Discuss relations and supports of uterus. Add a note on its applied anatomy.

Relations of the Uterus

The uterus maintains close relationships with several pelvic organs. These can be categorized based on direction:

Anterior Relations

• Urinary Bladder: The anterior wall of the uterus is covered by the vesicouterine peritoneum, which separates it from the urinary bladder. When the bladder is full, it can reach up to the level of the uterine fundus.
• Peritoneum: The anterior surface is covered by peritoneum, forming the anterior vesicouterine pouch (space of Retzius).

Posterior Relations

• Rectum: The posterior wall of the uterus is related to the anterior wall of the rectum. The rectouterine pouch (Douglas’ pouch) lies between them, representing the deepest part of the pelvic cavity.
• Sigmoid Colon: In some cases, particularly when the uterus is retroverted, the sigmoid colon may come into close proximity with the posterior uterine wall.
• Peritoneum: The posterior surface is covered by peritoneum, forming the posterior rectouterine pouch.

Lateral Relations

• Ureter: The ureter passes laterally along the pelvic brim and then curves medially to enter the bladder wall, running approximately 2.5 cm lateral to the uterine cervix.
• Internal Iliac Vessels: The uterine artery, a branch of the internal iliac artery, runs along the lateral aspect of the uterus, supplying it with blood. The uterine vein accompanies the artery.
• Pelvic Plexus: The pelvic plexus of nerves lies in the loose connective tissue surrounding the uterus.

Superior Relations

• Peritoneal Fold: The fundus of the uterus is related to the peritoneum covering the ileum and sigmoid colon.
• Uterine Tubes: The fallopian tubes originate from the uterine horns and extend laterally.

Supports of the Uterus

The uterus is maintained in its anteverted position by a complex system of supports, categorized into:

Ligaments

• Broad Ligament: A double layer of peritoneum extending from the lateral uterine walls to the pelvic walls. It contains the uterine vessels and nerves.
• Round Ligament: Runs from the uterine cornu (where the fallopian tube joins the uterus) through the inguinal canal to the labia majora. It helps maintain anteversion.
• Uterosacral Ligaments: Strong fibrous bands extending from the cervix to the sacrum. They provide significant support, preventing prolapse.
• Cardinal Ligaments (Transverse Cervical Ligaments): Extend from the cervix and upper vagina to the pelvic walls. They contain the uterine artery and are crucial for uterine support.

Pelvic Floor Muscles

• Levator Ani Muscle: Composed of the pubococcygeus, puborectalis, and iliococcygeus muscles. It forms the primary support of the pelvic organs, including the uterus.
• Coccygeus Muscle: Supports the pelvic floor posteriorly.

Applied Anatomy of the Uterus

A thorough understanding of the uterine relations and supports is crucial for clinical practice:

• Uterine Prolapse: Weakening of the pelvic floor muscles and/or uterosacral and cardinal ligaments can lead to uterine prolapse, where the uterus descends into the vaginal canal.
• Hysterectomy: Surgical removal of the uterus requires careful identification and ligation of the uterine vessels (branches of the internal iliac artery) and preservation of the cardinal ligaments to minimize postoperative complications.
• Pelvic Inflammatory Disease (PID): Inflammation can spread from the uterus to surrounding structures like the fallopian tubes, ovaries, and pelvic peritoneum, causing significant pain and potential infertility.
• Endometriosis: Ectopic endometrial tissue can implant on the peritoneum covering the uterus and surrounding organs, causing pain, adhesions, and infertility.
• Uterine Fibroids (Leiomyomas): These benign tumors can distort the uterine shape and compress adjacent organs, leading to symptoms like heavy menstrual bleeding and pelvic pain.
• Bladder Dysfunction: The close proximity of the bladder to the uterus means that uterine pathology can sometimes cause bladder irritation or urinary frequency.