Ref: Deep Tendon Reflexes

1. General considerations
2. Upper limb: supinator, biceps, triceps, fingers
3. Lower limb: knees, ankles, plantar
4.  
5. Increasing a reflex

General considerations

• Always compare one side to the other.
• Let hammer fall by gravity in most cases.
• Don't keep hammering a pt, if can't elicit it.

Upper limb reflexes

Supinator/Brachioradialis (C5-6):

• Pt's elbow at 90°, relaxed
• Hand exactly pronated [thumb exactly in the arc of flexion] and resting on pelvis.
• Hammer falls on distal end of radius.

Biceps (C5-6):

• Pt's elbow still at 90°, relaxed.
• Dr's finger over biceps tendon.
• Hammer falls on Dr's finger.

Triceps (C7-8):

Seated:

• Pt's arm crossed over, onto chest.
• Hammer held vertically, with mallet at bottom, swings into triceps tendon.

Supine:

• Pt's arm crossed over, onto chest.
• Hammer held with Dr's hand over hip, and mallet at elbow, swings into triceps tendon.

Fingers (C7-T1):

• Pt's hand palm up, fingers very slightly flexed.
• Dr's finger pads overlie pt's finger pads.
• Hammer taps Dr's fingers.

Lower limb reflexes

Knees (L3-4):

Supine:

• Dr lifts both knees with 1 arm, flexing legs slightly.
• Hammer falls on patellar tendon.

Seated:

• Pt crosses legs.
• Reflex holds hammer with mallet at bottom, and lets it swing into patellar tendon.

Ankles (S1-2):

3 options, all need ankle and knee joints both at 90° angle. The first 2 options also make hip abducted and externally rotated, which is good.

Supine, heel on shin method:

• Pt's lateral side of heel lies overtop opposite shin. Tell pt: "Place your heel on your opposite shin".
  ed.
• Since Dr standing on R side of pt, Dr places hammer in L hand. Dr. grasps end of foot with R hand to maintain the foot angle.
• Swing to tap Achilles tendon.

Supine, heel resting on bed method:

• Pt's R angle and knee joint are at 90°, with leg resting on bed.
• From R side of bed, Dr grabs R foot:
  • Index finger over the tibialis anterior tendon, to ensure that foot is relaxed enough.
  • Thumb wrapped underneath to feel for jerk.
• Swing to tap Achilles tendon.
• Move to end of bed [ask examiner first], and repeat above for L leg.

Pt kneeling on bed method:

• Pt kneels on bed, feet dangle over edge of bed, making ankle/knee 90°.
• Grasp end of foot to stabilize.
• Patellar hammer with mallet at bottom, swings to tap Achilles tendon.

Plantar (L5, S1-2):

• Tell pt. what about to do.
• Use key to stroke from heel, up lateral sole, then medially across to ball of foot.
• See if big toe goes up (UMNL) instead of its normal down.
• Alternatively: try with a fingernail first, before the key, so less pain to pt.
• See UMNL vs LMNL Reference.

Increasing a reflex

If can't elicit a reflex, can increase its visibility via any of 3 methods.

1. Clenching teeth.
2. Jendrassik's maneuver:
   • Pt clasps hands together tightly.
   • Pt. releases hands just before tap hammer.
3. Gripping an object.

Obviously, teeth clenching is the only appropriate one while testing upper limbs.