A patient with brachial plexus injury is likely to have sustained other concomitant injuries; head injury, fractures in the cervical spine, clavicle, scapula, and extremities, chest and abdominal trauma and vascular injuries. The neurological examination should determine the specific motor and sensory deficits. The British Medical Research Council grading system is used to measure the motor strength of each muscle.
A detailed neurological examination helps in identifying the site and severity of the injury and dictates the treatment algorithm. In partial injuries some of the functions in limb are intact. In upper brachial plexus palsy (C5, C6) shoulder and elbow functions are poor, however hand functions are preserved. Extended upper plexus palsy (C5,6,7) has additional weakness wrist and finger extension. Lower brachial plexus palsy (C8-T1) presents with poor hand functions with normal shoulder and elbow functions.
In total palsy entire limb is flail and insensate, superficial sensations being present only in the inner aspect of arm which receives innervation from the T2 dermatome. The limb hangs by the side of the body with arm and forearm being internally rotated. A positive Horner’s sign (Fig 1) indicates C8, T1 nerve root injuries with involvement of cervical sympathetics. Examination of individual muscle helps in indentifying the site of injury and forms a baseline to assess recovery. The neurological examination should determine the specific motor and sensory deficits. The British Medical Research Council (BMRC) grading system is used to measure the motor and sensory functions of the extremity (Table 1).
Table 1- Assessment of motor power by the British Medical Research Council grading system
| Muscle Grade | Description |
| 5 | Full range of movements against gravity with full resistance |
| 4 | Full range of movements against gravity with some resistance |
| 3 | Full range of movements against gravity |
| 2 | Full range of movements with gravity eliminated |
| 1 | Flicker of contraction |
| 0 | No contraction |
Sensory examination is performed using two-point discrimination or Semmes Weinstein monofilament testing (Table 2).
Table 2- Assessment of sensory functions by the British Medical Research Council grading system
| Grading | Description |
| S0 | No sensation |
| S1 | Recovery of deep cutaneous pain sensibility |
| S2 | Recovery of superificial cutaneous pain sensibility |
| S2+ | Same as S2, only with over response |
| S3 | Pain and touch sensibility with a disappearance of over response. Two-point discrimination > 15 mm |
| S3+ | Same as S3, only localization of the stimulus is good. Two-point discrimination 7 to 15 mm |
| S4 | Recovery of complete sensation. Two-point discrimination 2 to 6 mm |
An examination of individual muscles helps in indentifying the site of injury and forms a baseline to assess recovery (Table 3).
Table 3 – Brachial plexus examination sheet
| General Clinical examination | ||
| Sign | Implications | |
| Horner Sign | Sympathetic ganglion injury (T1) | |
|
Diaphragmatic palsy |
Phrenic nerve injury (C3-C5) | |
|
Tinel sign in neck |
Root rupture (Proximal root stump may be present) | |
| Deafferentation pain | Root avulsion | |
| Winged scapula | Long thoracic nerve injury(C5-C7) | |
| Muscle | Root value | Remarks (Bulk & Power) |
| Trapezius | C3,C4, Spinal accessory nerve | |
| Levator scapulae | C3,C4,C5 | |
| Rhomboids | C4,C5 | |
| Supraspinatus | C5,C6 | |
| Infraspinatus | C5,C6 | |
| Serratus anterior | C5,C6,C7 | |
| Teres major | C5,C6 | |
| Subscapularis | C5,C6,C7 | |
| Pectoralis major clavicle | C5,C6,C7 | |
| Pectoralis major sternocostal | C6,C7,C8 T1 | |
| Latissimus dorsi | C6,C7,C8 | |
| Biceps and brachialis | C5,C6 | |
| Deltoid | C5,C6 | |
| Teres minor | C5,C6 | |
| Pronator quadratus | C7,C8,T1 | |
| Pronator teres | C6,C7 | |
| Flexor carpi radialis | C6,C7 | |
| Flexor digitorum profundus II, III | C7,C8,T1 | |
| Flexor digitorum superficialis | C7,C8,T1 | |
| Flexor pollicis longus | C7,C8,T1 | |
| Abductor pollicis brevis | C6,C7,C8,T1 | |
| Opponens pollicis | C8,T1 | |
| Lumbricals | C8,T1 | |
| Triceps | C6,C7,C8 | |
| Supinator | C5,C6 | |
| Brachioradialis | C5,C6 | |
| Extensor carpi radialis longus | C6,C7 | |
| Extensor carpi radialis brevis | C6,C7,C8 | |
| Extensor carpi ulnaris | C7,C8 | |
| Extensor digitorum communis | C7,C8 | |
| Extensor digiti minimi | C7,C8 | |
| Extensor indicis | C7,C8 | |
| Extensor pollicis longus | C7,C8 | |
| Abductor pollicis longus | C6,C7 | |
| Flexor carpi ulnaris | C7,C8,T1 | |
| Abductor digiti minimi | C8,T1 | |
| Flexor digitorum prof. IV, V | C7,C8,T1 | |
| Abductor pollicis | C8,T1 | |
| Opponens digiti | C8,T1 | |
| Interossei | C8,T1 | |
