Laterality Disorders

Question 1

Situs solitus

Answer 1

Standard anatomy

Question 2

Situs inversus totalis

Answer 2

Global situs defect where everything is mirror image

Question 3

Asymetry of unpaired organs depends on

Answer 3

How they move from the midline

Question 4

Asymetry of paired organs depends on

Answer 4

Their morphology more than their position

Question 5

Situs ambiguus

Answer 5

Defect of asymetry of an unpaired organ, resulting in at least one organ with a reversed L/R oritentation
e.g. dextrocardia

Question 6

Isomerism

Answer 6

Asymetry of a paired organ e.g. left isomerism causing the formation of two morphologically left lungs, 2 left atrial appendages, polysplenism

Question 7

40yo M with R isomerism giving 2 morphologically R atrial appendages and 2 morphologically R lungs (tri-lobed) with asplenia
Died of cardiac failure

Answer 7

Raman., (2003)

Question 8

3 steps in the establishment of the L/R axis

Answer 8

Peeters and Devriendt, (2006)

Question 9

Situs inversus totalis usually clinically silent but other laterality disorders usually have functional consequences, especially regarding the heart
Up to 80% of children with situs ambiguus present with congenital heart disease

Answer 9

Levin, (2005)

Question 10

Affects transplantation

Transplantation of a normal heart into a 6yo boy with dextrocardia, demonstrated dextrocardia on post-op radiograph

Answer 10

Deuse et al., (2010)

Question 11

Situs anomalies may present with confusing symptoms relating to pathology especially regarding the abdomen

Answer 11

Fulcher and Turner, (2002)

Question 12

May be part of a larger sydrome

Kartegener triad: bronchiectasis, sinusitis and situs inversus

Answer 12

Salama et al., (2013)