somatic spinal cord reflexes and spinal cord lesions & spinal shock
TRANSCRIPT
Somatic spinal cord reflexesAnd
Spinal cord lesions & shock
Ashish Patil MD/PhD
All Saints School of Medicine Dominica
13-2
The Stretch Reflex stretch (myotatic) reflex - when a muscle is stretched, it ‘fights back’
and contracts which maintains increased tonus, making it stiffer than unstretched muscle helps maintain equilibrium and posture
head starts to tip forward as you fall asleep muscles contract to raise the head
stabilize joints by balancing tension in extensors and flexors smoothing muscle actions
stretch reflex is fine tuned by the brain not strictly a spinal reflex
knee-jerk (patellar) reflex is monosynaptic reflex one synapse between the afferent and efferent neurons
testing somatic reflexes helps diagnose many diseases
reciprocal inhibition - reflex phenomenon that prevents muscles from working against each other by inhibiting the antagonist
Inverse stretch refelex
reciprocal inhibition - reflex phenomenon that prevents muscles from working against each other by inhibiting the antagonist
Inverse stretch reflex
Deep Tendon reflexes
Withdrawal Reflex
Golgi Tendon Reflex
Golgi Tendon Reflex
Note Tapping on patellar tendon does not stretch golgi tendon of quadriceps femoris, it stretches quadriceps femoris
Supraspinal control of stretch refelx
Supraspinal control of stretch reflex
Brown Sequard Syndrome
Half sided cortex lesions
Half sided mid brain lesion
Spinal Shock
Spinal shock is a combination of areflexia/hyporeflexia and autonomic dysfunction that accompanies spinal cord injury. The initial hyporeflexia presents as a loss of both cutaneous and deep tendon reflexes below the level of injury accompanied by loss of sympathetic outflow, resulting in hypotension and bradycardia
Spinal Cord Blood Supply
Anterior Spinal Cord Syndrome
Syringomyelia
Central Cord lesions seen in syringomyelia
Polio affect anterior horn cells
ALS has both UMNL and LMNL
Subacute combined degeneration of spinal cord
Internal capsule all 3 limbs supplied by lenticulostriate artery
Stroke of lenticulostriate artery