lecture 5 hip arthrology Flashcards
Where is the femoral head?
located just inferior to mid 1/3 of inguinal lig
What is the shape of the femoral head?
2/3 of nearly perfect sphere
What is posterior to the center of the femoral head?
the fovea
What is the femoral head covered in (except fovea)?
articular cartilage
What is the ligamentum teres?
tubular, synovial-lined connective tissue housing acetabular artery, contains mechanoreceptors
Where ligamentum teres run?
Transverse acetabular ligament to fovea
What is the acetabulum?
deep, cuplike socket
What is the acetabular notch?
60-70 degree opening
What is the acetabular fossa?
floor of fossa, no cartilage, no contact, filled with fat/blood vessels/synovial membrane/lig
Where does the femoral head contact?
the lunate surface - covered in articular cartilage thickest along sup-ant region matching area of highest joint force with walking
When does the acetabulum notch widen, lunate deform, contact increase in area/ and pressure decrease during gait?
Midstance
How much does the area of the joint increase from the lunate surface during swing phase to the midstance phase?
20% during swing phase to 90% during mid stance phase
What is the acetabular labrum?
strong, flexible ring of fibrocartilage on the rim of the acetabulum
What lig spans the acetabular notch?
transverse acetabular lig
What blends with articular cartilage of the acetabulum - labro-chondral junction?
internal labrum
What does the acebtabular labrum do?
Provides mechanical stability “grip” and deepens socket
What does the “seal” of the acetabuluar labrum do?
keeps negative pressure, fluid sealed (reduced friction/contact stress and improved lubrication to joint)
What is the innervation and vascularization of the acetabular labrum?
poorly vascularized but well innervated (pain and proprioception)
What is dysplastic acetabulum?
malformed, does not fully cover the femoral head
- chronic dislocation/OA/Pain
What is the center edge CE? (defines dysplastic acetabulum)
degree acetabulum covers femoral head
What is the acetabular anteversion angle?
the extent to which it faces anteriorly
- NLs is 20 degrees
What is femoral version?
(ante/retro) defined as the angular difference between the axis of the femoral neck and transcondylar axis of the knee (craig’s test)
What is acetabular anteversion?
A measurement used on cross-sectional imaging especially pelvic CT for the assessment of acetabular morphology
What is femoral torsion?
the relative rotation between the bone’s shaft and neck
What is normal femoral torsion?
15 degrees
What is excessive anteversion?
> 15 degrees
What is infant torsion?
infant 40 degrees anteversion - derotates to 15 deg by 16 yo
What is excessive anteversion known to cause?
hip dislocation/OA/increase contact stress “in-toeing”
What do the iliofemoral/pubofemoral/ischiofemoral ligs do?
reinforce ext capsule, iliocapsularis, glut min and rectus femoris
What does the iiofemoral lig? What does it do?
thick, strong, upside down Y med and lat AIIS/rim of the acetabulum to the intertrochanteric line; full hip ext and full ER elongates it
When is the pubofemoral lig taut?
taut in hip abd/ext and a bit of ER
When is the ischiofemoral lig taut?
Taut in IR and abd
What is the closed packed position of the hip?
the greatest simultaneous stretch to many structures
- full ext, slight IR and abd
What is femoral-on-pelvis osteokinematics?
femur about a fixed pelvis
What is pelvis on femoral osteokinematics?
rotation of the pelvis over fixed femurs
What are sagittal plane femoral on pelvis motions?
- hip flex 120-140 deg
- with LE extended 70-80 degrees
- hip ext 18-30 degrees
What are frontal plane femoral on pelvis motions?
- abd/add
- abd limited by pubofemoral and adductor muscles
- add limited by abd/piriformis/ITB
What are transverse plane femoral on pelvis movements?
IR and ER
What are the 2 types of lumbopelvic rhythm?
- ipsidirectional
- contradirectional
What is ipsilateral lumbopelvic rhythm?
lumbar spine and pelvis move in tthe same direction, maximizes angular displacement of the entire trunk
What is contradirectional lumbopelvic rhythm?
lumbar spine and pelvis move in opposite direcitons. supralumbar can stay nearly stationary, used in walking where head and eyes need to be still
- lumbar spine is a decoupler
What is sagittal plane contradirectional lumbopelvic rhythm?
- hip flx, ant tilt, lumbar spine, ext
- hip ext, post tilt, spine flx
What are some frontal plane contradirectional lumbosacral rhythm?
- abd of support hip/opp iliac crest hikes/ opposite side spine lateral flx
- add opposite
What is pelvis-on-femoral IR of the hip?
nonsupport LE side rotates forward
- spine twists opposite
What is pelvis-on-femoral ER of the hip?
nonsupport LE side rotates backwards
- spine twists opposoite
What are the arthrokinematics of NWB/open chain in the hip?
F: roll ant/slide post & inf
E: roll post/slide ant & sup
IR: roll ante/slide post
ER: roll post/slide ant
ABD: roll sup/slides inf
ADD: roll inf/slide sup
