Ligaments, Blood Supply, and Anatomy of the Uterus, Cervix, Vagina, Ovaries, and Fallopian Tubes

Uterine Ligaments

The uterus is supported by several ligaments, which can be categorized as primary and secondary supports. These ligaments collectively are tri radiate ligaments, and maintain the uterus's position within the pelvis. Proper anatomical support ensures the uterus remains in its correct position, facilitating reproductive functions and preventing prolapse.

Primary Supports:

  • Pubocervical Ligament: Connects the cervix to the pubic symphysis, providing anterior support to the uterus and cervix. This ligament helps maintain the angle of the uterovesical junction.

  • Cardinal Ligament (Mackenrodt's Ligament or Transverse Cervical Ligament): A fan-shaped ligament extending from the uterus and cervix to the lateral pelvic wall. It is the primary support for the uterus, containing smooth muscle, fibrous tissue, and elastic fibers. It carries the uterine artery and vein, and damage can lead to uterine prolapse.

  • Uterosacral Ligament: Connects the uterus and cervix to the sacrum, providing posterior support. These ligaments are palpable during a rectovaginal examination and play a crucial role in preventing uterine prolapse. They also contain nerve fibers that contribute to pelvic pain syndromes.

It is important to note that the uterosacral and cardinal ligaments attach not only to the cervix and uterus but also to the vagina. During a hysterectomy, only the portions of these ligaments attached to the cervix or uterus need to be addressed. Surgeons must carefully dissect these ligaments to avoid damage to nearby structures such as the ureters and bladder.

Secondary Support:

  • Round Ligament: Located at the corner of the uterus, it helps maintain the uterus in an antiverted position but is considered an indirect support. It originates from the anterior aspect of the uterus near the fallopian tube insertion, passes through the inguinal canal, and inserts into the labia majora. Although it provides some support, its primary role is maintaining uterine position.

Broad Ligament

The broad ligament is not a true ligament but a peritoneal fold that supports the uterus, ovaries, and fallopian tubes. It extends from the lateral pelvic walls to the uterus, creating a mesentery-like structure. It consists of three parts:

  • Mesosalpinx: The part near the fallopian tube, containing the tubal branches of the uterine and ovarian vessels.

  • Mesometrium: The part near the uterus, constituting the majority of the broad ligament and containing the uterine vessels.

  • Mesovarium: The part near the ovary, suspending the ovary; however, the ovary itself is not within the broad ligament.

Contents of Broad Ligament (BROAD acronym):

  • B: Blood vessels (uterine and ovarian vessels and nerves)

  • R: Round ligament

  • O: Ovarian ligament

  • A: Artifacts (epoophoron, paraoophoron, Gartner's duct)

  • D: Oviduct (fallopian tube)

Note: While the ovary is not a content of the broad ligament, the ureter is now considered a content according to the 42nd edition of Gray's Anatomy. The ureter lies on the medial part of the broad ligament and is particularly vulnerable during hysterectomies. It crosses under the uterine artery, often referred to as 'water under the bridge.'

The ligaments surrounding the uterus are collectively known as the parametrium.

Additionally, the suspensory ligament of the ovary connects the ovary to the pelvic sidewall. This ligament contains the ovarian vessels and nerves, and it is crucial to ligate it during oophorectomy to control bleeding.

Blood Supply of the Uterus

  • Uterine Artery: Supplies 80% of the uterus; a branch of the anterior division of the internal iliac artery. It provides the primary blood supply to the uterus and undergoes significant changes during pregnancy to accommodate increased blood flow.

  • Ovarian Artery: Supplies the remaining 20% of the uterus. It originates from the abdominal aorta and anastomoses with the uterine artery, providing collateral circulation.

The uterine artery enters the broad ligament at the level of the internal os, approximately 2 cm laterally, and takes a sharp turn upwards to supply the uterus.


