UTERUS

UTERUS

1. Location: Uterus is a hollow, muscular organ located in the pelvic cavity. It is situated between the bladder and the rectum.

2. Shape and Size: The uterus is a pear-shaped organ, with the fundus being the top portion and the cervix being the lower portion. It measures about 7.5 cm in length and 5 cm in width.

3. Layers: The uterus is composed of three layers:

   • Perimetrium: The outermost layer, which is a thin layer of peritoneum.
   • Myometrium: The middle layer, which is composed of smooth muscle fibers.
   • Endometrium: The innermost layer, which is a mucous membrane that lining the uterus.

4. Functions: The main functions of the uterus are:

   • Support and nourishment of the developing fetus during pregnancy.
   • Menstruation: The process of shedding the endometrium in the absence of pregnancy.
   • Sexuality: The uterus plays an important role in female orgasm and sexual pleasure.

5. Development: → Primary Urethral Swellings: The development of the uterus starts from the primary urethral swellings. → Urethral Canal and Urethral Crest: The urethral canal and urethral crest develop from the primary urethral swellings. → Urogenital Fold: The urogenital fold develops from the urethral canal and urethral crest. → Paramesonephric Ducts: The paramesonephric ducts develop from the urogenital fold. → Formation of Uterus: The paramesonephric ducts eventually give rise to the formation of the uterus.

6. Blood Supply: The uterus receives its blood supply from:

   • Uterine arteries: Branches of the internal iliac arteries.
   • Vaginal arteries: Branches of the internal iliac arteries.

7. Lymph Drainage: The lymph drainage of the uterus is to the:

   • External iliac lymph nodes: Which then drain to the lumbar lymph nodes.

8. Nerve Supply: The nerve supply of the uterus is through the:

   • Uterine plexus: Which receives fibers from the T10-L1 spinal nerves.

Morphology of Uterus :

• The uterus is a hollow, muscular organ with a pear or a crescent shape.
• It has three layers: endometrium (innermost), myometrium (middle), and perimetrium (outermost).
• The endometrium is made up of simple columnar epithelium and is shed during menstruation.
• The myometrium is composed of smooth muscle fibers that contract during labor.
• The perimetrium is a thin layer of connective tissue that surrounds the uterus.

Relations of Uterus :

• Anteriorly: Bladder and pubic symphysis
• Posteriorly: Rectum and sacrum
• Laterally: Broad ligament of the uterus
• Superiorly: Ovarian ligament and fallopian tubes
• Inferiorly: Urethra and vagina

Ligaments and Supports of Uterus :

• Uterosacral ligaments: Attached to the cervix and sacrum
• Uterovesical ligaments: Attached to the cervix and pubic symphysis
• Round ligaments: Extend from the uterus to the labia majora
• Cardinal ligaments: Support the uterus and cervix
• Broad ligament: Supports the uterus and ovary

Blood Supply of Uterus :

• The uterus receives blood supply from the:
  • Uterine arteries: Branches of the internal iliac arteries
  • Ovarian arteries: Branches of the abdominal aorta
  • Vaginal arteries: Branches of the internal iliac arteries
  • Cervical arteries: Branches of the internal iliac arteries

Applied Anatomy of Uterus :

• The uterus is a vital organ in the female reproductive system.
• It expands to accommodate a growing fetus during pregnancy.
• It contracts during labor to push the baby out.
• The cervix opens during labor to allow the baby to pass through.
• The uterus returns to its normal size after childbirth.

Diagram:

uterus | |-- Upper part: Fundus |-- Middle part: Corpus |-- Lower part: Cervix | |-- Anteriorly: Bladder |-- Posteriorly: Rectum |-- Lateral: Broad ligament |-- Superior: Ovarian ligament and fallopian tubes |-- Inferior: Urethra and vagina

Flowchart:

Uterus → Uterosacral ligaments → Sacrum ↓ Uterovesical ligaments → Pubic symphysis ↓ Round ligaments → Labia majora ↓ Cardinal ligaments → Uterus and cervix ↓ Broad ligament → Uterus and ovary