The neurologic examination includes a search for focal weakness or muscle atrophy, focal reflex changes, diminished sensation in the legs, and signs of spinal cord injury. The examiner should be alert to the possibility of breakaway weakness, defined as fluctuating strength during muscle testing. Breakaway weakness may be due to pain or a combination of pain and underlying true weakness. Breakaway weakness without pain is due to lack of effort. In uncertain cases, electromyography (EMG) can determine whether or not true weakness is present. Findings with specific nerve root lesions are shown in Table 16-2 and are discussed below. Table 16-2 Lumbosacral. | Chapter 016. Back and Neck Pain Part 4 The neurologic examination includes a search for focal weakness or muscle atrophy focal reflex changes diminished sensation in the legs and signs of spinal cord injury. The examiner should be alert to the possibility of breakaway weakness defined as fluctuating strength during muscle testing. Breakaway weakness may be due to pain or a combination of pain and underlying true weakness. Breakaway weakness without pain is due to lack of effort. In uncertain cases electromyography EMG can determine whether or not true weakness is present. Findings with specific nerve root lesions are shown in Table 16-2 and are discussed below. Table 16-2 Lumbosacral Radiculopathy Neurologic Features Examination Findings Lumbo sacral Nerve Roots Reflex Sen sory Motor Pain Distribution L2a Up per anterior thigh Psoas hip flexion Anteri or thigh L3a Lo wer anterior thigh Ant erior knee Psoas hip flexion Quadriceps knee extension Thigh Anteri or thigh knee adduction L4a Quadriceps Me Quadriceps Knee knee dial calf knee extension medial calf Thigh Antero adduction lateral thigh Tibialis anterior foot dorsiflexion L5c Dor Peroneii Lateral sal foot eversion calf dorsal surface foot Lat eral calf Tibialis anterior foot dorsiflexion Gluteus foot posterolateral thigh .
