Intro to Sacrum

Question 1

Bony anatomy of sacrum: sacral canal

Answer 1

contains cauda equina

Question 2

Bony anatomy of sacrum: sacral hiatus

Answer 2

defect near the apex where the lamina failed to close

site of sacral epidural nerve blocks injected

Question 3

Bony anatomy of sacrum: Coccyx

Answer 3

4 vertebrae, some fused some not
attached to sacral apex via sacrococcygeal joint
possesses the ganglion impar

Question 4

Bony anatomy of sacrum: ganglion impar

Answer 4

where right and left sympathetic chains meet on the surface of the coccyx

Question 5

male vs female sacrum characteristics: angle between ischial tuberosities

Answer 5

more than 90 deg in women, 90 or less in men typically

Question 6

male vs female sacrum characteristics: sacrum

Answer 6

tilted forward in men, tilted backwards in women

Question 7

male vs female sacrum characteristics: pelvic outlet

Answer 7

big pelvic outlet in women, small pelvic outlet in men

Question 8

sacral sulci: location

Answer 8

two bilateral palpable grooves medial and slightly superior to the PSIS

Question 9

True pelvic ligaments

Answer 9

anterior sacroiliac lig
posterior sacroiliac lig
interosseous sacroiliac lig

Question 10

Accessory pelvic ligaments

Answer 10

sacrotuberous lig
sacrospinous lig
ililumbar lig

Question 11

accessory lig =

Answer 11

ligs that attach to other ligs, tendons, or fascia

Question 12

True Pelvic Ligaments: Anterior/ventral sacroiliac ligament

Answer 12

flat bands

attach from 3rd sacral segment to preauricular surace of ilium

Question 13

True Pelvic Ligaments: interosseous sacroiliac ligament

Answer 13

massive bands attaching medial sacral crests to the iliac tuberosities

Question 14

True Pelvic Ligaments: Posterior/Dorsal sacroiliac ligament

Answer 14

thicker with multiple layers
connects PSIS to 3rd and 4th sacral segments
close anatomical relations with the erector spinae muscles

Question 15

Sacrotuberous ligament

Answer 15

attaches sacrum to ischial tuberosity

glut max and tendon of biceps femoris attach

has “Friend” lig: sacrospinous lig

both stabilize anterior motion, prevents posterior/superior rotation

Question 16

sacrospinous lig

Answer 16

friend lig: sacrotuberous lig
stabilizes anterior otion

divides space and below into a greater and lesser sciatic foramen

Question 17

iliolumbar ligament

Answer 17

attaches 4th/5th lumbar vertebra to iliac crests

stabilizes posterior motion, restricting anterior motion of L4/L5

upper part blends in with sacroiliac lig

Question 18

Primary muscles of the pelvic diaphragm

Answer 18

levator ani group and coccygeus muscle

Question 19

levator ani group

Answer 19

primary muscle of the pelvic diaphragm. includes pubococcygeus m., puborectalis m., iliococcygeus m.

Question 20

coccygeus mm.

Answer 20

primary pelvic diaphragm m.

Question 21

secondary muscles “considered to have partial attachments to the true pelvis”

Answer 21

rectus abdominis
transverse abdominis

internal and external oblique

quadratus lumborum

Question 22

Dural connections between cranium and sacrum

Answer 22

cranial dural attachment: foramen magnum, C1 and C2

sacral dural attachment: S2

Question 23

Force closure

Answer 23

holding an object by pressure on the sides

created by muscles, ligaments, and fascia surrounding the SI joint

Question 24

Form closure

Answer 24

“stacking” or the use of a roman artch as a self supporting structure

sacrum acts as the keystone of the arch, being wedged between the iliums

Question 25

Sacral forces

Answer 25

angle of the SI joint, wedge the sacrum in an anterior direction significant pelvic forces pushing posteriorly significant dorsal SI ligaments help counteract the major pelvic forces pushing posteriorly

Question 26

Sacral axes

Answer 26

2 oblique 3 transverse axises 1 anterior-posterior axis 1 vertical axis

Question 27

respiratory axis

Answer 27

transverse axis 1: Superior (SI axis) respiratory axis as well as nutation/counternutation at level of articular process of S2, attachment of the dura

Question 28

Postural/Sacroiliac axis

Answer 28

transverse axis 2: middle (S2 axis) axis for flexion/extension in sitting and standing at the level of the body of S2

Question 29

Iliosacral axis

Answer 29

transverse axis 3: inferior S3 axis at the level of the inferior pole of the lower sacral articulation axis for rotation of the iliums on the sacrum at the level of the inferior pole of the lower sacral articulation

Question 30

Right oblique axis

Answer 30

diagonal axis named for cephalad side runs from superiorly right to inferiorly left

Question 31

LEft oblique axis

Answer 31

named for cepehalad side runs superiorly on the left to inferiorly on the right

Question 32

"dynamic motion"

Answer 32

occurs on oblique axis

Question 33

inherent motion

Answer 33

superior transverse axis

Question 34

inhalation and sacral movement around superior axis

Answer 34

sacral base moves posteriorly with inhalation | decreases lordosis

Question 35

exhalation and sacral movement around superior axis

Answer 35

sacral base moves anteriorly with exhalation | increases lordosis

Question 36

postural motion in standing/seated positions around the middle transverse axis flexion vs extension

Answer 36

``` flexion = base moves anteriorly, apex posteriorly extension = base moves posteriorly, apex anteriorly ```

Question 37

inherent motion

Answer 37

occurs around superior axis SBS movement from the sphenobasilar joint/synchondrosis/symphysis joint between cranial bones is transferred to the sacrum via the dural connections during craniosacral extension, the sacral base moves anteriorly and the apex moves posteriorly during craniosacral flexion, the sacral base moves posteriorly and the apex moves anteriorly during craniosacral flexion

Question 38

craniosacral extension

Answer 38

during craniosacral extension, the sacral base moves anteriorly and the apex moves posteriorly

Question 39

craniosacral extension

Answer 39

during craniosacral extension, the sacral base moves anteriorly and the apex moves posteriorly

Question 40

what is the relation between craniosacral flexion/extension and postural flexion/extension?

Answer 40

there isn't one. entirely different

Question 41

nutation

Answer 41

sacral base moves anterior, sacral apex moves posteior | occurs with craniosacralSBS extension

Question 42

counternutation

Answer 42

sacral base moves posteriorly. sacral apex movex anteriorly occurs with craniosacral/SBS flexion

Question 43

Anterior palpatory landmarks

Answer 43

iliac crests greater trochanter ASIS public symphysis

Question 44

posterior palpatory landmarks

Answer 44

PSIS, Sacral base, sacral sulci, inferiolateral angles | ischial tuberositiy

Question 45

cranioflexion vs anatomical flexion

Answer 45

during craniosacral flexion, the sacral base moves posteriorly and the apex moves anteriorly during during postural (sacral, or anatomical) flexion, the base moves anteriorly and the apex moves posteriorly