Anatomy of the Pelvis

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Major components of the bony pelvis, frontal superior view
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Major ligaments and notches of the female pelvis, posterior view of the female pelvis
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Muscles of the pelvic diaphragm, oblique view
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Muscles of the pelvic diaphragm, superior view
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Muscles of the pelvic diaphragm, inferior view
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Fascial and peritoneal relationships of the pelvic diaphragm
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Muscles of the deep perineal space, inferior view
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Muscles of the superficial perineal space, from below
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Ischiorectal fossa, frontal section
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Ischiorectal fossa and urogenital diaphragm, sagittal section
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External anal sphincter as viewed in dorsal lithotomy position
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Cutaneous nerve supply to the perineum
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Superficial perineal blood supply and nerves as viewed in dorsal lithotomy position
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Vessels and nerves of the deep perineal space
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Major organs of the pelvis, sagittal section
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Anatomy of the fallopian tube and ovary, posterior view
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Anatomic regions of the uterus, lateral view
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Anatomic relationships of the uterus, lateral view
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Broad ligament and contained organs, frontal view
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Organs of the pelvis, posterior view
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Major vessels of the pelvis, frontal view
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Major vessels of the pelvis, lateral view
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Blood supply to the uterus, fallopian tube, and ovary
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Blood supply to the vagina
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Major lymphatics of the pelvis
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Major nerves of the pelvis, lateral view
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Afferent innervation of the female genital tract
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Changes in the uterus with age and parity
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Changes in the uterus caused by pregnancy and parturition

* Figures for Appendix II are available at ExpertConsult.com .

Key Points

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To facilitate childbearing, the female pelvis—as opposed to the male pelvis—is characterized by a wider subpubic angle, increased width of the sciatic notch, and greater distance from the symphysis pubis to the anterior edge of the acetabulum.
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The levator ani, the major supporting structure for the pelvic viscera, is a tripartite muscle mass composed of the iliococcygeus, pubococcygeus, and puborectalis; the iliococcygeus is the broadest and most posterior portion.
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Innervation of the levator ani is through the third and fourth sacral nerves.
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The major nerve supply of the perineum is derived from the pudendal nerve. However, the ilioinguinal, genitofemoral, perineal branch of the posterior femoral cutaneous, coccygeal, and last sacral nerve also contribute; thus a pudendal nerve block anesthetizes only a portion of the perineum.
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The internal iliac (hypogastric) artery arises at the level of lumbosacral articulation. It can be distinguished from the external iliac by its smaller size and by its more medial and more posterior position.
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The ureter lies more superficially and is either medial or slightly anterior to the internal iliac artery.
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The cardinal ligaments are located at the base of the broad ligament and are continuous with the connective tissue of the parametrium; they are attached to the pelvic diaphragm through continuity with the superficial superior fascia of the levator ani.
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Because the origin of the uterine artery is variable, its isolation and ligation for control of postpartum bleeding are often fruitless. The uterine artery usually arises as an independent vessel from the internal iliac artery, but it may also arise from the inferior gluteal, internal pudendal, umbilical, or obturator arteries.
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Afferent pain fibers for the uterus, tubes, and ovary enter the cord at T10, T11, and T12; thus spinal or epidural anesthesia must extend to these levels. Fortunately, efferent fibers to the uterus enter above these levels and thus do not interfere with contractions.
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The body of the nonpregnant uterus weighs approximately 70 g, whereas at term it weighs approximately 1100 g.