Jean-Athanase Sicard (23 June 1872 – 28 January 1929) was a French neurologist and radiologist born in Marseille.
In 1899 he obtained his medical doctorate, and in 1910 was appointed chef de service at the Hôpital Necker.
With Jacques Forestier (1890-1978), he introduced lipiodol (radio-opaque iodized poppyseed oil) for use in radiological investigations.
Lipiodol was injected into a patients' cerebrospinal fluid for myelographic diagnosis and localization of intraspinal cysts and tumors.
[2] Along with Frédéric Justin Collet (1870-1966), Sicard is credited with identifying Collet-Sicard syndrome, a disorder in which neck trauma such as a Jefferson fracture causes damage to the cranial nerves.