Overview and Development

Overview

The uterus, cervix, and fallopian tubes are all important organs in the female reproductive tract.

Location

The uterus and fallopian tubes are pelvic organs.

• 2 fallopian tubes (left and right):
  • Arise from the superolateral portions of the uterus
  • Connect the ovaries Ovaries Ovaries are the paired gonads of the female reproductive system that contain haploid gametes known as oocytes. The ovaries are located intraperitoneally in the pelvis, just posterior to the broad ligament, and are connected to the pelvic sidewall and to the uterus by ligaments. These organs function to secrete hormones (estrogen and progesterone) and to produce the female germ cells (oocytes). Ovaries (female gonads) to the uterus
• Uterus: in the midline, between the bladder and the rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal
• Cervix: inferior portion of the uterus, connecting the uterine cavity to the vagina Vagina The vagina is the female genital canal, extending from the vulva externally to the cervix uteri internally. The structures have sexual, reproductive, and urinary functions and a rich blood supply, mainly arising from the internal iliac artery. Vagina, Vulva, and Pelvic Floor
• Relationship to peritoneal cavity:
  • Intraperitoneal (i.e., covered by peritoneum Peritoneum The peritoneum is a serous membrane lining the abdominopelvic cavity. This lining is formed by connective tissue and originates from the mesoderm. The membrane lines both the abdominal walls (as parietal peritoneum) and all of the visceral organs (as visceral peritoneum). Peritoneum and Retroperitoneum): 
    • Most of the uterus
    • Fallopian tubes are intraperitoneal structures
  • Subperitoneal (i.e., entirely below the peritoneal cavity): cervix

Function

• Uterus:
  • Site of implantation for a fertilized embryo
  • Growth and nourishment of the fetus
  • Able to shed its lining when pregnancy Pregnancy Pregnancy is the time period between fertilization of an oocyte and delivery of a fetus approximately 9 months later. The 1st sign of pregnancy is typically a missed menstrual period, after which, pregnancy should be confirmed clinically based on a positive β-hCG test (typically a qualitative urine test) and pelvic ultrasound. Pregnancy: Diagnosis, Maternal Physiology, and Routine Care does not occur (i.e., menstruation)
• Cervix:
  • Opening of the uterus into the vagina Vagina The vagina is the female genital canal, extending from the vulva externally to the cervix uteri internally. The structures have sexual, reproductive, and urinary functions and a rich blood supply, mainly arising from the internal iliac artery. Vagina, Vulva, and Pelvic Floor, which leads out of the body:
    • Allows passage of menstrual blood into the vagina Vagina The vagina is the female genital canal, extending from the vulva externally to the cervix uteri internally. The structures have sexual, reproductive, and urinary functions and a rich blood supply, mainly arising from the internal iliac artery. Vagina, Vulva, and Pelvic Floor 
    • Allows sperm into the uterus
  • Secretes fluid that can promote or inhibit sperm entry into the uterus, depending on the stage of the menstrual cycle Menstrual cycle The menstrual cycle is the cyclic pattern of hormonal and tissular activity that prepares a suitable uterine environment for the fertilization and implantation of an ovum. The menstrual cycle involves both an endometrial and ovarian cycle that are dependent on one another for proper functioning. There are 2 phases of the ovarian cycle and 3 phases of the endometrial cycle. Menstrual Cycle
  • In pregnancy Pregnancy Pregnancy is the time period between fertilization of an oocyte and delivery of a fetus approximately 9 months later. The 1st sign of pregnancy is typically a missed menstrual period, after which, pregnancy should be confirmed clinically based on a positive β-hCG test (typically a qualitative urine test) and pelvic ultrasound. Pregnancy: Diagnosis, Maternal Physiology, and Routine Care:
    • Keeps the uterus closed and protected during pregnancy Pregnancy Pregnancy is the time period between fertilization of an oocyte and delivery of a fetus approximately 9 months later. The 1st sign of pregnancy is typically a missed menstrual period, after which, pregnancy should be confirmed clinically based on a positive β-hCG test (typically a qualitative urine test) and pelvic ultrasound. Pregnancy: Diagnosis, Maternal Physiology, and Routine Care
    • Dilates during labor Labor Labor is the normal physiologic process defined as uterine contractions resulting in dilatation and effacement of the cervix, which culminates in expulsion of the fetus and the products of conception. Normal and Abnormal Labor to allow delivery of the fetus
• Fallopian tubes:
  • Accept an oocyte from the ovaries Ovaries Ovaries are the paired gonads of the female reproductive system that contain haploid gametes known as oocytes. The ovaries are located intraperitoneally in the pelvis, just posterior to the broad ligament, and are connected to the pelvic sidewall and to the uterus by ligaments. These organs function to secrete hormones (estrogen and progesterone) and to produce the female germ cells (oocytes). Ovaries upon ovulation
  • Facilitate movement of the oocyte along the tube to meet a potential sperm
  • Typical site of fertilization Fertilization To undergo fertilization, the sperm enters the uterus, travels towards the ampulla of the fallopian tube, and encounters the oocyte. The zona pellucida (the outer layer of the oocyte) deteriorates along with the zygote, which travels towards the uterus and eventually forms a blastocyst, allowing for implantation to occur. Fertilization and First Week by the sperm
  • Facilitate movement of a fertilized embryo into the uterus for implantation

