Anatomy and Dysmorphology Definitions

Question 1

Agenesis

Answer 1

Failure of an organ to form

ex renal agenesis, agenesis of the corpus callosum

Question 2

Dysgenesis

Answer 2

Anomalous structure due to disorganizations of the component tissues and cells

Question 3

What is the difference between rhizomelic and mesomelic?

Answer 3

Rhizomelic= short upper portion extremity
Mesomelic= short midportion extremity

Question 4

Where are the most common locations for minor malformations (name 4).

Answer 4

1. Face
2. Auricles
3. Hands
4. Feet

Question 5

Whenever you see a minor anomaly what should you consider?

Answer 5

1. Is it present in any other family members?

- if no, then can consider it a clue regarding altered morphogenesis or an underlying syndrome

Question 6

What is the embryologic/genetic meaning to a minor anomaly/malformation?

Answer 6

=indicators of altered morphogenesis in a general sense
OR
constitute valuable clues in the diagnosis of a specific pattern of malformation

Question 7

What can an unusually large fontanel represent?

Answer 7

=lag in osseus formation

• especially abnormal is a large posterior fontanel (97% of newborns have a fingertip)
• can be seen with skeletal dysplasias, hypothyroidism, or represent a sign of increased ICP

Question 8

What do the following dermal fingertip patterns suggest about the height of the fetal fingertip

Answer 8

whorl pattern=high fetal fingertip pad
loop= intermediate fingertip pad
arch=low fingertip pad

Question 9

What is the best way to examine for blue sclerae?

Answer 9

Pull down lower eyelid and have the child look up to expose more of the sclera, also have the child look fully to the right and fully to the left.

If you find blue sclerae, be sure to check the parents as well

Question 10

What does blue sclerae represent?

Answer 10

The characteristic blue sclera is caused by thinness and transparency of the collagen fibers of the sclera that allow visualization of the underlying uve

Question 11

What conditions can have blue sclerae?

Answer 11

Think of connective tissues (where collagen is affected)

• osteogenesis imperfect
• Marfan syndrome
• Ehler’s Danlos syndrome

Other systemic disorders where you can lay down pigment

• Alkaptonuria
• Addison’s disease

Ocular Disorders
Medication induced

Question 12

What is myotonia?

Answer 12

=sustained muscle contraction

hand grip myotonia=inability to quickly release hand grip due to sustained muscle contraction