Variation in the Origin of Superior Thyroid Artery

Abstract

The variations in the distribution pattern of superior thyroid artery are of great importance for head and neck surgeons because of its vital relationship to the external laryngeal nerve. In this case an unusual unilateral variation in the arterial supply of thyroid gland was found during routine dissection of an elderly male cadaver in the Department of Anatomy, GGS Medical College, Faridkot, Punjab. The left superior thyroid artery took origin from the anterior aspect of left common carotid artery and it exhibited a usual relationship with the left external laryngeal nerve. The inferior thyroid arteries did not show any unusual distribution. Knowledge of such arterial variations related to the thyroid gland is immensely helpful for surgeons in order to put ligature on anomalous artery and to avoid damage to vital structures in this area. It is also helpful to the radiologists in interpreting the angiograms.

Variations of the origin of superior thyroid artery and its relationship with the external branch of superior laryngeal nerve

“…In the standard anatomical, surgical and radiological textbooks, the STA is considered to have a relatively constant origin from the anterior surface of ECA[ 19 , 20 ]; but many studies have reported wide variations in the origins of the STA[ 2 , 8 , 21 – 23 ]. The STA frequently arises from the ECA just above the carotid bifurcation.…”

“…Past studies have reported the incidence of origin of the STA from the common carotid artery (CCA) as well as from the bifurcation of the CCA[ 2 , 3 ]. The artery has the following named branches: infrahyoid, superior laryngeal, sternocleidomastoid and cricothyroid [ 1 , 3 , 8 ].…”

“…The variations in the origin and distribution pattern of STA are great importance for head and neck surgeons because of its vital relationship to the EBSLN[ 8 , 11 ]. The EBSLN, which supplies the cricothyroid muscle, runs parallel to STA and later crossing the artery from lateral to medial either above or below the upper pole of the thyroid gland[ 4 , 7 ].…”

“…This can be predominantly significant for individuals using their voice professionally[ 13 ]. In case of thyroidectomy STA must be ligated and is highly essential to ensure proper hemostasis[ 8 ]. Because of its intimate relationship with STA, EBSLN is at risk when the artery is being ligated [ 8 , 11 , 14 ].…”

“…In case of thyroidectomy STA must be ligated and is highly essential to ensure proper hemostasis[ 8 ]. Because of its intimate relationship with STA, EBSLN is at risk when the artery is being ligated [ 8 , 11 , 14 ]. The injury of the EBSLN cause palsy of the cricothyroid muscle and alters lower airway protection mechanisms.…”