INTERNAL MEDICINE SERIES OMM LECTURE Sacrum and Innominates Julia Faller, D.O., PGY1.

INTERNAL MEDICINE SERIES

OMM LECTURE

Sacrum and Innominates

Julia Faller, D.O., PGY1

ANATOMY

Innominate: 3 bones; ilium, ischium and pubis

Sacrum: 5 fused vertebrae

Sacral base: top part of the sacrum

Sacral promontory: anterior portion of 1st segment

Sacral apex: bottom part of the sacrum

Sacral sulci: superior lateral part of sacrum

Inferior lateral angles (ILA’s): inferior lateral part of sacrum

ANATOMY

LIGAMENTS

True pelvic ligaments: sacroiliac ligaments that surround and help stabilize the SI joint Anterior Posterior Interosseous

LIGAMENTS

Accessory pelvic ligaments Sacrotuberous—originates at ILA and attaches

to ischial tuberosity Sacrospinous—originates at sacrum and

attaches to ischial spines Iliolumbar—originates from transverse

processes of L4 and L5 and attaches to medial side of iliac crest

LIGAMENTS

Board Points

The sacrospinous ligament divides the greater and lesser sciatic foramen

The iliolumbar ligament is often the first ligament to become painful in lumbosacral decompensation

MUSCLES

Primary pelvic muscles: levator ani and coccygeus (pelvic diaphragm)

Secondary: muscles that have partial attachment to the true pelvis Iliopsoas Obturator internus Piriformis

Clinical Point

Approximately 11% of the population will have the entire peroneal portion of the sciatic nerve running through the belly of the piriformis.

Piriformis hypertonicity can cause buttock pain that radiates down the thigh, but not usually below the knee.

MECHANICS

Innominates: rotate about an inferior transverse axis of the sacrum during the walking cycle.

Sacrum: four types of motion Respiratory Craniosacral Postural Dynamic

RESPIRATORY AXIS

Respiratory motion occurs about the superior transverse axis of the sacrum.

Located at S2

During inhalation the sacral base moves posterior.

During exhalation the sacral base moves anterior

RESPIRATORY AXIS

CRANIOSACRAL AXIS

Motion occurs about the superior transverse axis of the sacrum

AKA inherent motion

During craniosacral flexion the sacral base rotates posteriorly, counernutation

During craniosacral extension the sacral base rotates anteriorly, nutation

CRANIOSACRAL AXIS

POSTURAL AXIS

Motion occurs about the middle transverse axis of the sacrum.

As a person begins to bend forward, the sacral base moves anteriorly.

At terminal flexion the sacrotuberous ligaments become taut and the sacral base will move posteriorly.

POSTURAL AXIS

OBLIQUE AXIS

Motion that occurs during ambulation.

Dynamic motion

As weight bearing shifts from one side to the other while walking, the sacrum engages two sacral oblique axes.

Stepping forward with the right leg will cause a left sacral axis to be engaged.

OBLIQUE AXIS

INNOMINATE DYSFUNCTION

The side of the positive standing flexion test is the side of the dysfunction.

Types: Anterior/posterior rotation Superior/inferior innominate shear Superior/inferior pubic shear Inflare/outflare


Anterior innominate rotation: one innominate will rotate anteriorly

Inferior transverse axis

Tight quadriceps

ASIS inferior/PSIS superior

Longer leg ipsilaterally

ASIS restricted to compression

ANTERIOR INNOMINATE


Posterior innominate rotation: one innominate will rotate posteriorly

Inferior transverse axis

Tight hamstrings

ASIS superior/PSIS inferior

Shorter leg ipsilaterally


POSTERIOR INNOMINATE


Superior innominate shear: one innominate will slip superiorly

ASIS and PSIS superior

Pubic rami superior

Short leg ipsilaterally


SUPERIOR INNOMINATE SHEAR


Inferior innominate shear: one innominate will slip inferiorly

ASIS and PSIS inferior

Pubic rami inferior

Long leg ipsilaterally


INFERIOR INNOMINATE SHEAR


Superior pubic shear: one pubic bone is displaced superiorly compared to the other

Trauma or tight rectus abdominus

ASIS/PSIS level

Pubic bones superior ipsilaterally


SUPERIOR PUBIC SHEAR


Inferior pubic shear: one pubic bone is displaced inferiorly compared to the other

Trauma or tight abductors

ASIS/PSIS level

Pubic bones inferior ipsilaterally


INFERIOR PUBIC SHEAR


Innominate inflare: innominate rotates laterally

ASIS more lateral ipsilaterally therefore the distance between the ASIS and umbilicus is greater on the affected side

