An Unusual Superior Root of the Ansa Cervicalis.

Cureus. 2019 Apr 27;11(4):e4558. doi: 10.7759/cureus.4558.

Kikuta S, Iwanaga J, Kusukawa J, Tubbs RS.

---

Abstract

The ansa cervicalis is located around the carotid sheath and forms a neural loop, which consists of superior and inferior roots. It innervates the infrahyoid muscles. Anatomical variations of the superior root of the ansa cervicalis are uncommon. Herein, we present an extremely rare case of the superior root of the ansa cervicalis arising both from the hypoglossal and vagus nerves.

KEYWORDS:

anatomy; ansa cervicalis; neck surgery; vagus nerve; variation

Figure 1

Lateral view of the right neck. Note the branch from the vagus nerve (arrows) joins the branch from the hypoglossal nerve to form the common superior root

CCA, common carotid artery; CSR, common superior root; D, posterior belly of digastric; HN, hypoglossal nerve; IR, inferior root; NO, nerve to superior belly of omohyoid; NS, nerve to sternothyroid; OH, superior belly of omohyoid; SCM, sternocleidomastoid muscle; SH, sternohyoid; ST, sternothyroid; TH, thyrohyoid; X, vagus nerve.