Positional Plagiocephaly: This condition is the most common cause of a flat head in infants, resulting from prolonged periods of lying in the same position, which puts pressure on one part of the skull. It's particularly common in infants who sleep on their backs, as recommended to reduce the risk of SIDS.

Congenital Muscular Torticollis: This condition involves a shortening or tightening of the muscles on one side of the neck, causing the head to tilt towards the affected side. It can lead to plagiocephaly if the infant consistently lies on the flat side of their head.
Craniosynostosis: A condition where the bones of the skull fuse together prematurely, which can lead to an abnormal head shape. While less common than positional plagiocephaly, it's a significant consideration due to its implications for brain development and vision.

Hydrocephalus: Although rare, hydrocephalus (an accumulation of fluid in the brain) can cause the head to enlarge or become misshapen. Early detection is crucial for effective management and to prevent complications.
Brain Tumor: Tumors in the brain can cause increased intracranial pressure, leading to changes in head shape. While extremely rare in infants, missing such a diagnosis could have devastating consequences.

Apert Syndrome: A rare genetic disorder characterized by premature fusion of the bones of the skull, leading to an abnormal head shape, and often associated with other physical and developmental anomalies.
Crouzon Syndrome: Another rare genetic disorder involving premature fusion of certain suture lines of the skull, resulting in a misshapen head and facial abnormalities.