Final answer:
The word meaning small head is 'microcephaly,' which refers to a medical condition where an individual has an abnormally small head and brain size, potentially leading to developmental and intellectual issues.
Step-by-step explanation:
The word that means small head is microcephaly. The suffix –cephaly indeed refers to the head. In the medical context, 'micro-' is a prefix derived from the Greek word 'mikros' which means small or little. Therefore, when combined with '-cephaly', the term specifically describes a condition where an individual has a head size that is significantly smaller than normal for an individual's age and sex.
Microcephaly can be a congenital condition and it can also occur as a result of various genetic and environmental factors. It's important in the context of neurological development, as individuals with this condition often have developmental issues and intellectual disabilities due to a smaller than normal brain size. This is connected to the formation of the brain in its early stages, where the anterior end of the neural tube develops into sac-like vesicles which ultimately shapes the brain structure.