CHAPTER 22Cervical Adhesions
The clinical problems caused by a cervical adhesion will depend on the location of the adhesion on the cervix. Translumenal cervical adhesions can prevent a cervix from opening properly and pericervical adhesions involving the portio vaginalis may prevent a cervix from closing adequately. Adhesions of the portio vaginalis are often present with a cervical laceration and clinically will be associated with infertility because of cervical incompetency. Complete resolution of a cervical adhesion is rarely achieved, but some procedures may enhance the cervical function that remains.
ANATOMY
The cervix develops from a fusion of the paramesonephric duct system. It is supported by the caudal aspect of the broad ligament, and its serosal surface is confluent with the broad ligament. The lumen of the cervix consists of longitudinal cervical folds that extend from the longitudinal folds of the uterus. The dorsal and the ventral cervical fold may extend caudally to form a sagittal dorsal and/or ventral frenulum to the vaginal wall. A circular layer of smooth muscle contracts and relaxes to close and open the cervix, respectively. The caudal portion of the cervix (portio vaginalis) extends into vaginal fornix.1 During diestrus, when the genital tract is under progesterone influence, the cervical muscle contracts to close the cervix and the portio vaginalis is erect and protrudes into the cranial vagina. During estrus, estrogen concentrations are elevated and progesterone is absent. Consequently, the cervix dilates, and the portio vaginalis is edematous, flaccid, and lies on the floor of the cranial vagina. During anestrus, ovarian steroids are baseline and the cervix has little shape and does not close. Although in some anestrous mares the cervix may be closed, any manipulation will easily open it and it will remain dilated until ovulation occurs at the onset of the breeding season.
