Biomechanics Hip Flashcards
What type of joint is the hip?
Enarthrodial Joint
How many degrees of freedom does the hip have?
3
Where does stabilization for the hip come from?
Static-Ligaments
Dynamic-Muscles
Negative joint capsule pressure
What is the angle of inclination for the hip?
(In the frontal plane)
120-125 degrees
What’s the angle of inclination at birth?
150 degrees
What is Coxa vara
(
What is Coxa Valga
(>) greater than 135 degrees
Increased compression force on the femoral head
What is the anteversion?
~20 degrees
(allows the femoral condyles to face anteriorly
What is excessive anteversion?
(>) greater than 20 degrees (excessive angle)
What is retroversion?
(
What happens with anteversion
In-toeing (>) Increase angle increased anterior exposure increased chance of dislocation labral lesions Internal Rotation
What happens with retroversion?
toes pointed out
decreased angle
External Rotation
What type of joint is the femoralacetabular joint?
Synovial ball and socket joint
Where’s the axis of motion in the hip?
Through the center of the femoral head
What type of capsule encompasses the hip?
a loose, fibrous capsule
What’s the Zona Orbicularis?
A band of circular fibers that encircle the neck of the femur
(It’s stronger anteriorly)
What is the labrum?
Fibrocartilage that increases the articular surface of the of the acetabulum by 10%
What 3 ligaments strengthen the joint capsule?
Iliofemoral (Anterior)
Pubofemoral (Anterior)
Ischiofemoral (Posterior)
What movements do the ligaments in the joint prevent?
All prevent extension
Anterior portions prevent ER
Posterior prevent IR
Which ligament is referred to as the “Y” or Bigelow ligament?
Iliofemoral
Where does the iliofemoral ligament go?
AIIS to intertrochanteric line
Which ligament is the strongest?
Iliofemoral ligament
Where does the pubofemoral ligament go?
Pubis to intertrochanteric line
What motions does the pubofemoral ligament prevent?
Abduction, ER, and extension
Where does the ischiofemoral ligament go?
Posterior acetabulum to the trochanteric fossa
Limits IR
What is the ligamentum teres?
Intracapsular ligament that goes from acetabular notch to the fovea
What are some of the bursae around the hip?
Superficial and deep greater trochanter
Ischial bursa
Iliopsoas bursa
Where does the IT band run?
Runs along lateral hip and inserts distally below the knee (Gerdy’s tubercle)
What is the primary motion of the hip?
Spin of the femoral head (accompanied with a glide)
With femur-on-pelvis what are the arthokinamatics during flexion/extension
Flexion - Posterior/inferior spin & glide
Extension - Anterior/superior spin & glide
With femur-on-pelvis what are the arthokinamatics during Abduction/adduction?
Abduction - (NWB) - Superior roll/Inferior glide
Adduction - (NWB) - Inferior roll/superior glide
With femur-on-pelvis what are the arthokinamatics during IR/ER
IR - Anterior Roll/Posterior glide
ER - Posterior Roll/anterior glide