Hip
Describe the proximal and distal segments of the coxofemoral joint, what are the articulating surfaces and what are the ligaments?
proximal: 3 bones for os coxae: pubis, ischium, ilium, articulating surface is the labrum of the acetabulum and the transverse ligament connects the 2 inferior ends of the labrum
distal: the femoral head, the fovea is where the ligamentum teres attaches on the femoral head to supply blood to the femur head/neck
How will leaning toward the painful hip reduce the pain in gait? What other compensation would you consider?
With a cane on the opposite side, it helps to push the pelvis up to assist the Abductors of the hip
A lateral lean DECREASES the moment arm of gravity
When you flex/extend lumbar spine which way does the nucleus pulposus go?
Flexion: the sup. vertebral body pushes the nucleus pulposus posteriorly
Extension: the sup. vertebral body pushes the pulposus anteriorly
For the MCL, what is the primary role? What is the structure (attachments) and how does it influence the role? When is it at its strongest?
MCL limits VALGUS stress
It is taut in extension (strongest in knee extension)
Structure: broad, flat, long--> helps to resist valgus force, attaches to medial meniscus and continuous with joint capsule
When are the primary ligaments at most risk for injury? (MCL, LCL, PCL, ACL)
MCL: from valgus force when knee flexed (strongest in knee extension)
LCL: varus force when knee flexed
ACL: knee flexed and a person twists on their knee
PCL: knee extended?
What are abnormalities in the angle of inclination of the femoral head called? What about in the angle of torsion for the femur?
Abnormalities in angle of inclination: Normal inclination is 125 degrees, the angle of inclination is between the longitudinal axis of the femoral shaft and the line of the femoral head and neck in frontal plane
- coxa valga: > 125 degrees
- coxa valga: < 125 degrees
Abnormalities in the angle of torsion: angle of torsion is in between the femoral condyles and the line of the femoral head and shaft in the transverse plane, normal is 8-15 degrees
- Anteversion: pathological INCREASE in the angle of torsion, > 15 degrees
- Retroversion: pathological DECREASE in the angle of torsion, < 15 degrees
How will coxa valga, coxa vara and femoral anteversion affect gluteus medius strength?
Coxa Valga: The moment arm will decrease so there will be less force available for the gluteus medius
Coxa Vara: The moment arm will increase so the gluteus medius will have the ability to be stronger (if everything else is the same)
Anteversion: The moment arm will decrease????
Describe the menisci, including shape, attachments and function. Which ligaments attach to the medial meniscus and lateral meniscus?
Role: improves joint congruency, shock absorption and decreases friction
Shape: borders thick, centers thin
- Medial meniscus: C shaped
- Lateral meniscus: O shaped
Attachments: medial has more ligamentous and capsular restraints then lateral meniscus, BOTH menisci are attached indirectly or directly to the patella by the patellomeniscal ligament, Medial meniscus is firmly attached to the medial joint capsule by the MCL, Medial meniscus also attaches to the ACL and PCL, Lateral meniscus inserts on the tibia and the PCL and medial femoral condyle via meniscofemoral ligament
For the LCL, what is the primary role? What is the structure (attachments) and when is it strongest?
LCL resists VARUS forces and lateral rotation
There is NO attachment to lateral meniscus, it is outside of the joint capsule, attaches to fibular head
Relaxed in flexion, taut in extension (strongest here)
What function does the patella serve at the knee joint? How should the patella track?
Patella increases the moment arm of the quads- anatomical pulley, without it there would be no moment arm for the quads
During extension: the patella travels upward and moves from a lateral to medial position
What is the function of the hip joint capsule and ligaments?
Hip joint capsule function: osteokinematics (flexion, extension, abduction, adduction, IR, ER) and arthrokinematics
- anterior/superior part: thick
- posterior/inferior part: thin
Hip joint ligaments:
- Iliofemoral (Y ligament): attaches to AIIS and greater trochanter, checks hip extension
- Pubofemoral: attached to superior ramus of pubis and intertrochanteric fossa, checks extension
- Ischiofemoral: originates on posterior side (acetabular labrum) but wraps around to anterior side (greater trochanter) , also checks extension
You observe your patient during a single leg stance on the left/ Your patients right pelvis drops approx. 2 inches compared to the left. Which muscles/side are weak?
Left gluteus medius
Describe the arthrokinematics within the knee joint as the femur moves from full extension to full flexion (closed chain).
Femur (convex) is moving on the tibia (concave)
Femur roles posteriorly and tibia glides anteriorly
Role: restrains anterior tibial translation (best in extension) and hyperextension, also resists rotation when knee is slightly flexed
2 bundles: PLB (posterior lateral bundle): full extension, AMB (anterior medial bundle): increased flexion
Attaches to LATERAL CONDYLE medial portion of the femur and center of the tibia at the intercondylar ridge
Full ext/flex- patella least effective
What is the position of max congruency at the hip? What is the closed pack position of the hip? What position is the joint at greatest risk for dislocation?
Max congruence: flexion, abduction and ER
Closed pack position: extension, IR, slight abduction
Highest risk for dislocation: with the leg straight and hip adducted????
What is sacral nutation and what are the movements involved in sacral nutation? What about sacral counternutation?
Nutation: Posterior pelvic tilt, nutation of sacrum (top of sacrum tilts down, tail of sacrum comes upwards), hip extends, lumbar spine flexes
Counter nutation: anterior pelvic tilt, counter nutation (top of sacrum tilts backwards, tail goes inward), hip flexes, lumbar spine extends
What is terminal knee extension? What are the structures involved?
At the very end of knee extension, there is slight external rotation at the knee, the knee is then said to be in a "locked" position
The popliteus muscle can "unlock" the knee to bring it out of knee extension
What is the role of the PCL? What are the bundles and where are they most useful? Where does it attach?
Role: restrains posterior tibial translation
Bundles: ALB (anterolateral bundle): increased flexion, PMB (posterior medial bundle): full extension and deep squat
Structure: has a large surface area of attachment--> more stability, attaches from posterior portion of the tibia to the lateral side of the MEDIAL CONDYLE
Which facet of the patella is likely to undergo excessive degeneration? For example squatting down a lot in your job could cause damage to....
medial and lateral facets experience the most degeneration
What is the PROM generally available to the hip in flexion, extension, abduction, adduction, IR and ER? What structures limit each motion?
Flexion: 120 degrees, limiting structures for PROM: tight hip extensor muscles
Extension: 20 degrees, limiting structures for PROM: the 3 hip ligaments, tight hip flexor muscles
Abduction: 45 degrees, limiting structures for PROM: tight hip adductors
Adduction: 20 degrees, limiting structures for PROM: tight hip abductors
IR: 45 degrees, limiting structures for PROM: tight hip ER
ER: 45 degrees, limiting structures for PROM: tight hip IR
What muscles are involved in anterior pelvic tilt? What about posterior pelvic tilt?
Anterior: hip flexors (psoas), erector spinae
Posterior: abdominals, hamstrings
What happens to the menisci during knee motion?
the meniscus takes on a lot of load during knee motion so it is absorbing the load and also helping joint congruency/lubrication
If the meniscus is not there, the loads will increase on a smaller surface area which may disrupt hyaline cartilage
What are the posterior capsular ligaments of the knee? What do they restrict?
Oblique popliteal ligament and arcuate ligament
Both resist hyperextension
Describe patella alta/baja.
Patella alta: increase in length of patellar ligament, the patella rides high--> increases risk for instability
Patella baja: decrease in length of patellar ligament, patella rides lower