title: Anatomy and clinical implications of the ultrasound-guided subsartorial saphenous nerve block.
abstract: BACKGROUND
  We evaluated the anatomic basis and the clinical results of an ultrasound-guided saphenous nerve block close to the level of the nerve's exit from the inferior foramina of the adductor canal.
  
  
  METHODS
  The anatomic study was conducted in 11 knees of formalin-preserved cadavers in which the saphenous nerve was dissected from near its exit from the inferior foramina of the adductor canal. The clinical study was conducted in 23 volunteers. Using a linear probe, the femoral vessels and the sartorius muscle were depicted in short-axis view at the level where the saphenous nerve exits the inferior foramina of the adductor canal. Ten milliliters of 1.5% lidocaine was injected into the compartment structured by the sartorius muscle and the femoral artery.
  
  
  RESULTS
  The saphenous nerve was found to exit the adductor canal from its inferior foramina in 9 (81.8%) of 11 and at a more proximal level in 2 (18.2%) of 11 of the anatomic specimens. In a single specimen (9%), the saphenous nerve was formed by the anastomosis of 2 branches. In all the dissections, the saphenous nerve, after exiting the adductor canal, passed between the sartorius muscle and the femoral artery. Of the 23 volunteers, 22 responded with a complete sensory block, whereas a single volunteer demonstrated no sensory blockade. None of the volunteers experienced a motor block of the hip flexors and knee extensors.
  
  
  CONCLUSIONS
  Ultrasound-guided injection directly caudally from the inferior foramina of the adductor canal, between the sartorius muscle and the femoral artery, seems to be an effective approach for saphenous nerve block.
authors.affiliation: 2nd Department of Anesthesia and Cardiovascular Critical Care, School of Medicine, Attikon Hospital, Athens, Greece. thsaranteas@gmail.com
authors.forename: Theodosios
authors.initials: T
authors.lastname: Saranteas
authors.forename: George
authors.initials: G
authors.lastname: Anagnostis
authors.forename: Tilemachos
authors.initials: T
authors.lastname: Paraskeuopoulos
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Koulalis
authors.forename: Zinon
authors.initials: Z
authors.lastname: Kokkalis
authors.forename: Mariza
authors.initials: M
authors.lastname: Nakou
authors.forename: Sofia
authors.initials: S
authors.lastname: Anagnostopoulou
authors.forename: Georgia
authors.initials: G
authors.lastname: Kostopanagiotou
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000294:innervation*; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D010525:Peripheral Nerves / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D018084:Ultrasonography, Interventional / Q000379:methods*