Kinesiology Final High Yield

What type of joint is the hip?

Ball and socket

Which articular surface is convex at the hip?

Femoral head

Which articular surface is concave at the hip?

Acetabulum

What arthrokinematic rule applies during open chain hip motioon?

Convex on concave—>roll and glide occur in opposite directions

Which arthrokinematic rule applies during closed chain hip motion?

Concave on convex—>Roll and glide occur in opposite directions

What are the arthrokinematics of open chain hip flexion?

Anterior roll, posterior glide

What are the arthrokinematics of open chain hip extension?

Posterior roll, anterior glide

What are the arthrokinematics of open chain hip abduction?

Superior roll, inferior glide

What are the arhtrokinematics of open chain hip adduction?

Inferior roll, superior glide

What are the arthrokinematics of open chain hip internal rotation?

Anterior roll, posterior glide

What are the arthrokinematics of open chain hip external rotation?

Posterior roll, anterior glide

What are the arthrokinematics of closed chain hip flexion?

Posterior roll, posterior glide

What are the arthrokinematics of closed chain hip extension?

Anterior roll, anterior glide

What are the arthrokinematics of closed chain hip abduction?

Inferior roll, inferior glide

What are the arhtrokinematics of closed chain hip-adduction?

Superior roll, superior glide

What are the arthrokinematics of closed chain hip internal rotation?

Posterior roll, posterior glide

What are the arthrokinematics of closed chain hip external rotation?

Anterior roll, anterior glide

Why do roll and glide occur in opposite directions during open chain hip motion?

Because the convex femoral head moves on the concave acetabulum

Why do roll and glide occur in the same direction during closed chain hip motion?

Because the concave acetabulum moves on the convex femoral head

What is the Q angle?

The angle formed by the line from the ASIS to the center of the patella and the line from the center of the patella to the tibial tuberosity

What does the Q angle represent?

The lateral line of pull of the quadriceps on the patella

Normal Q angle in males

Approximately 10-15 degrees

Normal Q angle in females

Approximately 15-20 degreees

What happens when the Q angle increases

The quadriceps exert a greater lateral pull on the patella

How does an increased Q angle affect patellar tracking?

It increases lateral patellar tracking

What condition is associated with an increased Q angle?

Patellofemoral pain syndrome (PFPS)

Is increased risk of patellar subluxation or dislocation associated with a greater Q angle?

Yes

How does an increased Q angle affect patellofemoral joint stress?

It increases compressive stress on the lateral patellofemoral joint

What lower extremity alignment can increase the Q angle?

Femoral anteversion, genu valgum (knock knees), external tibial torsion, and excessive foot pronation

How does femoral anteversion increase the Q angle?

Internal rotation of the femur moves the patella medially relative to the ASIS and tibial tuberosity, increasing the lateral pull of the quadriceps

Which muscle helps resist the lateral pull caused by an increased Q angle?

Vastus medialis obliquus (VMO)

What is the angle of torsion (femoral version)

The angle between the femoral neck axis and the femoral condylar axis in the transverse plane

What is the normal angle of femoral torsiion in adults?

Approximately 12-15 degrees of anteversion

What is femoral anteversion?

An increased angle of torsion (greater than normal anterior orientation of the femoral neck)

How does femoral anteversion affect hip ROM?

Increases internal rotation and decreases external rotation

How does femoral anteversion affect the Q angle?

It increases the Q angle

How does an increased Q angle affect the patellla

It increaes the lateral pull of the quadriceps, promoting lateral patellar tracking

What knee condition is associated with femoral anteversion?

Patellofemoral pain syndrome (PFPS) and increased risk of patellar sublaxation/dislocation

What gait pattern is commonly seen with excessive femoral anteversion?

In toeing (toe in gait)

What is femoral retroversion?

A decreased angle of torsion (less anteversion than normal)

How does femorla retroversion affect hip ROM?

Decreases internal rotation and increases external rotation

What gait pattern is commonly seen with femoral retroversion?

Out toeing (toe out gait)

Which two muscles contribute the most to hip flexion torque?

Illiopsoas (Illiacus+psoas major) and rectus femoris

Which muscles assist with hip flexion?

Illiopsoas

Rectus femoris

Sartorius

TFL

Pectineus

Adductor Longus+Brevis+Magnus

Gracilis

How many muscles cross anterior to the hip joint?

9

What is the primary hip extensor?

Gluteus maximus

Which hamstrings extend the hip?

Biceps femoris (long head)

Semitendinosus

Semimembranosus

Which muscle is the strongest hip extensor during activities like rising from a chair or climbing stairs?

Gluteus maximus

What are the primary hip adductors?

Adductor longus+brevis+magnus

Gracilis

Pectineus

What are the primary hip abductors?

Gluteus medius and gluteus minimus

During single leg stance, which muscles prevent the pelvis from dropping on the unsupported side?

