Common postnatal findings in Trisomy 21 include which of the following?

Trisomy 21, also known as Down syndrome, is associated with a variety of characteristic physical features and findings that can be identified in the postnatal period.

A single palmar crease, often referred to as a simian line, is a common finding in individuals with Trisomy 21. This anatomical variation is observed in a significant proportion of those affected by Down syndrome and is used as one of the clinical indicators for diagnosis.

Short humerus is another notable feature often seen in individuals with Trisomy 21. The shortened long bones, including the humerus, are common skeletal features associated with this chromosomal condition, contributing to the characteristic stocky body habitus observed in these individuals.

Clinodactyly, which is the curvature of the fifth finger, is also a common finding in individuals with Down syndrome. This feature further exemplifies the variations in digit morphology that are often noted in patients with Trisomy 21.

Given that all three findings—single palmar crease, short humerus, and clinodactyly—are characteristic of Trisomy 21, the correct choice reflects the comprehensive nature of these common postnatal features associated with the syndrome.