A10. Examination of the pyramidal signs
Appearance
Pyramidal signs are signs which refer to a lesion of the pyramidal (corticospinal) tract. Presence of pyramidal signs in infants is physiological. The most important pyramidal sign is Babinski sign. These signs are specific for pyramidal injury, but they are not sensitive.
Hyperreflexia (= increased reflex response) and spasticity are also generally seen in pyramidal lesions but is not specific
Babinski sign
- Most important pyramidal sign
- Procedure:
- Ask patient to lie on their back
- Scratch the lateral half of the sole of the foot from bottom to top
- Response is usually not seen at the beginning of the movement but rather after some centimetres
- Negative:
- Plantarflexion, flexion of all toes
- Positive:
- Dorsiflexion of the big toe
- The other toes spread out
Triple flexion response/triflexion response
- Same procedure as for Babinski sign
- Can be felt more easily with one hand on the quadriceps muscle
- Negative:
- Plantarflexion of all toes
- Positive:
- Dorsiflexion of foot + flexion of knee + flexion of hip
Achilles clonus
- Procedure:
- Ask patient to lie on their back
- Dorsiflex the foot quickly
- Negative:
- No clonus in the gastrocnemius
- Positive:
- Clonus in the gastrocnemius
Patellar clonus
- Procedure:
- Ask patient to lie on their back
- Quickly thrust the patella downwards
- Negative:
- No clonus in the quadriceps
- Positive:
- Clonus in the quadriceps
Hoffman sign
- Procedure:
- Hold the PIP joint of the middle finger, stabilizing it
- Repeatedly flick down the distal phalanx of the middle finger
- Negative:
- No flexion of the distal phalanx of the thumb or the index finger
- Bilateral response may be normal
- Positive
- Flexion of the distal phalanx of the thumb or the index finger
Trömner sign
- Procedure:
- Hold the PIP joint of the middle finger, stabilizing it
- Suddenly flick the volar aspect of the distal phalanx of the middle finger
- Negative:
- No flexion of the distal phalanx of the thumb or the index finger
- Bilateral response may be normal
- Positive
- Flexion of the distal phalanx of the thumb or the index finger