Pelvis and Hip Flashcards
Pelvis made of
two innominates (ilium, ischium, pubis)
Sacrum
Pelvis Functions
Attachment point for many muscles of the LE and trunk
Transmits weight of the upper body/trunk to ischial tuberosities (sitting) or LEs (standing/walking)
Supports organs of bowel, bladder & reproduction
Characteristic Functions of the Hip Joint
- Stability during standing/walking/running
- Femoral head stabilized in deep socket (plus labrum & capsule)
- Many large/forceful muscles accelerate/decelerate the body from the hip
- Hip muscle weakness has profound affect on mobility/stability of the entire body
Femur
Provides long lever for
torque/power & long stride
Femur
Neck permits spacing to avoid
bony impingement against pelvis
Neck subject to large _______
Neck reinforced by thick ______
Neck is frequent site of _______
tensile and compressive forces
cortical and trabecular bone
fractures
Course of femur moves
medially for narrow spacing of feet
Femur is ________ anteriorly
__________ posteriorly
convex
concave
Shape of femoral shaft
_______ tension w/ ________ compression allows more force dissipation
anterior, posterior
Femur able to carry
greater loads without failure
Angle of Inclination at birth
165-170
Normal Angle of inclination in adulthood
125
Normal Angle of inclination in elderly
120
Coxa Varum
______ of normal
Presentation
<125
Adducted femur causes
- genu valgum
pronated foot
shorter ipsilateral LE
Coxa Valgum
________ of normal
Presentation
> 125
Abducted femur causes
- genu varum
supinated foot
longer ipsilateral LE
Normal Anteversion
15
Infants born with _____ anteversion
40
Growth, weight bearing & physical activity typically reduce it to≈
15 by age 16
An exaggerated internal rotation of the LE during gait MAY be a compensation of
excessive anteversion – to improve hip congruency
In toeing gait increases the moment arm of
hip abductors (which can be a response to reduced abduction torque with excessive anteversion)
Excessive femoral anteversion of ____ is common with CP
25-45
In-toeing typically persists in
ambulatory persons with CP
Spasticity or tightness of ______ and ______may contribute to their in-toeing (CP)
hip int rotators & adductors
If greater anteversion continues into adulthood, increased risk of:
Hip Dislocation
Articular Incongruence
Increased joint contact stress
Degeneration of articular cartilage
Degeneration of acetabular labrum
Result: increase risk of OA
Ligamentum Teres is a protective sheath for
acetabular artery, supplying femoral head of neonate
Primary circulation for hip joint is
circumflex arteries
Ligamentum teres May also stabilize fetal hip when acetabulum is
shallow & vulnerable to dislocation
Acetabulum faces
obliquely anterior, lateral, & inferior
Lunate Surface
horseshoe shape surface of rim that contacts femoral head
Rim incomplete inferiorly:
60-70° acetabular notch
Rim closed by
Transverse Acetabular Ligament
- Acetabular Labrum
- Like the shoulder,
Strong
Flexible
Fibrocartilage ring
Surrounding most of the acetabulum
Except @ transverse acetabular ligament spanning the acetabular notch
Labrochondral Junction: where the labrum blends with the
articular cartilage
Labrum deepens the socket by
5 mm
labrum grips the
femoral head
Labrum Forms a mechanical suction-seal of
negative intra-articular pressure
Labrum Forms fluid seal of synovial fluid lubricant to
lubricate articular cartilage
Labrum is poorly
vascularized - so limits healing
Labrum well supplied by
afferent nerves – so feels proprioception & pain
Labrum often involved in
Degenerative OA
Acute trauma
Developmental hip dysplasia
Repeated femoral-acetabular impingement
