Rule of Two: Xray

There are various topics in medicine that can briefly be remembered with a single number and such topics are included in this page titled RULE OF NUMBERS.

Rule of Two

Reading X-ray in Orthopedics

While reading  X-ray in orthopedics, rule of two applies. That is when-ever you read a X ray you need to have 2 views, one joint above the suspected injury site and 1 joint below, comparing both the limbs, repeated/taken 2 weeks apart and commented by 2 orthopedicians.

2 View: AP and lateral view recommended in mostly to see the deformity/ displacement , angulation

2 abnormalities: If one abnormality found always look for the next one as finding one might mask the concurrent another injury.

2 Joints: One joint above and 1 joint below to rule out involvement of joints (r/o assosciated subluxation and dislocations)

2 limbs:  If doubtful always compare with contralateral limb.

2 occasions: Always compare with previous Xray  if available.

2 evaluations: If no previous films, reevaluate the patient and repeat Xray on followup.

2 reviews:  If doubtful should always be reviewed by another observer.

Rule of 9: Burn

Wallace Rule of Nine
For rough estimation of the body surface area that is affected by Burn, Wallace rule of nine is used. It  is used for adult. Slight modification is done in case of children as they have larger head compared to adults and hence Lund and Browder chart is used. The skin is grossly allocated the value of 9% as demostrated in the chart and diagram below.

Wallace Rule of Nine
(source: https://twitter.com/pjonline_news/status/596994284466802688)

Body part
Head	9%
Right upper extremity	9%
Left Upper extremity	9%
Anterior Chest	9%
Posterior Chest	9%
Anterior right lower extremity	9%
Posterior left lower extremity	9%
Posterior right lower extremity	9%
Posterior left lower extremity	9%
Perineum	1%
Total	100%

Body part

Head

9%

Right upper extremity

9%

Left Upper extremity

9%

Anterior Chest

9%

Posterior Chest

9%

Anterior right lower extremity

9%

Posterior left lower extremity

9%

Posterior right lower extremity

9%

Posterior left lower extremity

9%

Perineum

1%

Total

100%

Rule of 10 : Pheochromocytoma

As previous site was dedicated to certain medical conditions that can be described with a certain number. So is this blog. This collects Number 5-10.

Rule of 10

Pheochromocytoma 

Pheochromocytoma is a tumor most commonly arising from the adrenal medulla and secrete catecholamines (Adrenaline and Noradrenaline) in the vascular system however 10% arise from extraadrenal sites such as sympathetic chain around spinal cord, aorta, ureter and bladder. Generally these are benign tumors but 10% are malignant. 90 % occurs unilaterally and 10% occur in the family. Recently 10 gene mutations have been associated with the condition to add up to its list of 10. It rarely occurs in children (10%). And has tendency to recur (10%) even after surgical excision. 10% have been identified after the patient develops Stroke following malignant Hypertension.

Rule of 10 in pheochromocytoma

Rule of Two: Meckel's Diverticulum

Meckel’s Diverticulum

It is a blind ended tube arising from the ante-mesenteric border of the intestine and is a remnant of Vitellointestinal Duct. It also follows the rule of two i.e it is 2 inch in length, 2 feet proximal to ileocaecal junction, occurring in only 2 % of population, 2% being symptomatic and 2 types of ectopic tissues found i.e Gastric and Pancreatic. 2 times more common in male and onset is around 2 years of age.

Rule of two in Meckel's Diverticulitis