The branches of the uterine artery to the uterus, from outside to inside, can be remembered using the mnemonic "U ARBS":

  • U: Uterine artery

  • A: Arcuate artery (supplies the outer one-third of the myometrium). These arteries run circumferentially within the myometrium.

  • R: Radial artery (supplies the inner two-thirds of the myometrium). These arteries penetrate deeper into the myometrium.

  • B: Basal artery (a branch of the radial artery, supplies the basal layer of the endometrium). These arteries are less sensitive to hormonal changes.

  • S: Spiral artery (a branch of the radial artery, supplies the functional layer of the endometrium). These arteries are highly sensitive to hormonal changes and are responsible for the cyclical changes in the endometrium during the menstrual cycle.

The uterine artery supplies blood to the fallopian tube, round ligament (via Samson artery), uterus, cervix, and vagina (via descending cervical artery), and the ureter.

The descending cervical artery is present at the 3 o'clock and 9 o'clock positions in the cervix. Paracervical blocks should be administered above (2 or 10 o'clock) or below (4 or 8 o'clock) these positions to avoid the artery. Injecting local anesthetic near these arteries can reduce bleeding during cervical procedures.

During menstruation, the spiral artery constricts, leading to the shedding of the superficial layer of the endometrium. This vasoconstriction is mediated by prostaglandins and other vasoactive substances.

Cervix Anatomy

The cervix, a part of the uterus, is mainly composed of connective tissue (collagen) with only 10% smooth muscle, while the body of the uterus is mainly smooth muscle. This composition allows the cervix to dilate, shorten, and thin during labor due to collagen breakdown and increased water content (effacement). The cervix also contains glycosaminoglycans, which contribute to its pliability.

The external os, where the cervix opens into the vagina, is a sphincter, similar to the internal os. The shape of the external os differs between nulliparous (pinpoint or circular) and multiparous females (transverse slit-like). Parity-induced changes are due to stretching and remodeling of the cervix during childbirth.

Cervix Components

  • Endocervix: The part of the cervix that continues above with the uterus, lined by columnar epithelium, and appears red on per speculum examination; also called the supravaginal part of the cervix. The columnar epithelium is responsible for mucus secretion, which varies throughout the menstrual cycle.

  • Exocervix: The part of the cervix present inside the vagina, lined by stratified squamous epithelium, and appears pink on per speculum examination; also called the portio vaginalis. The stratified squamous epithelium provides protection against abrasion and infection.

In non-pregnant females, the cervix is 2.5 cm long, with the endocervix and exocervix each measuring 1.25 cm. In pregnant females, the cervix is 4-5 cm long, with each part measuring 2-2.5 cm. Cervical length is an important factor in assessing the risk of preterm labor.

The columnar epithelium of the endocervix changes into the squamous epithelium of the exocervix (metaplasia). This change typically occurs near the external os in the transformation zone (squamocolumnar junction). The transformation zone is dynamic and changes position with age and hormonal influences. During puberty, pregnancy, and under the influence of pills, the transformation zone moves outward. With increasing age, it moves inward toward the endocervix.

During pregnancy, if the endocervix is visible outside the external os, it is called ectropion. In ectropion, the transformation zone has moved outside, and the red endocervix is visible around the external os. No biopsy is needed for ectropion during pregnancy, as it is a normal physiological change. However, it can cause increased vaginal discharge and bleeding.

Nabothian cysts or follicles are blocked cervical glands that indicate that the endocervix was once present on the exocervix. No biopsy or treatment is needed for Nabothian cysts, as they are benign and common findings.

The most common type of cervical cancer is squamous cell carcinoma, as it occurs where columnar epithelium changes into squamous epithelium. Human papillomavirus (HPV) infection is the primary risk factor. Adenocarcinoma, though less common, can occur in the endocervix.

Cervix Nerve and Lymphatic Supply

  • Nerve Supply: T10 to L1 (Frankenhäuser ganglion). This ganglion, also known as the uterovaginal plexus, is located in the cardinal ligament and is the primary nerve supply to the uterus and cervix.

