title: Absence of the genicular arterial anastomosis as generally depicted in textbooks.
abstract: BACKGROUND
  Textbook representations of the genicular arterial anastomosis show a large direct communication between the descending branch of the lateral circumflex femoral artery (DBLCFA) and a genicular branch of the popliteal artery but this is not compatible with clinical experience. The aim of this study was to determine whether the arterial anastomosis at the knee is sufficient, in the event of traumatic disruption of the superficial femoral artery, to infuse protective agents or to place a stent to restore flow to the lower leg.
  
  
  METHODS
  Dissection of ten cadaveric lower limbs was performed to photograph the arterial anatomy from the inguinal ligament to the tibial tubercle. Anastomosis with branches of the popliteal artery was classified as: 'direct communication', 'approaching communication' or 'no evident communication'.
  
  
  RESULTS
  A constant descending artery in the lateral thigh (LDAT) was found to have five types of origin: Type 1 (2/10 limbs) involved the lateral circumflex femoral branch of the femoral artery, Type 2 (3/10 limbs) the lateral circumflex femoral branch of the profunda femoris artery, Type 3 (1/10 limbs) the femoral artery, Type 4 (3/10 limbs) the superficial femoral artery and Type 5 (2/10 limbs) the profunda femoris artery. In one limb, there were two descending arteries (Types 4 and 5). Collateral circulation at the knee was also variable: direct communicating vessels (3/10 limbs); approaching vessels with possible communication via capillaries (5/10 limbs); no evident communication (2/10 limbs). Communicating vessels, if present, are too small to provide immediate collateral circulation.
  
  
  CONCLUSIONS
  Modern representations of the genicular arterial anastomosis are inaccurate, derived commonly from an idealised image that first appeared Gray's Anatomy in 1910. The afferent vessel is not the DBLCFA. The majority of subjects have the potential to recruit collateral circulation via the LDAT following gradual obstruction to normal arterial flow, which may be important if the LDAT is removed for bypass or flap surgery. A direct communication is rarely present and is never as robust as generally depicted in textbooks.
authors.affiliation: Canadian Forces Medical Service and Western University Canada.
authors.forename: M
authors.initials: M
authors.lastname: Sabalbal
authors.forename: M
authors.initials: M
authors.lastname: Johnson
authors.forename: V
authors.initials: V
authors.lastname: McAlister
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D003097:Collateral Circulation / Q000502:physiology; D005260:Female; D005263:Femoral Artery / Q000033:anatomy & histology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000098:blood supply*; D008297:Male; D008488:Medical Illustration; D008875:Middle Aged; D011150:Popliteal Artery / Q000033:anatomy & histology*; D013782:Textbooks as Topic; D013848:Thigh / Q000098:blood supply
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