An anomalous left external jugular vein draining into right subclavian vein

Knowledge of the varying drainage patterns of superficial veins of head & neck, in particular, jugular veins are not only important for anatomists but also for the surgeons operating at this level and to clinicians in general. The variations are important also for interventional radiologists, who perform trans-jugular procedures, such as port implantations and trans-jugular intra-hepatic porto-systemic shunts or selective venous samplings. Results of recent studies report that the superficial veins, especially the external jugular vein, have been increasingly utilized for cannulation to conduct diagnostic and therapeutic procedures. We report a very unusual left-sided presentation of external jugular vein in an embalmed male cadaver. Embryological evaluations of the anomaly was done & compared with available literature, which showed that the observed variation is rare (Fig. 1, Ref. 12).

Incidence, types and clinical implications of a non-metrical variant--mylohyoid bridging in human mandibles

Mylohyoid bridging (MB) is a non-metrical variant of the human mandible. The incidence and types of MB were investigated in 264 mandibles (edentulous 116, semi-dentulous 90 and dentulous 58). No mandible showed a complete type of MB, although 19 (7.2%) mandibles had a partial type. These were classified into two subtypes: distal partial (DP; Type I) and proximal partial (PP; Type II), depending on their location over the mylohyoid groove. The MB was present unilaterally in 7.76% of edentulous mandibles: right side 5.17% (3.45% PP type and 1.72% DP type) and left side 2.59% (1.72% PP type and 0.86% DP type). Of the semi-dentulous mandibles 3.33% had DP type of MB, 1.11% on the right side and 2.22% on the left side, and of the dentulous mandibles 1.72% had DP type of MB on the right side. A total of 13 mandibles out of 264 (4.92%) had unilateral MB. No dentulous mandible had bilateral MB, but 3.45% of edentulous and 2.22% of semi-dentulous mandibles did have. In total, 6 mandibles out of 264 bones (2.27%) had bilateral MB. Of the bilateral incidences 1.72% of edentulous mandibles had a DP-DP combination and the remaining 1.72% had a PP-DP combination. However, both instances of bilateral MB in semi-dentulous mandibles were of PP-DP combination. The incidence or types of MB showed no statistically significant differences between the groups or sides (p > 0.5; chi(2) test). In conclusion, the complete type of MB is a rare occurrence. The incidence increases with age, as edentulous mandibles had a higher incidence of MB than the other two groups. Clinically, MB may compress the mylohyoid neurovascular bundle, leading to neurological or vascular disorders.