Ferdinand Siegert (22 April 1865, in Neuwied am Rhein – 21 February 1946, in Köln) was a German pediatrician.
His name is associated with "Siegert's sign", defined as shortness and inward curvature of the terminal phalanges of the little fingers in Down syndrome.
[1] In 1889 he received his medical doctorate form the University of Strassburg, subsequently serving as a secondary physician in Mödling near Vienna.
Afterwards, he worked as an assistant under Friedrich Wilhelm Zahn at the institute of pathology in Geneva, and as an assistant to Oswald Kohts at the university children's clinic in Strassburg.
He was particularly interested in the inheritability of rickets as well as the nutritional needs of children (protein requirements).