Embryologic development

• The uterus, cervix, and fallopian tubes derive from the paramesonephric ducts (müllerian ducts)
• At 6 weeks of embryologic life, the müllerian ducts fuse at the caudal end:
  • The fused medial/caudal portion gives rise to the uterus and upper vagina Vagina The vagina is the female genital canal, extending from the vulva externally to the cervix uteri internally. The structures have sexual, reproductive, and urinary functions and a rich blood supply, mainly arising from the internal iliac artery. Vagina, Vulva, and Pelvic Floor.
  • The unfused lateral/cranial portions give rise to the fallopian tubes.
• A longitudinal midline septum exists within the uterine cavity where the müllerian ducts came together → usually regresses by week 20
• The gubernaculum gives rise to the supporting ligaments (broad and round ligaments).

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Gross Anatomy

Structure and size of the uterus

• Pear-shaped and hollow 
• Composed of smooth muscle
• Size: 
  • Length: 7–8 cm
  • Width: 4–5 cm
  • Thickness: 2.5–4 cm

Parts of the uterus

• Fundus: broad, superior curvature of the uterus
• Body: 
  • Main central portion
  • Uterine horns: superior lateral openings to the fallopian tubes
  • Uterine cavity: 
    • Internal cavity
    • Shaped like an inverted triangle
    • Also referred to as the endometrial cavity
• Isthmus: 
  • Narrowing of the uterus just inferior to its body 
  • The transition point between the uterine body and the cervix
• Cervix: 
  • Fibrous, cylindrical structure; makes up the inferior portion of the uterus
  • Connected to and leads into the vagina Vagina The vagina is the female genital canal, extending from the vulva externally to the cervix uteri internally. The structures have sexual, reproductive, and urinary functions and a rich blood supply, mainly arising from the internal iliac artery. Vagina, Vulva, and Pelvic Floor
  • Cervical canal: passage leading from the uterine cavity into the vagina Vagina The vagina is the female genital canal, extending from the vulva externally to the cervix uteri internally. The structures have sexual, reproductive, and urinary functions and a rich blood supply, mainly arising from the internal iliac artery. Vagina, Vulva, and Pelvic Floor
  • Internal os: internal opening of the canal into the uterine body
  • External os: external opening of the canal into the vagina Vagina The vagina is the female genital canal, extending from the vulva externally to the cervix uteri internally. The structures have sexual, reproductive, and urinary functions and a rich blood supply, mainly arising from the internal iliac artery. Vagina, Vulva, and Pelvic Floor
    • Visible on speculum exam
    • Has an anterior and a posterior lip
    • Shape and size of the external os differs between nulliparous and multiparous women.

Uterine orientations

The uterus is often tilted or bent forward or backward. It is clinically important to determine the orientation of the uterus before any uterine procedure in order to minimize risks of complications (like uterine perforation). The 5 orientations are:

• Anteverted: 
  • The entire uterus is tilted forward, over the bladder.
  • The most common orientation
• Anteflexed: forward bend in the body musculature, in addition to being anteverted
• Midposition: between anteverted and retroverted positions
• Retroverted: tilted posteriorly, toward the rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal
• Retroflexed: backward bend in the body musculature, in addition to being retroverted

Anatomic relationships of the uterus

The uterus is in contact with a number of other organs and spaces:

• Anteriorly: 
  • Bladder
  • Vesicouterine pouch: recess formed by the peritoneal fold between the uterus and bladder
• Posteriorly: 
  • Rectum
  • Rectouterine pouch
    • Also known as the Douglas pouch
    • The recess formed by the peritoneal fold between the rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal and the posterior uterine wall
    • Lowermost point of the peritoneum Peritoneum The peritoneum is a serous membrane lining the abdominopelvic cavity. This lining is formed by connective tissue and originates from the mesoderm. The membrane lines both the abdominal walls (as parietal peritoneum) and all of the visceral organs (as visceral peritoneum). Peritoneum and Retroperitoneum
• Laterally: 
  • Fallopian tubes
  • Ovaries
  • Broad ligament
  • Pelvic sidewall
• Superiorly: small intestines
• Inferiorly: vagina Vagina The vagina is the female genital canal, extending from the vulva externally to the cervix uteri internally. The structures have sexual, reproductive, and urinary functions and a rich blood supply, mainly arising from the internal iliac artery. Vagina, Vulva, and Pelvic Floor

Structure of the fallopian tubes

Fallopian tubes are also known as uterine tubes. These paired, thin muscular tubes are attached to the uterus and are approximately 10 cm in total length. There are 4 parts, as follows, in order from lateral to medial.

