Anatomy of the female reproductive organs of the pelvis

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Introduction0:00–0:43

The female reproductive system is made up of external and internal organs. The external organs lie in an area called the vulva, and they include the labia, the clitoris, and the vaginal opening.
The internal reproductive organs can be found within the pelvic cavity, and they include the ovaries, which produce the female sex cells, called oocytes, as well as sex hormones estrogen and progesterone; the uterine tubes, which carry the fertilized oocyte to the uterine cavity; the uterus, which houses the growing fetus during pregnancy; and the vagina, which is involved both in intercourse and fetal delivery.
Now, the ovaries, uterine tubes, and uterus lie within the pelvis and are covered by a double sheet of peritoneum called the broad ligament.

Broad ligament0:43–1:37

This extends from the sides of the uterus to the lateral wall and floor of the pelvis. To visualize the broad ligament, imagine yourself standing with your arms outstretched holding a ball in each hand, your body is the uterus, your arms are the uterine tubes and the balls are the ovaries.
Now, a sheet is draped over you and this sheet represents the peritoneum. You can see now how the broad ligament of the uterus is a double fold.
Now the broad ligament has three mesenteries; the mesovarium which is associated with the ovaries, the mesosalpinx which covers the uterine tubes and mesometrium which covers the uterus.
Let’s now look at each of the organs of the female reproductive system starting with the ovaries. The ovaries are the site of egg production, or oogenesis, and also release progesterone and estrogen during the different phases of the menstrual cycle.

Ovaries1:37–3:14

The ovaries usually sit near the lateral pelvic wall where the broad ligament attaches, and are suspended by a subdivision of the broad ligament called the mesovarium and the suspensory ligament of the ovary, which is a continuation of the mesovarium.
The ovarian vessels, nerves, and lymphatics pass through this ligament to enter or exit the superolateral surface of the ovary.
Now the mesovarium does not necessarily cover the ovary, it attaches the anterior portion of the ovary to the broad ligament and is continuous with the outermost layer of the ovary.
Medially, between the two layers of the mesovarium, there’s a fibrous band called the ligament of the ovary, which travels to the uterus then continues as the round ligament of the uterus.
The ligament of the ovary and the round ligament of the uterus are embryological remnants of a structure known as the gubernaculum.
The two gubernacula are embryonic structures that guide the ovaries in their descent from the abdomen to the pelvis. Now, each menstrual cycle, one of the ovaries releases an ovum, sometimes called an egg, into the peritoneal cavity in a process called ovulation.
The ovum can’t stay there forever or it won’t be able to be fertilized, and so it travels through the uterine tubes.The uterine tubes extend laterally from both sides of the horns of the uterus to the peritoneal cavity near the ovaries.

Uterine tubes3:14–4:35

These tubes lie inside the upper and anterior parts of the broad ligament, called the mesosalpinx. The uterine tubes have two main purposes; they carry the ovum from the peritoneal cavity near the ovaries to the uterine cavity.
Second, they form a space for the fusion of egg and sperm, a process called fertilization. All right, now each uterine tube is divided into four parts.
Let’s start with the most lateral part, called the infundibulum. The funnel-shaped infundibulum opens into the peritoneal cavity through an opening called the abdominal ostium.
Around this ostium, there are finger-like projections called fimbriae, which cover the surface of the ovaries. These fimbriae receive the ovum after ovulation, and they guide it inside the uterine tubes.
The next part is the ampulla, which is where fertilization usually occurs. Next is the isthmus, which is the narrowest part of the tube that ends by joining to the lateral walls of the uterus.
Finally, the uterine or intramural part passes through the uterine wall and opens into the uterine cavity through an opening called the uterine ostium.There are two main arteries that supply both the ovaries and the uterine tubes.

Arterial supply of ovaries and uterine tubes4:35–5:28

First is the ovarian arteries, which arise from the abdominal aorta and travel inferiorly behind the peritoneum and enter the suspensory ligaments of the ovaries to supply the lateral sides of the ovaries and the uterine tubes.
Next are the ascending branches of the uterine arteries, which arise from the internal iliac arteries. These branches ascend on the lateral sides of the uterus, reaching the medial sides of the ovaries and the uterine tubes.
Now, both ovarian and ascending uterine arteries terminate by bifurcating into ovarian and tubal branches, and these branches supply the ovaries and the uterine tubes, respectively.
These branches also anastomose to form a collateral circulation between abdominal and pelvic arteries. Now, veins draining the ovaries meet at the lateral end of the broad ligament to form a network of veins, called the pampiniform plexus.

