Uterus
How many layers of muscle are there in the myometrium?
3 layers of different muscle fibers
Normal post puberty measurements of the uterus
7.5-8cm long, 4-5cm width, 1.75-2cm in the anterior posterior dimension
What is a congenital uterine malformation
A deviation in the shape or structure of a woman's uterus that occurred during prenatal development
Describe uterus subseptus or septated
A mild anomaly marked by a midline myometrium septum between the endometrial canal. The two Müllerian ducts have fused but the partition between them is present
Describe the innermost layer of the uterus
A mucous membrane closely adherent to the myometrium. This layer is influenced by hormones and a woman's monthly cycle. It is continuous through the fimbriated extremity of the uterine tubes and with the lining of the vagina
Describe the isthmus of the uterus
A narrower area in the inferior portion of the uterus
Describe the outermost layer of the uterus
A thin layer of serous peritoneum that covers the fungus and the entire posterior and anterior uterus up to the isthmus
Describe the broad ligament
Anterior and posterior peritoneal reflections covering the uterus that extends anteriorly and laterally to the walls of the true pelvis draping over smaller structures. These double folds of parietal peritoneum extend from the uterine cornua to the lateral walls to form the broad ligaments
How is the endometrial cavity best visualized?
Anterior to posterior in the sagittal plane and the measurement of the endometrial thickness is more accurate in this plane
Name 4 variations of the uterus
Anteverted, anteflexed, retroverted, retroflexed
Where in the uterus is the site of implantation and growth of the fetus
Body of corpus of the uterus
describe anteverted uterus
Cervix and vagina form a 90 degree angle, with the body and the fundus resting on the empty bladder
Describe uterus didelphys:
Complete duplication of the uterus, cervix, and vagina. Is the result of failure of lateral fushion of the vagina and cervix
Describe retroflexed uterus
Corpus and fundus are bent at a greater posterior angle until the fundus is pointing inferiorly
Describe retroverted uterus
Corpus and fundus are tipped posteriorly and the angle of the cervix and vagina increase making them more lineally oriented
Path of the uterine artery
Courses along the lateral aspect of the uterus towards the fundus
Describe the blood supply chain to supply blood to the reproductive organs
Descending abdominal aorta bifurcates into the Lt and Rt common iliac arteries. Common iliac arteries branch into external and internal iliac arteries. Each internal iliac artery will have a parietal and visceral branch. These supply the blood to the reproductive organs
What is the narrow lumen within the cervix called
Endocervical or cervical canal
What layer is the innermost layer of the uterus?
Endometrium
Describe the location of the cardinal (lateral) cervical ligaments
Extend from lateral walls of the cervix and vagina to the obturator fascia at the lateral walls of the true pelvis
Describe the location of the uterosacral ligaments
Extend from the posterior and lateral aspect of the cervix around the lateral walls of the "" to the sacrum
Describe the location of the round ligaments
Extend laterally from the uterine Cornu to the anterior pelvic wall through the inguinal canal and anchor to the labia majora
Describe Unicornuate Uterus
Failure of one of the Müllerian ducts to form. Only one Müllerian duct forms given origin to the formation of half a uterus with only one uterine tube attachment
What is the myometrium responsible for?
For the dramatic enlarging during pregnancy and the contractions during childbirth
The part of the cervix that extends into the vagina is surrounded by what
Fornices
How does the uterus receive blood
From uterine artery which branches from the internal iliac artery
Name the 4 parts of the uterus
Fundus, body or corpus, isthmus and cervix
Describe bircornuate uterus
Have two uterine horns that are fused at one cervix. Both uteri have a uterine tune , endometrium and myometrial structures. The uterus is heart shaped. Most common of uterine malformations
What do the cardinal cervical ligaments do
Help suspend the uterus above the bladder and help to prevent downward displacement of the uterus
Briefly describe the uterus
Hollow muscular organ. Pear shaped
Flow in the spiral arteries is responsive to what
Hormonal changes of the menstrual cycle
Sonographic appearance of myometrium
Hypoechoic compared to the endometrium. Isoechoic to and continuous with the muscular walls of the vagina
What layer of the uterus is most muscular?
Myometrium is most muscular and middle layer
Are the broad ligaments true ligaments?
