MSCI 500 Anatomy of the Uterus ASSIGNMENTS 2022.pdf

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Anatomy of the Uterus

Sandy A. Y. Mentore

Liberty University

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of the organ. One must consider its components and clinical significance including but not

limited to embryology, developmental Variants, physical features, bordering organs, supporting

Structures along with the organ’s blood Supply/ Drainage, and Innervation. The hollow muscular

organ that is the uterus is the main hormone-regulated secondary sex organ of the female

reproductive system. Located in the female pelvis above the Vagina, between the Urinary

Bladder and Rectum, the uterus performs critical functions in menstruation, fertility, and

gestation (pregnancy). Ranging in size throughout a female’s developmental stages, the Uterus is

the smallest before puberty then grows exponentially after that, to its adult dimensions.

Furthermore, the uterus can also change size during pregnancy to accommodate a growing fetus.

Like many other body organs, the Uterus is prone to abnormalities and/or complications. These

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tract. This hollow and muscular organ is subdivided into four major parts: the Fundus, Corpus

(Body), Isthmus, and Cervix. Each anatomical segment is responsible for a specialized set of

functions. As the most superior part of the Uterus, the fundus is the widest and most curved area

connecting the fallopian tubes with the uterus. Immediately below the Fundus and the level of

the fallopian tubes is the main part of a uterus, the corpus which is the site of implantation of

fertilized eggs during pregnancy. This part of the Uterus continues down past the Isthmus which

can be viewed as the neck region of the uterus. The Isthmus is a thin area between the Corpus

and Cervix where the Uterus begins to narrow. The most inferior part of the Uterus is the Cervix,

extending downwards from the isthmus to the opening of the vagina[ CITATION Gas22 \l

1033 ].

anteflexed concerning the vagina and cervix, respectively. Other naturally occurring positions of

the uterus are anteverted/retroverted, anteflexed/retroflexed, or midline. It is important to note

that the uterus may be rotated, for example, during pregnancy. To support an organ with shape

and position such as the uterus, several ligaments are needed including the utero-ovarian

ligament, round ligament, broad ligament, cardinal ligament, and uterosacral ligaments.

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Furthermore, the pelvic diaphragm, urogenital diaphragm, and perineal body provide inferior

support to the uterus[ CITATION Ame22 \l 1033 ].

Structure and Function

At about 1 ounce in weight, 3 inches long, and with a wall thickness of about 1 inch, a major

function of the uterus is to provide nourishment to a fertilized ovum. To accomplish this, a

Embryology

The embryology of the uterus is of a complex nature which begins at about eight weeks of

gestation when the “primordia for both female and male internal genitalia the paramesonephric

(Mullerian) and mesonephric (Wolffian) ducts appear.” Thereafter, several factors influence

sexual differentiation including growth factors, hormones, and inherited genetic factors. Due to

the “absence of a Y chromosome and the lack of testosterone within a female embryo, the normal

developmental sequence results in the paramesonephric (Mullerian) ducts canalizing after fusing

in the middle of the pelvis with its counterpart forming the female pelvic organs the; uterus,

cervix, and upper 1/5th of the vagina.” Allowing for regression of the mesonephric (Wolffian)

ducts. During this phase of development, any abnormality that may occur would result in various

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arteries supply blood to all parts of the uterus beginning with its myometrium. The uterine

arteries then branch into the arcuate arteries, which further branches into the radial arteries. Once

at the endometrium, the uterine arteries branch into the basal and spiral arteries. Uterine arteries

also play a critical role in maintaining blood supply during pregnancy and menstrual cycles.

The Para-aortic lymph nodes are primarily responsible for the drainage of the superior portion of

the uterus. In contrast, the lower portion is drained via “uterine blood vessels into external and

internal iliac lymph nodes”. However, some drainage is the responsibility of the “superficial

ligament provides venous drainage vis a plexus system.

Innervation

Histology and Physiological variants

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endometrium consists of two parts, the functional (superficial) layer, and the basal layer. Where

the functional layer is the site of reproductive hormone activity and sheds during menstruation.

The Myometrium is the muscle layer composed of smooth cells and the Serosa/Perimetrium

layer is the thin outer layer of the uterus composed of epithelial cells[ CITATION Gas22 \l

1033 ].

Surgical Considerations

The uterus is prone to several anomalies including “Segmental hypoplasia (cervical, vaginal,

fundal, or combined) Unicornuate uterus, Uterine didelphys, Bicornuate uterus, Septate uterus,

and/or development of a T-shaped uterus via exposure to Diethylstilbestrol. Additionally, there

are a variety of gynecologic disorders affecting the uterus including prolapse, fibroids, polyps,

infections, cancer, malformations, Endometrial hyperplasia, Adenomyosis, Endometritis,

Endometriosis, and adhesions”[ CITATION Jay22 \l 1033 \m Bil18].

symptoms, and severity, it can range from hormone therapy, medications, and surgery including a

Hysterectomy. A Hysterectomy is the surgical removal of the uterus and is the recommendation

to remedy some uterine disorders is classified as the second most common surgical procedure to

be performed on women in the United States. While Uterine cancer is classified as the most

common gynecologic cancer in developed countries [ CITATION Jay22 \l 1033 ].

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Biler, A., Akdemir, A., Peker, N., & Sendag, F. (2018). A Rare Uterine Malformation:

Considerations. Journal of clinical medicine, 11(5), 1251. https://doi.org/10.3390/jcm11051251