Lecture 18: Pelvis and Hip Flashcards
What does the pelvic girdle comprise of?
two pelvic bones and sacrum
What are the coronal plane alignments of the pelvic girdle?
ASIS and pubic tubercles
left and right ASIS
What are the sagittal plane alignments of the pelvic girdle?
inferior coccyx and superior pubic symphysis
ASIS and PIIS
Where is the sacroiliac joint and what types of movements does it permit?
at the centre of our body, therefore centre of motion, and permits a very small amount of gliding and rotation
What is nutation?
superior sacrum moves anteriorly and inferiorly
ligaments limit the extent of nutation
What is counternutation?
occurs following nutation
superior sacrum moves superiorly and posteriorly
What is counternutation?
occurs following nutation
superior sacrum moves superiorly and posteriorly
What is the role of sacroiliac ligaments?
restrict lateral movement of ilia and anterior movement of sacrum
What is the role of sacrotuberous and sacrospinous ligaments?
resist nutation by limiting posterior rotation of inferior sacrum during weight bearing
What is the role of the pelvic girdle?
helps position the hip joint for effective limb movement
What are the movements of the pelvis?
posterior pelvic tilt, anterior pelvic tilt, lateral pelvic tilt and pelvic rotation
What happens during posterior pelvic tilt?
ASIS is tilted backward with respect to acetabulum, positions the head of femur in front of the femur to enable ease of flexion
What is the role of anterior pelvic tilt?
promotes femoral extension
What is the role of lateral pelvic tilt?
facilitates lateral movements of femur
What type of joint is the hip joint?
synovial multiaxial ball and socket which is able to produce movement in all three planes
What are the articular surfaces of the hip joint?
head of femur, acetabulum, acetabular notch and acetabular labrum
Where is the hip joint capsule strongest?
anteriorly and superiorly
What does the hip joint capsule attach to?
surrounding labrum, acetabulum
and transverse ligament at the notch
What does the synovial membrane of the hip joint capsule line?
the capsule, labrum & ligament of head of femur
Which ligaments strengthen the hip joint?
iliofemoral and pubofemoral ligaments (anteriorly) ischiofemoral ligament (posteriorly)
What are the bursae of the hip?
iliopsoas bursa, sciatic bursa of gluteus maximus, trochanteric bursa of gluteus medius and trochanteric bursa of gluteus maximus
What is the angle of inclination?
angle between femoral neck and femoral shaft in the coronal plane
What is coxa valga?
angle of inclination is increased
What is coxa vara?
angle of inclination is decreased
What is the weakest component of the femur?
the femoral neck as it has a smaller diameter than the rest of the femur
What do hip fractures normally imply?
fractures to femoral head, neck or trochanters
Which factors improve stability of the hip?
articular fit, acetabular labrum, strong joint capsule and many surrounding muscles and their line of pull across the hip joint
Which factors improve mobility of the hip?
acetabular labrum and ball and socket joint
Why is hip joint ROM small compared to shoulder?
to increase stability (due to its large weight bearing function)
What is an example of a two joint muscle in the lower limb and when it is active? What does this muscle act with?
rectus femoris
active during hip flexion and knee extension
acts with iliopsoas at hip
When does rectus femoris function more effectively as a hip flexor?
when knee is flexed e.g. kicking a ball
What happens when sarcomere length is either too short or too long?
the overlap is no longer active and a progressive decrease in force is observed
What is passive insufficiency?
two-joint muscle is lengthened to its maximum passive length at both joints, but is insufficient to allow full ROM at both joints simultaneously
What is active insufficiency?
two-joint muscle is shortened to its maximum length at both joints, but is insufficient to produce full ROM at both joints simultaneously
What type of muscle is gluteus maximus?
a massive, powerful hip extensor when the hip is flexed
What type of muscles are the hamstrings?
two joint muscles (not short head) that contribute to both hip extension and knee flexion
When are the hamstrings active?
during standing, running, normal locomotion, forward bending and lifting
What type of muscle is gluteus medius?
the major hip adductor, with gluteus minimus and TFL assisting
What is contraction of the hip abductors required for?
stabilising the pelvis during the swing phase of gait to prevent the swinging foot from dragging
What is the role of muscles that adduct the hip?
active during the gait cycle and pull the supporting leg into adduction, hence moving the
line of gravity over the supporting foot
What are the major medial rotators of the femur?
the gluteus minimus and medius, with assistance from the tensor fasciae latae, semitendinosus & semimembranosus
Why does lateral and medial rotation of the femur occur during the gait cycle?
to accommodate rotation of the pelvis
What does a forward bending motion involve?
lumbar flexion with hip flexion and anterior pelvic tilt
What is the prime mover of a forward bending motion?
initially eccentric contraction of erector spinae, semispinalis, multifidus
towards the end of full trunk flexion, concentric contraction of rectus abdominis, IO & EO & passive posterior ligamentous support
What are the synergists of a forward bending motion?
left and right obliques cancel out unwanted rotation to permit only flexion
What are the stabilisers of a forward bending motion?
segmental stabilisers i.e. multifidus, rotatores
What does anterior pelvic tilt facilitate? What does posterior pelvic tilt facilitate?
hip flexion and promotes lumbar flexion
hip extension and promotes lumbar extension
What are the concentric and eccentric muscles of anterior pelvic tilt?
concentric: erector spinae, hip flexors
eccentric: abdominal muscles, hip extensors
What are the concentric and eccentric muscles of posterior pelvic tilt?
concentric: abdominal muscles, hip extensors
eccentric: erector spinae, hip flexors
What are pelvic movements in the coronal plane?
pelvic drop and pelvic lift
What are pelvic movements in the horizontal plane?
pelvic rotation to the right and pelvic rotation to the left
