Final answer:
Small cracks starting in the cuticle and splitting the hair are called trichoptilosis, also known as brittle hair or fragilitis crinium. Trichoptilosis is distinct from other conditions such as pityriasis, trichorhexis nodosa, and pityriasis steatoides, which affect the skin or hair differently.
Step-by-step explanation:
Small cracks starting in the cuticle and splitting the hair entirely are known as brittle hair, fragilitis crinium, or trichoptilosis. The term you are looking for to describe this condition where the hair splits entirely is trichoptilosis. This condition is often a result of hair damage from various sources, such as excessive heat, harsh chemicals, or mechanical stress. The various layers of the hair, including the cuticle, cortex, and medulla, can become compromised. Other terms such as pityriasis, trichorhexis nodosa, and pityriasis steatoides describe different conditions affecting the skin or hair.
It's important to differentiate between these conditions since their treatments can vary. Pityriasis is a condition that causes scaling of the skin, while trichorhexis nodosa is characterized by thickened nodes on the hair shaft that cause it to break easily. Pityriasis steatoides, on the other hand, is a more severe form of dandruff. Establishing the correct diagnosis allows for proper care and management of these conditions.