Figure 3.

(A). Axial US scan of the Danger Zone, Case 2, at ten months. The Oesophageal tracheal groove (TEG) is a triangular danger zone where recurrent laryngeal nerve (RLN) can be injuried, as well as oesophagus (O) and tracheal wall (T). This is prevented by performing an oblique in-plane US-guided trans isthmic approach of the electrode (arrow). Double arrows show a 2.2 mm thickness of normal thyroid tissue between tracheal wall and local recurrence nodule. (B,C). US diagnosis of normal parathyroid gland. US axial & sagittal scans below the lower posterior left thyroid easily depict an ovoid, homogeneous, markedly hyperechoic 5.8 × 3.3 × 3.1 mm lower left parathyroid gland, typically brighter than the thyroid gland [14].