The dimensions and vascular anatomy of the cricothyroid membrane: relevance to emergent surgical airway access.

Following traumatic injury, rapid surgical access to the airway may be required, with surgical cricothyroidostomy the procedure of choice. Immediate complications of cricothyroidostomy include unsuccessful or incorrect site of tube placement and hemorrhage. Subglottic stenosis is the most common late complication. This project was undertaken to better define the dimensions and vasculature of the cricothyroid region. In 15 cadaveric specimens, cervical dissection revealed the average width of the cricothyroid membrane visible between cricothyroid muscles to be 8.2 mm, and the average height 10.4 mm. Latex injection of the carotid artery demonstrated a transverse cricothyroid artery arising from the superior thyroid artery in 93% of cases. The cricothyroid artery crossed the upper one-half of the cricothyroid membrane in all but one specimen. Branches of the cricothyroid artery penetrated the membrane and ascended along the undersurface of the thyroid cartilage. Unilateral superior thyroid artery injection demonstrated anastomoses between right and left cricothyroid arteries. In 54% of specimens, the superior thyroid artery coursed anterior to the sternothyroid muscle and then the lateral edge of the cricothyroid membrane. The membrane was also crossed by venous tributaries to the superior and inferior thyroid veins. To lessen the possibility of complications following cricothyroidostomy, a knowledge of the dimensions, relations, and vasculature of the cricothyroid membrane is of inestimable value.