Sphenoidal Fontanelle

Definition

The sphenoidal fontanelle is a small gap or opening that forms in the fetal skull during embryonic development, located between the sphenoid and frontal bones. It is one of the six fontanelles that allow the skull to change shape and pass through the birth canal during childbirth.

5 Must Know Facts For Your Next Test

1. The sphenoidal fontanelle typically closes and fuses by 6-12 months after birth as the skull bones mature.
2. It is the smallest of the six fontanelles and is located high on the back of the skull, near the crown.
3. The sphenoidal fontanelle allows the skull to change shape during childbirth, aiding the baby's passage through the birth canal.
4. Abnormalities in the size or closure of the sphenoidal fontanelle can be a sign of certain developmental or genetic disorders.
5. Palpating the sphenoidal fontanelle is an important part of a newborn physical exam to assess skull development.

Review Questions

• Explain the purpose and importance of the sphenoidal fontanelle during embryonic development and childbirth.
  • The sphenoidal fontanelle is one of the six fontanelles that form gaps or openings in the fetal skull during embryonic development. These fontanelles allow the skull to change shape and pass more easily through the birth canal during childbirth. The sphenoidal fontanelle, located between the sphenoid and frontal bones, is the smallest of these openings and typically closes by 6-12 months after birth as the skull bones mature. The presence and closure of the sphenoidal fontanelle is an important indicator of normal skull development and is assessed as part of a newborn physical exam.
• Describe the anatomical relationship between the sphenoidal fontanelle and the sphenoid and frontal bones.
  • The sphenoidal fontanelle forms the gap or opening between the sphenoid bone and the frontal bone during embryonic skull development. The sphenoid bone is a butterfly-shaped bone located at the base of the skull, while the frontal bone forms the forehead and part of the eye sockets. As the skull bones mature and fuse together, the sphenoidal fontanelle typically closes by 6-12 months after birth, marking the completion of this stage of cranial development.
• Analyze how abnormalities in the sphenoidal fontanelle can be indicative of developmental or genetic disorders.
  • Deviations from the normal size, shape, or timing of closure of the sphenoidal fontanelle can be a sign of underlying developmental or genetic disorders. For example, an abnormally large or persistent sphenoidal fontanelle may be associated with conditions like hydrocephalus, where excess fluid builds up in the brain and causes the skull to expand. Conversely, premature or incomplete closure of the fontanelle could indicate craniosynostosis, a disorder where the skull bones fuse together too early. Careful examination of the sphenoidal fontanelle during a newborn physical exam can therefore provide important clues about a child's neurological and skeletal development.

Related terms

Fontanelle: A fontanelle is a soft spot or gap in the infant skull where the bones have not yet fused together, allowing the skull to change shape during childbirth.

Sphenoid Bone: The sphenoid bone is a butterfly-shaped bone located at the base of the skull that forms part of the eye sockets, nasal cavity, and cranial cavity.

Frontal Bone: The frontal bone is a paired bone that forms the forehead and part of the eye sockets, and joins with the sphenoid bone during development.