Transcript Hip Lecture

The Lower
Extremity:
Functional
Consequences
of Bipedality
Form
Follows
Function
(From J.G. Fleagle’s Primate Adaptation & Evolution, 1988)
Bipedal Locomotion
ONLY in humans!!!
(From R.M. Alexander’s The Human Machine, 1992)
Why are we so unique?
MUST STAND UPRIGHT!
4 Design Considerations for
Bipedal Gait and Upright Posture
1) Stability in Upright Posture
2) Ability to Raise & Control Trunk
Over Hindlimbs
3) Ability to Balance on One Leg
4) Walk with Feet Underneath Body
Stability
lower extremities
larger & heavier than
upper extremities
Weebles wobble but
they don’t fall down!
Ability to Raise
& Control Trunk
Over Hindlimbs
Gluteus
Maximus
sacral
attachment
Ability to Balance
on One Leg
Well-developed
Hip Abductors
gluteus medius
gluteus minimus
Tm
TW
W
ANGLE OF FEMUR
14-15 degrees
moves CM more directly over
base of support
DON’T HAVE TO SHIFT
LATERALLY WHEN YOU
WALK!
ilium
sacrum
head
greater
trochanter
acetabulum
ischium
pubis
neck
Obturator foramen
ANTERIOR VIEW
lesser
trochanter
POSTERIOR VIEW
Comparison to Shoulder
• the hip is a “weight bearing” joint
• both are ball-and-socket joints
• acetabulum much deeper than glenoid fossa
– both have a “labrum” to increase depth of the socket
• hip has more bony support than shoulder
• left and right shoulder girdles are more
independent than the corresponding portions of the
pelvis/femur
Gender
• Females have pelvic
girdles that are lighter,
thinner and wider than
their male counterparts.
• The female pelvis flares
out more laterally in the
front and the sacrum is
wider in the back,
creating a broader pelvic
cavity than males.
Pelvic movement
• Concomitant movement of the pelvic girdle
and the thigh at the hip joint are necessary
for efficient joint actions.
• Movements of the pelvis are described by
monitoring the ilium - specifically the
anterior superior iliac spine.
Anterior Tilt
• forward tilting and
downward
movement of the
pelvis
• occurs when the hip
extends
Posterior Tilt
• tilting of the pelvis
posteriorly
• occurs when the
hip flexes
Lateral Tilt
• tilting of the pelvis from neutral
position to the right or left
• lateral tilt tends to occur
naturally when you support
your weight on your leg
• this allows you raise your
opposite leg enough to swing
through during gait
Pelvic Rotation
• rotation of the pelvis defined by the
direction in which the anterior aspect
of the pelvis moves
• occurs naturally during unilateral leg
movements (walking)
– as the right leg swings forward
during gait the pelvis rotates left
Hip Joint
capitis femoris ligament
(round ligament)
acetabular
labrum
•The femoral head and
acetabulum have large
amounts of spongy,
trabecular bone to help
attenuate forces.
•Approximately 70% of
the head of the femur
articulates with the
acetabulum.
sagittal view of right hip
Hip Ligaments
anterior view of
right hip
iliofemoral
(Y-shaped)
Resists extension,
internal rotation and
some external rotation.
pubofemoral ligament
Resists abduction and
some external rotation.
Hip Ligaments
ischiofemoral ligament
Resists adduction and
internal rotation.
Note: none of these
ligaments restrict
flexion.
posterior view of right hip
Femoral Neck
•The neck holds the femur
away from the pelvis.
•It is formed by cancellous
trabecular bone and reinforced
with cortical bone, particularly
on the inferior portion.
•The angle of inclination is
measured in the frontal plane
and typically ranges from 90
to 135 degrees.
Coxa Vara
•If the angle of inclination is
less than 125 degrees it is
termed coxa vara.
•This shortens the limb,
increases the effectiveness of
the abductors, reduces the load
on the femoral head and
increases the load on the
femoral neck.
Coxa Valga
•If the angle of inclination is
greater than 125 degrees it is
termed coxa valga.
•This lengthens the limb,
reduces the effectiveness of
the abductors, increases the
load on the femoral head and
reduces the load on the
femoral neck.
Angle of Anteversion
•The angle of the femoral neck
in the transverse plane is
termed the angle of
anteversion.
•Normally the femoral neck is
rotated anteriorly 12 to 14
degrees with respect to the
femur.
Excessive Anteversion
•Excessive anteversion beyond
14 degrees causes the head of
the femur become uncovered.
•In order to keep the head of
the femur within the
acetabulum a person must
internally rotate the femur.
Retroversion
•If the angle of anteversion is
reversed so that it moves
posteriorly, it is termed
retroversion.
•This condition causes the
person to externally rotate the
femur.
Hip Range of Motion
Movement
Range
flexion
70-140o
hyperextension
4-15o
adduction
20o
abduction
30o
internal rotation
70o
external rotation
90o
Primary Hip Flexors
psoas major
iliacus
(aka iliopsoas)
Assisting Hip Flexors:
pectineus
rectus femoris
sartorius
tensor fascia latae
Assisting Hip Flexors:
pectineus
tensor fascia latae
sartorius
rectus femoris
Hip Extensors
Gluteus maximus
Hamstrings
biceps femoris
semitendinosus
semimembranosus
semimembranosus
M
medial
semitendinosus
T
biceps femoris
B
lateral
long head
short head
Biceps Femoris
Hip Extensor
gluteus maximus
Hip Abductors
gluteus medius & minimus
Hip Adductors
pectineus
adductor brevis
adductor longus
adductor magnus
anterior view
Hip Adductors
gracilis
posterior view
Medial Rotation
of the Hip
• due primarily to the
gluteus medius and
minimus
– extension of hip tends to
laterally rotate femur so
medial rotators needed to
neutralize this effect
– not usually performed
against resistance, thus not a
lot of muscular support
– medial much weaker than
lateral rotation
Assisting Muscles
semimembranosus, semitendinosus,
tensor fascia latae, and hip adductors
Lateral Rotation of the Hip
• lateral rotation - 5 muscles
– lateral rotation is a natural
movement in human gait to
accommodate pelvic
rotation
Phases of Walking
Muscle Activity During Walking
Muscle
Footstrike Midsupport Toe-off Swing Decel.
Dorsiflexors
***
**
**
**
**
Intrinsic Foot
***
Gluteus Maximus
*
**
***
*
Gluteus Medius
**
***
**
*
Gluteus Minimus
**
***
**
*
Hamstrings
***
**
**
*
**
Iliopsoas
***
Plantar Flexors
*
**
Quadriceps
*
***
**
*
Sartorius
**
*
Tensor Fascia Latae *
**
*
***
Thigh Adductors
**
**
*
**
*
Hip Fractures
•
•
•
•
•
occurs in neck of femur
usually due to a decreased bone mineral density
87% are 65 or older
current annual cost is more than $9.8 billion
accounts for more hospital days, by far, than any
other musculoskeletal injury
• results in increased mortality, reduced mobility,
and, for many, the inability to live independently
– American Academy of Orthopaedic Surgeons
Hamstring Injuries
• few activities require simultaneous hip
flexion and knee extension
– usually little hamstring stretch except for
specific exercises
– hamstrings susceptible to strain due to this poor
extensibility
– injuries most often occur during sprinting particularly when muscle is fatigued
Hamstring Injuries - Theories
• overstretching of muscle
– for example: during overstriding
• development of maximal tension when
muscle is fully elongated
– development of max tension necessary to act
antagonistically to quads which are stronger
Which side of the body do you use a cane on
when your hip is hurt?
opposite
same
hurt
leg
W
hurt
leg
W