Venous drainage of ovaries and uterine tubes5:28–6:02

This plexus gives rise to the right and left ovarian veins. The right ovarian vein ascends to drain into the inferior vena cava, and the left ovarian vein ascends to drain into the left renal vein.
Finally, venous blood from the uterine tubes drains into the ovarian veins and uterine venous plexuses, which lie along the lateral sides of the uterus.All right, now, let’s discuss the nerves that supply the ovaries and the uterine tubes.

Innervation of ovaries and uterine tubes6:02–6:33

These nerves arise from two plexuses; the ovarian plexus, which descends along the ovarian blood vessels, and the uterovaginal plexus, which accompanies the uterine arteries at the sides of the uterus.
Now, the ovaries and the uterine tubes lie above the pelvic pain line which means their visceral afferent pain fibers travel with the sympathetic fibers of the ovarian plexus and the lumbar splanchnic nerves.
Okay, now let’s take a deep breath and have a quick quiz! Can you name these parts of the broad ligament?

Quiz6:33–6:45

All right, now, let’s look at the uterus, which is a hollow, pear-shaped organ that carries the developing fetus throughout pregnancy.

Uterus6:45–7:39

The uterus has two main parts called the body and the cervix. Let’s start with the body, which forms the upper two thirds of the organ.
It is freely movable and lies between the layers of the broad ligament. The superior, rounded part of the body that lies above the uterine openings of the uterine tubes is called the fundus of the uterus.
The inferior part of the body forms a constricted segment called the isthmus of the uterus which is where the body of the uterus is continuous with the cervix.
The cervix is a narrow cylinder that forms the lower third of the uterus and has two openings. The first is called the external os that opens into the vagina and the second is the internal os which opens into the uterine cavity.
All right, now let’s look at the internal features of the uterus. First, is the uterine cavity which extends superolaterally, forming the regions where the uterine tubes join, called the uterine horns.

Features of the uterus7:39–9:09

Next is the cervical canal, located within the cervix. This canal extends from the anatomical internal os, which opens into the uterine cavity, to the external os, where it communicates with the lumen of the vagina.
During delivery, the fetus descends through the cervical canal and the vagina, together called the birth canal. All right, now that we know about the external and internal features of the uterus, let’s talk about its location and orientation in the pelvis.
The uterus lies in the lesser pelvis, with the body resting on the upper surface of the urinary bladder and the cervix lying between the bladder and the rectum.
The uterus itself is covered by the mesometrium of the broad ligament, which is a double layer of peritoneum. This peritoneum continues over the anterior and posterior surfaces of the uterus, except for the cervix.
Anteriorly, the peritoneum reflects from the uterus onto the superior surface of the bladder, forming the vesicouterine pouch.
Posteriorly, the peritoneum reflects from the body of the uterus and the supravaginal part of the cervix onto the anterior surface of the rectum, forming the rectouterine pouch, or pouch of Douglas.Now the position of the uterus can get a bit confusing, so let’s break it down.

Position of uterus9:09–10:14

Most commonly, the uterus is in an anteverted and anteflexed position. Now what does that mean?
Well, these are just angles on different parts of the uterus and cervix. The angle of version is formed by an imaginary longitudinal line through the cervix and one through the vagina.
An anteverted uterus is tilted anteriorly, with an almost 90 degree angle. The angle of flexion is formed by an imaginary longitudinal line through the body of the uterus and one through the cervix.
An anteflexed uterus has an angle measuring about 170 degrees. Although the uterus is usually in an anteflexed and anteverted position, some individuals can have a retroverted, retroflexed uterus.
Retroverted means that the uterus tilts posteriorly over the vagina, which increases the angle of version. Retroflexed means that the fundus of the uterus tilts posterior over the cervix, which increases the angle of flexion.
Now, the uterus is anchored within the pelvis by various mechanisms, including uterine ligaments, which attach to the superior and lateral surfaces of the uterus.

Supports of the uterus10:14–11:44

The ligaments that attach to the superior surface include the mesometrium and the round ligaments. The mesometrium is the largest part of the broad ligament that lies below the mesovarium and mesosalpinx.
Next is the round ligament of the uterus, which starts antero-inferior to the junction between the uterus and the uterine tubes.
Then, they run through the inguinal canal reaching the labia majora. Remember, the round ligament of the uterus and the ligament of the ovary are the remnants of the ovarian gubernaculum.
Now, the ligaments that attach to the lateral surface of the uterus include the cardinal and uterosacral ligaments. The cardinal ligament, also called the transverse cervical ligament extends from the lateral surfaces of the cervix and the vagina to the lateral pelvic walls.
The uterosacral ligaments extend superiorly and posteriorly from the sides of the cervix to the middle of the sacrum. The lower surface of the uterus is supported by structures of the pelvic floor, including the levator ani, perineal membrane, and perineal body.
The uterus is also supported by its position over the bladder, especially in an anteverted anteflexed orientation. And just a quick note, the arterial blood supply of the uterus comes mainly from the uterine arteries, which arise from the internal iliac arteries.

