Novel Anatomic Characteristics of the Laryngeal Framework: A Computed Tomography Evaluation. (April 2016)

• Record Type: Journal Article
• Authors: Sagiv, Doron; Eyal, Ana; Mansour, Jobran; Nakache, Gabriel; Wolf, Michael; Primov-Fever, Adi
• Is Part Of: Otolaryngology--head and neck surgery. Volume 154:Number 4(2016:Apr.)
• Page Start: 674
• Page End: 678
• Publication Date: 2016-04
• Subjects: thyroid cartilage -- thyroid prominence -- interlaminae angle -- cricothyroid membrane -- thyroid anatomy -- vocal cords; Head -- Surgery -- Periodicals; Neck -- Surgery -- Periodicals; Otolaryngology -- Periodicals; 617.51
• DOI: 10.1177/0194599815627781
• Languages: English
• ISSNs: 0194-5998

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. Study Design: Cohort imaging study. Setting: Tertiary academic referral center. Subjects and 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.