In human peripheral nervous system, how many pairs of peripheral nerves (cranial plus spinal) are present altogether?

Introduction:
The human nervous system is divided into the central nervous system and the peripheral nervous system. The central part comprises the brain and spinal cord, while the peripheral part consists of nerves that connect these centres to different organs and tissues. This question focuses on the total number of pairs of peripheral nerves in humans, combining both cranial and spinal nerves into a single count.

Given Data / Assumptions:
- We are dealing with peripheral nerves, not central nervous tissue. - Peripheral nerves in humans are classified as cranial nerves and spinal nerves. - The options include 41, 42, 43 and 44 pairs. - We assume the standard anatomical counts used in human biology.

Concept / Approach:
Humans have 12 pairs of cranial nerves that arise from the brain and brainstem, and 31 pairs of spinal nerves that emerge from the spinal cord. Together, these supply the head, neck, trunk and limbs. The total number of pairs of peripheral nerves is the sum of cranial and spinal pairs: 12 plus 31 equals 43 pairs. Therefore, the correct answer is 43 pairs, not 41, 42 or 44.

Step-by-Step Solution:
Step 1: Recall that there are 12 pairs of cranial nerves numbered I to XII. Step 2: Recall that there are 31 pairs of spinal nerves, distributed as 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal pair. Step 3: Add the number of cranial nerve pairs and spinal nerve pairs: 12 + 31. Step 4: Perform the addition to get 43 pairs in total. Step 5: Match this total with the options and select 43 as the correct answer.

Verification / Alternative check:
Human anatomy textbooks and standard diagrams consistently list 12 cranial nerves and 31 spinal nerves. Charts illustrating the peripheral nervous system show their distribution along the brain and spinal cord. No mainstream reference suggests a different count in normal individuals. Adding these yields 43 pairs of peripheral nerves, which matches long established anatomical teaching and confirms the correctness of the answer.

Why Other Options Are Wrong:
41: This would require either fewer cranial or fewer spinal nerve pairs, which is not supported by standard anatomy. 42: This total is also inconsistent with the fixed counts of 12 cranial and 31 spinal nerve pairs. 44: This would suggest extra pairs beyond normal cranial and spinal numbers, which does not occur in typical human anatomy.

Common Pitfalls:
A common mistake is to remember one of the numbers correctly but not the other. Some students remember 12 cranial nerves but misremember spinal nerves as 30 or 32, causing an incorrect sum. Others may know 31 spinal nerves but mistakenly think there are 10 cranial nerve pairs. To minimise errors, it is helpful to memorise both numbers along with their detailed breakdown and to practice adding them so that 43 pairs becomes a familiar total for peripheral nerves.

Final Answer:
The total number of pairs of peripheral nerves in humans is 43 (12 cranial + 31 spinal).