  • Cervix and Upper Vagina: S2 to S4. These nerves contribute to pain sensation and autonomic function.

  • Perineum and Lower Vagina: Pudendal nerve (S2 to S4). This nerve is important for sensation and motor function in the perineal region.

Lymphatic Drainage

  • Corpus: Internal and external iliac lymph nodes, then common iliac lymph nodes. Lymphatic drainage follows the vasculature and is important for staging and treatment of uterine cancers.

  • Fundus: Para-aortic lymph nodes. The fundus drains superiorly along the ovarian vessels.

  • Cornua: Superficial inguinal lymph nodes. Drainage to the inguinal nodes is less common but can occur.

  • Cervix (HOPE):

    • H: Hypogastric (internal iliac) lymph nodes

    • O: Obturator lymph nodes

    • P: Paracervical lymph nodes (sentinel lymph nodes). These are often the first nodes to be involved in cervical cancer metastasis.

    • E: External iliac lymph nodes

The cervix does not drain into superficial inguinal lymph nodes.

Per Speculum Examination Instruments

  • Sims Posterior Vaginal Wall Non-Self Retaining Speculum: Retracts the posterior wall of the vagina. It requires manual retention and is often used in conjunction with an anterior wall retractor.

  • Anterior Vaginal Wall Retractor: Used with the Sims speculum to retract the anterior wall of the vagina. It provides better visualization of the cervix when used with the Sims speculum.

  • Cusco's Self-Retaining Bivalved Speculum: Retracts both the anterior and posterior walls of the vagina. It allows hands-free examination and is available in various sizes.

  • Wall Sellum: Holds the lips of the cervix. Has rat-like teeth. For a pregnant cervix, sponge-holding forceps are used instead to avoid trauma.

  • Uterine Sound: Determines whether the uterus is anteverted or retroverted and measures the length of the uterine cavity (normally 3 inches). It is similar to a bladder sound, but the uterine sound has a more prominent curve, is calibrated, and has an olive tip. Proper technique is essential to avoid uterine perforation.

  • Hagard's Dilators: Dilates the cervix. These are graduated dilators used to gradually open the cervical canal for various procedures.

  • Curette (Blunt and Sharp): Used for dilatation and curettage (D&C). Blunt curettes are used for pregnant uteri to minimize the risk of perforation, while sharp curettes are used for non-pregnant uteri, except after molar evacuation. Molar pregnancies require suction curettage.

  • Leach Wilkinson Cannula: Inject dye for hysterosalpingography (HSG). Has a funnel-shaped end to prevent backflow of the contrast dye.

Vagina Anatomy

The vagina is a fibromuscular tube that connects the introitus to the cervix, making a 90-degree angle with the cervix and a 45-degree angle with the horizontal. The posterior vaginal wall is longer than the anterior wall by approximately 2 cm. This difference in length contributes to the formation of the vaginal fornices.

The cervix projects into the vagina, forming pockets called fornices (anterior, posterior, and two lateral). The posterior fornix is the deepest and is clinically significant as it is close to the Pouch of Douglas.

Relationships of the Lateral Fornix:

  • Cardinal ligament

  • Uterine artery

  • Ureter

The vagina is lined by non-keratinized stratified squamous epithelium, consisting of superficial cells (predominate with estrogen), intermediate cells (predominate with progesterone), and parabasal/basal cells (predominate with no hormonal influence). Cytologic examination of these cells is the basis for the Pap smear.

The vagina lacks glands, and vaginal secretions come from cervical glands, endometrial glands, and Bartholin glands. The pH of the vagina is acidic, maintained by Döderlein bacilli (lactobacilli), which convert glycogen in the vaginal epithelium into lactic acid. These bacilli appear at puberty and disappear after menopause due to decreased estrogen levels.

The presence of estrogen and Döderlein bacilli is necessary for an acidic vaginal pH. This acidic environment protects against pathogenic bacterial growth.

