Viva Questions of Motor Examination by Dr Junaid

Central Nervous System (CNS) Examination Concepts
📌 Examiners frequently ask about definitions like hypotonia, hypertonia, Upper Motor Neuron (UMN) lesion, and Lower Motor Neuron (LMN) lesion during CNS examinations.
📌 Key terms to understand include crossed hemiplegia (cranial nerve involvement on the same side as the paralysis) and uncrossed hemiplegia (cranial nerve involvement on the opposite side).
📌 Different types of paralysis are defined based on limb involvement: diplegia (both lower limbs), brachial plegia (upper limbs), and quadriplegia (all four limbs).

Reflex Root Values and Classification
📌 Specific spinal root values are tested for reflexes: Biceps reflex is C5 and C6, Triceps reflex is C7 and C8.
📌 The Plantar reflex root value is S1, while Abdominal reflexes range between T8 and T12.
📌 Superficial reflexes include the corneal reflex, conjunctival reflex, abdominal reflex, and the plantar reflex (often categorized by the "Two Cs and the P").

Pathological Reflexes and Lesion Localization
📌 The upgoing plantar reflex (Babinski sign) is associated with conditions like deep coma, hypoglycemia, epileptic fits, and UMN lesions.
📌 A plantar reflex may be absent if the patient has S1 dermatome sensory loss, paralysis of the great toe muscles, or if the patient is in spinal shock following cord transection.
📌 UMN lesions present with increased tone and reflexes and an upgoing plantar reflex, whereas LMN lesions show decreased tone/reflexes, muscle wasting, and fasciculations.

Focal Neurological Deficit Localization
📌 Focal deficits help localize the lesion: Inferior quadrantanopia suggests a lesion in the parietal lobe.
📌 Homonymous hemianopia indicates a lesion in the occipital lobe.
📌 Lesions in the brainstem cause crossed hemiplegia, localized further by involved cranial nerves (e.g., CN V and VI involvement suggests the Pons).
📌 If all four deep reflexes are absent, the lesion is likely above the C5 spinal segment.

Key Points & Insights
➡️ Familiarize yourself with the definitions distinguishing UMN vs. LMN lesions—especially regarding tone, reflexes, and muscle wasting presence/absence.
➡️ When localizing brain lesions, use visual field deficits like hemianopia or quadrantanopia to pinpoint involvement in the occipital or parietal lobes, respectively.
➡️ Brainstem lesions causing crossed hemiplegia can be precisely located by identifying the involved cranial nerves (e.g., CN VI and VII point to the Pons).
➡️ For spinal cord sensory tract involvement, the exact lesion site is typically located a few segments above the highest sensory level deficit observed.

📸 Video summarized with SummaryTube.com on Feb 22, 2026, 22:10 UTC