Block quiz 3 Flashcards
- True or false. Small amounts of symmetrical movement of the sacrum in relation to the pelvis is possible at the sacroiliac joints???
Very small amounts of movement (rotation and translation) are possible
This movement may be symmetrical or asymmetrical Nutation(“nod”) is the anterior tilt of the sacrum relative to the ilium
Trunk flexion & bilateral hip flexion
Counternutationis the posterior tilt of the sacrum relative to the ilium
Trunk extension & bilateral hip extension
Note:
Sacrum also articulates with the ilium at the sacroiliac joint Changes from a synovial joint to a cartilaginous joint during maturity
Articulating surfaces become rough and mobility decreases Reinforced by an extensive thick set of ligaments
What two structures help to resist anterior shear at the lumbosacral junction?
Lumbosacral (L5-S1) junction is supported against anterior shear by:
Facet joint orientation
Iliolumbar ligament
- Why is it important for the sacroiliac joints to maintain stability?
Stability is required to facilitate load transfer from the HAT to the ischialtuberosities when sitting and from the lower extremities to the trunk when standing and moving
- Describe the alignment of the head of the femur in relation to the acetabulum?
In normal standing the head of the femur is directed slightly anteriorly and superiorly within the acetabulum
- -It contacts the acetabulum only along its lunate surface
- -The lunate surface and a large portion of the femoral head are covered in articular cartilage
- What are two consequences of a coxa vara deformity at the hip joint?
Limb is shortened
Moment arm for hip abductors INCREASED
Bending loads on femoral neck INCREASED
- What compensatory actions may occur as a result of excessive anteversion at the hip joint?
Compensatory changes such as hip internal rotation and lateral tibial torsion
May also lead to increases hip joint contact loads
May lead to a “toe-out” position
- Even though both are ball and socket joints, what passive mechanisms allow the hip joint to be considerably more stable than the glenohumeral joint?
Stability
Passive: Deep acetabulum that has a curvature similar to the femoral head
Labrum
Acetabulum + labrum covers > 50% of the femoral head
Joint capsule
Ligaments
Additional: Intra-articular pressure
What are two ways that flexion of femur in relation to the pelvis may be described?
When the hip has reached the end of its available range of flexion, posterior pelvic tilt contributes to apparent hip flexion as the femur is moved towards the trunk
Conversely, when the hip has reached the end of its available range of extension, anterior pelvic tilt contributes to apparent hip extension while extending the lumbar spine
- If you stand on your right leg and your pelvis tilts downwards on the left side can this be described as abduction or adduction at the right hip? If this occurs this might be reflect a weakness in which muscle group?
Adductors…
Weak ABDuctors
- What actions are tensor facia latae responsible for producing at the hip joint?
Hip internal rotation when hip is flexed
Flexion of the leg at the hip
Abduction of the leg
- When the hip is extended which two muscles are able to contribute to hip external rotation
Semi membranous
Semi tendinosis
Palpate the right gluteus medius just superior to the greater trochanter. Now walk a few steps and comment on when you feel the muscle becomes taut. Why is the muscle active at this point in the gait cycle..
It works to stabilise the stance leg and activates in the second part of the gait phase
What are two consequences of a coxa VALGA deformity at the hip joint?
Limb is lengthened
Moment arm for hip abductors DECREASED
Bending loads on femoral neck DECREASED
If you we supporting your body weight on your left leg during the stance phas elf gait and your pelvis tilts downwards in the frontal plane on the right side is this apparent abduction or add at the left hip
Adduction
If your pelvis rotates forwards in the transverse plane on the right side (backwards on the left side) during the swing phase of gait is this apparent internal it external rotation of the right
External rotation
Q. What purpose does the femoral neck serve?
To allow for compressive loading through joint and….
Serves to displace the primal shaft of the femur laterally away from th joint, thereby reducing the likelihood of bony impingement against the pelvis
The location of the greater trochanter distal to the femoral neck lengthens the moment arms of the attached muscles
Gluteus maximus
Moment arm is maximum in a ….. position (decreases with hip flexion
Neutral
Adductors 1
Bilateral cooperation
When performing an in-step kick in football (soccer) the adductors contract on both the fixed and swing leg sides
Just read
Adductors 2 28
In hip flexion angles >70°adductor longus has a moment arm at the hip that allows it to contribute to extension
In hip flexion angles
Just. Read
Why are the extensors the strongest muscle groups?
They are needing to constantly overcome the body weight of the individual
Muscles acting on the hip.. In flexion (5)
Pectineus Sortorius Tensor fascia latae Rectus femoris Illiopsoas
Muscles acting on the hip to extend leg?
Gluteus maximumus Semi membranous Semi tendinosis Adductor Magnus Biceps femoris
Muscles acting on hip to Adduct leg?
Pectineus Gracillis Adductor brevis Adductor longus Adductor Magnus
Muscles acting on hip to ABDUCT leg
Gluteus minimus
Gluteus medius
Tensor fascia latae
