Ha 37 - Intact Pelvis

Front 1

Bony Pelvis

Back 1

formed by left and right hip bones, the sacrum and the coccyx, divided by the pelvic brim into Pelvis major (false) and Pelvis minor (true)

Front 2

Pelvis Major

Back 2

False pelvis - a large, bowl-shaped superior portion of the pelvis

Front 3

Pelvis Minor

Back 3

True pelvis - a smaller, cone-shaped inferior portion

Front 4

Hip (innominate) bones

Back 4

Ilium, pubis and ischium, the union of these 3 parts takes place in the walls of the acetabulum (head of femur articulates here)

Front 5

Articulations of the pelvis

Back 5

all but pubic symphysis are synovial joints
1. Sacroiliac joint
2. Pubic symphysis - cartilaginous joint
3. Joins vertebral column at the intervertebral disk between LV5 and sacrum (supported by iliolumbar ligament)
4. Sacrotuberous ligament
5. Sacrospinous ligament

Front 6

Sacroiliac joint

Back 6

Between rough articular surfaces of sacrum and ilium. 3 parts:
a. ventral sacroiliac ligament - thickening of capsule anteriorly especially near the arcuate line
b. interosseous sacroiliac ligament - massive and strong, forms chief bond between the bones
c. Dorsal sacroiliac ligament - between sacrum and ilium posteriorly; relatively weak

Front 7

Pelvic basin (total pelvis)

Back 7

Made up of pelvic brim, pelvis major, pelvis minor, pelvic outlet

Front 8

Pelvic brim

Back 8

oval-shaped rim of bone. Made up of:
superior aspect of the symphysis pubis
crest of the pubic bone
pecten pubis
arcuate line of the ilium, ala of the sacrum
sacral promontory
(surrounds the pelvic inlet - the superior aperture of the true pelvis)

Front 9

Pelvis major

Back 9

Greater pelvis, false pelvis
lies superior to the pelvic brim and is considered the inferior extent of the abdominal cavity. Bounded by:
LV5 and SV1 vertebrae posteriorly
Abdominal wall anteriorly
iliac fossa laterally

Front 10

Pelvis minor

Back 10

true pelvis/lesser pelvis
lies inferior to the pelvic brim, limited superiorly by superior pelvic aperture
inferiorly by inferior pelvic aperture
posteriorly by sacrum and coccyx
laterally by ischial spine, parts of ischium body, obturator internus muscle, sacrotuberous and sacrospinous ligaments

Front 11

Pelvic outlet

Back 11

inferior aperture of the true pelvis
Bounded by the inferior aspect of: symphysis pubis, ischiopubic rami, ischial tuberosities, sacrotuberous ligaments, coccyx

Front 12

Female vs. Male pelvis

Back 12

Female - wider, less prominent markings, wide circular pelvic inlet, wider pubic angle.
Male - more oval inlet, shorter distance between ischial spines, narrower

Front 13

Obturator foramen

Back 13

oval aperture surrounded by the body and rami of the pubis and the ischium. Lays inferomedial to the acetabulum and nearly closed by a thin aponeurosis - obturator membrane. Covered internally by the obturator internus muscle (serves as partial origin for the muscle). Membrane is incomplete at the obturator canal - opening for the exit/entrance of obturator nerve and vessels

Front 14

Greater sciatic notch

Back 14

Indentation of the ilium and ischium above the ischial spine. Becomes greater sciatic foramen by sacrotuberous and sacrospinous ligaments

Front 15

Structures passing through greater sciatic foramen

Back 15

Piriformis muscle tendon
nerves of the sacral plexus
branches of the internal iliac vessels

Front 16

Lesser sciatic notch

Back 16

indentation of the ischium below the ischial spine & converted to a foramen by the sacrospinous and sacrotuberous ligments

Front 17

Structures passing through Lesser sciatic foramen

Back 17

Obturator internus muscle exits the pelvis into the gluteal region
internal pudendal vessels and pudendal nerve

Front 18

Muscles of the pelvis - groupings

Back 18

Muscles of lateral wall: piriformis and obturator internus muscles
Muscles of pelvic floor - 2 levator ani muscles, 2 coccygeus muscles and their fasciae (form pelvic diaphragm)

Front 19

Piriformis muscle

Back 19

o: with pelvic cavity from anterior aspect of the sacrum and sacrotuberous ligament
i: leaves pelvis via greater sciatic foramen and passes posterior to head of femur and inserts on superior border of the greater trochanter of the femur
in: ventral rami of S1 and S2 spinal nerves
a: lateral rotator and ABductor, holds head of femur in acetabulum

Front 20

Obturator internus muscle

Back 20

o: internal surface of the margins of the obturator foramen and the obturator membrane
i: merge as a strong tendon and pass thru lesser sciatic foramen, makes right angle turn posterior to hip joint and inserts on medial surface of the greater trochanter
in: nerve to the obturator internus from the sacral plexus (L5, S1, S2 from sacral plexus)
a: laterally rotates thigh, helps hold femoral head in the acetabulum