MSK 22 - Hip joint Flashcards
what bones form the acetabulum - what parts do they make up
ilium (superior part)
ischium (posterior part)
pubis (anterior part)
what is the lunate surface of the hip joint
the rim of cartilage that covers most of the articular surface
what is the surface that gets worn out in OA
lunate surface
what is the acetabular fossa and what is different about its structure
central area
doesnt have cartilage over bone
what fills the acetabular fossa
fat
the acetabular fossa has a blood vessel that is inside a ligament
what is the name of the ligament and blood vessel
ligamentum teres
branch of obturator artery
what does the ligamentum teres do
connect acetabular fossa to fovea of femoral head
prevents hip dislocation
what does the obturator artery do
in infancy supplies blood to femoral head but overtime as an adult it atrophies and supplies very little blood
where is the transverse acetabular ligament located
between the 2 ends of the lunate surface
covers acetabular notch inferiorly where there is no cartilage
what does the transverse acetabular ligament do
suspends femoral head in acetabulum
what does the acetabular labrum do for the hip joint
increases articular area
how is the femoral neck directed
superomedially and slightly anteriorly in its articulation with the acetabulum
what is the bony ridge that runs between the 2 trochanters of the femur
intertrochanteric line
what does the angle of the femur allow
greater mobility at the hip joint and puts force through the femoral neck
where is most of the force on the femoral neck and what is the structural difference here to address this
on lower half of neck
the inferior part of the neck is thicker to support the weight transmitted through the head
what is the role of the joint capsule at the hip
hold things together tightly to prevent dislocations
where does the joint capsule of the hip joint attach to on the pelvis and femur
proximally attach to acetabulum and transverse acetabular ligament
distally into intertrochanteric line of femur
how many parts/ligaments does the joint capsule of the hip have
3
what is the orbicular zone of the hip joint capsule created by
created by fibres that circle around the femoral head
the fibres of the hip joint take a spiral course what does this mean when you move the thigh in flexion and extension
the fibres are tightened as you extend the thigh and unwind when you flex the thigh
this allows more flexion than extension
the thicker parts of the joint capsule of the hip also have what role when regarding the femoral head
pulls femoral head medially into the acetabulum
what 3 muscles are responsible for hip flexion
iliopsoas
rectus femoris
sartorius
what myotome levels and nerves are involved in hip flexion
L2 and L3
femoral nerve
what 2 muscles are responsible for hip extension
gluteus maximus
hamstrings
what myotome levels and nerves are involved in hip extension
L4, L5 and S1
tibial nerve L4-S1 and inferior gluteal nerve L5-S2
what 5 muscles are responsible for hip adduction
adductor magnus
adductor longus
adductor brevis
pectineus
gracilis
what myotome levels and nerves are involved in hip adduction
L2-4
obturator nerve
what 5 muscles are responsible for hip adduction
gluteaus medius
gluteus minimus
tensor fascia lata
piriformis
sartorius
what myotome levels and nerves are involved in hip abduction
L5 and S1
superior gluteal nerve L4-S1
what are the 2 arteries that supply the hip joint
where do they branch off from
medial and lateral circumflex arteries
branch off from profunda femoris artery
the two circumflex arteries form anastomoses with which arteries
with the superior and inferior gluteal arteries and minor anastomoses with the obturator artery
where do the medial and lateral circumflex arteries run relative to the femoral neck
medial artery runs posteriorly around the femoral neck
lateral artery runs anteriorly around the femoral neck
femoral artery gives off profundal femoris branch at what level
at level of neck of femur
the femoral artery extends down which side of the leg and how does it travel down from the thigh to the leg
extends down the medial side of the leg
until it joins the adductor hiatus where it then goes posteriorly into the popliteal region
what do the perforating arteries of profunda femoris artery supply
muscles of anterior thigh
branches of the perforating arteries also supply the posterior part of leg
what arteries come off the internal iliac artery
gluteal arteries
what vessels come off the circumflex arteries
retinacular arteries
how do the retinacular arteries travel
off the circumflex arteries to pierce the capsule and run in the retinacular folds of synovial membrane and up into the femoral head
what does the retinacular arteries supply
femoral head and neck
what is hiltons law
nerves supplying a joint come from any that cross it or any that supplies muscles that cross the joint
which 5 nerves supply the hip joint
femoral nerve
obturator nerve
superior gluteal nerve
nerve to QF
sciatic nerve
what muscle is supplied by the femoral nerve
iliacus
what group of muscles is supplied by the obturator nerve
medial compartment adductors
what muscle is supplied by the superior gluteal nerve
gluteus medius
what part of the hip joint is supplied by the nerve to QF
the posterior portion
is bone more sensitive to ischemia or is cartilage
why is this
bone is more sensitive to ischaemia as cartilage does not rely on blood supply and can still get nutrients from the synovial fluid
ischaemic bone develops what condition
avascular necrosis
what are the 5 types of femur fractures and which are intra/extracapsular
capital (intracapsular)
subcapital (intracapsular)
transcervical (intracapsular)
intertrochanteric (extracapsular)
subtrochanteric (extracapsular)
which of the 5 femur fractures are most dangerous
the intracapsular fractures capital, subcapital and transcervical
why are intracapsular fractures dangerous
they involve the blood supply to femoral head and prevent retinacular artery from getting to the head
what is a capital femur fracture
through the femoral head
what is a subcapital femur fracture
base of femoral head
what is a transcervical femur fracture
across neck of femur
what are the risks of a DHS
might put nails and screws too far in the femur and hit the profunda artery
most hip dislocations are in which direction
posterior
where does the femoral head land in posterior dislocation
superiorly
what is the mechanism of a posterior hip dislocation - what position does this normally happen in
flexed hip that is adducted and internally rotated
how is the leg oriented after sustaining a posterior hip dislocation
internally rotated
what are the associated structures that could be damaged by a hip dislocation
soft tissue an joint capsule
risk of avascular necrosis from arterial damage
why are hip joint dislocations common after hip joint replacement
youve cut through the fascia lata to get to hip joint so less stable post op
what is the mechanism of an anterior hip dislocations
forceful abduction with external rotation of leg
where does the femoral head end up in a anterior hip dislocation?
inferior to pelvis
