Two Rare Anatomical Variations of External Jugular Vein - an Embryological Overview

Maxillary and superficial temporal veins unite within the substance of parotid gland to form the retromandibular vein (RMV) which soon divides into anterior and posterior divisions. Anterior division unites with facial vein (FV) at variable distances below the angle of the mandible to form the common facial vein (CFV) which ends by draining into the internal jugular vein (IJV). The posterior division of RMV unites with the posterior auricular vein (PAV) to form external jugular (EJV) vein which runs down the neck to drain into the subclavian vein (SV) (Standring, 2005). There is wide variation in the formation and termination of the EJV. According to Choudhury et al. (1997) in 5% cases FV ultimately drains into EJV. In one case, reported by Prakash & Bhagath (2007), CFV on the left side drained directly into the SV. EJV is superficially visible and easily approachable and so is used very frequently for intra venous cannulation for diagnostic and therapeutic purposes (Prakash et al., 2006). We present here, two rare variations of EJV in regards to its formation, course, termination and communication. CASES REPORT