title: Novel Anatomic Characteristics of the Laryngeal Framework: A Computed Tomography Evaluation.
abstract: OBJECTIVE
  The thyroid cartilage (TC) in men has a more prominent thyroid notch and a narrower interlaminae angle (ILA) as compared with women. Anatomy textbooks classically stipulate that the ILA is 90° in men and 120° in women. Our observation, based on thyroid chondroplasty operations, of a much narrower angle led to the current investigation.
  
  
  METHODS
  Cohort imaging study.
  
  
  METHODS
  Tertiary academic referral center.
  
  
  METHODS
  Computed tomography angiography neck images of adult patients were studied. The ILA was measured on 2 axial planes: at the level of the vocal processes (and the upper portion of thyroarytenoid muscles) and 5 mm superior and parallel to the former. The anterior projection of the TC and the vertical dimensions of the midline cricothyroid membrane (CTM) were also measured.
  
  
  RESULTS
  A total of 126 patients were included in the study. The average ILAs were 63.5°±20.6° and 93.3°±16.6° for men and women, respectively (P < 10(-14)), and were significantly narrower at the upper level in comparison with the vocal process level (P < 10(-7) for men, P = .004 for women). The anterior projection of the TC in men was more prominent as compared with women (P = .0003) and significantly correlated with the ILA (P = .0159). The length of the midline CTM was 11.1±2.3 mm in men and 10.3±1.7 mm in women (P = .0355).
  
  
  CONCLUSIONS
  The ILA is narrower than that reported in the classic anatomy textbooks. In male patients, the upper part of the TC becomes narrower and projects anteriorly like a "jug's spout." The mean vertical dimension of the midline CTM was 10 to 11 mm.
authors: Department of Otolaryngology-Head and Neck Surgery, Sheba Medical Center, Tel-Hashomer, Israel Doron.Sagiv@sheba.health.gov.il.
authors: Doron
authors: D
authors: Sagiv
authors: Department of Diagnostic Imaging, Neuroradiology Unit, Sheba Medical Center, Tel-Hashomer, Israel.
authors: Ana
authors: A
authors: Eyal
authors: Department of Otolaryngology-Head and Neck Surgery, Sheba Medical Center, Tel-Hashomer, Israel.
authors: Jobran
authors: J
authors: Mansour
authors: Department of Otolaryngology-Head and Neck Surgery, Sheba Medical Center, Tel-Hashomer, Israel.
authors: Gabriel
authors: G
authors: Nakache
authors: Department of Otolaryngology-Head and Neck Surgery, Sheba Medical Center, Tel-Hashomer, Israel Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors: Michael
authors: M
authors: Wolf
authors: Department of Otolaryngology-Head and Neck Surgery, Sheba Medical Center, Tel-Hashomer, Israel Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors: Adi
authors: A
authors: Primov-Fever
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059925:Anatomic Landmarks; D005260:Female; D006801:Humans; D007830:Larynx / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D013957:Thyroid Cartilage / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed
keywords: cricothyroid membrane; interlaminae angle; thyroid anatomy; thyroid cartilage; thyroid prominence; vocal cords