**Question:** Which of the following is affected in spinal paralytic polio: September 2011

**Core Concept:** Poliomyelitis, caused by the poliovirus, is a viral infection that primarily affects the motor neurons in the spinal cord and brainstem, leading to muscle weakness and paralysis.

**Why the Correct Answer is Right:** Spinal paralytic polio results from the infection of motor neurons in the spinal cord, specifically anterior horn cells. This infection leads to the destruction of these neurons, causing the degeneration of the motor axons and ending up in muscle weakness and paralysis. The correct answer, B, refers to the spinal cord involvement in poliomyelitis, which is the main feature of spinal paralytic polio.

**Why Each Wrong Option is Incorrect:**

A. Cervical poliomyelitis: Although polio can affect the cervical region, this question specifically asks about spinal paralytic polio.

C. Bulbar poliomyelitis: Poliomyelitis affecting the brainstem's motor neurons, also known as bulbar poliomyelitis, is not the focus of the question.

D. Generalized poliomyelitis: This option refers to the general symptoms of polio infection, rather than the specific spinal cord involvement discussed in the question.

**Clinical Pearl:** Poliomyelitis has three types: cervical, lumbar, and bulbar. Spinal paralytic polio refers to the involvement of spinal cord motor neurons, while bulbar polio affects the brainstem's motor neurons. Cervical polio is characterized by symptoms in the upper limbs and face, while lumbar polio affects the lower limbs and perineal region.

**Correct Answer:** B. Spinal paralytic polio (also known as lumbar polio) refers to the involvement of the spinal cord, which results in muscle weakness and paralysis in the lower limbs and perineal region.