This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
What is the length of poio vaginalis in centimeters? 
Select and explain. 
A. 8-Jun, B. 9-May, C. 4-Feb, D. 0.5-1
C: 4-Feb
Answer: C: 4-Feb 
Explanation: The cervix, also called the poio vaginalis, is somewhat barrel-shaped and is 2-4 cm in length, its lower end joining the vagina at an angle varying from 45-90 degrees. The cavity of the cervix is fusiform in shape, with longitudinal folds or furrows. Must Know: The endocervical canal is composed of columnar, mucus-secreting cells, whereas the external cervix is lined by nonkeratinizing squamous epithelium. The junction between these 2 areas is called the squamocolumnar junction or transitional zone. Ref: Heitmann R.J. (2013). Chapter 1. Anatomy of the Female Reproductive System. In A.H. DeCherney, L. Nathan, N. Laufer, A.S. Roman (Eds), CURRENT Diagnosis & Treatment: Obstetrics & Gynecology, 11e.