25.4 Anat: hip joint Flashcards
What forms the acetabulum in the hip? When is there an epiphysis until?
Iliem, ischium and pubis (epiphysis until puberty)
Which part of the acetabulum is articular/weightbaring?
Lunate surface: weight baring
Acetabular notch and fossa: non-articular?
Where in the acetabulum is the fat pad located?
Intra-articular but extra-synovial
What is the fovea in the femur for?
ligament attachment
What do the trochanters allow? What does this form?
For muscle attachment, forms traction epiphysis
What are pressure epiphysis dependent on?
Appropriate blood supply from surrounding vessels
What can happen if there is disruption to the blood supply for the head of femur during growth?
Capital epiphysis may not grow, Perthes disease
Which part of the head of femur lies outside the acetabulum? What protects it?
Anterior part, outside acetabulum
protected by psoas bursa
What does the narrow femoral neck allow?
Greater ROM without touching acetabulum rim
What can become irritated in repeated hip flexion? What muscle is involve? Where does it attach?
Bursa Iliopsoas (primary hip flexor) passes and attaches to lesser trochanter
What are the components of the 2 systems of trabecular system that intersect (sup/inf)? How are these formed?
Sup: medial and arcuate (compression through head, neck)
Inf: medial and lateral (muscles pulling on greater, lesser troachanters)
What is clinically relevant about the site of weakness in the femur?
Where cross-hatched trabeculae are absent, site of weakness esp. in elderly/osteoporosis
What is coxa valga and coxa vara?
Coxa valga, >125 angle
Coxa vara,
How is the neck-shaft angle different to newborn/adult (female)?
Newborn: >150
Adult: 135
(female, smaller angle due to width of pelvis)
What can coxa vara cause?
Increased stress on femoral neck, so ‘slipped capital femoral epiphysis’
Where does the line of gravity pass at the hip and ankle joint?
Behind the hip joint,
in front of the ankle joint
What is the position of greatest stability for the lower limb?
Close packed (extension, abduction, medial rotation)
What are the supporting ligaments for the hip?
Iliofemoral (strong, in front), pubofemoral and ischiofemoral (weaker behind)
Why is the hip most stable in extension?
The iliofemoral ligament spirals outside the joint tightening the capsule
What is the joint rimmed by? When can this be damaged?
Labrum, susceptible to injury in posterior hip dislocation
What is important for femoral head blood supply? What holds them there?
Retinacular vessels (bound by retinacular fibres from the capsule)
What are the movements of the hip?
F>E
Abduction/adduction
Media (with extension)l/lateral rotation
What muscles abduct the hip and maintain position of pelvis on walking?
Gluteus medius and minimus
What happens to gait if the hip adductors are paralysed?
Trendellenberg gait
