Anatomy of the Human Skull: Bones and Structures

Posted on Jan 19, 2025 in Human Biology

Lower Vision of the Skull

Nostril (smaller sphenoid wing), middle cranial fossa (petrous bone), posterior cranial fossa (holds the cerebellum).

Frontal Bone

Form: Most of the anterior cranial fossa, the roof of the orbits, and the forehead. Anatomical Features: Squama, parietal border, brow ridge, supraorbital margin with supraorbital notch, zygomatic process, nasal spine, ethmoidal notch, frontal sinus. Formed from 2 points of ossification, between which is the metopic suture.

Sphenoid Bone

Form: Much of the middle cranial fossa and the lowest part of the anterior, the lateral cranial wall, and part of the orbital walls. Parts and Anatomical Features:

Body: Sella turcica, dorsum sellae, anterior and posterior clinoid processes, sphenoid sinus (hollow cavity inside the body of the sphenoid, which communicates with the nostrils).
2 Pterygoid Processes: With medial and lateral plates.
2 Greater Wings: Superior orbital fissure (between wings).
2 Lesser Wings: Optic canal.

Ethmoid Bone

Form: Part of the anterior cranial fossa, the inner wall of the orbit, the roof of the nostrils, the upper nasal septum, and part of the side walls of the nostrils. Anatomical Features: Cribriform plate, perpendicular plate, crista galli, and ethmoid cells.

Parietal Bone

Form: Much of the side walls of the cranial vault. Anatomical Features:

4 Borders: Sagittal, frontal, occipital, and squamous.
2 Faces:
- Internal: Middle meningeal grooves.
- External: Superior and inferior temporal lines.

Zygomatic Bone (Zygoma)

It forms: The prominence of the cheek, the side wall and the floor of the orbit, and the zygomatic arch (anteriorly).

Maxillary Bone (Upper Jaw)

Form: Part of the internal wall and floor of the orbit, most of the hard palate, and part of the side wall and floor of the nasal cavity.

Occipital Bone

Form: The posterior fossa and the back of the cranial vault. Parts and Anatomical Features:

Basilar Portion (most anterior).
Lateral Portions (side of the foramen magnum): On the lower side, it has the occipital condyles to articulate with the atlas.
Occipital Squama:
- External Surface: External occipital crest and external occipital protuberance.
- Internal Surface: Internal occipital crest, transverse sinus grooves, superior sagittal sinus groove, and internal occipital protuberance.

Temporal Bone

Parts and Anatomical Features:

Squamous Portion:
- Borders: Parietal and sphenoid.
- Faces:
  - Temporal: Temporal articular groove.
  - Cerebral: Blood vessel groove.
- External auditory canal.
- Zygomatic Process: Glenoid fossa and condyle.
Petrous Portion: Contains the inner ear and semicircular canals, canal for the Eustachian tube, internal acoustic meatus, styloid process, stylomastoid foramen, and carotid canal.
Mastoid Portion: Mastoid cells, canal for the sigmoid portion of the transverse sinus, mastoid foramen, occipital border.

Palatine Bone

They form part of: The orbital floor, side walls of the nose, and palate. Parts and Anatomical Features:

Orbital Process.
Perpendicular Plate: Sphenoid process, sphenopalatine notch, nasal surface with conchal crest and ethmoidal crest, maxillary surface, pyramidal process.
Horizontal Plate: Posterior nasal spine.

Mandibular Bone (Lower Jaw)