and Rehabilitation, Korea University College of Medicine, Seoul, Korea.
authors.forename: Byung Kyu
authors.identifier: 0000-0001-8445-7099
authors.initials: BK
authors.lastname: Park
authors.affiliation: Department of Physical Medicine and Rehabilitation, Korea University College of Medicine, Seoul, Korea.; Practical Anatomy Center, Korea University College of Medicine, Seoul, Korea.
authors.forename: Dong Hwee
authors.identifier: 0000-0002-8116-0078
authors.initials: DH
authors.lastname: Kim
keywords: Cadaver; Electromyography; Median nerve; Pronator quadratus