Stepwise examination of reflexes with images or videos
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I now have all the material needed for a comprehensive, well-illustrated guide. Here is the full stepwise examination:
Stepwise Examination of Reflexes
Reflex testing is one of the most localizing parts of the neurological exam - it distinguishes upper motor neuron (UMN) from lower motor neuron (LMN) lesions, identifies the spinal cord level affected, and helps detect subclinical neurological disease.
Step 1 - Equipment & Patient Positioning
Equipment needed: Reflex (Taylor/Queen Square) hammer. The weight and swing of the hammer matter - a sharp, brisk flick of the wrist delivers more reliable strikes than a slow tap.
Patient positioning:
- Relaxed - muscle tension will suppress reflexes
- The tested muscle should be positioned midway between full contraction and full extension
- Expose the limbs for direct tendon access
- Compare both sides sequentially for each reflex
Key rule: Aim for the smallest stimulus that elicits a reflex, NOT the maximal possible hit. Grading is about threshold, not amplitude.
Step 2 - Reinforcement (Jendrassik Maneuver)
When reflexes appear absent or diminished, use reinforcement to unmask them:
- Upper limbs: Ask the patient to clench the teeth, or hook the flexed fingers of both hands together and pull hard apart (Jendrassik maneuver proper)
- Lower limbs: Hook flexed fingers of both hands together and pull apart while you test the Achilles; alternatively ask patient to clench fists
- Why it works: Voluntary contraction of distant muscles temporarily increases gamma motor neuron activity, lowering the reflex threshold
Step 3 - Deep Tendon Reflexes (DTRs)
These are the muscle stretch (myotatic) reflexes. Test them in a logical sequence - upper limbs first, then lower.
3A. Biceps Reflex - C5, C6
| Position | Elbow flexed ~90°, forearm supinated, resting on patient's thigh or examiner's forearm |
| Technique | Place your thumb firmly over the biceps tendon in the antecubital fossa. Strike your thumb with the hammer |
| Normal response | Elbow flexion |
| Root tested | C5 (primarily), C6 |
| Absent = LMN | C5/C6 root, musculocutaneous nerve |
| Exaggerated = UMN | Corticospinal tract lesion above C5 |
3B. Brachioradialis Reflex - C5, C6
| Position | Forearm resting loosely, in slight pronation, on patient's thigh |
| Technique | Strike the brachioradialis tendon at the distal radius (radial side, ~5 cm above wrist) |
| Normal response | Forearm flexion ± slight radial deviation |
| Root tested | C5, C6 |
| Inverted reflex | If the brachioradialis fails to contract but finger flexors contract instead, this "inverted brachioradialis reflex" suggests a lesion at C5-C6 with UMN release of lower levels |
3C. Triceps Reflex - C6, C7
| Position | Elbow flexed ~90°, arm supported by examiner or hanging loosely across abdomen |
| Technique | Strike the triceps tendon just above the olecranon |
| Normal response | Elbow extension |
| Root tested | C7 (primarily), C6 |
Video reference: Upper Extremity Reflexes (YouTube - MSK Medicine)
3D. Finger Flexor Reflex (Trömner / Hoffmann) - C8, T1
Hoffmann's Sign:
- Hold the patient's middle finger loosely and flick the fingernail downward
- Positive: Thumb flexes and adducts (flexion of IP joint)
- Indicates heightened reflexes in the finger flexor muscles, suggesting a UMN lesion above C8
Trömner Sign:
- Flick the middle finger upward (from below)
- Same interpretation as Hoffmann's
3E. Patellar Reflex (Knee Jerk) - L3, L4
| Position | Sitting: knee bent at ~90°, legs hanging freely. Supine: support the knee in ~30-45° flexion by placing your arm under the popliteal fossa |
| Technique | Strike the patellar tendon just below the patella sharply |
| Normal response | Knee extension (quadriceps contraction) |
| Root tested | L3, L4 |
Absent patellar reflex = likely L4 root lesion, femoral neuropathy, or diabetic neuropathy. Hyperactive = UMN lesion above L3.
3F. Achilles Reflex (Ankle Jerk) - S1, S2
| Position | Knee flexed, foot in slight dorsiflexion. Can be tested: (a) seated with legs dangling, (b) supine with knee bent and externally rotated ("frog-leg"), (c) patient kneeling on a chair - Achilles tendon exposed |
| Technique | Dorsiflex the ankle slightly with one hand to put tendon on mild stretch; strike the Achilles tendon |
| Normal response | Plantar flexion of the foot |
| Root tested | S1 (primarily) |
| Clinical pearl | The Achilles reflex is the most commonly lost reflex in L5-S1 disc herniation and peripheral neuropathy (e.g., diabetes) |
Video reference: Deep Tendon Reflex Exam (YouTube)
Step 4 - Reflex Grading Scale
| Grade | Description |
|---|---|
| 0 | Absent - no response even with reinforcement |
| 1+ | Trace/hyporeflexic - seen only with reinforcement |
| 2+ | Normal |
| 3+ | Brisk - increased but no clonus |
| 4+ | Hyperactive with non-sustained clonus |
| 5+ | Sustained clonus |
0 and 4+/5+ are abnormal. 1+, 2+, and 3+ are normal unless asymmetrical or there is a dramatic disparity between upper and lower limbs (which suggests a spinal cord lesion).
