hip and pelvis

pelvic girdle is made up of 4 bones

2 innominates

sacrum

coccyx

innominate includes

ilium

ischium

pubis

the pelvic girdle is

a large diarthrodial joint

sulcus

the depth between PSIS and base (top) of sacrum

female pelvic bone thickeness

lighter, thinner, smoother

male pelvic bone thickness

heavier, thicker, more prominent markings

female pubic arch angle

80-90

male pubic arch angle

50-60

female acetabula

small; further apart

male acetabula

large, closer together

female sacrum

wider, shorter, sacral curvature is accentuated

male sacrum

narrow, longer, sacral promontory more ventral

female coccyx

more movable; straighter

male coccyx

less movable, curves ventrally

pelvic girdle function

load-transfer dissipation of loads

supports body weight

protects viscera

attachment site for muscles

bony birth canal

deepens the sulcus

nutation

shallows the sulcus

coutnernutation

sacroiliac motions

nutation/counternutation

rotation

sidebending

nutation occurs

by anterior sacrial on iliac rotation, posterior ilium on sacral motion, or both

counternutation occurs

by posterior sacral on iliac rotation, anterior ilium on sacral rotation, or both

attachment site of main contents of pelvic floor

coccyx

can move up to 30 deg anterior and up to 1cm laterally

coccyx

ilium on sacrum movement

anterior/posterior pelvic rotation (tilt)

superior shear or upslip

inferior shear or downslip

outflare/inflare

outflare of ilium on sacrum

adbuction/ER

inflare of ilium on sacrum

adduction/IR

R rotation on R axis

L bases nutates (anterior)

L rotation on R axis

L base counternutates (posterior)

L rotation on L axis

R base nutates (anterior)

R rotation on L axis)

R base counternutates (posterior)

innominate motion with lumbar flexion

anterior rotation

sacrum motion with lumbar flexion

nutation, then counternutation

innominate motion with lumbar extension

slight posterior rotation

sacrum motion with lumbar extension

nutation

innominate motion with lumbar rotation

ipsilateral: posterior rotation

contralateral: anterior rotation

sacrum motion with lumbar rotation

nutates ipsilaterally

innominate motion with lumbar side bend

ipsilateral: anterior rotation

contralateral: posterior rotation

sacrum motion with lumbar sidebend

ipsilateral: side bends ipsilaterally

contralateral: side bends contralaterally

angle of inclination of femur can affect

blood supply, labrum, joint congruency

normal angle of inclination

125

coxa vara

105

relative adduction

can cause hip dysplasia

coxa valga

140

relative abduction

can produce FAI

in coxa vara

abduction: passive insufficiency

adduction: active insufficiency

in coxa valga

abduction: active insufficiency

adduction: passive insufficiency

center edge angle

degree to which acetabulum covers the femoral head

low center edge angle

risk of dislocation, less contact area in joint

high center edge angle

lead to FAI, injury to hip during extreme motions

femoral torsion

common in kids due to developing bones

shaft of femur is twisted

normal anteversion

15

with excessive anteversion

anterior femoral head in acetabulum

35 degrees

shaft of femur is externally rotated

Excessive anteversion presents as

In toeing (internal rotation of femoral head)

with retroversion

5 degrees

posterior femoral head in acetabulum

shaft of femur is IR

Retro

version presents as

Out toeing (external rotation of femoral head)

inflare can cause

widening of SI joint

outflare can cause

compression of SI joint

acetabulum is

concave

femur is

convex

closed pack position of hip

full extension, IR, abduction

open pack position of hip

30 degrees flexion, 30 degrees abduction, ER

capsular pattern of hip

with pathology, restriction of IR with flexion and abduction

may be limited extension, no restrictions in ER or ADD

iliofemoral ligament (Y ligament of Bigelow)

tightly coiled and fully taut in extension and ER/IR to prevent hyperextension

pubofemoral ligament

taut during hip extension and abduction, reinforcing inferior joint capsule

ischiofemoral ligament

taut during extension, adduction, IR and stabilizing the posterior capsule

ipsilateral lumbopelvic rhythm

trunk flexion

with flexion, everything shifts forward

contra-directional lumbopelvic rhythm

trunk extension

anterior tilt of innominates

nutation of sacrum

pelvis motion flexion

anterior tilt

pelvis motion extension

posterior tilt

pelvis motion abduction

lateral tilt

pelvis motion adduction

contralateral drop

pelvis motion rotation

ipsilateral internal

contralateral external

end feel of hip motions

all firm

flexion can occasionally be soft

hip flexion causes

knee flexion and ankle DF

hip extension causes

knee extension and ankle DF

IR hip rotation causes

femur rotates medially on a fixed tibia @ knee, pronation of the foot, and eversion of calcaneus

ER hip rotation causes

femur rotating laterally on fixed tibia at knee, supination of the foot and inversion of the calcaneus

inner unit muscles in SIJ stability

diaphragm

pelvic floor m

multifidus

transverse abdominus

outer unit muscles in SIJ stability

posterior oblique system

anterior oblique system

lateral system

deep longitudinal system

form closure

occurs when the joint surfaces are congruent with each other and no external forces are required for stability

force closure

combination of friction of force closure and lateral compressive forces to counteract shear loads

posterior oblique sling

ipsilateral: latissimus dorsi, TLF to

contralateral: glute max, IT band, biceps femoris

posterior oblique sling leads to

force closure of SIJ

posterior oblique sling provides stability

in the diagonal

anterior oblique sling

ipsilateral: pectorals, oblique abdominals, transverse abdominus to

contralateral: addutors

anterior oblique sling leads to

force closure of the pubic symphysis

lateral system

ipsilateral glute med/min

contralateral adductors

longitudinal sling

deep multifus, deep layer of TLF, sacrotuberus ligament via long head of biceps femoris

longitudinal sling leads to

force closure of SIJ and compression of L5-S1