Blood in the vagina, such as during menstruation, makes the pH alkaline because blood is alkaline. This alteration in pH can increase the risk of vaginal infections during menstruation.

Ovary Anatomy

The size of the ovary is 3 x 2 x 1 cm with a volume of approximately 6-7 cc. If the volume exceeds 10 cc, it may indicate polycystic ovarian syndrome. Ovarian size and volume can be assessed using ultrasound.

The ovary is located in the lateral pelvic wall in the fossa of Waldeyer. It descended from the abdomen during early intrauterine life with the help of the gubernaculum. The uterus divides the gubernaculum into the round ligament and ovarian ligament.

Ligaments of the Ovary:

  • Ovarian Ligament: Connects the ovary to the corner of the uterus. It is a remnant of the gubernaculum and provides medial support to the ovary.

  • Infundibulopelvic Ligament (Suspensory Ligament of the Ovary): Connects the ovary to the lateral pelvic wall. The ovarian artery and nerve run within this ligament. During hysterectomy, this ligament should not be cut if the ovaries are to be preserved. Ligation of this ligament is crucial during oophorectomy to prevent bleeding.

  • Mesovarium: The posterior part of the broad ligament. It suspends the ovary but does not completely enclose it.

Relations of the Ovary:

  • Anterior/Superior: External iliac artery. This artery is an important landmark during pelvic surgery.

  • Posterior: Ureter and internal iliac artery. The ureter's proximity necessitates careful dissection during oophorectomy.

  • Lateral: Obturator nerve and infundibulopelvic ligament. Damage to the obturator nerve can cause pain to the medial side of the thigh.

  • Medial: Ovarian ligament.

The blood supply to the ovary is via the ovarian artery (a branch of the abdominal aorta at L2), with venous drainage through the ovarian vein. Understanding the vascular supply is critical during surgical procedures such as oophorectomy.

The left ovarian vein drains into the left renal vein, while the right ovarian vein drains into the inferior vena cava. This difference in venous drainage has implications for the spread of ovarian cancer.

The nerve supply is through the ovarian plexus, and lymphatic drainage is through para-aortic lymph nodes. This lymphatic drainage pattern is important in staging and managing ovarian cancer.

Fallopian Tube Anatomy

The parts of the fallopian tube from medial to lateral are:

  • Interstitial (intramural) part

  • Isthmus

  • Ampulla

  • Infundibulum (with fimbriae)

Fallopian Tube Components

The fallopian tube is approximately 4 inches (10-12 cm) long. The length of each section from medial to lateral is as follows:

  • Interstitial (Intramural) Part: 1.2 cm long, 1 mm in diameter (narrowest part, acts as an anatomical sphincter). It is located within the uterine wall.

  • Isthmus: 2.5 cm long, 2 mm in diameter (second narrowest part, acts like a physiological sphincter). It is a thicker, more muscular part of the tube.

  • Ampulla: 5 cm long (widest and longest part, fertilization occurs here). It has a convoluted structure and is the most common site for ectopic pregnancies.

  • Infundibulum: 1.2 cm long, up to 6 mm in diameter. It has fimbriae that sweep the ovum into the tube after ovulation.

The fallopian tube is lined by a single layer of ciliated columnar epithelium, which helps the zygote move toward the uterine cavity. These cilia beat in the direction of the uterus.

Key Notes:

*Fertilization occurs in ampulla.

*The dual blood supply of the fallopian tube is made of medial two-thirds by the uterine artery, and lateral one-third by the ovarian artery.

*The lymphatic drainage of the entire tube is the para-aortic lymph node.

Fallopian tube, uterus, cervix, and upper one third of vagina, originate from the Mullerian duct, and lower two thirds of vagina, originate from the sinovaginal bulb.

It further emphasizes the importance of surgical anatomy of the fallopian tube relating to salpingectomy, the anatomical ligament's relationship with Fimbria, Ovaries, Fallopian tubes, and the broad ligament.