An unusual origin and course of the thyroidea ima artery, with absence of inferior thyroid artery bilaterally.

We report an unusual origin and course of the thyroidea ima artery in a male cadaver. The ima artery originated from the right subclavian artery very close to origin of the right vertebral artery. The artery coursed anteriorly between the common carotid artery medially and internal jugular vein laterally. It then coursed obliquely, from below upwards, from lateral to medial superficial to common carotid artery, to reach the inferior pole of the right lobe of thyroid and branched repeatedly to supply the anteroinferior and posteroinferior aspects of both the thyroid lobes and isthmus. The superior thyroid arteries were normal. Both the inferior thyroid arteries were absent. The unusual feature of this thyroidea ima artery is its origin from the subclavian artery close to vertebral artery origin, the location being remarkably far-off from the usual near midline position, and the oblique and relatively superficial course. This report is a caveat to neck surgeons to consider such a superficially running vessel to be a thyroidea ima artery.

Overcoming Barriers in a Traditional Medical Education System by the Stepwise, Evidence-Based Introduction of a Modern Learning Technology.

INTRODUCTION: Histology teaching in India and in other developing countries has not changed much over the past decades and has not joined the global movement of using virtual microscopy (VM). Many factors may have contributed to this academic inertia-including curricular requirements for traditional microscopy (TM) skills, assessments that are heavily based on TM, and unfamiliarity with modern technology among faculty, as well as infrastructural shortcomings. This study is aimed at overcoming these roadblocks by using a blended approach combining VM with TM in a tradition-centered curricular setting. METHODS: For validation of this approach, the authors conducted a non-randomized controlled trial with a crossover design on first year medical students at the Government Medical College, Thiruvananthapuram, India. Examination scores and responses of a student group taught with VM as an adjunct to TM were compared with a student group taught with TM only. RESULTS: The test group had significantly better results when compared to the control group for knowledge-based tests (p = 0.012; analysis of co-variance) and for an unannounced visual-based test conducted 1 month later (p = 0.001; Mann-Whitney U test). Feedback collected from students showed highly favorable responses to the use of VM for teaching histology. CONCLUSION: This study should encourage Indian medical colleges and schools in other developing countries to start using VM as a supplementary approach for their histology education programs. Furthermore, as the Medical Council of India recommends the introduction of new competency-based integrated curriculum in India starting in 2019, the use of VM may facilitate more effective learning in the new scenario. TRIAL REGISTRATION: CTRI/2018/04/012928.

Can the angle between optic nerves indicate whether optic chiasm is prefixed, normofixed or postfixed? An anatomical study with radiologic and neurosurgical implications.

PURPOSE: The objective of this study was to measure the angle (Interneural angle, INA) between intracranial segments of optic nerves (ISON), and to look for any relation between it and the relative anteroposterior location (RAPL) of the optic chiasm (OC)-viz. prefixed, normofixed and postfixed. METHODS: The sample comprised of 100 autopsy specimens from South Indian population. INA was measured using software-aided processing of digital photographs. Length of the ISON was measured on each side using Vernier calipers. RAPL of the OC was noted during dissection. These were analysed with statistical methods. RESULTS: RAPL of OC was found to be prefixed in 24 %, normofixed in 65 % and postfixed in 11 %. The INA had an overall mean of 69.9° (SD 9.29°). ANOVA confirmed statistically significant difference in INA among different groups; the corresponding mean value for the group was as follows: 79.61° (prefixed), 68.10° (normofixed) and 59.48° (postfixed). ROC curve was plotted for the use of various 'cut off' values of INA to 'diagnose' prefixed OC; an INA ≥71.4° was seen to diagnostically correlate with prefixed OC with 83.3 % sensitivity and 75 % specificity. CONCLUSIONS: The INA is wider when OC is prefixed, intermediate when normofixed and narrowed when postfixed. This observation throws light on the possibility of using INA as a marker of RAPL of OC. As INA can be measured in axial MRI sections, it can be used in differentiation of the cases with prefixed OC from others during pre-operative work up for pituitary surgeries and to identify individuals 'at risk' during subfrontal approach for pituitary lesions.

A Morphometric Study of the Foramen of Diaphragma Sellae and Delineation of Its Relation to Optic Neural Pathways through Computer Aided Superimposition.

The diaphragma sellae (DS) is a fold of dura that forms a partial roof over the pituitary gland. The foramen of the diaphragma sellae (FDS) is thereby a pathway for suprasellar extension of pituitary tumors. The purpose of this study was to describe the anatomical dimensions of the DS and FDS and to understand the relationship of FDS with the overlying optic chiasma. The study was conducted in 100 autopsy cases. Measurements were taken using vernier calipers. Photographs, taken before and after removal of optic pathway, were superimposed using image processing software. The results showed that the mean A-P dimension of DS was 1.17 ± 0.48 cm; the lateral dimension of DS was 1.58 ± 0.60 cm. The mean A-P dimension of FDS was 0.66 ± 0.42 cm; the lateral dimension of FDS was 0.82 cm ± 0.54 cm. The shapes of FDS were irregular (40%), transversely oval (29%), circular (13%), sagittally oval (11%), or trapezoid with posterior dimension more than the anterior one (6%) or anterior dimension more than the posterior one (1%). The margins of FDS were either well defined (31%) or ill defined (69%). The positional relation of FDS to optic chiasma was also found out.