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Anatomy of the Female Pelvis


Commonly Used Quadrant Terminology:
RUQ - Right Upper Quadrant
RLQ - Right Lower Quadrant
LUQ - Left Upper Quadrant
LLQ - Left Lower Quadrant
***Abdomen is divided by a sagittal plane crossing through midline at umbilicus and a transverse plane crossing through the abdomen at the level of the umbilicus


ANATOMY

Internal Organs:
  • Uterus
  • Fallopian Tubes
  • Ovaries
  • Vagina
  • Accessory Glands
  • Skene glands-paraurethral gland
  • Bartholin glands-on either side of vagina
  • Mammary glands- within the breasts

External Structures:
  • Mons Pubis- fatty prominence covering the symphysis pubis
  • Labia Majora- outer lips covering vaginal opening
  • Labia Minora- inner lips, smaller
  • Clitoris- lies below the junction of the labia majora
  • Linea Terminalis- imaginary line connecting superior sacrum to symphysis pubis, separates true and false pelvis
Greater/False Pelvis:
  • Above the pelvic brim
  • Communicates with the abdominal cavity
  • Contains sigmoid colon and ileum
  • Muscles
    • Rectus Abdominis - forms the anterior wall of abdominopelvic cavity, from xiphoid to symphysis pubis
    • Transverse Abdominis - form the anterolateral borders of the abdominopelvic cavity
    • Psoas Major - 2 muscles (left and right) originate in the lumbar vertebral region and extend to the iliac crests
    • Iliopsoas - psoas muscle connects with the iliacus muscle to form the iliopsoas muscle
Lesser/True Pelvis:
  • Below the pelvic brim
  • Formed by the bony bowl of the pelvic bones
  • Enclosed inferiorly by membranes and muscles
  • Contains uterus, vagina, fallopian tubes, ovaries, rectum and bladder
Pelvic Muscles in True Pelvis:
  • All muscles should be hypoechoic to the surrounding pelvic organs, some have visible striations
  • Levator Ani
    • Most inferior structure
    • Pubococcygeus and Iliococcygeus muscles together are referred to as the levator ani muscles
    • Connects the coccyx and the pubis bone
    • Forms the floor of the pelvis and has 3 openings for urethra, vagina and rectum
    • Pelvic diaphragm = levator ani + coccygeus muscles
    • Weakness in the levator ani muscles can lead to uterine or rectal prolapse
    • Can be identified on ultrasound imaging as the flat muscle extending laterally on both sides of the vaginal cuff
  • Obturator Internus
    • Located laterally at the acetabulum
    • Triangular sheet
    • Covers the anterior and lateral walls of the pelvis
  • Piriformis
    • Superior and lateral to the levator ani muscles
    • Originates from the both sides of the sacrum and they connect to the greater trochanters
    • Covers the posterior wall
    • Most commonly mistaken for ovaries on ultrasound imaging
  • Coccygeus
    • Forms the posterior portion of the pelvic wall
    • Originates from the coccyx
  • Psoas
    • Originates in the lumbar vertebral region
    • Connects with the iliacus muscle to form the iliopsoas muscle
  • Rectus Abdominis
    • Forms the anterior abdominal wall
    • Extends from the xiphoid process to the symphysis pubis
    • Linea alba separates the muscles in the midline of the abdomen, extends from xiphoid to pubis

Functions of the Pelvic Skeleton:
  • Provides a weight bearing bridge between the spine and ribs
  • Directs the pathway of the fetal head during childbirth
  • Protects reproductive organs
    • Innominate bones
      • AKA hip bones
      • Ischium
      • Ilium (the ileum is in the GI tract, the ilium is a pelvic bone)
      • Pubis
    • Sacrum
    • Coccyx
  • Bones are echogenic with posterior shadowing on ultrasound imaging
Pelvic Spaces:
  1. Anterior Cul-de-Sac:
    • Fold in the peritoneum between the anterior uterus and posterior bladder
    • AKA vesicouterine pouch
  1. Posterior Cul-de-Sac:
    • Fold in the peritoneum between the posterior uterus and anterior rectum
    • AKA rectouterine pouch or pouch of Douglas
    • Most dependent portion of the pelvis
    • Most likely location for pooling of free fluid
  1. Space of Retzius:
    • Anterior to bladder, posterior to symphysis pubis
    • Space between the transversalis layer and outer fascia of the peritoneum
    • AKA retropubic space
    • Not contiguous with abdominopelvic cavity
    • Very unusual for fluid collection
    • Usually contains fat
Ligaments:

Broad Ligaments:
  • NOT true ligaments
  • Wing like folds of the peritoneum extending from the uterine cornua to the lateral pelvic walls
  • Separates the pelvic cavity into anterior and posterior portions
  • Covers the anterior and posterior surfaces of the uterus
  • Encases most of the fallopian tubes and round ligament, ovarian ligament and vessels
  • Loosely positions the uterus in the pelvic cavity and supports the tubes and ovaries
    • Mesovarium - portion of the peritoneum connecting the anterior ovary to the posterior broad ligament; contains vessels
    • Mesosalpinx - free margin of the broad ligament where the fallopian tube travels; contains vessels
    • Adnexa - spaces within the peritoneal cavity that are posterior to the broad ligaments
  • Fluid in the pelvis (ascites) will cause the broad ligament to become visible Sonographically
Round Ligaments:
  • Fibromuscular bands extending from the uterine horns to the labia majora
  • Maintains normal uterine fundal position and provides structural support
  • Assists in the birthing process
Cardinal Ligaments:
  • AKA Transverse Cervical Ligament of Mackenrodt
  • Band of fibrous tissue and muscle
  • Extends from the upper lateral cervix to lateral pelvic wall
  • Contains the uterine and vaginal vessels
  • Determines the cervix position/orientation in the pelvis with the uterosacral ligaments
Uterosacral Ligaments:
  • Extend from the upper cervix to lateral sacrum
  • Determines the cervix position/orientation in the pelvis with the cardinal ligaments
Suspensory Ligaments:
  • AKA infundibulopelvic ligament
  • Folds of peritoneum that contain the ovarian vessels
  • Supports the fallopian tubes and ovaries within the pelvis
Ovarian Ligaments:
  • Positioned within the folds of the broad ligament
  • Support the medial aspect of the ovary and its position relative to the uterine cornua
  • Connect the medial ovary to the lateral uterine wall


The questions below are reading comprehension questions intended to help evaluate your retention of the material presented on the page. To access our registry exam practice questions or the CME post test, please refer to your login instructions for information on accessing the dedicated testing site (if your subscription included exam access).


Correct answer is "Skene glands-paraurethral gland, Bartholin glands-on either side of vagina, Mammary glands- within the breasts ".


Correct answer is "Linea terminalis".


Correct answer is "Rectus Abdominis".


Correct answer is "Levator Ani".


Correct answer is "levator ani and coccygeus".


Correct answer is "Hypoechoic to pelvic organs".


Correct answer is "Pouch of Douglas".


Correct answer is "Space of Retzius".


Correct answer is "Broad ligament".


Correct answer is "Adnexa".


Correct answer is "Uterosacral and cardinal".


Correct answer is "Ovarian".