title: Ultrasound of the lateral femoral cutaneous nerve in asymptomatic adults.
abstract: BACKGROUND
  To define the sites where the lateral femoral cutaneous nerve (LFCN) is more easily visualized and to describe the anatomical variations of the LFCN.
  
  
  METHODS
  A total of 240 LFCNs in 120 volunteers were evaluated with 18 MHz ultrasound; the intermuscular space between the tensor fasciae latae muscle and the sartorius was used as an initial sonographic landmark. The time taken to identify the nerve was recorded. The number of nerve branches at the level of the inguinal ligament (IL) and the relationship between the LFCN and the IL was assessed. The nerve cross-sectional area (CSA) of the LFCN and the distance between the LFCN and the anterior superior iliac spine was measured.
  
  
  RESULTS
  Each nerve was identified using ultrasound in all participants. The mean time for identifying the nerve was 7s for unilateral LFCNs. The nerve passed under the IL in 198 cases, whereas in 44 cases, it passed through to the IL. The LFCN consisted of 1-4 branches just after its passage under or through the IL. The CSA of the LFCN was 1.04 ± 0.44 mm(2), and the mean distance between the LFCN and the anterior superior iliac spine was 15.6 ± 4.2 mm.
  
  
  CONCLUSIONS
  It is easier to identify the LFCN if the intermuscular space between the tensor fasciae latae muscle and the sartorius is used as an initial sonographic landmark. The anatomical variation of the LFCN can be viewed with high-frequency ultrasound.
authors.affiliation: Department of Ultrasound, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, 600 Yishan Rd, Shanghai 200233, China. zhuja@sjtu.edu.cn
authors.forename: Jiaan
authors.initials: J
authors.lastname: Zhu
authors.forename: Yiwen
authors.initials: Y
authors.lastname: Zhao
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.forename: Yunxia
authors.initials: Y
authors.lastname: Huang
authors.forename: Junjie
authors.initials: J
authors.lastname: Shao
authors.forename: Bing
authors.initials: B
authors.lastname: Hu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging; D016009:Chi-Square Distribution; D005260:Female; D005267:Femoral Nerve / Q000002:abnormalities / Q000000981:diagnostic imaging*; D006801:Humans; D008022:Ligaments / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging; D015588:Observer Variation; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D013131:Spine / Q000000981:diagnostic imaging; D014463:Ultrasonography; D055815:Young Adult