Hip and Pelvis Flashcards
What is the innominate formed from?
3 bones of the pelvis: Illium, Ischium, and Pubis
What are the important features of the ilium?
gluteal lines, ASIS, AIIS, PSIS, PIIS, iliac crest, iliac fossa
What are the important features of the Ischium?
ischial spine, greater and lesser sciatic notch, ischial tuberosity
What are the important features of the pubis?
superior pubic ramus, body, crest, pectineal line, pubic symphysis, inferior pubic ramus
What is the acetabular orientation? And what is it’s goal?
Acetabular orientation
Lateral
Inferior
Slightly anterior (20º)
Goal: provide OPTIMAL femoral head coverage
What part of the acetabulum is nonarticular?
Acetabular fossa
What part of the acetabulum is non-articular?
Acetabular fossa
What is the purpose of the acetabular labrum?
Stability: deepens and seals
What is the femoral head covered with?
Articular cartilage
What attaches to the fovea capitis
ligament of head of femur (ligamentum teres)
What is the orientation of the femoral head?
slightly anteriorly, medially and superiorly
What is the position of the femoral shaft prior to 8 weeks in utero?
abducted, flexed and laterally rotated position (relative to neck)
What is the position of the lowers limbs after 8 weeks in utero? What is this for?
After week 8: lower limbs adduct and medially rotate
Parallel position of LE in erect stance
Brings condyles anteriorly
What is the Angle of inclination?
Angle through femoral head/neck and shaft
NORM = 125° (± 5°)
What does the angle of inclination start out as after birth?
165°
What is coxa valga
Angle of inclination > 125°
What is coxa vara?
Angle of inclination < 125°
What are the resultant stresses of coxa valga?
Valga = < bending < MA of abductors
What are the resultant stresses of coxa vara?
Vara = > bending > MA of abductors
What is the angle of torsion and what are its norms?
Medially rotated position of distal femoral condyles and shaft in relation to the head and neck (in utero)
Axis through femoral head/neck and DISTAL femoral condyles
NORM = 15-20°
What is anteversion? What degrees and what stresses does it cause?
Anteversion > 20°
Changes in:
IR>ER ratio
Comprises Hip stability
Stresses on distal joints
What is a toeing in gait compensation for?
Excessive anteversion, knee MR to improve coverage of femoral head
What can lateral tibial torsion be a result of?
Compensation from toeing in gait: Keeps feet straight in stance, but still has underlying excessive anteversion
What is retroversion? What degrees and what stresses does it cause?
Retroversion <15°
Implicated with FAI (femoral acetabular impingement) & labral pathology
Over-coverage!
What is the Center edge angle? (CEA)
Degree to which acetabulum covers femoral head
What is the acetabular anteversion angle?
Degree to which acetabulum faces anteriorly
What is the anatomic axis of the hip joint?
Line through femoral shaft
What is the mechanical axis of the hip joint?
Vertical; connects center of hip and knee joint
What kind of forces are created from the disconnect between the anatomic and mechanical axis of the hip joint?
Creates bending force through shaft of femur
Vertical loading results in bending forces
Tensile forces laterally
Compressive forces medially
What kind of force (weight) is transferred through the femoral head?
HAT (head, arms, and trunk)
What kind of force is transferred through the shaft of the femur?
GRF (gravitation reaction force)
What is the net result of the HAT and GRF at the femur?
2 forces parallel & opposite in direction BENDING moment
What are trabeculae?
Calcified plates of tissue within cancellous bone allowing femoral head/neck to absorb stresses and resist bending moments produced by HAT and GRF
What are the two main trabeculae of the femur?
Medial (principal) compressive
Lateral (principal) tensile (arcuate)
What are the 3 minor trabeculae of the femur?
Secondary compressive, secondary tensile, trochanteric
What are the strongest parts of the adaptive trabeculae?
Areas of crossing
What is the weakest part of the femur head known as? Where is it?
Zone of weakness
What is the primary WB surface of the acetabulum?
Superior lunate surface
Where is the articular cartilage the thickest?
Thickest over superior aspect of head of femur and superior lunate surface
How does the articular cartilage of the hip joint get its nutrition?
