Normal radiological anatomy of thyroid cartilage in 600 Chinese individuals: implications for anterior cervical spine surgery

Abstract

BackgroundThyroid cartilage is an important barrier in anterior cervical approach surgery. The objective of this study is to establish normative values for thyroid cartilage at three planes and to determine their significance on preoperative positioning and intraoperative traction in surgery via the anterior cervical approach.MethodsNeck CT scans were collected from 600 healthy adults who did not meet any of the exclusion criteria. Transverse diameters (D1, D2, and D3) of the superior border of the thyroid cartilage (SBTC), inferior border of the thyroid cartilage (IBTC), and the trachea transverse diameters of the inferior border of the cricoid cartilage (IBCC) were measured on a horizontal plane.ResultsAll measured variables had intra-class correlation coefficients (ICCs) of ≥ 0.7. The differences in transverse diameters on the same plane between males and females were significantly different (all p < 0.001). The SBTC is most often at C4 in women (59.5%) and C4/5 in men (36.4%), the IBTC is most often at C5 in women (48.1%) and men (46.2%), and the IBCC is primarily located at C6 in women (45.2%) and C6 or C6/7 in men (34.4%) (all p < 0.001).ConclusionWe present normative values for thyroid cartilage at three planes of SBTC, IBTC, and IBCC in Chinese individuals. The individual and gender differences in the location of the thyroid cartilage and the size of the thyroid cartilage and the cricoid cartilage provide an anatomical basis to localize the skin incision, to predict the difficulty of intraoperative exposure and retractor pulling, and to identify that the thyroid cartilage protected the pharyngoesophageal wall.

The Right Internal Jugular at the Cricoid Cartilage Level May Represent the Optimal Central Vein Puncture Site in Pediatric Patients

“…These results were demonstrated by the present study again, in which the IJV at the level of CC was bulkier than that at the level of SBTC. Because SBTC is approximately equal to transverse process of C4 and CC approximately equal to the transverse process of C6 ( 18 , 19 ), the IJV on the level of CC was larger than that on the level of SBTC for both the right and left sides. In this study, the CSA disparity between the two levels was ~41–46%.…”

Recommended Maximum Laryngeal Prominence Size in Adult Females: A Cross-Sectional Study Proposing a Laryngeal Prominence Size Standard for Chondrolaryngoplasty in Male-to-Female Transgender Individuals

“…In a study that assessed the anterior projection of the thyroid cartilage in adult subjects, this projection was more pronounced in males than in females and was correlated with thyroid angle. 38 In other studies, larynx size 22,23 and thyroid cartilage size 5,[19][20][21][22]24,26,27,30,[32][33][34]36 were larger in males than in females, and thyroid angle was wider in females than in males. 4,5,[19][20][21][22]27,29,[32][33][34]36 Our results showed no differences in laryngeal prominence size among white, Asian, and black races in males and females.…”

“…Only several metrical studies of the thyroid cartilage have been published. 4,5,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] Most of these studies are cadaveric studies. 5,[19][20][21][22][23][26][27][28][29][30][31][33][34][35][36][37][38] The results of these studies show considerable variability, which may be based on methodological differences.…”

“…5,34 In addition, larynx size was similar in Nigerian and European subjects. 22 Results of studies performing measurements of the anterior height of the thyroid cartilage and/or the thyroid angle 4,5,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] show considerable variability within races and even within countries, which may be based on methodological differences.…”

“…2 Moreover, several metrical studies of the thyroid cartilage have been published. 4,5,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] However, extensive database research revealed no adequate data about real-life laryngeal prominence size in the general population.…”