The Pelvis & Pelvic Organs I & II
All images are sources from the following texts, unless otherwise noted:
• Clinically Oriented Anatomy, 8th Ed. Moore, Dalley, &
Agur. LWW. 2018.
• Atlas of Human Anatomy, 6th Ed. Netter & Saunders.
2014.
• Atlas of Anatomy, 2nd Ed. Gillroy, McPherson, & Ross.
Thieme. 2012.
• Gray’s Anatomy for Students, 3rd Ed. Drake, Vogl, &
Mitchell. Elsevier. 2015.
Session Objectives
1.Identify the osseous, ligamentous, and muscular anatomy of the pelvis, and how
different tissue layers contribute to the compartmentalization of this region
2.Detail the attachments, actions, and innervation of the musculature of the pelvic
walls and pelvic diaphragm
3.Describe the structural anatomy and distinguishing features of each pelvic organ
and their functional relevance in males and females
4.Detail the arterial supply, venous drainage, lymphatic drainage, and innervation of
the pelvic organs
5.Describe common clinical disorders associated with various pelvic organs in both
males and females
Pelvic Cavity
Pelvic Cavity
• Funnel-shaped cavity
• Bounded by ligaments, bone,
muscles
• Pelvic Diaphragm (“floor”)
• Pelvic Wall
• Perineum
Pelvic Cavity
Pelvic Diaphragm:
• Coccygeus (n. to coccyges
S3-S4)
• Levator ani (n. to levator
ani S3-S4)
• Puborectalis
• Pubococcygeus
• Iliococcygeus
Levator ani
Superior View • Anterolateral wall of pelvic diaphragm
• “sling”
• Support for organs
• Urinary & fecal continence
Levator ani
Puborectalis
• U-shaped sling around
anorectal canal
• Maintains anorectal angle
(fecal continence)
• Bounds urogenital hiatus
Pelvic Diaphragm
Levator ani
Inferior View
Pelvic Cavity
Pelvic Wall: (muscles of the hip)
• Piriformis (anterior rami S1-S2)
• Obturator internus (n. to obturator internus L5-S2)
The Perineum
• Anal triangle
• Urogenital triangle
The Pelvis
Functions:
• Bears weight of
upper body
• Contains & protects
pelvic organs
• Support for
abdominopelvic
organs
• Attachment for
erectile bodies of
external genitalia
The Pelvis
The Pelvis
The Pelvis
The Pelvis
Greater (False) Pelvis
Lesser (True) Pelvis
• Pelvic Brim
• Pelvic Inlet
• Pelvic Outlet
• Perineum
The Pelvis
Female
Male
Joints
• Sacro-iliac
• Pubic symphysis
• Lumbosacral
• Sacrococcygeal
• Reinforced by ligaments
Pelvis: Ligaments & Spaces
Ligaments:
• Anterior Sacro-iliac
• Interosseous Sacro-iliac
• Posterior Sacro-iliac
• Iliolumbar ligaments
• Sacrotuberous
• Sacrospinous
Foramen/Spaces:
• Sciatic foramen
• Greater Sciatic foramen
• Lesser Sciatic foramen
Pelvis: Ligaments & Spaces
Pelvis: Ligaments & Spaces
Pelvic Peritoneum
• Peritoneum continues into superficial pelvic cavity (ends before pelvic diaphragm)
• Reflects onto superior surface of viscera
• Forms peritoneal folds & fossae (differ between males & females)
Pelvic Peritoneum
Females:
Males:
• Supravesical fossa • Supravesical fossa
• Rectovesical pouch • Vesico-uterine pouch
• Ureteric fold • Broad ligament
• Recto-uterine pouch (of Douglas)
Pelvic Pain Line
• Inferior limit of peritoneum
• Structures superior to PPL
• Visceral afferent fibers follow
sympathetic pathways to T11-L2
spinal ganglia
• Structure below PPL
• Visceral afferent fibers follow
parasympathetic pathways to S2-
S4 spinal ganglia
Somatic Innervation
• Anterior surface of piriformis
• Sacral plexus (L4-S4)
• Coccygeal plexus (S4-S5)
• Obturator n. (L2-L4)
Somatic Innervation
Sacral plexus (L4-S4):
• Sciatic n. (L4-S3)
• Pudendal n. (S2-S4)
• Motor branches to muscles of
gluteal region, pelvic wall,
pelvic floor, skin
Somatic Innervation
Sciatic n. (L4-S3)
• Greater sciatic foramen
inferior to piriformis
• Posterior lower limb
Somatic Innervation
Pudendal n. (S2-S4)
• Greater sciatic foramen
inferior to piriformis
• Under sacrospinous ligament
• Enter Lesser sciatic foramen
• Primary somatic nerve of
perineum
• Sensory to external genitalia
Somatic Innervation
Obturator n. (L2-L4)
• Into lesser pelvis via obturator
canal
• Medial thigh
• No pelvic structures supplied
Somatic Innervation
Coccygeal plexus: (S4-S5 &
coccygeal n.)