No
Uterus location
Normally lies at midline in the true pelvis. It tilts forward resting on the bladder
What is the most outer layer of the uterus?
Perimetrium or serosa
The perimetrium is reflected posteriorly onto the rectum to form a shallow pouch called what?
Pouch of Douglas, recto-uterine pouch OR posterior cul de sac
Describe the Arcuate Uterus
Presents a mild indentation at the level of the fundus
What do the broad ligaments do for the uterus
Provide minimal support for the uterus and prevent side to side movement of the uterus
The uterus is stabilized by what?
Several pairs of Suspensory ligaments formed by the peritoneum
Sonographic appearance of the cervix
Similar to the rest of the uterus. The endocervical canal is a continuation of the endometrial canal and appears as a fairly thin, bright echogenic strip
Sonographic appearance of perimetrium
Smooth contour and otherwise we cannot see it
Describe the walls of the cervix
Smooth muscle fibers, interlaced with collagen fibers, creating a more rigid framework
The straight arteries supply the first layer of the endometrium with smaller branches called?
Spiral arteries
The radial arteries give rise to what
Straight arteries
Name the layers of the endometrium
Superficial or functional and deep or basil
How do the uterosacral ligaments support the uterus
Supports the uterus to hold it in place preventing forward movements
What are the spaces located within the peritoneal cavity located posterior to the broad ligaments called?
The adnexa
Each uterine artery branch gives origin to what? What do they branch into?
The arcuate arteries. They loop around the uterus and branch into radial arteries
Sonographic appearance of the endometrium
The basil or deep layer appears highly echogenic and the superficial layer generally appears hypoechoic in comparison with the basil layer
What are the layers borders of the fundus of the uterus?
The cornua, this is where the uterine tubes attach and come into the uterus
The cervical canal is continuous with what
The endometrial canal superiorly and the vagina inferiorly
The spiral arteries perfuse or feed what?
The functional layer of the endometrium
What layer of the endometrium increases in size during the menstrual cycle? Explain
The functional layer. It increases in size and partially sloughs off at the time of menses
Describe anteflexed uterus
The fundus and the body are bent at a greater anterior angle until the fundus is pointing inferiorly and resting on the cervix
What do the radial arteries feed?
The myometrium
What is anteriorly reflected over the urinary bladder to form a shallow pouch and what is that pouch called?
The perimetrium. Pouch is called the Vesico-uterine pouch OR anterior cul de sac
Describe the fundus of the uterus
The top of the uterus below the pelvic brim and arching above the entry of the uterine tubes
Describe the body/corpus of the uterus
The upper two thirds portion narrowing from the fundus to the cervix. The thickest portion
What is located between the two layers of each broad ligament?
The uterine tube, round ligament, ovarian ligament and vascular structures of the uterus and ovaries
Name the 4 fornices
Two lateral fornices, one anterior fornix and one posterior fornix (deepest)
Name the congenital uterine anomalies
Uterus didelphys, bircornuate uterus, uterus sebseptus or septated, unicornuate uterus, arcuate uterus and uterine aplasia
Name the female reproductive organs that are in the pelvic cavity
Uterus, ovaries, uterine tubes and portion of the vagina
How does the size and shape of the uterus vary?
Varies greatly by age and prior pregnancies
Describe uterine aplasia
When the uterine tubes come to a blind end and only a small ribbon of fibromuscular tissue is present but no uterine body exists
Where are the arterial and venous uterine branches located
Within the peritoneal folds of the broad ligaments
Can you sustain a pregnancy with didelphys?
Yes, you can sustain a normal pregnancy in either uterus
What are the three layers of the uterus?
perimetrium, myometrium, endometrium
What allows the uterus considerable mobility
Ligaments
Describe the cervix
Lower one third cylinder segment that extends downward into the upper portion of the vagina
Where is the uterus located?
In the true pelvis between the bladder and the rectum and superior to the vagina
Describe each opening of the cervix
Internal os is the junction of the cervical canal with the endometrium canal External os is the junction of the cervical canal and the vagina
Name the openings to the cervix and what they are closest to
Internal os which is located closest to the internal uterus. External os which is located closest to the vagina
What do the round ligaments help do?
Keep the body flexed anteriorly (anteversion) and help prevent posterior movement of the uterus