How many paired spinal nerves do humans have?

Appeared in: CIP Ranchi 2023

Explanation

The human body has a total of 31 pairs of spinal nerves.
These nerves are part of the peripheral nervous system and emerge from the spinal cord.
The breakdown is as follows: 8 pairs of cervical nerves, 12 pairs of thoracic nerves, 5 pairs of lumbar nerves, 5 pairs of sacral nerves, and 1 pair of coccygeal nerves.
This totals 8 + 12 + 5 + 5 + 1 = 31 pairs.

Option A: 19 is an incorrect and significantly underestimated count of spinal nerve pairs.
Option B: 30 is incorrect. While close to the correct number, it omits one pair of spinal nerves, likely the single coccygeal pair.
Option D: 32 is an incorrect count. This number is slightly higher than the actual total of 31 pairs.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy of the Peripheral Nervous System as background academic context rather than a clinical decision trigger.
Knowledge of the 31 spinal nerve pairs is crucial for assessing sensory and motor deficits related to spinal cord injuries. The level of injury determines which nerves are affected.
Nurses use the concept of dermatomes (areas of skin supplied by a single spinal nerve) to pinpoint the level of spinal cord lesions or nerve root compression by testing for sensory changes.
What if a patient has loss of sensation in the legs and feet but normal arm function? This pattern suggests an injury at or below the thoracic spinal level, sparing the cervical nerves that supply the arms.

How to Approach the Question

This is a factual recall question from the subject of Anatomy.
Identify the key term in the question: 'paired spinal nerves'.
Recall the standard anatomical count of these nerves in the human body.
Mentally review the breakdown by region (Cervical, Thoracic, Lumbar, Sacral, Coccygeal) to confirm the total.
Sum the pairs: 8 (C) + 12 (T) + 5 (L) + 5 (S) + 1 (Co) = 31.
Select the option that matches this total.

Concept Tested & Keywords

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E6 Anatomy Grays 43e Vol 1 Part 3 pp. 33-35, 64-66

E6 Anatomy Grays 43e Vol 2 Part 2 p. 46-48

Practise the full CIP Ranchi 2023

Attempt every question from this paper in a timed mock, then review the full solution for each one.