Achondroplasia Overview and Characteristics

What is a characteristic feature of the skull in individuals with achondroplasia?

Which of the following describes the thorax of a person with achondroplasia?

In the axial skeleton of individuals with achondroplasia, which feature is associated with lumbar spine abnormalities?

What describes the pelvis in individuals with achondroplasia?

Which of the following describes a feature of the appendicular skeleton in achondroplasia?

Achondroplasia Overview

Achondroplasia is a skeletal dysplasia.
It's an autosomal dominant disorder.
Eighty percent of cases are due to new mutations.
It impacts enchondral bone growth.

Skull Characteristics

Large skull, small base, and sella.
Steep clivus.
Small, funnel-shaped foramen magnum.
Variable hydrocephalus severity.

Thorax Characteristics

Thick, stubby sternum.
Short ribs with significant anterior concavities.

Axial Skeleton Characteristics

Decreasing interpedicular distance in the lumbar spine.
Short lumbar pedicles and narrow spinal canal.
Posterior scalloping of vertebrae.
Anterior vertebral body beak at T12/L1/L2.
This can lead to a gibbus deformity when sitting.
The gibbus may reverse and become lumbar hyperlordosis when walking.

Pelvis Characteristics

Square iliac wings.
Champagne-glass shaped pelvic cavity.
Short, narrow sacrosciatic notch.
Horizontal sacrum articulating low on the iliac bones.

Appendicular Skeleton Characteristics

Rhizomelic micromelia (shortened long bones).
Bowed long bones.
Widened metaphyses.
Ball-and-socket at epiphyseal/metaphyseal junction.
Broad and short proximal and middle phalanges.
Trident-shaped hands.
Increased angle between middle and ring fingers.

Explore the distinctive features of achondroplasia, a common skeletal dysplasia. This quiz covers its genetic roots, skull, thorax, axial skeleton, pelvis characteristics, and their implications. Test your knowledge on how these traits affect individuals with this autosomal dominant disorder.