- UMN: spasticity, hyperreflexia, clonus, positive Babinski. No fasciculations, mild wasting
- LMN: flaccid, hyporeflexic / arreflexic, absent Babinski. Severe wasting with fasciculations
Upper limb motor innervation:
Action | Muscle | Nerve | Root |
Shoulder abduction | Deltoid | Axillary | C5 |
Elbow flexion | Biceps | Musculocutaneous | C5,6 |
Elbow extension | Triceps | Radial | C7,8 |
Wrist flexion | Flexor carpii | Median & ulnar | C6,7 |
Wrist extension | Extensor carpii | Radial | C7,8 |
Finger flexors | FDP, FDS | Median & ulnar | C8,T1 |
Finger extensors | Extensor digitorum | Posterior interosseous | C7,8 |
Finger abduction | Dorsal interossei | Ulnar | T1 |
Finger adduction | Palmar interossei | Ulnar | T1 |
Thumb abduction | Abductor pollicis brevis | Median | T1 |
Thumb adduction | Adductor pollicis | Ulnar | T1 |
Lower limb motor innervation:
Action | Muscle | Nerve | Root |
Hip flexion | Iliopsoas | Femoral | L1,2 |
Hip adduction | Hip adductors | Obturator | L2,3 |
Hip abduction | Gluteus minimus, medius | Superior gluteal | L4,5 |
Hip extension | Hip extensors | Inferior gluteal | L5,S1 |
Knee extension | Quadriceps | Femoral | L3,4 |
Knee flexion | Hamstrings | Sciatic | L5,S1 |
Ankle dorsiflexion | Tibialis anterior | Deep peroneal | L5,S1 |
Ankle plantarflexion | Gastrocnemius | Tibial | S1,2 |
Foot inversion | Tibialis posterior | Tibial | L4,5 |
Foot eversion | Peroneus longus | Superficial peroneal | L5,S1 |
Toe extension | EHL | Deep peroneal | L5,S1 |
Reflexes:
- Biceps: C5,6
- Supinator: C6,7
- Triceps: C7,8
- Knee: L3,4
- Ankle: S1,2