Nutrition maintained by WB
Compression and release of load
What happens when we change alignment of the hip joint?
ALTERED Stresses
Where will degenerative changes most likely occur?
In the areas of the joint that receive the most load from misalignment (or in general)
In what position is there max articular contact in the hip joint?
Flexion, Abd, ER (slight)
What is the close pack position of the hip joint?
hip extension, slight abd, IR
What structures contribute to the stability of the hip?
Acetabular fossa
Capsuloligamentous structures
Labrum
Where is the capsule of the hip and what are some of its features?
Proximal to acetabulum and labrum & distally to femoral neck
Thickest & strongest anteriorly and superiorly
Lined with synovium
What is the lowest ligamentous tension position of the hip joint?
flexion, slight abd and ER
What is the strongest hip ligament?
Iliofemoral ligament
Where are the attachments of the iliofemoral ligament?
AIIS intertrochanteric line of femur
What are the two bands of the iliofemoral ligament?
medial and lateral fasciuli
What does the iliofemoral ligament resist?
Extension & ER
Taught in standing
Where is the center of gravity in relation to the iliofemoral ligament?
Superior, and posterior
Where does the Pubofemoral ligament attach?
Anterior pubic ramus anterior intertrochanteric line
What does the pubofemoral ligament resist?
Hip abduction and extension and to a lesser degree ER
Where does the ischiofemoral ligament attach?
Posterior surface of acetabular rim and labrum inner portion of greater trochanter
What is the weakest of the 3 extra-articular ligaments?
Ischiofemoral ligament
What does the ischiofemoral ligament resist?
Resists IR (esp combined with abd) and slightly taught in extension
What is the intra-articular ligament of the hip called and where does it attach?
Ligamentum teres
,Acetabular notch fovea of femur
What is the purpose of the Ligamentum teres
Conduit for blood supply to femoral head (in children)
Contributes to hip stability
What is the acetabular labrum?
Triangular shaped fibrocartilagenous structure surrounding periphery of acetabulum
What are some functions of the acetabular labrum
Innervated
Function
Deepen socket
Stability- forms seal
Proprioception
What is Lumbopelvic rhythm and what kind of motion is it?
kinematic relationship between movement of the pelvis over the femoral heads which changes the position or configuration of the lumbar spine
Pelvis on Femur Motion
What are the two types of lumbopelvic rhythem?
Ipsidirectional vs. contradirectional
What pelvic on femur motion occurs in the sagittal plane?
Anterior/posterior pelvic tilt
Ant relative hip flexion & lumbar hyperextension
Post relative hip extension & lumbar flexion
What pelvic on femur motion occurs in the frontal plane?
Lateral pelvic tilt / hip hike
Frontal plane motion
One hip is axis of motion for the other
Mostly in SLS
What pelvic on femur motion occurs in the transverse plane?
Forward / backward rotation
Occurs in SLS with one WB hip joint (axis); motion named for NWB hip
What are the arthrokinematics of the hip?
Convex on concave with femur on pelvis motion
Flex/ext mostly pure spin
IR/ER & abd/add include roll and glide
What are the 4 primary flexors of the hip?
Iliopsoas**
Rectus femoris
also EXT knee
Sartorius
Tensor fascia latae
Flex, abd and IR hip*
Maintain tension in ITB to reduce tensile stresses on femur
What is the innervation of the rectus femoris and the sartorius?
Femoral n
What is the innervation of the ilipsoas?
lumbar plexus L1-4; femoral n
What is the innervation of the TFL?
Superior gluteal
What are the secondary flexors of the hip?
Pectineus, Adductor Longus, Adductor Magnus and Gracilis
What are the muscle actions with femur on pelvis hip flexion?
Occurs with knee flexion during swing phase of walking and running
Requires activation of abdominals
What are the muscle actions with pelvis on femur sagittal motion?
Anterior pelvic tilt- combined action of hip flexors and lumbar extensors
What are the adductors of the hip?
Superficial layer: Pectineus, Adductor longus, gracilis
Middle layer: Adductor brevis
Deep layer: Adductor magnus
Action of hip adductors in frontal plane?