• Infundibulum:
  • Lateral-most part of the tubes, in close association with the ovaries Ovaries Ovaries are the paired gonads of the female reproductive system that contain haploid gametes known as oocytes. The ovaries are located intraperitoneally in the pelvis, just posterior to the broad ligament, and are connected to the pelvic sidewall and to the uterus by ligaments. These organs function to secrete hormones (estrogen and progesterone) and to produce the female germ cells (oocytes). Ovaries
  • Funnel-shaped with finger-like projections called fimbriae 
  • Opens into peritoneal cavity
• Ampulla: 
  • The widest and longest portion of the tube
  • Usual site of fertilization Fertilization To undergo fertilization, the sperm enters the uterus, travels towards the ampulla of the fallopian tube, and encounters the oocyte. The zona pellucida (the outer layer of the oocyte) deteriorates along with the zygote, which travels towards the uterus and eventually forms a blastocyst, allowing for implantation to occur. Fertilization and First Week
  • Approximately 7–8 cm long
• Isthmus:
  • Narrowing portion that approaches the uterus (at the uterine horns)
  • Thicker walls
  • Approximately 4 cm long
• Uterine portion (also called the intramural or interstitial part):
  •  Located within the uterine wall
  • Opens into uterine cavity through uterine ostium
  • Shortest segment (< 1 cm)

Ligaments

There are 5 major ligaments that attach to the uterus and/or fallopian tubes: the broad, cardinal, round, utero-ovarian, and uterosacral ligaments.

• Broad ligament:
  • A thin sheet of peritoneum Peritoneum The peritoneum is a serous membrane lining the abdominopelvic cavity. This lining is formed by connective tissue and originates from the mesoderm. The membrane lines both the abdominal walls (as parietal peritoneum) and all of the visceral organs (as visceral peritoneum). Peritoneum and Retroperitoneum that drapes over the uterus and fallopian tubes like a sheet hanging over a clothesline
  • Connects the pelvic organs to the lateral pelvic wall
  • Divided into 3 parts: mesosalpinx, mesovarium, and mesometrium
  • Mesosalpinx: 
    • Area adjacent to the fallopian tubes
    • Contains the tubal branches of the ovarian and ascending uterine arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries
  • Mesovarium: 
    • Area adjacent to the ovaries Ovaries Ovaries are the paired gonads of the female reproductive system that contain haploid gametes known as oocytes. The ovaries are located intraperitoneally in the pelvis, just posterior to the broad ligament, and are connected to the pelvic sidewall and to the uterus by ligaments. These organs function to secrete hormones (estrogen and progesterone) and to produce the female germ cells (oocytes). Ovaries
    • Contains the ovarian branches of the ovarian and ascending uterine arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries
  • Mesometrium: 
    • Area below the utero-ovarian ligament
    • Inferiorly, contains the cardinal ligament and ureters
•  Cardinal ligament (ligamentum transversum cervicis):
  • Connects the cervix with the pelvic wall
  • Found at the base of the broad ligament in the mesometrium
  • Contains the uterine vessels
• Round ligament (ligamentum teres):
  • A thickening of the broad ligament off the anterior surface of the uterus
  • Connects the anterior uterine horns to the anterior abdominal wall Anterior abdominal wall The anterior abdominal wall is anatomically delineated as a hexagonal area defined superiorly by the xiphoid process, laterally by the midaxillary lines, and inferiorly by the pubic symphysis. Anterior Abdominal Wall before passing through the inguinal canal Inguinal canal The inguinal region, or the groin, is located in the RLQ and LLQ of the anterior abdominal wall, bordered by the thigh inferiorly, the pubis medially, and the iliac crest superolaterally. The inguinal canal is a tubular structure that runs in a straight line from the anterior superior iliac spine to the pubic tubercle. Inguinal Canal and Hernias and terminating in the labia majora
• Utero-ovarian (UO) ligament:
  • Also known as the ovarian ligament
  • Connects the uterus to the ovary 
  • A thickened portion of the broad ligament within the mesovarium
• Uterosacral ligament:
  • Connects the posteroinferior portion of the uterus (at the level of the cervix) to the sacrum
  • A thicker, stronger ligament, providing important structural support (i.e., preventing uterine prolapse into the vagina Vagina The vagina is the female genital canal, extending from the vulva externally to the cervix uteri internally. The structures have sexual, reproductive, and urinary functions and a rich blood supply, mainly arising from the internal iliac artery. Vagina, Vulva, and Pelvic Floor)

Microscopic Anatomy

Microscopic anatomy of the uterine body

Histologically, the uterus is composed of 3 layers: 