Blood supply of the uterus11:44–12:10

Deoxygenated blood from the uterus drains into the uterine venous plexus, which lies between the two layers of the broad ligament.
The plexus drains into the uterine veins, which exit the broad ligament on each side and drain into the internal iliac veins.
Okay, now let’s take a deep breath and have a quick quiz! Can you name the internal features of the uterus on this image?Finally, let’s discuss the vagina, which is a musculomembranous tube that provides a passage for the menstrual fluid, forms the lower part of the birth canal, and receives the penis and the ejaculate during sexual intercourse.

Quiz12:10–12:22

Vagina12:22–13:19

The vagina extends from the cervix to the external opening called the vaginal orifice. This orifice, along with the external urethral orifice and the openings of the great vestibular glands, open into the cleft between the labia minora, called the vestibule of the vagina.
Now, the upper part of the vagina forms a recess around the cervix, called the vaginal fornix. The fornix has four parts; two lateral parts and an anterior and posterior part.
The posterior vaginal fornix is the deepest part, and lies directly anterior to the rectouterine pouch. The vagina lies posterior to the urinary bladder and urethra and anterior to the rectum.
Arterial blood supply for the upper part of the vagina is provided by the uterine arteries, while that for the middle and lower parts comes from the vaginal and internal pudendal arteries.

Blood supply of the vagina13:19–14:01

Venous blood from the vagina enters a plexus of veins along the sides of the vagina, called the vaginal venous plexus, which is drained by the vaginal veins.
The vaginal venous plexus combines with the uterine venous plexus, to form the uterovaginal venous plexus, which is mainly drained by the uterine veins into the internal iliac veins.
The uterovaginal plexus also communicates with the vesical and rectal venous plexuses. Finally, let’s discuss the innervation of the vagina and the uterus.

Innervation of the vagina and uterus14:01–15:15

The innervation of the vagina divides roughly into an upper three quarters and a lower quarter. The lower quarter of the vagina is the only portion that receives somatic innervation by a branch of the pudendal nerve, called the deep perineal nerve, making this area sensitive to touch and temperature.
The innervation of the upper three quarters of the vagina, on the other hand, overlaps with the innervation of the uterus.
The innervation of these structures is visceral, and the nerve fibres come from the uterovaginal nerve plexus. These fibers include sympathetic, parasympathetic, and visceral afferent fibers.
Lastly, the innervation of the uterus is divided by the pelvic pain line, which is an imaginary line in the pelvis. Structures that lie above the pelvic pain line, like the fundus and the body of the uterus, send pain impulses along visceral afferent fibers that follow the sympathetic nerve fibers.
Structures that lie below the pelvic pain line, like the cervix and the vagina, send pain impulses along visceral afferent fibers that follow the parasympathetic nerve fibers.All right, as a quick recap.

Review15:15–17:34

The ovaries, uterine tubes, and the uterus are covered by a double sheet of peritoneum called the broad ligament. The broad ligament has three parts; the mesovarium that is associated with the ovaries, the mesosalpinx that covers uterine tubes and the mesometrium that covers the uterus.
The ovaries are the site of egg production and hormone release and are supported by the suspensory ligament that carries the vessels that supply them, and the ligament of the ovary.
The uterine tubes have four parts: the infundibulum with its fimbriae, the ampulla, the isthmus, and the intramural part.
The ovarian artery and the ascending branch of the uterine artery supply the ovaries and the uterine tubes. The pampiniform plexus drains the ovaries and uterine tubes and merges to form a right and left ovarian vein that drains into the inferior vena cava and left renal vein, respectively.
The uterus lies in the lesser pelvis, with the body resting on the upper surface of the urinary bladder and the cervix lying between the bladder and the rectum.
The ligaments that support the uterus include the broad, round, cardinal, and uterosacral ligaments. The blood supply of the uterus is provided by the uterine arteries, and the veins drain into the internal iliac veins.Lastly, the vagina is a musculomembranous tube that extends from the cervical canal to the vaginal orifice.
There are three arteries supplying the vagina; the uterine arteries, which supply the upper part, and the vaginal and internal pudendal arteries, which supply the middle and lower parts.
With the exception of the lower one quarter of the vagina, which is under somatic innervation, the pelvic organs of the female reproductive system are under visceral innervation.
The ovaries, uterine tubes, fundus and body of the uterus lie above the pelvic pain line and their visceral afferent fibres follow the sympathetic fibres.
The cervix and upper three quarters of the vagina lie below the pelvic pain line and their afferent fibres