Special Signs and Other Tests
In this chapter, a number of signs are described which are used on particular occasions:
1 PRIMITIVE REFLEXES
Snout reflex
What to do
Ask the patient to close his eyes. Tap his mouth gently with a patella hammer.
Palmo-mental reflex
What to do
Scratch the palm of the patient’s hand briskly across the centre of the palm and look at the chin.
Grasp reflex
What to do
Place your fingers on the patient’s palm and pull your hand away, asking the patient to let go of your hand.
What it means
All these primitive reflexes may be found in normal people. They occur more frequently in patients with frontal pathology and diffuse encephalopathy. If unilateral, they strongly suggest contralateral frontal lobe pathology.
2 SUPERFICIAL REFLEXES
Cremasteric reflex
This reflex can be performed in men. The inner aspect of the upper thigh is stroked downward. The movement of the testicle in the scrotum is watched. Cremasteric contraction elevates the testicle on that side.
Anal reflex
What to do
Lie the patient on his side with the knees flexed. Lightly stroke the anal margin with an orange stick.
What it means
This tests the integrity of the reflex arc with segmental innervation of S4 and S5 for sensory and motor components. If no contraction seen this indicated a lesion in this reflex arc. Most commonly a cauda equina lesion.
3 TESTS FOR MENINGEAL IRRITATION
Neck stiffness
What to do
N.B. Not to be performed if there could be cervical instability—for example, following trauma or in patients with rheumatoid arthritis.
The patient should be lying flat.
Place your hands behind the patient’s head.