• Endometrium:
  • Innermost layer
  • A mucosal layer containing:
    • Simple columnar epithelium Epithelium The epithelium is a complex of specialized cellular organizations arranged into sheets and lining cavities and covering the surfaces of the body. The cells exhibit polarity, having an apical and a basal pole. Structures important for the epithelial integrity and function involve the basement membrane, the semipermeable sheet on which the cells rest, and interdigitations, as well as cellular junctions. Surface Epithelium (lines the uterine cavity)
    • Tubular glands
    • Lamina propria (also called stroma): made up of connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue
  • Divided into 2 layers:
    • Stratum functionalis: superficial layer that proliferates and sheds each month during the menstrual cycle Menstrual cycle The menstrual cycle is the cyclic pattern of hormonal and tissular activity that prepares a suitable uterine environment for the fertilization and implantation of an ovum. The menstrual cycle involves both an endometrial and ovarian cycle that are dependent on one another for proper functioning. There are 2 phases of the ovarian cycle and 3 phases of the endometrial cycle. Menstrual Cycle
    • Stratum basalis: deeper layer; does not shed, and regenerates the functionalis each cycle
  • Supplied by small spiral arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries that constrict, rupture, and bleed during menstruation
• Myometrium:
  • Middle layer
  • Thick muscular layer
  • Made up of smooth muscle and loose connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue
  • Contains the larger branches of the neurovasculature 
• Perimetrium:
  • Also known as the serosa
  • Outer layer, which is also the visceral layer of the peritoneum Peritoneum The peritoneum is a serous membrane lining the abdominopelvic cavity. This lining is formed by connective tissue and originates from the mesoderm. The membrane lines both the abdominal walls (as parietal peritoneum) and all of the visceral organs (as visceral peritoneum). Peritoneum and Retroperitoneum
  • Becomes the broad ligament laterally
  • Thin layer of connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue

Microscopic anatomy of the cervix

Epithelial lining:

• Ectocervix:
  • Lines the intravaginal part of the cervix; visible on speculum exam
  • Made of nonkeratinizing stratified squamous epithelium Epithelium The epithelium is a complex of specialized cellular organizations arranged into sheets and lining cavities and covering the surfaces of the body. The cells exhibit polarity, having an apical and a basal pole. Structures important for the epithelial integrity and function involve the basement membrane, the semipermeable sheet on which the cells rest, and interdigitations, as well as cellular junctions. Surface Epithelium
• Endocervix:
  • Lines the cervical canal
  • Simple columnar epithelium Epithelium The epithelium is a complex of specialized cellular organizations arranged into sheets and lining cavities and covering the surfaces of the body. The cells exhibit polarity, having an apical and a basal pole. Structures important for the epithelial integrity and function involve the basement membrane, the semipermeable sheet on which the cells rest, and interdigitations, as well as cellular junctions. Surface Epithelium with cervical glands (produces mucus)
• Transitional zone (also called the transformation zone):
  • The location where squamous and columnar epithelium Epithelium The epithelium is a complex of specialized cellular organizations arranged into sheets and lining cavities and covering the surfaces of the body. The cells exhibit polarity, having an apical and a basal pole. Structures important for the epithelial integrity and function involve the basement membrane, the semipermeable sheet on which the cells rest, and interdigitations, as well as cellular junctions. Surface Epithelium overlap
  • Squamocolumnar junction: transition point at which the epithelium Epithelium The epithelium is a complex of specialized cellular organizations arranged into sheets and lining cavities and covering the surfaces of the body. The cells exhibit polarity, having an apical and a basal pole. Structures important for the epithelial integrity and function involve the basement membrane, the semipermeable sheet on which the cells rest, and interdigitations, as well as cellular junctions. Surface Epithelium becomes entirely stratified squamous (i.e., ectocervix). 
  • Site of infection with human papilloma virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology: Overview ( HPV HPV Human papillomavirus (HPV) is a nonenveloped, circular, double-stranded DNA virus belonging to the Papillomaviridae family. Humans are the only reservoir, and transmission occurs through close skin-to-skin or sexual contact. Human papillomaviruses infect basal epithelial cells and can affect cell-regulatory proteins to result in cell proliferation. Papillomaviridae: HPV), metaplasia, and most cervical cancers

Stroma:

• Made up primarily of fibroelastic connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue
• < 10% smooth muscle 
• Necessary for the stretching capacity during childbirth

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Microscopic anatomy of the fallopian tubes

The fallopian tubes have 3 layers:

• Mucosa:
  • Simple columnar epithelium Epithelium The epithelium is a complex of specialized cellular organizations arranged into sheets and lining cavities and covering the surfaces of the body. The cells exhibit polarity, having an apical and a basal pole. Structures important for the epithelial integrity and function involve the basement membrane, the semipermeable sheet on which the cells rest, and interdigitations, as well as cellular junctions. Surface Epithelium and lamina propria
  • Heavily folded
  • Ciliated cells: 
    • Assist in movement of sperm, oocytes, and embryos
    • Cilia beat more strongly in the presence of estrogen
  • Peg cells (< 10%): 
    • Nonciliated, secretory cells
    • Secretions are primarily under the influence of estrogen
    • Secrete nutritious fluid to support fertilization Fertilization To undergo fertilization, the sperm enters the uterus, travels towards the ampulla of the fallopian tube, and encounters the oocyte. The zona pellucida (the outer layer of the oocyte) deteriorates along with the zygote, which travels towards the uterus and eventually forms a blastocyst, allowing for implantation to occur. Fertilization and First Week
• Muscular layer:
  • Smooth muscle
  • ↑ Concentrations of estrogen present around ovulation stimulate peristaltic waves of contraction → enhances movement of sperm, oocytes, and embryos 
  • Contains an inner circular and outer longitudinal layer
• Serosa: 
  • Thin outer layer made up of connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue
  • This visceral peritoneum Peritoneum The peritoneum is a serous membrane lining the abdominopelvic cavity. This lining is formed by connective tissue and originates from the mesoderm. The membrane lines both the abdominal walls (as parietal peritoneum) and all of the visceral organs (as visceral peritoneum). Peritoneum and Retroperitoneum (i.e., broad ligament) covers the tubes.

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Neurovasculature

Vasculature

The primary blood supply to the uterus is via the uterine artery. The fallopian tubes are supplied by the anastomosis between the uterine and ovarian arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries.

• Uterine artery:
  • A branch of the anterior division of the internal iliac artery
  • Located within the broad ligament near the level of the cervix
  • Approaches the uterus at a 90-degree angle at the level of the internal cervical os → splits into ascending and descending branches
    • These branches run longitudinally along the lateral edges of the uterine body and cervix.
    • Ascending branches: anastomose with the ovarian artery
    • Descending branches: anastomose with branches off the vaginal artery
• Ovarian artery:
  • Originates directly from the aorta 
  • Runs along the pelvic wall → reaches the lateral side of the ovary 
  • Splits into ovarian and tubal branches:
    • Both branches anastomose with the ascending branch of the uterine artery.
    • The tubal branch is often referred to as the utero-ovarian artery.
• Supplying the myometrium and endometrium:
  • Arcuate arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: 
    • Branch off the ascending and descending uterine arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries at an approximately 90-degree angle 
    • Travel in a rough circle around the uterus (in a transverse plane) 
    • Anastomose with arcuate arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries coming from the oppose side
    • Give off smaller spiral arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries
  • Spiral arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries:
    • Tortuous vessels that supply the endometrium between the glands
    • Rupture and constrict during menses → menstrual bleeding, ischemia, and endometrial shedding

Venous drainage

• Uterine body:
  • Via the uterine venous plexus, which runs down the lateral side of the uterus
  • Located in the broad ligament near the level of the cervix
  • Drains into the uterine vein → into the internal iliac vein
• Fallopian tubes: drain via tubal veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins → ovarian veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins
  • Right ovarian vein → directly into the inferior vena cava (IVC)
  • Left ovarian vein → renal vein → IVC

Lymphatic drainage

The primary lymphatic drainage for each section of the uterus and fallopian tubes is through:

• Fallopian tubes: aortic nodes (follows drainage of the ovaries Ovaries Ovaries are the paired gonads of the female reproductive system that contain haploid gametes known as oocytes. The ovaries are located intraperitoneally in the pelvis, just posterior to the broad ligament, and are connected to the pelvic sidewall and to the uterus by ligaments. These organs function to secrete hormones (estrogen and progesterone) and to produce the female germ cells (oocytes). Ovaries)
• Fundus:
  • Aortic nodes 
  • Superficial inguinal nodes (areas near the round ligaments)
• Uterine body: external iliac nodes 
• Cervix: 
  • Internal iliac nodes 
  • Sacral nodes (especially areas near the uterosacral ligaments)
  • Obturator nodes
• Fallopian tubes: internal iliac nodes and inguinal nodes (via the broad ligament)

Innervation

The uterus and tubes are innervated by the autonomic nervous system Autonomic nervous system The ANS is a component of the peripheral nervous system that uses both afferent (sensory) and efferent (effector) neurons, which control the functioning of the internal organs and involuntary processes via connections with the CNS. The ANS consists of the sympathetic and parasympathetic nervous systems. Autonomic Nervous System (ANS). Nerve fibers of the ANS pass via splanchnic nerves → inferior hypogastric plexus → uterovaginal plexus

• Sympathetic fibers: 
  • Pass via lumbar splanchnic nerves 
  • Arise from levels T10–L2
• Parasympathetic fibers: 
  • Pass via pelvic splanchnic nerves
  • Arise from levels S2–S4
• Visceral afferent pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain fibers ( labor Labor Labor is the normal physiologic process defined as uterine contractions resulting in dilatation and effacement of the cervix, which culminates in expulsion of the fetus and the products of conception. Normal and Abnormal Labor, menstrual cramps):
  • Intraperitoneal structures (tubes, fundus, uterine body): 
    • Follow the sympathetic innervation in a retrograde direction
    • Visceral uterine pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain from labor Labor Labor is the normal physiologic process defined as uterine contractions resulting in dilatation and effacement of the cervix, which culminates in expulsion of the fetus and the products of conception. Normal and Abnormal Labor is felt in the T10–L2 dermatomes
  • Subperitoneal structures (lower uterus/cervix): 
    • Follow the parasympathetic innervation in a retrograde direction
    • Visceral cervical pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain from labor Labor Labor is the normal physiologic process defined as uterine contractions resulting in dilatation and effacement of the cervix, which culminates in expulsion of the fetus and the products of conception. Normal and Abnormal Labor is felt in the S2–S4 dermatomes
• Visceral afferent fibers unrelated to pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain: follow the parasympathetic innervation

