Hip Flashcards
What is the angle of inclination at birth? As an adult?
140-150 degrees
125 degrees
Coxa vara
Angle is less than 125 degrees.
Disturbs length tension relationship of gluteus medius
Positive: Increased moment arm for hip abductor force, alignment can improve joint stability.
Negative: increase moment arm bending and sheering forces across the femoral neck, especially bad for people with osteoporosis because their femoral neck is already weak.
Overall decreased functional length of hip abductor muscles (going to be shorter), going to be harder to control trendelenberg gait
Coxa valga
Angle is greater than 125 degrees
Disturbs length tension relationship of gluteus medius
Positive: decreased bending moment arm and decreases shearing forces across femoral neck
Increased functional length of hip abductor muscles
Negative: decreased moment arm for hip abductor force
Alignment may favor joint dislocation
Normal torsion angle of femoral neck
10-15 degrees anteversion
Excessive anteversion
Greater than 15 degrees
Femoral head moves anteriorly and greater trochanter moves posteriorly. Shaft of femur does not move.
Disturbs length tension relationship of gluteus medius.
If body compensates, the whole lower extremity will internally rotate and person will walk with a toes in position. If child compensates then they correct for that proximally and maintain length tension relationship (good).
Can go undiagnosed if child doesn’t compensate
Retroversion
Less than 10 degrees
Femoral head moves posteriorly and greater trochanter moves anteriorly
Out toeing
Femoral head is located
Just inferior to middle 1/3 of inguinal ligament
Head has a fovea with ligamentum teres
Branch of obturator artery brings small blood supply to femoral head
Acetabular labrum
Fibrocartilage
Deepens the socket
Cartilage of the dome is thickest
Along the superior/inferior region because this is where weight bearing happens
Iliofemoral ligament
AIIS to intertrochanteric line
Full extension stretches the ligament and full ER stretches the lateral bundle of the ligament
If someone cuts this ligament you will get huge increase in extension, if it scars down you won’t get any extension
One of the strongest ligaments in the body
Ischiofemoral ligament
Ischium to greater trochanter
Superficial fibers get taut with extension and IR
Superior fibers get taut with adduction
Inferior fibers get taut with flexion
Pubofemoral ligament
Anterior/inferior rim of acetabulum, superior pubic ramus and then blends with medial fibers of iliofemoral ligament
Taut with hip extension and abduction
Closed pack position of the hip
Extension, IR, abduction
Position of maximal congruency for the hip
90 degrees hip flexion, moderate ER, and abduction
Little passive tension to the ligaments in this position
Full hip flexion
120 degrees with knees bent
80 degrees with knees straight because hamstring is short
If you bend your knee and it’s still that still happens it’s a capsular issue, have to mobilize here
Slackens most ligaments but stretches inferior capsule
Hip extension
20 degrees beyond neutral with knee straight
Limited to neutral with knee bent (because rectus is on full stretch)
Stretches all ligaments and hip flexor muscles
Abduction
40 degrees
Limited by tension in the pubofemoral ligament
Adduction
25 degrees beyond neutral
Limited by hip abductor muscles, contralateral limb, and superficial fibers ischiofemoral ligament and ITB
Hip internal rotation
35 degrees
Unchanged by flexion/extension of hip
Limited by piriformis and parts of the ischiofemoral ligament
Hip external rotation
45 degrees
Limited with increased amounts of hip flexion (because soft tissues in post gluteal region are wound up in this position)
Limited by TFL and lateral fibers of the iliofemoral ligament
Ipsidirectional lumbopelvic rhythm
Pelvis and spine rotate in the same direction
Contra-directional lumbopelvic rhythm
Pelvis rotates in one direction while lumbar spine rotates in the opposite direction
So pelvis goes forward into anterior tilt and lumbar spine goes back into extension
Osteokinematics of pelvis on femoral movement all use contra-direction lumbopelvic rhythm
Force couple anterior tilt
Between erector spinae in the back and iliopsoas and rectus femoris in the front
Increase in lumbar lordosis
Greater lordosis will increase compression forces at the facet joints
Force couple posterior tilt
Between the abdominals in the front and gluts and hamstrings in the back
Reduces lumbar lordosis
Example SLR exercise
Requires forceful contraction of the abdominals
If someone has exaggerated lumbar lordosis, their abs may be really weak, unlikely except for polio patients
