3D CONTENT
3D OSTEOLOGY
3D NEUROCRANIUM

ETHMOID BONE ANATOMY

Ethmoid bone anatomy 360-degree interactive viewer showing cribriform plate, perpendicular plate, crista galli, ethmoidal labyrinths, and overall cuboid structure

Ethmoid Bone - General Structure, Preview from the app. Download 3D OSTEOLOGY for full 3D control—multiple views, x-ray mode, and unlimited zoom.

TABLE OF CONTENTS

GENERAL CHARACTERISTICS

  • Unpaired cuboid-shaped bone
  • Located between the orbital cavities
  • Functions:
    • Forms part of the anterior cranial fossa
    • Contributes to the nasal cavity structure
    • Participates in the medial orbital wall

Articulations

Ethmoid bone articulations 360-degree viewer showing connections with frontal, sphenoid, vomer, palatine, lacrimal, nasal bones, inferior nasal conchae, and maxillae

Ethmoid Bone - Articulations, Preview from the app. Download 3D OSTEOLOGY for full 3D control—multiple views, x-ray mode, and unlimited zoom.

  • Frontal bone
  • Sphenoid bone
  • Vomer
  • Inferior nasal conchae
  • Palatine bones
  • Lacrimal bones
  • Nasal bones
  • Maxillae

STRUCTURAL COMPONENTS

  • Composed of four main parts:
    • Cribriform plate
    • Perpendicular plate
    • Two ethmoidal labyrinths
  • Lightweight yet structurally robust

CRIBRIFORM PLATE

Cribriform plate 360-degree viewer showing crista galli, cribriform foramina, ala of crista galli, and ethmoidal notch of frontal bone

Cribriform Plate, Preview from the app. Download 3D OSTEOLOGY for full 3D control—multiple views, x-ray mode, and unlimited zoom.

  • Horizontal portion of the ethmoid bone
  • Occupies the ethmoidal notch of the frontal bone
  • Features a deeply grooved surface
  • Provides support for the olfactory bulb

Cribriform Foramina

  • Numerous small perforations
  • Allow passage of olfactory nerve fibres
  • Connect nasal cavity to the brain
  • Enable the sense of smell

Crista Galli

  • Vertical bony projection
  • Arises from the midline of the cribriform plate
  • Serves as attachment for the falx cerebri
  • Falx cerebri separates cerebral hemispheres

Ala of Crista Galli

  • Paired extensions
  • Flank the anterior border of crista galli
  • Articulate with the frontal bone
  • Provide additional stability to the ethmoid

PERPENDICULAR PLATE

Perpendicular plate of ethmoid bone 360-degree viewer showing thin vertical lamina forming superior nasal septum and articulations with vomer and septal cartilage

Perpendicular Plate, Preview from the app. Download 3D OSTEOLOGY for full 3D control—multiple views, x-ray mode, and unlimited zoom.

  • Thin vertical bony lamina
  • Descends from the inferior surface of cribriform plate
  • Forms the superior portion of the nasal septum
  • Divides the nasal cavity into left and right halves
  • Articulations:
    • Inferiorly with the vomer
    • Anteriorly with the septal cartilage
  • Functions:
    • Supports nasal structure
    • Contributes to proper airflow through nasal passages

ETHMOIDAL LABYRINTH

Ethmoidal labyrinth 360-degree viewer showing lateral masses with ethmoidal cells, ethmoidal bulla, uncinate process, and semilunar hiatus

Ethmoidal Labyrinth, Preview from the app. Download 3D OSTEOLOGY for full 3D control—multiple views, x-ray mode, and unlimited zoom.

  • Two lateral masses flanking the perpendicular plate
  • Composed of thin-walled air-filled cavities
  • Contains ethmoidal cells (ethmoidal sinuses)

Ethmoidal Cells

  • Grouped into three categories:
  • Anterior Cells:
    • Located at the front of the labyrinth
    • Covered by the lacrimal bone
  • Middle Cells:
    • Situated between anterior and posterior groups
    • Covered by the orbital plate of ethmoid
    • Contribute to the medial orbital wall
  • Posterior Cells:
    • Located at the back of the labyrinth
    • Covered by the orbital plate

Orbital Plate

Orbital plate of ethmoid bone 360-degree viewer showing thin smooth lamina papyracea forming medial orbital wall

Orbital Plate (Lamina Papyracea), Preview from the app. Download 3D OSTEOLOGY for full 3D control—multiple views, x-ray mode, and unlimited zoom.

  • Thin smooth bony sheet
  • Covers middle and posterior ethmoidal cells
  • Forms significant portion of medial orbital wall

Ethmoidal Bulla

  • Prominent rounded elevation
  • Formed by the middle ethmoidal cells

Uncinate Process

  • Curved lamina
  • Located anterior to the ethmoidal bulla
  • Descends posteroinferiorly
  • Articulates with ethmoidal process of inferior nasal concha

Semilunar Hiatus

  • Crescent-shaped groove
  • Located between uncinate process and ethmoidal bulla
  • Leads into the ethmoidal infundibulum

Ethmoidal Infundibulum

  • Connecting passage
  • Opens into the middle nasal meatus
  • Facilitates drainage of frontal sinus
  • Facilitates drainage of maxillary sinus

NASAL CONCHAE

Nasal conchae 360-degree viewer showing superior and middle nasal conchae extending from ethmoidal labyrinth into nasal cavity

Nasal Conchae, Preview from the app. Download 3D OSTEOLOGY for full 3D control—multiple views, x-ray mode, and unlimited zoom.

Superior Nasal Concha

  • Thin curved bony plate
  • Extends from medial surface of ethmoidal labyrinth
  • Smallest and most superior concha
  • Forms upper boundary of superior nasal meatus

Middle Nasal Concha

  • Thin curved bony plate
  • Extends from medial surface of ethmoidal labyrinth
  • Larger than the superior concha
  • Projects from the inferior border of the labyrinth
  • Forms part of the lateral nasal cavity wall

Functions of Conchae

  • Increase surface area within nasal passages
  • Enhance warming of inhaled air
  • Promote humidification of inhaled air
  • Improve filtration of inhaled air

BIBLIOGRAPHY

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

⋮⋮ Ethmoid Bone Quiz
1/3 Score: 0