Clinical Relevance

Related anatomical structures

• Pelvis: consists of the pelvic girdle, pelvic cavity, pelvic floor, and all the viscera, vessels, and muscles contained within. The pelvic cavity houses various GI and urogenital structures. 
• Ovaries: paired gonads of the female reproductive system. The ovaries Ovaries Ovaries are the paired gonads of the female reproductive system that contain haploid gametes known as oocytes. The ovaries are located intraperitoneally in the pelvis, just posterior to the broad ligament, and are connected to the pelvic sidewall and to the uterus by ligaments. These organs function to secrete hormones (estrogen and progesterone) and to produce the female germ cells (oocytes). Ovaries are located intraperitoneally in the lesser pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 "hip" bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis, just posterior to the broad ligament. 
• Vagina and vulva Vulva The vulva is the external genitalia of the female and includes the mons pubis, labia majora, labia minora, clitoris, vestibule, vestibular bulb, and greater vestibular glands. Vagina, Vulva, and Pelvic Floor: The vulva Vulva The vulva is the external genitalia of the female and includes the mons pubis, labia majora, labia minora, clitoris, vestibule, vestibular bulb, and greater vestibular glands. Vagina, Vulva, and Pelvic Floor is the external female genitalia and includes the mons pubis, labia majora, labia minora, clitoris, vestibule, vestibular bulb, and the greater vestibular glands. The vagina Vagina The vagina is the female genital canal, extending from the vulva externally to the cervix uteri internally. The structures have sexual, reproductive, and urinary functions and a rich blood supply, mainly arising from the internal iliac artery. Vagina, Vulva, and Pelvic Floor is the genital canal in the female, extending from the vulva Vulva The vulva is the external genitalia of the female and includes the mons pubis, labia majora, labia minora, clitoris, vestibule, vestibular bulb, and greater vestibular glands. Vagina, Vulva, and Pelvic Floor to the cervix uteri.

Physiology

• Menstrual cycle: cyclic pattern of hormonal and tissular activity responsible for the preparation of a suitable uterine environment for the implantation and development of a fertilized embryo
• Pregnancy: fertilization Fertilization To undergo fertilization, the sperm enters the uterus, travels towards the ampulla of the fallopian tube, and encounters the oocyte. The zona pellucida (the outer layer of the oocyte) deteriorates along with the zygote, which travels towards the uterus and eventually forms a blastocyst, allowing for implantation to occur. Fertilization and First Week of the ovum and implantation into the uterine wall. Pregnancy usually lasts 40 weeks from the 1st day of the last menstrual period. Numerous physiologic changes to the uterus and many other organs occur during pregnancy Pregnancy Pregnancy is the time period between fertilization of an oocyte and delivery of a fetus approximately 9 months later. The 1st sign of pregnancy is typically a missed menstrual period, after which, pregnancy should be confirmed clinically based on a positive β-hCG test (typically a qualitative urine test) and pelvic ultrasound. Pregnancy: Diagnosis, Maternal Physiology, and Routine Care.

Clinical evaluation

• Diagnostic procedures in gynecology: includes, among others, Pap smears and colposcopy for the screening and diagnosis of cervical cancer Cervical cancer Cervical cancer, or invasive cervical carcinoma (ICC), is the 3rd most common cancer in women in the world, with > 50% of the cases being fatal. In the United States, ICC is the 13th most common cancer and the cause of < 3% of all cancer deaths due to the slow progression of precursor lesions and, more importantly, effective cancer screening. Cervical Cancer, invasive uterine tests for the diagnosis of pelvic conditions such as uterine biopsies, and mammography for the diagnosis of breast conditions. 
• Imaging of the uterus and ovaries Ovaries Ovaries are the paired gonads of the female reproductive system that contain haploid gametes known as oocytes. The ovaries are located intraperitoneally in the pelvis, just posterior to the broad ligament, and are connected to the pelvic sidewall and to the uterus by ligaments. These organs function to secrete hormones (estrogen and progesterone) and to produce the female germ cells (oocytes). Ovaries: to assess abnormal uterine bleeding Abnormal Uterine Bleeding Abnormal uterine bleeding is the medical term for abnormalities in the frequency, volume, duration, and regularity of the menstrual cycle. Abnormal uterine bleeding is classified using the acronym PALM-COEIN, with PALM representing the structural causes and COEIN indicating the non-structural causes. Abnormal Uterine Bleeding, pelvic pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain, and other suspected pelvic pathologies. The 1st-line imaging method of choice for the uterus and ovaries Ovaries Ovaries are the paired gonads of the female reproductive system that contain haploid gametes known as oocytes. The ovaries are located intraperitoneally in the pelvis, just posterior to the broad ligament, and are connected to the pelvic sidewall and to the uterus by ligaments. These organs function to secrete hormones (estrogen and progesterone) and to produce the female germ cells (oocytes). Ovaries is almost always ultrasonography.

