Variable Origin of the Superior Laryngeal Artery and Its Clinical Significance

The superior laryngeal artery (SLA) is the dominant arterial supply of the laryngeal muscles, mucosa and glands. The purpose of the present study was to document the variable origin of the SLA in the carotid triangle. Although the variation in the SLA origin and morphology is important during the partial laryngectomy and reconstruction surgery of the larynx, the description of the SLA in modern literature is vague. The anatomy of SLA was studied in 37 adult South Indian preserved cadavers aged between 48 to 81 years. The anterolateral region of the neck was exposed. After the visualization of laryngeal prominence, the strap muscles were resected and the SLA and the internal branch of the superior laryngeal nerve (ILN) were exposed. The variable origin of SLA was observed. The origin of the SLA was variable and was classified in to four different groups. Type I: Subtype Ia, the SLA originates from the superior thyroid artery (STA) (SLA with a transverse course) [75.6%] and subtype Ib, the SLA originates from the STA (SLA with an initially ascending course) [4%]; type II: the SLA originates from the lingual artery [5.4%]; type III: the SLA originates directly from the external carotid artery (ECA) [12.1%]; type IV: the SLA originates from the linguo-facial trunk [2.7%]. In addition to above variations, in a single case the SLA was duplicated and in three instances the posterior glandular branch of the thyroid gland was arosed from the SLA.