Expansion
Counting 1, 2, 3, 4, 5, 6, 7, 8 from the ankle upwards
Expansion
| Reflex | Roots | Nerve |
|---|---|---|
| Ankle | S1, S2 | Tibial |
| Knee | L3, L4 | Femoral |
| Biceps | C5, C6 | Musculocutaneous |
| Supinator | C5, C6 | Radial |
| Triceps | C7, C8 | Radial |
The pairs run S1,2 - L3,4 - C5,6 - C7,8, which is simply 1 to 8 read upwards from the foot. “S1,2 buckle my shoe; L3,4 kick the door; C5,6 pick up sticks; C7,8 lay them straight” is the traditional rhyme.
Superficial reflexes
- Plantar: L5, S1, S2. Extensor (Babinski) indicates an upper motor neurone lesion
- Abdominal: T8 to T12, lost in upper motor neurone lesions and in multiple sclerosis
- Cremasteric: L1, L2
- Anal: S2, S3, S4, relevant in cauda equina
Interpretation
- Absent or reduced reflexes indicate a lower motor neurone, root, nerve or muscle problem; also seen in early spinal shock
- Brisk reflexes with an extensor plantar indicate an upper motor neurone lesion
- Absent reflexes with extensor plantars is a specific combination, seen in subacute combined degeneration, motor neurone disease, Friedreich’s ataxia, taboparesis and combined cord and peripheral nerve disease
- An inverted supinator jerk localises to C5 or C6 with cord compression below