• Join to form anococcygeal
nerves
• Coccygeus
• Levator ani (part)
• Sacrococcygeal joint
• Skin in anal triangle
Lymphatic Drainage of Pelvic Cavity
• Most viscera drain into nodes along
internal & external iliac arteries & their
branches, to common iliac, to
abdominal aorta, to lumbar trunks, to
thoracic duct
Lymphatic Drainage of Pelvic Cavity
• Most viscera drain into nodes along
internal & external iliac arteries & their
branches, to common iliac, to
abdominal aorta, to lumbar trunks, to
thoracic duct
Blood Supply
6 main branches in Female; 4 main
branches in Males
1. 2 Internal Iliac aa.
2. Median Sacral a.
3. Superior Rectal a.
4. 2 Ovarian aa. (Females)*
(Testicular aa. enter inguinal canal; not
pelvis)
Blood Supply- Internal Iliac Arteries
• Anterior & Posterior divisions
• Posterior division supplies
posterior abdominal wall,
posterior pelvic wall, gluteal
region
• Anterior division supplies pelvic
viscera, perineum, gluteal
region, adductor region
Blood Supply- Internal Iliac Arteries
Posterior division:
• Iliolumbar aa.- Psoas major,
quadratus lumborum, iliacus,
ilium
• Lateral Sacral aa.- spinal
meninges, sacrum, skin over
sacrum, erector spinae m.
• Superior Gluteal aa.- muscles &
skin in gluteal region
Blood Supply- Internal Iliac Arteries
Anterior Division
• Umbilical a.
• Obturator aa.
• Inferior Vesicle aa./ Vaginal aa.
• Uterine aa. (females)
• Middle Rectal aa.
• Internal pudendal aa.
• Inferior Gluteal aa.
Blood Supply- Ovarian Arteries
• Abdominal aorta
• Ovarian branch (ovaries) &
tubal branch (uterine tubes)
Blood Supply- Medial Sacral Artery
• Abdominal aorta
• Anastomose with lateral sacral aa.
Blood Supply- Superior Rectal Artery
• Continuation of IMA
• Supply rectum to internal anal
sphincter
Autonomic Innervation of the Pelvis
• Sympathetics inhibit peristalsis in rectum & stimulate
internal genitalia during (ejaculation)
• Parasympathetics stimulate peristalsis in rectum &
bladder (defecation & micturition) & inhibit internal
genitalia (erection)
Autonomic Innervation of Urinary Organs
• Pre-synaptic sympathetic fibers exit
trunks via lesser (T10-T11), least (T12),
lumbar (L1-L2) splanchnic, nn.
• Synapse with peri-arterial ganglia
(aorticorenal)
• Post-synaptic sympathetic fibers via renal
& ureteral plexuses (renal arteries) to
kidneys, suprarenal glands, proximal
ureters
• Parasympathetic fibers via Vagus n.
Autonomic Innervation of Urinary Organs
• Pre-synaptic sympathetic fibers exit
trunks via lumbar (L1-L2) splanchnic nn.
• Synapse with inferior mesenteric ganglion
• Post-synaptic sympathetic fibers via the
superior hypogastric plexus to join inferior
hypogastric plexus to urinary bladder,
distal ureters, seminal glands, prostate
• Parasympathetic fibers via pelvic
splanchnic nn. (S2-S4) to join inferior
hypogastric plexus
Autonomic Innervation of Pelvic Organs & Rectum
• Pre-synaptic sympathetic fibers exit
trunks via lesser (T10-T11), least (T12), &
lumbar (L1-L2) splanchnic nn.
• Synapse with superior mesenteric
ganglion
• Post-synaptic sympathetic fibers via the
superior hypogastric plexus to join inferior
hypogastric plexus to middle & lower
rectum & pelvic viscera
• Parasympathetic fibers via pelvic
splanchnic nn. (S2-S4) to join inferior
hypogastric plexus
Pelvic Organs
Ureters & Urinary Bladder
• Hallow muscular tubes
• Retroperitioneal
• Arterial supply is variable
• Superior to pelvic pain line
• Pain referred to ipsilateral lower
abdominal quadrant
Urinary Bladder
Ureters & Urinary Bladder
• Subperitoneal
• Temporary reservoir for urine
• 4 surfaces:
• Superior, Posterior, 2
Inferolateral
• 4 parts:
• Apex
• Fundus
• Body
• Neck
• Detrusor muscle
Urinary Bladder
• Ureteric orifices & Internal urethral
orifices at trigone
• Encircled by detrusor musculature-
tightens & prevents reflux of urine
• Males: involuntary urethral
sphincter
• Contracts during ejaculation
• Prevents reflux of semen into
bladder
Urinary Bladder
• Arterial supply by branches of
internal iliac a.
• Venous drainage parallels arteries
to internal iliac v.
• Mostly below pelvic pain line
(except superior surface covered by
peritoneum)
Male Urethra
• Muscular tube- transmits urine &
semen
• Internal urethra orifice (bladder) to
external urinary orifice (penis)
• 4 parts:
• Intramural (preprostatic) part
• Prostatic urethra
• Intermediate (membranous) part
• Spongy urethra
Female Urethra
• Urine from internal urethral orifice
to bladder
• No internal urethral sphincter
• Para-urethral glands
• Arterial supply by internal pudendal
& vaginal arteries
