External and Internal Morphology of the Skull Quiz

External and Internal Morphology of the Skull

The skull is a bony structure that supports the face and forms a protective cavity for the brain. It is comprised of many bones, formed by intramembranous ossification, and joined by sutures (fibrous joints). The skull can be divided into two main parts: the cranium (also known as the neurocranium) and the face.

Cranial Bones

The cranium is formed by the following bones:

1. Frontal bone
2. Occipital bone
3. Parietal bones (two)
4. Temporal bones (two)
5. Sphenoid bone
6. Ethmoid bone

The cranium can be subdivided into a roof and a base:

• Cranial roof: Comprised of the frontal, occipital, and two parietal bones. It is also known as the calvarium.
• Cranial base: Comprised of the frontal, sphenoid, ethmoid, occipital, parietal, and temporal bones. These bones articulate with the facial bones to form the skull base.

Sutures of the Skull

Sutures are a type of fibrous joint that are unique to the skull. They are immovable and fuse completely around the age of 20. The main sutures in the adult skull are:

1. Coronal suture: Fuses the frontal bone with the two parietal bones.
2. Sagittal suture: Fuses both parietal bones to each other.
3. Lambdoid suture: Fuses the occipital bone to the two parietal bones.

These sutures are important in the context of trauma, as they represent points of potential weakness in the skull.

Facial Bones

The facial skeleton is composed of 14 bones:

1. Vomer
2. Two inferior nasal conchae
3. Two nasal bones
4. Two maxillae
5. Mandible
6. Two palatine bones
7. Two zygomatic bones
8. Two lacrimal bones

These bones provide support for all of the facial structures.

Cavities of the Skull

The skull contains several cavities that house and protect various structures, such as the cerebrum, cerebellum, brainstem, and orbits. The skull is divided into the following fossae:

1. Anterior cranial fossa: Contains the frontal lobe of the cerebral cortex, olfactory bulb, olfactory tract, optic nerve, orbital gyri, and other structures.
2. Middle cranial fossa: Contains the trochlear, basal ganglia, and thalamus.
3. Posterior cranial fossa: Contains the cerebellum.

The skull also has various openings for the passage of nerves and blood vessels, such as the optic canal, superior orbital fissure, foramen spinosum, foramen rotundum, foramen ovale, and hypoglossal canal.

Understanding the external and internal morphology of the skull is essential for studying its development, growth, and clinical relevance in various aspects of human anatomy and medicine.