Different patterns of variations in the venous drainage have been observed in the past. A case of FV uniting with the RMV at a higher level in the right parotid gland was observed by Kopuz C et al, 1995
2. FV draining into the superficial temporal vein, with an undivided RMV was also reported
3. CFV draining into EJV, an incidence of 5% was noted in the study done by Choudhry R et al, 1997
4. In another study conducted by Gupta V et al, 2003
5, the incidence of this particular variation was 9%. Therefore, the incidence of 7.7% in the present study is at par with the reported incidence which ranges between 5-9%
4,5. However, the co-existence of undivided RMV and the FV terminating into EJV is not previously reported in literature.
The ventral pharyngeal vein (VPV) which drains the mandibular and hyoid arches is the first identifiable vein 6. This VPV receives the tributaries from the face and the tongue to be known as linguofacial vein 7. A strong tributary draining the temporal region termed the RMV drains into the linguofacial vein (18mm stage of the embryo) to form a common trunk named the common facial vein. At about 22mm stage of embryo, from the tissues of neck, appears the EJV which has anterior communication with the FV, and a posterior communication with the RMV. The posterior auricular vein drains into the posterior communication 8,9. The FV draining into EJV represents a persistent anterior anastomotic channel to the facial vein. This anomalous pattern could be the phylogenic retention of the drainage pattern found in horse, ox and dog, where the veins draining the face terminated into the external jugular vein 5. In the other variation there is the persistence of the anterior anastomotic channel and also the failure of the RMV to drain into the linguofacial trunk. This causes the undivided appearance of the RMV and also the FV will drain into the EJV.
Knowledge of varying venous pattern is important for surgeons performing head and neck micro vascular surgeries 9, to avoid unnecessary bleeding during intra operative trial and error procedures 10. Ultrasound guided venous puncture is a viable possibility in cases of variations and their knowledge is important for surgeons doing reconstructive surgery 5. The FV and EJV, both are used as autogenous patch, grafted into the carotid during endarterectomy 11.
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