For hormonal study, sample should be taken from which wall of vagina

Lateral walls of vaginaThe upper one third is related with the pelvic cellular tissue at the base of broad ligament in which ureter and uterine aery lie approximately 2cm from lateral fornicesThe middle third is blended with levator ani The lower third is related to bulbocavernosus muscle, vestibular bulbs and Baholin glands.Ref: D.C. Dutta&;s Textbook of Gynaecology, 6th edition, page no: 5