Appendix 12.1. Localization of Spinal Cord Lesions
Foramen Magnum Syndrome and Lesions of the Upper Cervical Cord
Suboccipital pain and neck stiffness, Lhermitte's sign, occipital and fingertip paresthesias.
Sensory dissociation may be present.
Sensory findings of posterior column dysfunction may be present.
High cervical compressive findings (spastic tetra-paresis, long tract sensory findings, bladder disturbance).
Lower cranial nerve palsies (CN IX–XII) may occur from regional extension of the pathologic process.
Lesions affecting the C5 segment may compromise the diaphragm.
With C5 segment lesions, biceps and brachioradialis reflexes are absent or diminished, whereas the triceps reflex and the and flexor reflex are exaggerated (because of corticospinal tract compression at C5).
With C6 segment lesions, biceps, brachioradialis, and triceps reflexes are diminished or absent but the finger flexor reflex (C8–T1) is exaggerated.
Lesions of the Seventh Cervical Segment
Paresis involves flexors and extensors of the wrists and fingers.
Biceps and brachioradialis reflexes are preserved, and the finger flexor reflex is exaggerated.
May result in flexion of the forearm following olecranon tap. (Weakness of the triceps prevents its contraction and elbow extension, whereas muscles innervated by normal segments above the lesion are allowed to contract.)
Sensory loss at and below the third and fourth digits (including medial arm and forearm).
Lesions of the Eighth Cervical and First Thoracic Segments
Weakness that predominantly involves the small hand muscles, with associated spastic paraparesis.
With C8 lesions, the triceps reflex (C6–C8) and finger flexor reflex (C8–T1) are decreased.
With C8 lesions, the triceps reflex (C6-C8)and but the finger flexor reflex is decreased.
Possible unilateral or bilateral Homer's syndrome with C8–T1 lesions.
Sensory loss involves the fifth digit, medial forearm and arm, and rest of the body below the lesion.
Lesions of the Thoracic Segments
Root pain or paresthesias that mimic intercostal neuralgia.
Segmental lower motor neuron involvement is difficult to detect clinically.
Paraplegia, sensory loss below thoracic level, and bowel and bladder disturbances occur.
With lesions above T5, vasomotor control may be impaired.
With a cord lesion at the T10 level, upper abdominal musculature is preserved but lower abdominal muscles are weak. For example, when the head is flexed against resistance with the patient supine, the intact upper abdominal muscles pull the umbilicus upward (Beevor's sign).
If the lesion lies above T6, superficial abdominal reflexes are absent.
If the lesion is at or below T10, upper and middle abdominal reflexes are absent.
If the lesion is below T12, all abdominal reflexes are present.
Lesions of the First Lumbar Segment
Weakness in all muscles of the lower extremities. Lower abdominal muscle paresis.
Sensory loss includes both the lower extremities up to the level of the groin and the back to a level above the buttocks.
With longstanding lesions, the patellar and ankle jerks are brisk.
Lesions of the Second Lumbar Segment
Spastic paraparesis but no weakness of abdominal musculature.
Cremasteric reflex (L2) is not elicitable, and patellar jerk may be depressed.
Ankle jerks are hyperactive.
Lesions of the Third Lumbar Segment
Some preservation of hip flexion (iliopsoas and sartorius) and leg adduction (adductor longus, pectineus, and gracilis).
Patellar jerks are decreased or not elicitable.
Ankle jerks are hyperactive.
Lesions of the Fourth Lumbar Segment
Better hip flexion and leg adduction than in L1–L3 lesions.
Knee flexion and leg extension are better performed, and the patient is able to stand by stabilizing the knees.
Patellar jerks are absent, and ankle jerks are hyperactive.
Lesions of the Fifth Lumbar Segment
Normal hip flexion and adduction and leg extension. Patient can extend legs against resistance when extremities are flexed at the hip and knee (normal quadriceps).
Patellar reflexes are present.
Ankle jerks are hyperactive.
Lesions of the First Sacral Segment
Achilles reflexes are absent, but patellar reflexes are preserved.
Complete sensory loss over the sole, heel, and outer aspect of the foot and ankle.
Anesthesia over medial calf, posterior thigh.
Conus Medullaris Lesions
Paralysis of the pelvic floor muscles and early sphincter dysfunction.
Disruption of the bladder reflex arc results in autonomous neurogenic bladder characterized by loss of voluntary initiation of micturition, increased residual urine, and absent bladder sensation.
Constipation and impaired erection and ejaculation common.
May have symmetric saddle anesthesia.
Pain may involve thighs, buttocks, and perineum.
Cauda Equina Lesions
Early radicular pain in the distribution of the lumbosacral roots due to compression below the L3 vertebral level.
Pain may be unilateral or asymmetric and is increased by the Valsalva maneuver.
With extensive lesions, flaccid, hypotonic, areflexic paralysis develops, affecting the glutei, posterior thigh muscles, and anterolateral muscles of the leg and foot, resulting in a true peripheral type of paraplegia.
Sensory testing reveals asymmetric sensory loss in saddle region, involving anal, perineal, and genital regions and extending to the dorsal aspect of the thigh, anterolateral aspect of the lateral aspect of the foot.
Achilles reflexes are absent, and patellar reflexes are variable in response.
Sphincter changes are similar to those with a conus lesion, but occurrence tends to be late in the clinical course.
Although it can be concluded that lesions of the conus result in early sphincter compromise, late pain, and symmetric sensory manifestations, whereas cauda lesions have early pain, late sphincter manifestations, and asymmetric sensory findings, this distinction is difficult to establish and is of little practical value.
Source: Data abstracted from Biller J, Brazis PW: The localization of lesions affecting the spinal cord. In Brazis PW, Masdue JC, Biller J (eds). Localization in Clinical Neurology. Boston: Little, Brown and Company, 1996: 63–85.
Appendix 12.2. British Medical Research Council Scale of Muscle Strength
No muscular contraction
Muscular contraction without joint involvement
Muscular contraction moves joint but not against gravity
Muscular contraction moves joint just overcoming gravity
Muscular contraction overcoming gravity and appreciable force
Muscular contraction not overcome by examiner
Source: Modified from Aids to the Examination of the Peripheral Nervous System. London: Bailltière Tindall, 2000. By permission of the Guarantors of Brain.