The extra bones that sometimes develop between the flat bones of the skull are called:

• A. Fontanelles
• B. Wormian bones
• C. Sesamoid bones
• D. Sutural bones

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the context of the question. The problem is asking about extra bones that develop between the flat bones of the skull. These bones are not part of the standard anatomy but can appear in some individuals.
2. Step 2: Review the definitions of the terms provided in the options. Fontanelles are soft spots on a baby's skull that allow for growth and flexibility during birth. Wormian bones are small, irregular bones that can form within sutures of the skull. Sesamoid bones are small bones embedded in tendons, typically found in areas of high stress like the hands, feet, or knees.
3. Step 3: Focus on the term 'Sutural bones,' which is another name for Wormian bones. These bones are extra bone pieces that occur within the sutures of the skull, particularly in the lambdoid suture. They are considered anatomical variations and are not present in all individuals.
4. Step 4: Eliminate incorrect options based on their definitions. Fontanelles and sesamoid bones do not fit the description of extra bones between the flat bones of the skull. Wormian bones, also known as sutural bones, are the correct answer.
5. Step 5: Conclude that the correct term for extra bones that develop between the flat bones of the skull is 'Sutural bones,' which are synonymous with Wormian bones.