Closed chain abduction
Support hip abduction occurs as you’re raising or hiking iliac crest on the nonsupport hip
Lumbar spine bends in the direction opposite of the rotating pelvis
Closed chain adduction
Support hip adduction occurs as you lower iliac crest on the nonsupport hip
Closed chain IR
Closed chain ER
Closed chain IR of the support hip occurs as the nonsupport hip rotates forward
Closed chain ER of the support hip occurs as the nonsupport hip rotates backward
Primary hip flexors
Iliopsoas, sartorius, TFL, rectus femoris, pectineus, adductor longus
Secondary hip flexors
Adductor brevis, gracilis, anterior fibers of glut minimis
In the abducted position the iliopsoas can assist in
External rotation
Rectus femoris is responsible for
1/3 of total isometric flexor torque at the hip
The axis of rotation is
Behind the hip joint and anterior to the knee joint normally
Osteoarthritis causes anterior tilt so the axis of rotation moves in front of hip and posterior to the knee
Changed the way body weight should fall through lower extremity
Iliofemoral ligament and psoas major and hamstrings get really short
Primary hip adductors
Pectineus, adductor longus, brevis, Magnus, gracilis
Secondary hip adductors
Long head biceps femoris, gluteus maximus inferior fibers, quadratus femoris
Superficial on cadaver, middle, and deep
Pectineus, AL, gracilis
Adductor brevis
Adductor Magnus (biggest)
Why do soccer and hockey players pull their groin?
Because it is constant stop and go. Muscles are vulnerable here
What happens when you kick leg across body (in adduction)
Right leg is open chain adduction, concentric contraction, needs to produce a lot of force
Left leg closed chain adduction because right pelvis dropping down, glut med on this side may be eccentrically lengthening to control some of the closed chain adduction that may be happening on opposite pelvis
Also adductor Magnus on right side trying to stabilize so we don’t get hip flexion
Sagittal plane adductors
Regardless of hip position the post fibers of add Magnus are always a potent extensor of the hip, too far posterior
Remaining adductors can become
Flexors or extensors depending on position
In hip flexion adductor longus
In hip extension
Is posterior to the axis of rotation so it becomes a hip extensor
Is anterior to the axis of rotation so it becomes a hip flexor
Secondary internal rotators of hip
Anterior fibers of gluteus minimis, glut medius, TFL, AL, AB, pectineus, semitendinosis, semimembranosis
What happens to secondary internal rotates when hip is flexed 90 degrees
The line of force becomes perpendicular to the axis of rotation which increase torque potential so they become primary internal rotators
In an anatomical position most adductors can
Produce modest amount of IR of the hip
Linear aspera is
Anterior to the longitudinal axis of rotation, because of this the adductors have the ability to produce IR
The more hip flexion the more torque you can produce
If you want to strengthen internal rotators
Put hip in flexed position first, especially if they had a bad groin pull)
So if you want gluteus minimis to function as hip internal rotators you need to put it in hip flexion
Greatest glut medius EMG activity is found
In side lying and internal rotation in the position of a clam shell
Primary hip extensors
Glut max, hamstrings, posterior head of adductor Magnus
Secondary hip extensors
Posterior fibers glut medius and adductors with hip flexed more than 50 degrees
From about 75 degrees of hip flexion adductor Magnus and hamstrings
Produce equal extension torque
Primary hip abductors
Glut medius, minimis, TFL
Secondary hip abductors
Sartorius, piriformis
Which muscle has greater abductor moment arm and largest cross sectional area
Gluteus medius
Gluteus medius is broken up into
Anterior fibers: IR/flexion
Posterior fibers: ER/extension
Middle fibers
If you want to strengthen glut medius
Stay away from hip flexion, in hip flexion they will get stronger as IR
Why and when are the hip abductors important during gait
During swing phase when the stance side hip abductors keeps the pelvis from dropping (trendelenburg)
The quadratus lumborum on the swing phase will concentrically fire to assist
Primary hip external rotators
Glut max, sartorius, piriformis, obturator internus, sup/inf gemellus, quadratus femoris
Secondary hip external rotators
Post fibers of glut medius, glut minimis, long head biceps femoris, obturator externus
Why is the obturator externus secondary
Sine line of force only milimeters posterior from axis of rotation (small MA)