Ischial tuberosity more medial ipsilaterally

ASIS restricted to compression ipsilaterally


Innominate outflare: innominate rotates medially

ASIS more medial ipsilaterally therefore the distance between the ASIS and umbilicus is less on the affected side

Ischial tuberosity more lateral ipsilaterally

ASIS restricted to compression ipsilaterally

SACRAL DYSFUNCTION

Three types of dysfunction Sacral torsion on an oblique axis Sacral shear (unilateral sacral

flexion/extension) Bilateral sacral flexion/extension

SACRAL TORSION

Sacral rotation about an oblique axis along with somatic dysfunction at L5

The axis is named for the side of the superior pole it runs through

SACRAL TORSION RULES

When L5 is sidebent, a sacral oblique axis is engaged on the same side as the sidebending

When L5 is rotated, the sacrum rotates the opposite way on an oblique axis

The seated flexion test is positive on the opposite side of the oblique axis

Board Points

Know the rules of L5 on the sacrum

MOTION OF TORSIONS

Motion present over the part of the sacrum that moved anteriorly

Motion restricted over the part of the sacrum that moved posteriorly

Motion restricted over the poles that make up the oblique axis

SACRAL TORSION

Forward sacral torsion AKA anterior sacral torsion.

Rotation is on the same side of the axis.

Left on left/right on right

Negative lumbosacral spring test

SACRAL TORSION: L on L

Left on left

Right sulcus deeper

Left ILA posterior and inferior

Lumbar curve convex to the right

Motion at right base only

SACRAL TORSION: R on R

Right on right

Left sulcus deeper

Right ILA posterior and inferior

Lumbar curve convex to the left

Motion at left base only

SACRAL TORSION

Backward sacral torsion AKA posterior sacral torsion

Rotation is on the opposite side of the axis

Right on left/left on right

Positive lumbosacral spring test

Positive backward bending test

L5 will be non-neutral

SACRAL TORSION: R on L

Right superior sulcus moves posterior and the left ILA moves anterior

Right sulcus shallow

Left ILA anterior and superior

Lumbar curve convex to the right

Motion at left ILA only

SACRAL TORSION: L on R

Left superior sulcus moves posterior and the right ILA moves anterior

Left sulcus shallow

Right ILA anterior and superior

Lumbar curve convex to the left

Motion at right ILA only

BILATERAL SACRUM

Bilateral flexion and extension

The entire sacral base moves anterior or posterior about a middle transverse axis

Common in the postpartum female

BILATERAL SACRAL FLEXION

Right and left sulci deep

ILA’s shallow bilaterally

Increased lumbar curve

False negative seated flexion test

Motion at base

Negative spring test

BILATERAL SACRAL EXTENSION

Right and left sulci shallow

ILA’s deep bilaterally

Decreased lumbar curve

False negative seated flexion test

Motion at both ILA’s

Positive spring test

SACRAL SHEARS

AKA unilateral sacral flexion/extension

The sacrum will shift anteriorly or posteriorly around a transverse axis

UNILATERAL SACRAL FLEXION

Ipsilateral deep sulcus

Ipsilateral inferior ILA

Ipsilateral ILA posterior

Ipsilateral positive seated flexion test

Ipsilateral motion at sulcus

Ipsilateral restriction at ILA

Negative lumbosacral spring test

UNILATERAL SACRAL EXTENSION

Ipsilateral shallow sulcus

Ipsilateral superior ILA

Ipsilateral ILA anterior

Ipsilateral positive seated flexion test

Ipsilateral motion at ILA

Ipsilateral restriction at sulcus

Positive lumbosacral spring test

Question 1

Which structure divides the greater and lesser sciatic foramen?

a. Sacrotuberous ligament

b. Sacrospinous ligament

c. Sacroiliac ligament

d. Tendon of the obturator internus

e. Tendon of the piriformis

Question 2

Which of the following movements will cause the sacral base to move anterior?

a. Cranial extension

b. Counternutation

c. Exhalation

d. Weight bearing on right leg

e. Weight bearing on left leg

Question 3

Which of the following findings is present in a left innominate anterior rotation?

a. PSIS inferior on left

b. PSIS superior on right

c. PSIS superior on left

d. ASIS superior on left

e. PSIS and ASIS posterior on left

INTERNAL MEDICINE SERIES OMM LECTURE Sacrum and Innominates Julia Faller, D.O., PGY1.

Documents

Transcript of INTERNAL MEDICINE SERIES OMM LECTURE Sacrum and Innominates Julia Faller, D.O., PGY1.