This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Gynae), Subject name: Gynaecology & Obstetrics
Which of the following is the largest skull diameter? 
Select and explain. 
A. Occipitobregmatic, B. Sub mento regmatic, C. Mento vertical, D. Occipito frontal
C: Mento vertical
Answer: C: Mento vertical 
Explanation: Ans: c (Mentovertical) Ref: Dutta, 6th ed, p. 85Mento vertical extends from mid point of chin to the highest point on sagittal suture.It measures 14cm.Attitudeofhead will be partial extension with brow presentation. DiametersAttitude of the headPresentation1Suboccipito - bregmatic - 9.5 cm (3 3/4 ")Complete flexionVertex2Suboccipito - frontal - 10 cm (4")Incomplete flexionVertex3Occipito - frontal - 11.5 cm (4 1/2 ")Marked deflexionVertex4Mento-vertical - 14 cm (5 1/2 ")Partial extensionBrow5Submento-vertical- 11.5 cm (4 1/2 ")Incomplete extensionFace6Submento-bregmatic-9.5 cm (3 3/4 ")Complete extensionFace