HFA213 Hip in locomotion
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HUMAN FUNCTIONAL ANATOMY 213
THE HIP IN LOCOMOTION
HFA213 Hip in locomotion
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WALKING EFFICIENTLY
Moving from point A to point B (Translation)
Minimum of energy ---- in a straight line
Best done with wheels...(Centre of gravity stays at the
same level)
THIS WEEKS LAB:
Arm and thigh
In this lecture
Walking efficiently
Extension (stance) and Flexion (swing)
Medial rotation (stance) and lateral rotation (swing)
Adduction (stance) and adbuction (swing)
Limps: examples from pathology
Abductor
Extensor
Flexor
But we do it with levers
To get efficient translation with levers we need to minimise sideways
or vertical movement of the CoG
Readings
1. Stern – Core concepts – section 101
2. Grants Method of Anatomy – shoulder in joints of the
upper limb
3. Stern:- 'Use of the lower limb muscles in walking'
4. Basmajian:- Muscles alive; section on walking
5. Any kinesiology book (locomotion section)
a. Eg. Steindler., Rasch and Burke, Brunnstrom
HFA213 Hip in locomotion
Need to consider:
1. The gait cycle.
2. The movements of the joints
3. Understand what causes the movements
a. Muscle action – Muscles act as prime movers (agonist)
b. Momentum produces movement – muscles resist (synergists)
c. Ground reaction – Impact with ground at heel strike
requires the synergistic action of muscles.
4. Appreciate how the muscles contribute
5. How each movement and muscle action improve efficiency
6. How efficiency is reduced in abnormal gaits.
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HFA213 Hip in locomotion
THE GAIT CYCLE
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HIP IN LOCOMOTION
Sagittal movement
STANCE PHASE & SWING PHASE
STANCE PHASE
Begins at heel strike
Then toe come down (foot flat)
Then heel comes off the ground (heel off)
Finally the toes come off the ground (toe off)
SWING PHASE
Begins at toe off
Ends at heel strike
Stance phase
Movement = Extension
Causation
1. Heel strike
Extensor muscles (resist flexion due to
ground reaction force)
2. Most of stance phase - Momentum (hamstrings silent)
HS
Swing phase
HS
FF
MS HO
TO
Always at least one limb in contact with the ground (not in
running)
Period when there are two feet on the ground (Double support
phase)
The double support phase is variable (speed of walking etc.)
FF
MS HO
TO
Movement = Flexion
Causation
Toe off
Flexors start swing movement
Most of swing Momentum (swing)
End of swing Extensors decelerate the limb (get ready for impact
of heel strike)
If it's only flexion and extension then the CoG will move up and down a lot
High in the middle of the stance phase
Low in the double support phase
Wasted energy ----- additional mechanisms......
HFA213 Hip in locomotion
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HIP IN LOCOMOTION
Horizontal plane movement - Rotation
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HIP IN LOCOMOTION
Frontal plane movement - Adduction and abduction
Raises the trough of the wave (double support phase)
No pelvic rotation
HFA213 Hip in locomotion
Lowers the peak of the wave (middle of stance)
with pelvic rotation
Top view
Front view
Side view
Adduction at the hip - Left and right feet fall on a straight line
Rotation of the pelvis on the trunk
Early stance phase Movement = Adduction
Gives same stride length for less flexion and extension of the hip
Therefore less fall in double support phase
Causation: Trunk muscles and Momentum
Causation: Ground reaction/gravity (resisted by the abductors acting
eccentrically)
Late stance phase Movement = Abduction
Rotation at the hip - Keeps lower limb in sagittal plane
Stance phase Movement = Medial rotation
Causation: Abductors acting concentrically
Causation: Ground fixation and movement of trunk
Swing phase
Movement = Lateral rotation
Causation: Lateral rotators acting concentrically
HFA213 Hip in locomotion
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HIP IN LOCOMOTION
Abductor limp - Stance phase
Frontal plane stability
During stance phase when the weight of the
body is supported on one limb there is a
tendency for the body to fall to the unsupported
side. Abductors normally prevent this excess
adduction of the supporting hip
If the abductors are paralysed the body would
fall to the unsupported side during each stance
phase - this would be very unstable and
inefficient
Instead people with this deficiency tend to throw
their trunk towards the affected side in stance
phase - Trendelenburg gait
This is typical:
1. We do not see the deficient muscle group
letting the patient down
2. But the body's compensation for the
deficiency
HFA213 Hip in locomotion
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HIP IN LOCOMOTION
Extensor limp - Stance phase
Absorbing the shock of heal strike
The hip extensors act at heal strike to prevent hip flexion
which would occur due to the forward momentum of the body
acting over the newly grounded limb. (“jack-knifing”)
If the hamstrings were paralysed you might expect that the body
would jack-knife at each heel strike. – The person with the injured
hamstring would collapse at each heel strike!
The body compensates for a deficiency in the hamstrings by
throwing the weight of the trunk backwards just before heel
strike. This brings the centre of gravity of the upper body well
behind the hip joint so that gravity prevents hip flexion at heel
strike.
AGAIN - what you see is
1. We do not see the deficient muscle group letting the
patient down
2. But the body's compensation for the deficiency
HFA213 Hip in locomotion
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HIP IN LOCOMOTION
Flexor and/or adductor limp - Swing phase
Swinging the limb
Adductors and iliopsoas act late in stance and early in swing
phase.
1. Late in stance to decelerate the extension of the hip caused
by momentum and ground reaction force.
2. Early in swing (concentric action) to get the limb swinging
forwards
It is vital that the limb is swung forwards so that it is ready to
stop you falling over!!
If the hip flexors (and adductors) are paralysed, the limb must be
swung forward by some other means:
1. Rotation of the pelvis on the trunk.
2. Forceful medial rotation of the opposite hip.
3. Possibly extra toe off.