Upper limb dermatome assessment Flashcards
What is a dermatome?
An area of the skin innervated by a single spinal nerve root
Why do we assess dermatomes?
To help pinpoint the location and nature of nerve damage or injury by assessing sensory loss or changes in specific areas of skin supplied by particular spinal nerve roots
Light touch & superficial pain
Light touch - testing the DORSAL COLUMN
Superficial pain - testing the LATERAL SPINOTHALAMIC TRACT
- Use cotton wool & neurological pin
- Demonstrate sensation to patient on opposite limbs
- Ask patient to close eyes and test each dermatome C5-T1
- Ask patient to repeat “sharp” or “soft”
- If a deficit is found, test the full dermatome starting distally to try and locate the area of the lesion
- ALWAYS STATE! I would never do a test in isolation, I would always do a full neurological assessment in order to triangulate my findings
Temperature
Testing the lateral spinothalamic tract
- Use a cold metallic object (tuning fork) & warm object (cotton wool)
- Demonstrate sensation to patient on opposite limbs
- Ask patient to close eyes and test each dermatome C5-T1
- Ask patient to repeat “cold” or “hot”
Vibration sense
Testing the dorsal column
- Use a tuning fork
- Demonstrate sensation to patient on sternum & ask them to identify when the sensation stops
- Ask patient to close eyes and test on distal interphalangeal joint of finger
- Ask patient to say “stop” when the sensation is deminished
Joint position sense
Testing the dorsal column
- Demonstrate to the patient by flexing and extending their distal phalanx
- Ask patient to close eyes and say “up” or “down”
Stereognosis
Parietal lobe damage (especially on the side opposite the affected hand)
Sensory cortex lesions
Peripheral nerve damage (if sensation is reduced or absent)
Stroke, tumors, or neurodegenerative diseases
- Ask patient to close eyes and place a familiar object in their hand
- Ask patient to identify the object by touch
Graphaesthesia
Abnormal results may indicate cortical sensory loss, often due to stroke, tumours, or lesions affecting the parietal cortex.
- Ask patient to close eyes and drawer the number 8 in the palm of their hand
- Ask patient to state the number
Sensory inattention
Common in patients with hemispatial neglect, often from a stroke in the right hemisphere.
Helps distinguish between true sensory loss and inattention due to cortical dysfunction.
- Ask patient to identify touch sensation on the left side and right side
- Ask patient to close eyes and identify left and right sided sensation
