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Related Subjects:
|Neurological History taking
|Cortical functions
|Motor System
|Sensory System
|Mental state Examination
|Speech and Language Exam
|Cranial nerves and examination
|Assessing Cogniton
Anatomy
- Conscious sensation passes ultimately from sense organ to contralateral parietal lobe
- From sensory receptor passes into the cord through the dorsal root.
- Passes into either through
- Dorsal columns
- Carry afferent proprioception, vibration and fine touch.
- Fibres remain on the same side of the cord
- Fibres cross over at the foramen magnum
- Spinothalamic tracts.
- Cross over to other side of cord very quickly after entering
- Ascends in spinal cord and passes to ipsilateral thalamus
- Then crosses over to contralateral parietal lobe
- Minimum exam
- Cutaneous sensation is pinprick and light touch (cotton wool) over dermatomes comparing right and left
- Test for temperature as well as proprioception
- Proprioception (Dorsal Column)
- Testing: Tests dorsal columns which also carry vibration and touch sensation.
- Choose distal joint and move proximally. Hold joint by side and isolate joints above and below so that only one is moved. Ask the patient to describe the orientation of the digit or toe or foot. With eyes closed get the patient to touch nose.
- Romberg test: Patient stands with feet together. Push to chest to see if the patient can maintain a stance. If unable to then this is instability which could be for a variety of reasons. Repeat with eyes closed and see and if this makes a marked difference then suggests that visual input vital to maintaining posture and there is a problem with dorsal column function carrying proprioception information
- Vibration (Dorsal Column)
- Use a 128 Hz tuning fork and apply to distal bony points e.g. bony part of the big toe, medial malleolus, patella
- See if a vibrating can be distinguished from a non-vibrating fork
- Temperature (Spinothalamic)
- See if patient appreciates the coolness of the tuning fork
- Isolated loss can be seen in hemi-cord lesions and lateral medullary syndrome
- Fine touch (Dorsal Column)
- Use cotton wool ball in each of the dermatomal areas or any area of decreased sensation working to that with normal sensation.
- Pinprick (Pain) (Spinothalamic)
- Use disposable pins. Move from areas with sensory loss to normal. Spinothalamic
Interpretation
- Patterns of Sensory loss
- Sensory loss - over one side of body face/arm and leg is seen with contralateral intracranial pathology
- Symmetrical cape-like loss of pain and temperature over shoulders and hands suggests syringomyelia
- Loss of proprioception suggests B12 involvement with SACD or Tabes dorsalis
- Glove and Stocking loss suggests peripheral neuropathy
- Sensory loss below a certain area symmetrically suggests spinal cord disease
- Reduced perineal sensation suggests cauda equina damage
- Perineal Examination
- Becomes important when there is concern that lower sacral nerves have been affected usually by a suspected cauda equina lesion
- Ask about urinary incontinence or overflow or retention and erectile dysfunction
- Do a rectal exam and ask the patient to squeeze on your finger looking for signs of weakness
Dermatomes
- Thumb:C6
- Middle finger:C7
- Little finger: C8
- Breast nipple:T4
- Umbilicus:L4
- Big toe:L5
- Little toe:S1
- Inner back of legs: S2
- Saddle area: S1 to S5