Coelurus is a small, highly curosial form, with well-developed pleurocoels in the cervical and dorsal vertebral centra and with cervicals that possess diapophyseal shelves that are broad and decurved. In addition, Ostrom (1976) restored the forelimb of Coelurus with a semilunate carpal. 

On this basis alone, Gauthier (1986) assigned Coelurus to the Maniraptora; however, since the cervicals lack hypapophysus (a key maniraptorian character), this taxon is regarded as a provisionally valid species (pending the work of Ostrom) but its relations within the Theropoda are uncertain. Named for vertebrae with "their centra so much excavated that the walls are reduced to a thin shell," found in the "anterior caudal [tail] vertebrae" as well as the "dorsal and lumbar region."