STRUCTURE OF THE PELVIC WALL - Marshall University Anatomy... · STRUCTURE OF THE PELVIC WALL • Bones of the Pelvis – Sacrum – Coccyx – Innominate bone ... Pelvic diaphragm,

STRUCTURE OF THE PELVIC WALL

• Bones of the Pelvis– Sacrum

– Coccyx

– Innominate bone• Ilium, ischium, & pubis

– Joints & ligaments

• Divisions of the Pelvis– True & false pelvis

• Pelvic Inlet Measurements for Obstetrics

• Sexually Dimorphic Pelvis– Distinction between the female & male pelvis

• Walls of the True Pelvis

• Pelvic Diaphragm

• Endopelvic Fascia

• Lumbosacral Plexus

Netter’s Atlas of Human Anatomy 6th ed., Plate 243

Pelvis

Thoracic vertebrae

Lumbar vertebrae

Pelvis

Sacrum

Coccyx

Sacrum-anterior view

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 2.14A

Sacral

promontory

Ala

S1

S2

S3

S4

S5

Coccyx

Anterior sacral

foramen

Sacrum-posterior view

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 2.14B

Posterior sacral

foramen

Median sacral

crest

Sacral canal

Sacral hiatusCoccyx

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 4.200

Sacral hiatus

Sacral

promontory

Conus medullarisCauda equina

S1

S2

L5

Dural sac

Sacrum-epidural anesthesia injection into sacral canal

Coccyx

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 2.14

S1

S2

S3

S4

S5

Coccyx Coccyx

cornuacoccygeal transverse

process

Innominate (hip) bone

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 26.3A

Ilium

Pubis

Ischium

AnteriorPosteriorLateral view of innominate (hip) bone

Ilium

Pubis

Ischium

Acetabulum (hip socket)

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 16.3A (Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 16.3B

Anterior PosteriorMedial view of innominate (hip) bone

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 16.2B

Ilium

Pubic Tubercle

Ischial Spine

Iliac crest

Iliac fossa

Anterior Superior

Iliac Spine (ASIS)

Greater Sciatic Notch

Lesser Sciatic Notch

Ischial Tubercle

Ischial Ramus

Anterior Inferior

Iliac Spine (AIIS)

Netter’s Atlas of Human Anatomy 6th ed., Plate 473

Auricular Surface

Pubis

Obturator foramen

Pubic symphysis

Inferior ramus

Superior ramus

Body

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 16.5A

Pubic arch

Pelvic BrimAbove=false pelvis

Below=true pelvis

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 16.1

Lateral mass of sacrum

Arcuate line of

ilium

Pecten pubis

Pubic crest Pubic tubercle

Orientation of Pelvis

Gray’s Anatomy for Students, 3rd ed., Fig. 5.26

Sacroiliac Joint

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 26.3A

Sacroiliac joint

Sacroiliac Ligaments

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 16.10A, B

Posterior Sacroiliac

ligaments

Interosseous Sacroiliac

ligamentsAnterior Sacroiliac

ligaments

Sacroiliac Ligaments

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 16.11A, B

Posterior Sacroiliac

ligaments

Interosseous Sacroiliac

ligaments

Anterior Sacroiliac

ligaments

Anterior Sacroiliac

ligaments

Sacroischial Ligaments

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 16.10A, B

Sacrospinous

ligament

Sacrotuberous

ligament

Sacrotuberous

ligament

Sacrospinous

ligament

Greater sciatic

foramen

Lesser sciatic

foramen

Sacroischial Ligaments

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 16.11A, B

Sacrospinous

ligament

Sacrotuberous

ligament

Sacrotuberous

ligament

Sacrospinous

ligament

Greater sciatic

foramen

Lesser sciatic

foramen

Function of sacrotuberous and sacrospinous ligaments:Resistance to rotational forces

Essential Clinical Anatomy 4th ed., Fig. 3.5C

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 16.8

Pubic symphysis

Sacral promontory

Pelvic Measurements

Manual measurement

of diagonal conjugate

Inferior view of pelvis:

Transverse diameter

Transverse

diameter

Ischial

tuberosity

Pubic

symphysis

Sacrotuberous

ligament

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 16.7

Pelvic inlet and outlet: sex differences

Female Male

Sex differences of pelvis

MaleFemale

Pelvic inlet

Pelvic outlet

Pelvic cavity

Pubic arches

Obturator foramen

and membrane

(Gilroy et al.) Atlas of Anatomy 2nd ed., Figs. 16.10A, 16.11A

Sacrotuberous

ligament

Sacrospinous

ligament

Greater sciatic

foramen

Lesser sciatic

foramen

Obturator internus m.Sagittal section through pelvis

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 26.13

Obturator internus m.

