Anatomy for Laryngeal Framework Surgery

Abstract

After exposure of the thyroid cartilage, design in laryngeal framework surgery starts with marking the projection point of the anterior commissure on the thyroid cartilage. Anatomical studies trying to locate the projection point from various landmarks have all revealed quite a large individual variation, whatever landmark is selected. According to Seiffert (1943¹⁴), the projection point is 7–10 mm above the lower margin of the thyroid cartilage (d in Fig. 5.1). Based on the measurements of 100 cadaver larynges (65 male, 35 female) Gurr (1948¹⁴) reported that it is 3.5–6.0 mm below the thyroid prominence (Pin Fig. 5.1) in males, and 3.0–5.0 mm in females. Minnigerode (1955¹⁴) described the point as a relative measure, i.e., the lower two-fifths of the distance between the uppermost and lowermost margins of the thyroid ala (Fig. 5.2). If a variation of ±1.5 mm is taken into account, 97% of the examples falls within that range. With the thyroid incisure and lower margin taken as the reference points, the relation is reversed to the lower three-fifths of the distance in 79% of cases, and with ±0.75 mm, 92% falls within that range (Fig. 5.2). This can be converted to a thyroid prominence (Adam’s apple)-oriented measurement, according to Minnigerode (1955¹⁴), by taking into account the fact that the distance between the notch and the prominence is always about 3 mm.