title: The sublime bridge: anatomy and implications in median nerve entrapment.
abstract: OBJECTIVE
  The sublime bridge is a potential site of entrapment of the median nerve in the forearm. To the authors' knowledge, this structure and its relationship to the median nerve have not been studied. The aim of the present study was to quantitate this structure and elucidate its relationship to the median nerve.
  
  
  METHODS
  Sixty adult cadaveric forearms underwent dissection of the sublime bridge. Relationships of this structure were observed, and measurements of its anatomy were made. The relationship of the median nerve to the sublime bridge was observed with range of motion about the forearm.
  
  
  RESULTS
  The sublime bridge was found to be tendinous in the majority (45 [75%]) of specimens and muscular in the remaining forearms (15 [25%]). The maximal mean width of the sublime bridge was 7 cm proximally, and the minimal mean width was 3 cm distally. The mean distance from the medial epicondyle to the apex of the sublime bridge was found to be 8.1 cm. The relation of the median nerve to the bridge was always intimate. On 2 sides (1 left and 1 right) from different male specimens, the median nerve was attached to the deep aspect of the sublime bridge by a strong connective tissue band, thus forming a tunnel on the deep aspect of this structure. With range of motion of the forearm, increased compression of the median nerve by the overlying sublime bridge was seen with extension but no other movement.
  
  
  CONCLUSIONS
  Based on the authors' study, pronator syndrome is an incorrect term applied to compression of the median nerve at the sublime bridge. This potential site of median nerve compression is distinct and has characteristics that can clinically differentiate it from compression of the median nerve between the heads of the pronator teres. The authors hope that these data will be of use to the surgeon in the evaluation and treatment of patients with proximal median nerve entrapment.
authors.affiliation: Pediatric Neurosurgery, Children's Hospital, Birmingham, Alabama 35233, USA. rstubbs@uab.edu
authors.forename: R Shane
authors.initials: RS
authors.lastname: Tubbs
authors.forename: Tyler
authors.initials: T
authors.lastname: Marshall
authors.forename: Marios
authors.initials: M
authors.lastname: Loukas
authors.forename: Mohammadali M
authors.initials: MM
authors.lastname: Shoja
authors.forename: Aaron A
authors.initials: AA
authors.lastname: Cohen-Gadol
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003238:Connective Tissue / Q000473:pathology; D004551:Elbow Joint / Q000502:physiology; D005260:Female; D005542:Forearm / Q000294:innervation* / Q000473:pathology*; D006801:Humans; D008297:Male; D020423:Median Neuropathy / Q000473:pathology*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology*; D009408:Nerve Compression Syndromes / Q000473:pathology*; D016059:Range of Motion, Articular / Q000502:physiology; D013710:Tendons / Q000473:pathology*