Which is not true regarding myelopathy?
Ans. is 'b' i.e., Brisk jaw jerk Brisk jaw jerk as it occurs when lesion is supranuclear /above pons. Hyperactive pectoralis reflex Hyperactive pectoralis reflex is an indicator of upper cervical spinal cord compression. Normally myelopathy is accompanied with brisk triceps jerks and absent biceps jerks. The common level of myelopathy is C5/C6. But when myelopathy cause spinal cord compression above this level there is paucity of signs to localize the lesion. Hyperactive pectorals jerk is an important sign of upper cervical myelopathy as it is important to determine the level responsible for the symptom. Brisk pectoralis jerk is seen in spinal cord compression at C2VC3or C3/C4 levels. Of them C3/C4 is clinically common. The hyperactive deltoid muscle jerk is seen in C3/C4 and C4/C5 lesions. Of the two, the hyperactive pectoralis jerk is more specific and extremely useful in locating upper cervical spinal cord compression. Facial sensory impairment Facial sensory supply is mainly through trigeminal nerve Trigeminal cranial nerve has its nucleus in pons as well as it has spinal nucleus which descends down to the pons and medulla into the upper cervical cord as far as C3/C4. The spinal muscles of the trigeminal nerve may be involved in myelopathy. The above statement is true since in high cervical cord injury- due to destruction of the spinal/sensory nucleus of trigeminal nerve sensory loss over face can occur. Bladder urgency Bladder urgency can occur in myelopathy above the level of the sacral cord and it is a feature of UMN bladder. A hyperreflexic spastic bladder occurs with lesions above the bladder centre S2, S3 and S4 and below the level of pontine micturition centre. Brisk jaw jerk The normal jaw jerk is monosynaptic reflex of small amplitude and is often imperceptible but when exaggerated it provides an important diagnostic due for the corticobulbar disease. Jaw jerk afferent impulse of this reflex are carried through sensory portion of the trigeminal nerve the efferent impulse through trigeminal nerve with its reflex centre in PONS. Jaw jerk will be exaggerated in supranuclear lesions of the trigeminal nerve (amyotrophic lateral sclerosis, extensive multiple sclerosis, b/l corticobulbar infarction with pseudobulbar palsy) the jaw jerk may occur. For Jaw jerk to be exaggerated the lesion should be above pons where motor nucleus of trigeminal nerve is located.
Sensory loss of facial area
Brisk jaw jerk
Brisk pectoral jerk
Bladder urgency
Spinal Cord Diseases