Sacrotuberous

ligament

Sacrospinous

ligament

Lesser sciatic

foramen

Greater sciatic

foramen

Medial attachment: Inner surface of obturator membrane

Lateral attachment: Medial surface of greater trochanter

Innervation: Nerve to obturator internus (L5-S2)

Action: Laterally rotate extended thigh

Abduct flexed thigh

Piriformis m.

Obturator internus m.Posterior view

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 26.20

Obturator internus m.Quadratus femoris m.

Piriformis m.

Gemellus superior and

inferior mm.

Sacrotuberous

ligament

Piriformis m.

Ischial spine

Coccygeus m.

Greater sciatic

foramen

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 26.13A

Piriformis m.Posterior wall of true pelvis

Medial attachment: Pelvic surface of sacrum

Lateral attachment: Greater trochanter

Innervation: Nerve to Piriformis (S1-S2)

Action: Laterally rotate thigh

Abduct thigh

Piriformis m.Posterior view

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 26.20

Obturator internus m.Quadratus femoris m.

Piriformis m.

Gemellus superior and

inferior mm.

Sacrotuberous

ligament

Pelvic diaphragm:

coronal section

Pelvic

diaphragm

Perineum

Main pelvic

cavity

Rectum

Pelvic inlet

Anal canal

Pelvic diaphragm, inferior view

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 16.13B

Piriformis m.

2. Coccygeus m.

Obturator

internus m.

1. Levator ani mm.

Ischial spine

Ischial tuberosity

Coccygeus:

Medial attachment: Inferior end of sacrum

Lateral attachment: Ischial spine

Innervation: Nerve to coccygeus S3-S4

Action: Support pelvic viscera, flex coccyx

Pelvic diaphragm, inferior viewSubdivisions of Levator ani

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 16.13BCoccygeus m.

2. Pubococcygeus m.

1. Puborectalis m.

3. Iliococcygeus m.

Medial attachment: Tendinous arch

Lateral attachment: Coccyx, anococcygeal body

Innervation: Nerve to levator ani (S3-S4)

Action: Support pelvic viscera, resist changes in abdominal viscera

Pelvic diaphragm, sagittal section

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 16.13C

Piriformis m.

Coccygeus m.

Levator ani m.

Obturator internus m.

(obturator fascia)

Tendinous arch of

levator aniIschial spine

Pelvic diaphragm, midline structures

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 16.13B

Coccyx

Perineal body (raphe)

Anococcygeal body

(raphe)

Urogenital hiatus

Anorectal

hiatus

Pelvic diaphragm, superior view

Tendinous arch of

levator ani

Obturator internus m.

(obturator fascia)

Piriformis m.

Coccygeus m.

1. Puborectalis m.

2. Pubococcygeus m.

3. Iliococcygeus m.

(Gilroy et al.) Atlas of Anatomy 2nd ed., Fig. 16.13A

Anococcygeal body

(raphe)

Lumbosacral Plexus

Netter’s Atlas of Human Anatomy 6th ed., Plate 484

L2

L3

L4

L5

S1S2S3

Lumbar Plexus: T12-L5

Sacral Plexus: L4-S4

Green=Anterior Division

Yellow=Posterior Division

Sacral plexus on posterior pelvic wall

Lumbosacral trunk

Superior gluteal n.

Sciatic n.S5

S4

L4

L5

S1

S2

S3

Pudendal n.

Piriformis m.

Coccygeus m.

Levator ani

Gray’s Anatomy for Students, 3rd ed., Fig. 5.61

Netter’s Atlas of Human Anatomy 6th ed., Plate 486

Sacral plexus in situ

Obturator n.

Psoas

major m.

L4

L5

S1

S2

S3

Superior gluteal a. and n.

Inferior gluteal a.

Pudendal n.

Internal pudendal a.

Nerve to levator ani

Sacral plexus-Posterior Division

Netter’s Atlas of Human Anatomy 6th ed., Plate 486

S5

S4

L4

L5

S1

S2

S3

CoCommon fibular n. L4-S2

Superior gluteal n. L4-S1

Inferior gluteal n. L5-S2

Nerve to Piriformis S1-S2

Posterior femoral cutaneous n. S1-S3

Lumbosacral trunk

Sciatic n.

Sacral plexus-Anterior Division

Netter’s Atlas of Human Anatomy 6th ed., Plate 486

S5

S4

L4

L5

S1

S2

S3

CoTibial n. L4-S3

Nerve to quadratus femoris m.

and inferior gemellus m. L4-S1

Nerve to obturator internus m.

and superior gemellus m. L5-S2

Posterior femoral cutaneous n. S1-S3

Lumbosacral trunk

Pudendal n. S2-S4

Nerve to levator ani and coccygeus m. S3-S4

Sciatic n.