Documenting reflexes - the Stick Figure Method:
A quick, universally understood documentation method is the stick figure, with reflex grades written at the joints:
Fig: A normal stick figure. Upper limb reflexes 2+, patellar 3+, Achilles 2+, plantar arrows pointing downward = flexor.
Step 5 - Cutaneous / Superficial Reflexes
5A. Plantar Reflex (Babinski Test)
Technique:
- Use a blunt object (tongue blade handle, end of a pen, or key)
- Stroke the lateral sole from the heel, forward toward the small toe, then arc medially toward the big toe
- Apply firm, continuous pressure - not too light (ticklish withdrawal) and not painful
Responses:
Fig: (A) Normal plantar response - toes flex downward. (B) Extensor plantar response / Babinski's sign - great toe extends up, other toes fan outward.
| Response | Interpretation |
|---|---|
| Flexor (toes curl down) | Normal in adults |
| Extensor (Babinski sign) | UMN lesion above S1 level |
| Silent (no movement) | If one side silent while other is downgoing, the silent side is abnormal |
Important caveat (Harrison's 22e): Despite its fame, Babinski's reliability for UMN weakness is limited. Tests of tone, strength, and stretch reflexes are more reliable overall.
Alternative elicitation techniques (when plantar withdrawal interferes):
- Oppenheim: stroke firmly down the tibia
- Gordon: squeeze the calf muscle
- Chaddock: stroke under the lateral malleolus
- Schafer: squeeze the Achilles tendon
5B. Abdominal Reflexes - T9 to T12
- Stroke each quadrant of the abdomen diagonally toward the umbilicus with a sharp object (e.g., wooden end of a cotton swab)
- Normal: Umbilicus pulls toward the stimulated quadrant
- Absent: UMN lesion (lost when corticospinal input is disrupted)
- Clinical use: Preservation of upper (T9) but loss of lower (T12) abdominal reflex localizes a lesion between T9-T12
5C. Cremasteric Reflex - L1, L2
- Stroke the upper inner thigh in males
- Normal: Ipsilateral elevation of the testicle
- Absent: L1-L2 root lesion, femoral nerve lesion, or UMN lesion above L1
5D. Anal (Perianal) Reflex - S2, S3, S4
- Scratch the perianal skin with a blunt pin
- Normal: Contraction of the external anal sphincter ("anal wink")
- Test when: Suspected spinal cord injury or cauda equina syndrome
Step 6 - Clonus Testing
Test when reflexes are hyperactive (3+ or 4+):
Ankle clonus:
- With the knee extended, grasp the foot and sharply dorsiflex the ankle
- Maintain upward pressure
- Sustained repetitive oscillations = pathological clonus = UMN lesion
- 1-2 beats = may be normal in anxious patients
- Asymmetric sustained clonus is always abnormal
Patellar clonus:
- Grasp the patella between thumb and forefinger
- Push sharply distally and hold
- Sustained oscillations = pathological
Step 7 - Primitive / Frontal Release Signs
Seen with frontal lobe pathway disease (e.g., dementia, bilateral UMN lesions):
| Sign | Elicitation | Response |
|---|---|---|
| Grasp reflex | Stroke between thumb and index finger of the patient's palm | Forced grasping of examiner's hand |
| Suck reflex | Lightly touch center of lips with tongue blade | Sucking movement |
| Root reflex | Touch corner of lips | Patient turns lips toward stimulus |
| Palmomental reflex | Scratch palm diagonally | Ipsilateral contraction of mentalis (chin) muscle |
Releasing the grasp reflex: stroke the back of the patient's hand - this often causes release.
Summary Table: DTRs, Root Levels & Localization
| Reflex | Spinal Roots | LMN (Absent) | UMN (Exaggerated) |
|---|---|---|---|
| Biceps | C5, C6 | C5/C6 root or musculocutaneous nerve | Cord lesion above C5 |
| Brachioradialis | C5, C6 | C5/C6 | Above C5 |
| Triceps | C6, C7 | C7 root or radial nerve | Above C6 |
| Finger flexors | C8, T1 | C8/T1 | Above C8 |
| Patellar | L3, L4 | L3/L4 root or femoral nerve | Above L3 |
| Achilles | S1, S2 | S1 root or sciatic/tibial nerve | Above S1 |
Recommended Video Resources
- Deep Tendon Reflex Exam - Complete Upper & Lower (YouTube) - biceps, brachioradialis, triceps, patellar, Achilles
- Upper Extremity Reflexes (MSK Medicine) - excellent close-up technique
- Deep Tendon Reflexes Nursing Head-to-Toe (YouTube) - nursing assessment format
- Stanford Medicine 25 - Reflex Exam - interactive online guide with video clips
Sources: Harrison's Principles of Internal Medicine 22e (2025); Neuroanatomy through Clinical Cases 3e (Blumenfeld); Adams and Victor's Principles of Neurology 12e; Neuroanatomy through Clinical Cases 3e, Table 3.6.
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