Gluteus medius+minimus

During single leg stance, which muscles prevent the pelvis from dropping on the unsupported dside?

Gluteus medus and gluteus minimus of the stance limb

Weakness of which muscles produce a Trendelenburg gait?

Gluteus medius+minimus

Name the deep external hip rotators

Piriformis

Superior gemellus

Inferior gemellus

Obturator internus

Obturator externus

Quadratus femoris

Whichc large superficial muscle is also an external rotator of the hip?

Gluteus maximus

Which muscles are listed as hip internal rotators?

Gluteus medius

Gluteus minimus

TFL

Pectineus

Adductor longus+brevis

Which muscles are listed as hip internal rotators?

Gluteus medius

Gluteus minimus

TFL

Pectineus

Adductor longus+brevis

When does the piriformis function as a hip internal rotator?

When the hip is flexed greater than 60 degrees

A patient stands on their right leg and the left side of the pelvis drops, which muscles are weak

Right gluteus medius and minimus

A patient demonstrates a compensated Trendelenburg gait by leaning over the stance limb. Which muscle group are they compensating for?

Hip abductors (primarily gluteus medius and minimus)

What is the normal angle of inclination (neck shift angle)

125 derees

What is coxa vara?

Decreased angle of inclination (<125 degrees)

What is coxa valga?

Increased angle of inclination >125

How does cova vara affect the hip abductor moment arm?

Increases the abductor moment arm

How does coxa vara affect the force required from gluteus medius/minimus

Less abductor force is required because the moment arm is larger

How does coxa vara affect the force required from the gluteus medius/minimus?

Less abductor force is required because the moment arm is larger

How does coxa vara affect femoral neck stress?

Increases bending stress on the femoral neck

How does coxa valga affect the hip abductor moment arm?

Decreases the abductor moment arm

How does coxa valga affect the force required from the gluteus medius/minimus

More abductor force is required because the moment arm is shorter

How does coxa valga affect femoral neck stress?

Decreases bending stress on the femoral neck

Which condition increases abductor moment arm?

Coxa vara

Which condition decreases abductor moment arm?

Coxa valga

Which condition requires greater gluteus medius/minimus force during single leg stance?

Coxa valga

Which condition requires less gluteus medius/minimus force during single leg stance?

Coxa vara

During open chain (NWB) knee motion, which bone moves?

Tibia moves on the femur

During closed chain (WB) knee motion, which bone moves?

Femur moves on tibia

What are the three degrees of freedom of the tibiofemoral joint?

Flexion/extension (primary)

Internal external rotation

Abduction/Adduction (varus\valgus)

What type of joint is the tibiofemoral joint?

Modified hinge (double condyloid joint)

Open chain knee flexionL roll and glide?

Posterior roll+posterior glide of tibia

Open chain knee extension: roll+glide?

anterior roll+anterior glide of tibia

Closed chain knee flexion: roll and glide?

Femur rolls posterior and glides anterior

Closed chain knee extension: roll and glide

Femur rolls anterior and glides posterior

Which femorla condyle acts as the pivot during knee rotatioon?

Medial femoral condyle

Which femoral condyle moves through the greater arc during rotatioon?

Lateral femoral condyle

What is the screw home mechanism?

Obligatory coupled motion during terminal knee extension

Knee extension is coupled with what two motions?

External rotation and valgus (abduction)

During open chain (NWB) terminal knee extension, what occurs during the screw home mechanism

Tibia externally rotates on the femur (last 20-30 degrees of extension)

During the closed chain (WB) terminal knee extension, what occurs during the screw home mechanism?

Femur internally rotates on the fixed tibia (equivalently, the tibia is externally rotated relative to the femur)

What is the purpose of the screw home mechanism?

Locks the knee into a stable, close packed position during full extension with minimal musclar effort

What unlocks the knee from the screw-home mechanism in open chain (NWB)?

Popliteus medially (internally) rotates the tibia

What unlocks the knee from the screw home mechanism in closed chain (WB)?

Popliteus laterally (externally) rotates the femur

What three factors contribute to the screw home mechanism?

Longer medial femoral epicondyle

Tension in ACL

Pull of quadriceps during terminal extension

What is the primary function of the quadriceps?

Knee extension

What is the function of the quadriceps at the patella?

Pulls the patella superiorly through the quadriceps tendon and patellar tendon

What mechanical advantage does the patella provide for the quadriceps?

Acts as an anatomic pulley that increases the quadriceps moment arm

What is the function of vastus medialis?

Contributes to knee extension as part of the quadriceps

What is the function of vastus lateralis?

Contributes to knee extension as part of the quadriceps

What is the function of the hamstrings?

Help offset anterior sheaer force created by quadriceps/ACL mechanism

What shear force does the quadriceps produce at the knee?

Anterior shear of the tibia on the femur