The Harris dictum describes the typical size and location of which of the following organs using a series of odd numbers?

Appeared in: BTSC Staff Nurse 31 July-2025

Explanation

The Harris dictum, or the 'rule of odd numbers,' is a classic anatomical mnemonic specifically for the spleen.
It uses the odd numbers 1, 3, 5, 7, 9, and 11 to describe the spleen's key features.
The mnemonic stands for: 1 inch thick, 3 inches wide, 5 inches long, 7 ounces in weight, and located between the 9th and 11th ribs.
This memory aid helps students and clinicians recall the normal characteristics of the spleen for assessment purposes.

Option A: The pancreas is a retroperitoneal gland whose size and J-shaped location across the posterior abdominal wall are not described by the Harris dictum.
Option B: The liver is the largest internal organ, located in the right upper quadrant. Its size, weight (approx. 1.5 kg), and location are far different from the parameters described in the Harris dictum.
Option D: The stomach is a J-shaped organ whose size is highly variable depending on its contents. It is not associated with the fixed measurements of the Harris dictum.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomical mnemonics for organ identification as background academic context rather than a clinical decision trigger.
The Harris dictum is a practical tool for nurses during physical assessment. A normal spleen is not palpable. If a spleen can be felt below the left costal margin, it suggests splenomegaly (enlargement), which is a significant clinical finding requiring further investigation.
Knowledge of the spleen's location (under ribs 9-11) is vital for understanding patterns of injury. Trauma to the left lower rib cage can cause a splenic rupture, a life-threatening emergency due to severe internal bleeding.
What if? A patient involved in a motor vehicle accident complains of left upper quadrant pain and pain in their left shoulder (Kehr's sign). The nurse should have a high index of suspicion for a ruptured spleen, a condition where knowledge of the spleen's location is critical for assessment and anticipating emergency interventions.

How to Approach the Question

First, identify the key term in the question: 'Harris dictum'.
Recognize that this is a factual recall question asking you to retrieve a specific piece of anatomical knowledge.
Recall or deduce that 'Harris dictum' is a mnemonic, a memory aid.
Systematically review the options (Pancreas, Liver, Spleen, Stomach) and try to associate the mnemonic with one of them.
The 'rule of odd numbers' (1, 3, 5, 7, 9, 11) is uniquely associated with the spleen's dimensions and location. Select 'Spleen' as the correct answer.

Concept Tested & Keywords

QNrm10abo577XZdJW8AZmf

E6 Anatomy BDChaurasia V2 10e Part 2 p. 70-72

Practise the full BTSC Staff Nurse 31 July-2025

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