Normal gait cycle
The gait cycle has six phases:
- Heel-strike:- initial contact of the heel with the floor.
- Foot flat:- weight is transferred onto this leg.
- Mid-stance:- the weight is aligned and balanced on this leg.
- Heel-off:- the heel lifts off the floor as the foot rises but the toes remain in contact with the floor.
- Toe-off:- as the foot continues to rise the toes lift off the floor.
- Swing:- the foot swings forward and comes back into contact with the floor with a heel strike (and the gait cycle repeats).
Hemiplegic gait
- A hemiplegic gait is typically caused by a lesion in the central nervous system (e.g. stroke) which results in unilateral weakness and spasticity.
- Patients with hemiplegia exhibit spastic flexion of the upper limb and extension of the lower limb.
- Due to the extension of the lower limb (fixed ankle plantar flexion and knee extension), the leg is elongated meaning patients have to circumduct their leg to prevent their foot from dragging on the ground.
Associated clinical features
Clinical features which may be associated with a hemiplegic gait include:
=> Increased tone with clasp-knife spasticity
=> Hyperreflexia with or without clonus
=> Upgoing plantars (i.e. positive Babinski)
=> Reduced power
=> Sensory deficit: the pattern of sensory loss depends on the site of the lesion in the nervous system
Causes
Unilateral cerebral lesion:
=> Stroke
=> Space-occupying lesion
=> Trauma
=> Multiple sclerosis
Hemisection of the spinal cord:-
=> Trauma
Diplegic gait
=> A diplegic gait (a.k.a scissoring gait) may be caused by a lesion in the central nervous system (e.g. stroke, or complete transection of the spinal cord).
=> Clinical findings are similar to those in hemiplegic gait but are bilateral in nature. Spasticity is typically worse in the lower limbs compared to the upper limbs.
=> The hips and knees are flexed and abducted whilst the ankles are extended and internally rotated.
=> The knees are forced together due to spasticity in the adductor muscles resulting in leg overlap when walking (a.k.a. scissoring).
=> In an attempt to overcome this adduction, the patient circumducts both legs during the swing phase.
=> The upper limb may have flexor posturing of the elbows and wrist with shoulders and fingers in adduction (known as ‘low guard’ or ‘mid-guard’ position). They also typically lack the swinging movements present in a normal gait.
Associated clinical features
Clinical features which may be associated with a diplegic gait include:
=> Increased tone with clasp-knife spasticity
=> Hyperreflexia with or without clonus
=> Upgoing plantars (i.e. positive Babinski)
=> Reduced power
=> Sensory deficit – if a diplegic gait is caused by spinal cord pathology, the ‘sensory level’ (ie. the lowest dermatome level with normal sensation) correlates with the level of spinal cord pathology
=> Wasting and fasciculations (consider motor neuron disease)
Causes
Spinal cord lesion (sensation usually affected):
=> Prolapsed intervertebral disc
=> Spinal spondylosis
=> Spinal tumour
=> Transverse myelitis
=> Spinal infarct
=> Syringomyelia
=> Hereditary spastic paraparesis
Bilateral brain lesion:
=> Cerebral palsy
=> Multiple sclerosis
=> Bilateral brain infarcts
=> Midline tumour (e.g. paraspinal meningioma)
Motor neuron disease:- associated with lower motor neuron findings.