3D CONTENT
3D OSTEOLOGY
3D NEUROCRANIUM

FRONTAL BONE ANATOMY

Author: Dr. Bogdan Leahu
← Temporal Bone Parietal Bone →
Frontal bone anatomy 360-degree interactive viewer showing articulations with sphenoid, ethmoid, parietal, nasal, maxillae, lacrimal, and zygomatic bones
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TABLE OF CONTENTS

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GENERAL CHARACTERISTICS

What is the frontal bone?

  • Major cranial bone forming your forehead
  • Contributes to your orbital roofs
  • Contributes to anterior cranial floor

What does the frontal bone articulate with?

  • Articulations:
    • Sphenoid bone
    • Ethmoid bone
    • Paired parietal bones
    • Paired nasal bones
    • Paired maxillae
    • Paired lacrimal bones
    • Paired zygomatic bones

SQUAMOUS PART

External surface of squamous part 360-degree viewer showing frontal eminences, superciliary arches, glabella, supraorbital margin, and forehead contour
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What is the squamous part of the frontal bone?

  • Vertical flattened region forming your forehead
  • External aspect is smooth and convex
  • Faces outward toward your scalp

Frontal Eminences

What are the frontal eminences?

  • Paired rounded prominences
  • Located approximately 3 cm above supraorbital margin
  • Positioned on either side of midline
  • Contribute to your forehead contour

Superciliary Arches

What are the superciliary arches?

  • Paired elevations
  • Located directly above supraorbital margin
  • Accentuate your brow prominence

Glabella

What is the glabella?

  • Smooth midline elevation
  • Situated between superciliary arches

Frontal Portion of Orbital Margin

What is the frontal portion of the orbital margin?

  • Forms inferior boundary of squamous part

External Surface Features

What is the supraorbital notch or foramen?

  • Smooth convex surface
  • Forms your visible forehead area
  • Supraorbital Notch or Foramen:
    • Located on medial aspect of supraorbital margin
    • Transmits neurovascular structures

What is the frontal notch or foramen?

  • Frontal Notch or Foramen:
    • Positioned medial to supraorbital notch
    • Provides passage for vessels and nerves
    • Supplies your forehead region

TEMPORAL SURFACE

Temporal surface of frontal bone 360-degree viewer showing zygomatic process, temporal line, parietal margin, and temple region contribution
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What is the temporal surface of the frontal bone?

  • Lateral aspect of frontal bone
  • Contributes to your temple region

What is the parietal margin?

  • Parietal Margin — posterior border
    • Articulates with parietal bones

What is the zygomatic process of the frontal bone?

  • Zygomatic Process — prominent lateral projection
    • Located at lateral end of supraorbital margin
    • Articulates with zygomatic bone
    • Forms part of lateral orbital wall
    • Forms part of orbital rim

What is the temporal line?

  • Temporal Line:
    • Extends superiorly from zygomatic process
    • Extends posteriorly from zygomatic process
    • Divides into superior and inferior temporal lines
    • Attachment for temporalis muscle
    • Attachment for temporal fascia

INTERNAL SURFACE OF SQUAMOUS PART

Internal surface of squamous part 360-degree viewer showing frontal crest, foramen cecum, sagittal sulcus, and cranial cavity features
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What is the internal surface of the squamous part?

  • Faces your cranial cavity

What is the frontal crest?

  • Frontal Crest — midline ridge
    • Formed by convergence of sagittal sulcus margins
    • Located at inferior midline

What is the foramen cecum?

  • Foramen Cecum:
    • Located at inferior end of frontal crest
    • Formed by small notch uniting with ethmoid bone
    • Transmits small veins
    • Connects nasal cavity to superior sagittal sinus

NASAL PART

Nasal part of frontal bone 360-degree viewer showing nasal spine, nasal margin, and articulations with nasal bones and perpendicular plate of ethmoid
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What is the nasal part of the frontal bone?

  • Inferior extension of frontal bone
  • Positioned between supraorbital margins

What is the nasal spine of the frontal bone?

  • Nasal Spine — midline bony projection
    • Extends inferiorly from center of nasal part
    • Articulates with nasal bones
    • Articulates with perpendicular plate of ethmoid

What is the nasal margin?

  • Nasal Margin — inferior border
    • Articulates with superior borders of nasal bones
    • Contributes to your nasal bridge formation

ORBITAL PART

Orbital part of frontal bone 360-degree viewer showing orbital plates, ethmoidal notch, trochlear fovea, fossa for lacrimal gland, and sphenoidal margin
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What is the orbital part of the frontal bone?

  • Composed of two horizontal triangular plates called orbital plates
  • Forms your orbital roofs
  • Forms anterior cranial fossa floor

What is the ethmoidal notch?

  • Ethmoidal Notch — gap between orbital plates
    • Accommodates cribriform plate of ethmoid bone

What is the orbital surface?

  • Orbital Surface:
    • Inferior-facing aspect of each orbital plate
    • Directed into the orbit

Key Features of Orbital Surface

What is the trochlear fovea?

  • Trochlear Fovea — small medial depression
    • Located near nasal part
    • Attachment site for trochlea
    • Serves superior oblique muscle

What is the fossa for the lacrimal gland?

  • Fossa for Lacrimal Gland — shallow depression
    • Located laterally
    • Houses your lacrimal gland

What is the sphenoidal margin?

  • Sphenoidal Margin:
    • Articulates with greater wing of sphenoid bone
    • Completes anterior cranial fossa

FRONTAL SINUSES

Frontal sinuses 360-degree viewer showing paired irregular cavities, septum of frontal sinuses, drainage openings, and position superior to orbits
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What are the frontal sinuses?

  • Paired irregular cavities
  • Located within frontal bone
  • Positioned superior to your orbits
  • Positioned posterior to superciliary arches

What is the septum of the frontal sinuses?

  • Septum of Frontal Sinuses — thin bony partition
    • Separates the two cavities
    • Variable position
    • Often results in asymmetrical sinuses

What are the drainage openings of the frontal sinuses?

  • Drainage Openings:
    • Open into your nasal cavity
    • Located on either side of nasal spine
    • Positioned anterior to ethmoidal notch

What are the functions of the frontal sinuses?

  • Functions:
    • Humidification of the air you breathe in
    • Enhancement of your voice resonance
    • Reduction of your skull weight

BIBLIOGRAPHY

1. Henry G, Warren HL. Osteology. In: Anatomy of the Human Body. 20th ed. Philadelphia: Lea & Febiger; 1918. p. 129–97.