Retrostyloid and retromandibular courses of the external carotid artery.

BACKGROUND

The external carotid artery (ECA) branching pattern has been extensively studied in the current literature. However, its topographical variability has been barely reported. The aim of the current study was to assess the ECA in relationship with the styloid process (SP) and the mandible.

MATERIALS

100 computed tomography angiograms were randomly selected and retrospectively investigated on the neck region for the ECA course in relation to the SP and the mandible.

RESULTS

A retrostyloid course of the ECA was identified on 18 sides (9%). Six patients had a bilateral retrostyloid ECA, and six patients had a unilateral variant. The side and sexes did not affect the prevalence of this variant. The elongated SP or variable ossification of the stylohyoid chain did not affect the retrostyloid course. The ECA retromandibular course of type 1 (straight course deep to the ramus of the mandible) was identified in 30.5%, type 2 (lateral retromandibular loop) in 20%, and type 3 (lateral retromandibular loop behind the ramus of the mandible) in 45.5%. The side and sexes did not affect the prevalence of this variant.

CONCLUSIONS

Our study enhances the current knowledge on the ECA topography. Both variants investigated in the current study, displace the ECA into the parapharyngeal space. Knowledge of these anatomic variations are of importance preoperatively to avoid iatrogenic injuries.