There are various cervices to be found in human physiology, including not just the cervix uteri alone but also such necks as the cervix vesicae urinariae, the cervix femoris, or even the cervix dentis. That’s because cervix just means “neck” (or here “narrowing”), with the remaining words in the genitive/possessive case, so you have “the neck of the uterus” — or more simply the uterus’s neck, the urinary bladder’s neck, the femur’s neck, or the tooth’s neck.
The cervical vertebrae are the top seven ones up in that neck upon which sits your head, which we number C1–C7 descending from the topmost one.
The Online Biology Dictionary says that cervix means:
neck, a term denoting the front portion of the collum or neck (the part
connecting the head and trunk) or a constricted part of an organ (for
example cervix uteri).
Cervix columnae posterioris medullae spinalis = cervix cornus dorsalis medullae spinalis.
Cervix cornus dorsalis medullae spinalis, neck of dorsal horn of spinal
cord: the constricted portion of the dorsal horn or column, of grey matter
in the spinal cord between the base of the horn and the head, also called
cervix cornus posterioris medullae spinalis and neck of posterior horn of
Cervix dentis, the slightly constricted region of union of the crown and
the root or roots of a tooth, also called collum dentis, dental neck and
neck of tooth.
Cervix glandis = collum glandis penis.
Cervix mallei = collum mallei.
Cervix uteri, neck of uterus: the lower and narrow end of the uterus,
between the isthmus and the ostium uteri.
(With edits for formatting and abbreviation expansion.)