Uterine disorders

• Congenital uterine abnormalities (müllerian anomalies): usually due to abnormal fusion of the paramesonephric ducts, incomplete regression of the longitudinal septum, or complete agenesis of part of the structures. Individuals may present with recurrent pregnancy Pregnancy Pregnancy is the time period between fertilization of an oocyte and delivery of a fetus approximately 9 months later. The 1st sign of pregnancy is typically a missed menstrual period, after which, pregnancy should be confirmed clinically based on a positive β-hCG test (typically a qualitative urine test) and pelvic ultrasound. Pregnancy: Diagnosis, Maternal Physiology, and Routine Care loss, infertility Infertility Infertility is the inability to conceive in the context of regular intercourse. The most common causes of infertility in women are related to ovulatory dysfunction or tubal obstruction, whereas, in men, abnormal sperm is a common cause. Infertility, preterm delivery, breech presentation, or placental abruption. Surgical repair is possible in certain cases.
• Endometrial hyperplasia Endometrial Hyperplasia Endometrial hyperplasia (EH) is the abnormal growth of the uterine endometrium. This abnormal growth may be due to estrogen stimulation or genetic mutations leading to uncontrolled proliferation. Endometrial Hyperplasia and Endometrial Cancer (EH) and endometrial cancer (EC): Endometrial hyperplasia Endometrial Hyperplasia Endometrial hyperplasia (EH) is the abnormal growth of the uterine endometrium. This abnormal growth may be due to estrogen stimulation or genetic mutations leading to uncontrolled proliferation. Endometrial Hyperplasia and Endometrial Cancer is abnormal growth of the uterine endometrium, which is usually due to abnormal estrogen stimulation or genetic mutations leading to uncontrolled proliferation. Endometrial cancer Endometrial Cancer Endometrial carcinoma (EC) is the most common gynecologic malignancy in the developed world, and it has several histologic types. Endometrioid carcinoma (known as type 1 EC) typically develops from atypical endometrial hyperplasia, is hormonally responsive, and carries a favorable prognosis. Endometrial Hyperplasia and Endometrial Cancer is the most common gynecologic malignancy in the developed world. The diagnosis is histologic, and management most often involves surgery, hormonal therapy, and adjuvant radiation therapy (for advanced disease).
• Menstrual cycle abnormalities: alterations in frequency, volume, and/or duration of the menstrual cycle Menstrual cycle The menstrual cycle is the cyclic pattern of hormonal and tissular activity that prepares a suitable uterine environment for the fertilization and implantation of an ovum. The menstrual cycle involves both an endometrial and ovarian cycle that are dependent on one another for proper functioning. There are 2 phases of the ovarian cycle and 3 phases of the endometrial cycle. Menstrual Cycle that are usually associated with the term abnormal uterine bleeding Abnormal Uterine Bleeding Abnormal uterine bleeding is the medical term for abnormalities in the frequency, volume, duration, and regularity of the menstrual cycle. Abnormal uterine bleeding is classified using the acronym PALM-COEIN, with PALM representing the structural causes and COEIN indicating the non-structural causes. Abnormal Uterine Bleeding (AUB).
• Endometrial polyps Endometrial polyps Endometrial polyps are pedunculated or sessile projections of the endometrium that result from overgrowth of endometrial glands and stroma around a central vascular stalk. Endometrial polyps are a few millimeters to a few centimeters in size, can occur anywhere within the uterine cavity, and, while usually benign, can be malignant, particularly in postmenopausal women. Endometrial Polyps: pedunculated or sessile projections of the endometrium that result from overgrowth of endometrial glands and stroma around a central vascular stalk. Endometrial polyps Endometrial polyps Endometrial polyps are pedunculated or sessile projections of the endometrium that result from overgrowth of endometrial glands and stroma around a central vascular stalk. Endometrial polyps are a few millimeters to a few centimeters in size, can occur anywhere within the uterine cavity, and, while usually benign, can be malignant, particularly in postmenopausal women. Endometrial Polyps present with AUB or postmenopausal bleeding, though many are asymptomatic and discovered incidentally. These polyps are best diagnosed with saline infusion sonography (SIS) and are usually treated with hysteroscopic resection. 
• Uterine leiomyomas: also known fibroids. Uterine leiomyomas are common, benign, myometrial neoplasms that typically present with AUB, dysmenorrhea, and/or pelvic pressure/bulk symptoms. Uterine leiomyomas are usually diagnosed on pelvic ultrasonography and are best treated surgically if symptomatic.
• Endometriosis Endometriosis Endometriosis is a common disease in which patients have endometrial tissue implanted outside of the uterus. Endometrial implants can occur anywhere in the pelvis, including the ovaries, the broad and uterosacral ligaments, the pelvic peritoneum, and the urinary and gastrointestinal tracts. Endometriosis: common disease in which ectopic normal endometrial tissue is implanted outside the uterus. Individuals present with severe dysmenorrhea and/or other pelvic pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain symptoms, such as dyspareunia. Bleeding patterns are frequently normal.

