The document summarizes the anatomy of the pelvis. It describes the bones that form the pelvic walls, including the hip bones, sacrum, and coccyx. It outlines the joints of the pelvis and ligaments supporting it. Key structures like the pelvic inlet, outlet, and cavity are defined. Muscles of the pelvic floor and lateral pelvic wall are identified. Blood vessels like the internal iliac and median sacral arteries are noted. Finally, the sacrum, nerves of the sacral plexus, and sympathetic trunk are briefly described.

1. PELVIS

2. Formation of the pelvic wall
1- BONES:
a.2 hip bones: front and sides
b. Sacrum and coccyx: posteriorly.
2- 4 JOINTS:
.a
a. Pubic symphysis: secondary cartilaginous joint.
b. Lumbosacral joint: 2ry cartilaginous joint.
c. Sacrococcygeal joint:2ry cartilaginous joint.
d.Sacroiliac joint : plane synovial joint.

3. 3-LIGAMENTS:
a. Sacrotuberous ligament.
B. Sacrospinous ligament.
4-MEMBRANES:
a. Perineal membrane: between the pubic arches
B. Obturator membrane: across the obturator
foramen.
5- MUSCLES:
a. Side wall: obturatour internus and piriformis.
b. Floor (pelvic diaphragm): levetor ani and
coccygeus

7. Pelvic inlet (Pelvic Brim):bounded by
1. Anterior: upper border of pubic symphysis.
2.Posterior:
a. Sacral promontory (in middle).
B. Ala of the sacrum (on each side).
3.Sides: iliopectineal line (arcuate line &pectineal
Line.

9. Pelvic Outlet: diamond shaped and bounded by
1.Anterior: lower border of pubic symphysis.
2.Posterior: tip of the coccyx.
3.Sides:
a. pubic arch: anterior
b. Ischial tuberosity: middle
C. Sacrotuberous ligament: posterior.

11. Pelvic Cavity:
It is divided by the pelvic inlet into:
1.False pelvis: above the pelvic inlet and contains
abdominal viscera.
2.True pelvis: between the inlet and the outlet and
contains the pelvic organs.

13. Sacrum
•
-It is formed of 5 sacral vertebrae fused together at puberty.
•
-they are separated by 4 sacral foramina (4 Ant &4post).
•
-The body of the first sacral vertebra projects anteriorly to form
the sacral promontory.
•
-The lateral part of the first sacral vertebra is called ala of the
sacrum.

14. The sacrum has:
1.Pelvic surface: concave and has 4 anterior sacral
foramina.
2. Dorsal surface: irregular and presents :
a.Median sacral crest: formed by the fused spines.
b. Sacral haitus: gap in the posterior wall of the sacral
canal opposite S5.
c. Sacral cornu: projection on each side of the sacral
haitus.
d.4 posterior sacral foramina: transmit dorsal rami of
sacral nerve.

16. 3. Lateral surface : ( articular surface )
a. Articulate with the ilium of the hip bone to form
the sacroiliac joint.
b. It extends to S2 in the female and S3 in the male.
4.Sacral canal :continuation of the vertebral canal.
Articulation of the Sacrum:
a. Lumbosacral joint(L5 &2ry cartilaginous joint)
b. Sacrococcygeal joint(coccyx & 2ry cartilaginous)
c. Sacroiliac joint(ilium& plane synovial joint)

17. Relation of pelvic surface of the sacrum:
3 Muscles:
iliacus ,piriformis, coccygeus
3Arteries:
-median sacral artery along the midline.
-lateral sacral arteries enter the anterior sacral foramina.
-Iliolumbar artery ascends on the ala of the sacrum
4 Nerves:
-sympathetic chain(mediam margin of sacral foramina)
-upper4sacral nerves(ant sacral foramina)
-lumbosacral trunk &Obturator nerve.

18. Rectum : in front of lower 3 pieces of the sacrum.
Relations of the Ala of Sacrum
1. Origin of iliacus muscle
2. Lumbosacral trunk.
3.Obturator nerve .
4.Iliolumbar artery between 2 nerves.

20. Structure passing through the sacral canal
1.Filum terminal : continuation of the pia matter.
2.Cauda equine: roots of the sacral &coccygeal
nerve.
3.Dura & arachnoid matter : end at the 2cd sacral
vertebra.
4.Branches of lateral sacral arteries.
5.Venous plexus
6, fat

22. Structure passing through the sacral hiatus
1. filum terminale to be attached to the back of
coccyx .
2.fifth sacral nerve on each side.
3. coccygeal nerve: on each side.