Frontal plane function
Adduct the femur
Provide stability for pelvis in stance
Action of the hip adductors in the sagittal plane?
Flexion and/or extension depending on position of the hip
What are the extensors of the hip?
Gluteus maximus
Extends the hip and ER hip in neutral extension
Strong extensor
Hamstrings
3 muscles
All extend the hip and flex the knee joint
Origin: ischial tuberosity
Posterior (hamstring) portion of adductor magnus
What is the innervation of the extensors?
Glut. Max - inferior gluteal nerve
Hamstrings and Posterior (hamstring) portion of adductor magnus
- Greater Sciatic
What are the positions of the hip and lumbar spine in posterior pelvic tilt?
How do the hamstings control the forward lean of the body?
hamstrings contract eccentrically; lengthened across both attachments
What happens in femur on pelvis hip extensor action?
Produces large and powerful hip extension torque to rapidly accelerate the body forward and upward
Flexed position of the hip favors greater extension torque
How does the gluteus medius function as a hip abductor?
Abductors Gluteus medius
3 portions (ant, middle and posterior)
Abduct always; 2nd Action dependent on position of hip
In FLEXION All IR
In Neutral
Ant/middle IR
Posterior ER
(superior gluteal nerve innervation)
What does the gluteus minimus do? What is it’s inneveration
Deep and anterior to the medius
Abduction and flexion
(Superior gluteal nerve)
What is the function of the hip abductors in standing (closed chain)
maintain LEVEL pelvis in SLS
Critical for frontal plane stability during walking (single limb stance)
What are the external rotators of the hip?
Obturator internus & externus
Gemellus superior & inferior
Quadratus femoris
Piriformis
What is the innervation of the external rotators of the hip?
Obturator nerve
What is the femur on pelvis action of the external rotators?
External rotation of the hip
What role do the extra rotators of the hip provide and pelvis on femur motion?
Provide stability in WB
Creates compressive moment throughout hip ROM
Move acetabulum on fixed femur in gait (pelvic ER) stance limb contracts to rotate pelvis AWAY
True or false, no single muscle performs internal rotation of the hip
True
What are the largest contributors to internal rotation at the hip joint?
Anterior fibers of gluteus medius
Gluteus minimus
TFL
Adductors (adductor longus, brevis and pectineus)
What is the important function of internal rotation and gait in the hip joint?
Produces IR of the pelvis on femur in the early part of stance
What is the most optimal position for internal rotation of the hip?
Increased IR torque (3x) with hip flexion compared to hip extended position
How much of the HAT is supported by the pelvis and how is that divided?
Pelvis supports 2/3 HAT
1/3 body weight on each hip
Gravitational torque equal on both hips WR x DR = WL x DL
What happens to the hip joint in a unilateral stance?
Joint compression forces:
Body weight compression force (Fbw)
Muscular compression (Fm):
Moment produced around 1 hip
Abductor muscle contraction to counter adduction moment
Prevents pelvic drop in SLS
Total force at hip is approximately 2.4-2.6 x body weight
What is a result of gluteus medias weakness?
Excessive drop termed Trendelenburg
Compensated for by the trunk lateral lean towards affected side
As a result of gluteus maximus weakness?
Posterior lean towards affected side as compensation
What is an Antalgic Gait?
Lateral trunk lean resulting from painful hip joint
also called gluteus medius gait if due to hip abductor weakness
What does ipsilateral trunk lean do?
IPSILATERAL trunk lean will decrease MA
How should you use a cane for the hip joint?
One of the most effective methods to reduce compressive loads at the hip is to use a cane in the OPPOSITE side of the affected hip
Why does using a cane on the opposite side work?
Use of the cane reduces the activation of the hip abductor muscles
Pressure through the UE and cane produces a counter-torque in the same rotary direction as that produced by the hip abd muscles
How does carrying loads affect the contralateral side?
Carrying loads on the contralateral side increases the MA for gravitational torque about R hip
How does external loads affect the hip abductors?
Hip abductors must generate a larger countertorque to maintain frontal plane stability of the hip
What advice would you give patients with hip weakness and/or pain for carrying loads?
Avoid carrying heavy items if possible
When carrying items carry the loads on involved side or split loads evenly between two UE
