Lecture 5 (test 2): Hip Arthrology Flashcards
where is the femoral head located
just inferior to mid 1/3 of inguinal ligament
describe the femoral head
2/3 is nearly a perfect sphere
just posterior to center = the fovea
covered by articular cartilage except fovea
describe ligamentum teres
tubular
synovial lined connective tissue
houses acetabular artery
contains mechanoreceptors
runs from transverse acetabular ligament to fovea
describe the acetabulum of the hip
deep and cuplike socket
how deep is the acetabular notch
60-70 degree opening
describe the acetabular fossa floor
floor of fossa
no cartilage
no contact
filled with fat, blood vessels, synovial membrane, and ligament
where does the femoral head generally contact (describe this surface)
normally contacts along lunate surface
lunate surface is covered in articular cartilage and is thickest along the superior anterior region which is where there is the highest joint force when walking
describe the forces (%BW) generated at the acetabulum during swing and mid stance
13% at swing and 300% BW at midstance
what all occurs at the hip joint during midstance
notch widens
lunate deforms
increase contact area
decrease pressure
how much compression forces (% BW) occur during the stance and swing phases
stance = 0-60%
swing = 60-100%
how does the area of joint contact increase from swing to stance
increases from about 20% of the lunate surface during swing to 98% during mid stance
describe the hip labrum
string flexible ring of fibrocartilage rim of acetabulum
provides mechanical stability “grip” and deepens socket
mechanical seal keeps neg pressure, and fluid sealed to reduce friction/contact stress and lubrication
poor vascularization but well innervated
where does the transverse acetabular ligament span
the acetabular notch
the internal labrum blends with what to form what
blends with articular cartilage of acetabulum to form labro-chondral junction
how does hip joint project
laterally, inferior and anterior inclincation
what is dyplastic acetabulum
malformed and does not fully cover the femoral head
chronic dislocation/OA/pain
what measures define dyplastic acetabulum
center edge (CE)=degree acetabulum covers the femoral head
what is the acetabular anteversion angle
extent to which the femur faces anteriorly
NLs is 20 degrees
what is femoral version (ante/retro)
defined as the angular difference between axis of femoral neck and transcondylar axis of the knee (craig’s test)
what is acetabular anteversion
measurement used on a cross section imaging especially pelvic CT for the assessment of acetabular morphology
what is femoral torsion
relative RT between the bones shaft and neck
normal = 15 degrees
what is consdiered excessive anteversion or retroversion
ante = >15
retro = < 15
what is the femoral torsion of an infant
originally around 40 degrees anteversion
it derotates to about 15 degrees by 16 years old
excessive anteversion can cause what issues
dislocation
OA
increase contact stress
“in-toeing”