24. Differences between male and female sacrum
male
female
Longer &narrower
Shorter &wider
Length & width
More projection
Less projection
Sacral
promontory
Nearly straight
Sharply curved
forward at S3
Curved or straight
Reaches s3
vertebra
Reaches S2
vertebra
Articular surface

25. Differences between male and female pelvis
male
Female
smaller
larger
size
Narrower & heart
shaped
Wider &circular
Pelvic inlet
narrower
Wider
Pelvic outlet
Narrower& longer
Wider & shorter
Pelvic cavity
narrower
wider
Great sciatic notch
Narrower 60
Wider 90
Subpubic angle
Nearly straight
Curved at S3
Curve of the sacrum

27. Muscle of the lateral wall of the pelvis
Action
innervation
insertion
origin
Lateral rotation of
the hip joint
Nerve to obturator
internus
Medial surface of
great trochanter
Inner surface of
obturator
membrane
&surrounding
bone
Obturator
internus
same
S1&S2 nerves
Upper border of
the great
trochanter
Anterior surface of
the middle 3 pieces
of the sacrum
piriformis

29. Muscle of pelvic floor(pelvic diaphragm)
•
-the pelvic diaphragm separates the pelvic cavity from the perineum
•
-the pelvic diaphragm is formed of 2 muscle:
•
1.Levator ani: main component
•
2.coccygeus:along the pelvic surface of the sacrospinous ligament.
•
Has 2 hole :
•
1.the urogenital hiatus: anterior for the passage of the urethra and the
vagina .
•
2.the anal hiatus : posteriorly for the passage of anal canal.

30. Levator Ani Muscle
•
-origin:
•
1.Anterior:pelvic surface of the body of pubis.
•
2.Side:white line of fascia of obturator internus(tendinous arch).
•
3.posterior:the ischial spine.
•
Insertion:
•
1.perineal body.
•
2.Around the anal canal.
•
3.Anococcygeal body(between coccyx& anal canal).
•
Nerve supply: S2,3,4,5
•
1.upper surface (pelvic ):S4 and S5.
•
2.lower surface (perineal):inferior rectal from pudendal nerve S2,3,4

32. Action of levator ani:
•
1. support the pelvic viscera
•
2.Resist increase in intra-abdominal pressure during coughing or
lifting heavy objects.
•
3.Urinary and fecal continence.
•
4.pubovaginalis(sphincter vaginae): sphincter of vagina.
•
5.levator prostate: support the prostate.
•
Parts of levator ani:
•
1.puborectalis:the anterior (medial )fibers.
•
2.pubococcygeus:the middle fiber (lateral to puborectalis).
•
3.iliococcygeus: the posterior fibers.

33. ARTERIES OFTHE PELVIS
•
1.Superior rectal artery:
-it is continuation of the inferior mesenteric artery in front of The
middle of the left common iliac artery.
•
- it supplies the rectum and upper half of anal canal.
•
2.Ovarian artery:
•
-it arises from the abdominal aorta opposite L2.
•
-it enters the suspensory ligament of ovary ( the infundibulopelvic
ligament) then passes in the mesovarium to supply the ovary and
uterine tube.

35. 3. Median sacral artery:
-arises from the back of the abdominal aorta opposite L4.
-It ends in front of the coccyx in a fibrocellular body called
glomus coccygeum.
-Branches:
a. fifth lumber artery.
b. branches to the rectum and sacral canal.
- the median sacral vein end in the left common iliac vien.

37. 4. internal iliac artery:
-Origin: one of the 2 terminal branches of the common iliac artery in front of the sacroiliac
joint.
-Termination: divides into anterior and posterior divisions.
-Branches:
a. posterior division: all branches are parietal branches (to body wall)
-iliolumbar artery.
-lateral sacral arteries .
-superior gluteal artery.
b. Anterior division : give 3 parietal and 3 visceral in male or 4in female
-parietal branches:1.obturator artery 2.internal pudendal artery 3.inferior gluteal artery
-Visceral Branches: 1.umbilical artery 2.middle rectal artery .
3. inferior vesical artery in male or vaginal artery in female
4.uterine artery in female.

39. Nerves of the pelvis
-SACRAL PLEXUSES:
Formed by lumbosacral trunk (L4 &L5 ) and the ventral rami of upper 4sacral
nerves ( S1 & S4).
-Important branches:
1. Muscular branches : to levator ani ,coccygeus , piriformis and obturator internus.
2.Branches to gluteal region.
3.pelvic splanchnic nerves (S2, S3 & S4):carry parasympathetic fibers to supply the
hindgut and the pelvic organs.
4. 2Terminal branches:
a. Sciatic nerve: to the lower limb.
b. pudendal nerve(S2 ,S3,& S4): to the perineum and external genitalia.

41. Sympathetic chain
-Descends on the pelvic surface of the sacrum medial to the
anterior
Sacral foramina.
-Each trunk (chain) has 4 ganglia.
-The 2 trunk end in one ganglion in front of the coccyx called
ganglion
Impar.
-it gives sympathetic fibers to pelvic plexus , pelvic organs and
lower limb.

43. Thank you