What physical findings identify the approximate level of common cervical nerve root lesions?
Nerve
Sensory Loss
Motor Weakness a
Reflex
C5 (5%)
Lateral upper arm
Deltoid, biceps
Biceps
C6 (35%)
Lateral forearm, thumb, index finger
Wrist extensors, biceps
Radial b, biceps
C7 (35%)
Middle finger
Wrist flexors, finger extensors, triceps
Triceps
C8 (25%)
Medial forearm, ring finger, little finger,
Finger flexors, thumb extensor,hand intrinsics
None
T1 (rare)
Medial arm at elbow
Finger abductors
None
a Attributing weakness of upper extremity muscles to a specific cervical level is often difficult since innervations usually occur by two or more nerve roots.
b Radial (brachioradialis) reflex is also called the supinator jerk (tap on the brachioradialis muscle near the distal end of radius).
