Cephalometry is the study and measurement of the head, usually the human head, especially by medical imaging such as radiography. Craniometry, the measurement of the cranium (skull), is a large subset of cephalometry. Cephalometry also has a history in phrenology, which is the study of personality and character as well as physiognomy, which is the study of facial features. Cephalometry as applied in a comparative anatomy context informs biological anthropology. In clinical contexts such as dentistry and oral and maxillofacial surgery, cephalometric analysis helps in treatment and research; cephalometric landmarks guide surgeons in planning and operating.

Craniometry is measurement of the cranium, usually the human cranium. It is a subset of cephalometry, measurement of the head, which in humans is a subset of anthropometry, measurement of the human body. It is distinct from phrenology, the pseudoscience that tried to link personality and character to head shape, and physiognomy, which tried the same for facial features. However, these fields have all claimed the ability to predict traits or intelligence.