title: Variable extension of the transitional zone in the medial structure of carotid artery tripod.
abstract: BACKGROUND
  The goal of our study was to demonstrate the extension of the transitional zone (TZ) between elastic and muscular medial structure in carotid artery tripod.
  
  
  METHODS
  A histologic study of 56 probes from 8 carotid artery tripods was performed. The probes were obtained from autopsies of 4 adults (mean age: 47.5 years, range 38 to 55 years) and were taken from 7 different topographic sites.
  
  
  RESULTS
  At each level of the CCA (at 1 cm and 2 cm proximal to the bifurcation as well as at the bifurcation) we observed an elastic arterial type in 24 (42.8%) probes with 11 to 20 (medium 15.0) elastic fibers per view field (200 x magnification) in the media. In contrast the histologic structure of the ICA and ECA varied as follows: in 8 sections (14.3%) elastic arterial type with 11 to 16 (medium 13.1) elastic fibers, in 11 sections (19.6%) muscular arterial type with 2 to 5 (medium 3.5) elastic fibers and in 9 sections (16.1%) a transitional arterial type with 6 to 8 (medium 6.7) elastic fibers in the media. Atherosclerotic lesions have prevented the assessment of the arterial type in 4 probes (7.1%). The TZ in the medial structure of carotid artery tripods is exclusively localized in the ICA/ECA but not in the CCA. The ICA/ECA presented a TZ with a length up to 0.5 cm (4 probes; 25%), up to 1.5 cm (4 probes; 25%) and longer than 1.5 cm (6 probes; 37.5%).
  
  
  CONCLUSIONS
  In this study we confirmed that in the carotid artery tripod, a TZ--an arterial segment with transition from elastic to muscular type--does exist, involving a variable length. Furthermore studies on the impact of the biomechanical properties of the TZ as a potential factor in atherosclerotic disease are justified. In addition, the complex biomechanical behavior of the TZ should be considered prior to interventional procedures.
authors: Unité d'Anatomie et de Cytologie Pathologiques, Hôpital Saint-Michel, Paris, France. jkr.janzen@lycosmail.com/jkr.janzen@lycos.de
authors: J
authors: J
authors: Janzen
authors: P
authors: P
authors: Lanzer
authors: K
authors: K
authors: Rothenberger-Janzen
authors: P N
authors: PN
authors: Vuong
mesh_terms: D000328:Adult; D002339:Carotid Arteries / Q000473:pathology*; D002341:Carotid Artery Thrombosis / Q000473:pathology; D016893:Carotid Stenosis / Q000473:pathology; D002544:Cerebral Infarction / Q000473:pathology; D004547:Elastic Tissue / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000473:pathology; D017540:Tunica Media / Q000473:pathology*