Cervical disorders

Cervical cancer: typically arises from the transformation zone out of premalignant lesions due to infection with high-risk HPV HPV Human papillomavirus (HPV) is a nonenveloped, circular, double-stranded DNA virus belonging to the Papillomaviridae family. Humans are the only reservoir, and transmission occurs through close skin-to-skin or sexual contact. Human papillomaviruses infect basal epithelial cells and can affect cell-regulatory proteins to result in cell proliferation. Papillomaviridae: HPV strains. Early cervical neoplasia is asymptomatic, though it may present with contact bleeding (e.g., bleeding with intercourse). Diagnosis is often made by routine screening with a cervical Pap smear with cytology and high-risk human papillomavirus Human papillomavirus Human papillomavirus (HPV) is a nonenveloped, circular, double-stranded DNA virus belonging to the Papillomaviridae family. Humans are the only reservoir, and transmission occurs through close skin-to-skin or sexual contact. Human papillomaviruses infect basal epithelial cells and can affect cell-regulatory proteins to result in cell proliferation. Papillomaviridae: HPV (hrHPV) testing, and biopsy.

Fallopian tube disorders

• Ectopic pregnancy Ectopic pregnancy Ectopic pregnancy refers to the implantation of a fertilized egg (embryo) outside the uterine cavity. The main cause is disruption of the normal anatomy of the fallopian tube. Ectopic Pregnancy: implantation of the blastocyst outside the uterine cavity. Individuals usually present with severe pelvic pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain (may be unilateral), vaginal bleeding, and a positive pregnancy Pregnancy Pregnancy is the time period between fertilization of an oocyte and delivery of a fetus approximately 9 months later. The 1st sign of pregnancy is typically a missed menstrual period, after which, pregnancy should be confirmed clinically based on a positive β-hCG test (typically a qualitative urine test) and pelvic ultrasound. Pregnancy: Diagnosis, Maternal Physiology, and Routine Care test. If the tube ruptures with the growing pregnancy Pregnancy Pregnancy is the time period between fertilization of an oocyte and delivery of a fetus approximately 9 months later. The 1st sign of pregnancy is typically a missed menstrual period, after which, pregnancy should be confirmed clinically based on a positive β-hCG test (typically a qualitative urine test) and pelvic ultrasound. Pregnancy: Diagnosis, Maternal Physiology, and Routine Care, life-threatening hemorrhage can result. Diagnosis is made with ultrasonography and trending hCG levels. Management may be medical, with methotrexate, or surgical, with resection.
• Pelvic inflammatory disease Pelvic inflammatory disease Pelvic inflammatory disease (PID) is defined as a polymicrobial infection of the upper female reproductive system. The disease can affect the uterus, fallopian tubes, ovaries, and adjacent structures. Pelvic inflammatory disease is closely linked with sexually transmitted diseases, most commonly caused by Chlamydia trachomatis, Neisseria gonorrhoeae, and Gardnerella vaginalis. Pelvic Inflammatory Disease (PID): defined as a polymicrobial infection of the upper female reproductive system. This disease can affect the uterus, fallopian tubes, ovaries Ovaries Ovaries are the paired gonads of the female reproductive system that contain haploid gametes known as oocytes. The ovaries are located intraperitoneally in the pelvis, just posterior to the broad ligament, and are connected to the pelvic sidewall and to the uterus by ligaments. These organs function to secrete hormones (estrogen and progesterone) and to produce the female germ cells (oocytes). Ovaries, and adjacent structures and is often (though not always) caused by ascending cervicovaginal infections, most commonly from Chlamydia Chlamydia Chlamydiae are obligate intracellular gram-negative bacteria. They lack a peptidoglycan layer and are best visualized using Giemsa stain. The family of Chlamydiaceae comprises 3 pathogens that can infect humans: Chlamydia trachomatis, Chlamydia psittaci, and Chlamydia pneumoniae. Chlamydia trachomatis, Neisseria Neisseria Neisseria is a genus of bacteria commonly present on mucosal surfaces. Several species exist, but only 2 are pathogenic to humans: N. gonorrhoeae and N. meningitidis. Neisseria species are non-motile, gram-negative diplococci most commonly isolated on modified Thayer-Martin (MTM) agar. Neisseria gonorrhoeae, and organisms associated with bacterial vaginosis, such as Gardnerella vaginalis. Management is with antibiotics.