3D CONTENT
3D OSTEOLOGY
3D THORAX

THORACIC SKELETON ANATOMY

Author: Dr. Bogdan Leahu
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Thoracic skeleton anatomy 360-degree interactive viewer showing thoracic cage, ribs, sternum, costal cartilages, and thoracic vertebrae
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TABLE OF CONTENTS

THORAX OVERVIEW

  • The thoracic cage is a structure made up of bones and cartilage that plays a vital role in protecting the thoracic organs like the heart, lungs, and great vessels
  • Composed of the ribs, thoracic vertebrae, and sternum, which together create a flexible yet sturdy framework crucial for breathing
  • The thoracic cage forms a cavity that has two key openings

Thoracic Cage

Thoracic cage 360-degree viewer showing bony and cartilaginous structures protecting heart, lungs, and great vessels
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  • Consists of bony and cartilaginous structures
  • Protects vital organs: heart, lungs, and great vessels
  • Formed by ribs, thoracic vertebrae, and sternum
  • Provides structural support and flexibility for breathing

Thoracic Cavity

  • Houses and protects the heart and lungs
  • Allows space for lung expansion during respiration
  • Lined by the thoracic skeleton for protection and movement efficiency

Superior Thoracic Aperture

Superior thoracic aperture showing upper opening of thoracic cavity bounded by first thoracic vertebra, manubrium, and first ribs
Superior Thoracic Aperture - Sourced from the app 3D OSTEOLOGY
  • Upper opening of the thoracic cavity
  • Slopes downward and forward
  • Boundaries:
    • First thoracic vertebra (back)
    • Manubrium of the sternum (front)
    • First ribs (sides)
  • Allows passage of trachea, esophagus, and major blood vessels

Inferior Thoracic Aperture

Inferior thoracic aperture showing lower boundary of thoracic cavity bounded by twelfth thoracic vertebra and costal cartilages
Inferior Thoracic Aperture - Sourced from the app 3D OSTEOLOGY
  • Lower boundary of the thoracic cavity
  • Boundaries:
    • Twelfth thoracic vertebra
    • Eleventh and twelfth ribs (sides)
    • Costal cartilages of seventh to tenth ribs (front)
    • Subcostal angle formed at convergence
  • Sealed by the diaphragm
  • Separates thoracic cavity from the abdominal cavity
  • Aids in respiration

THORACIC FEATURES

  • The thorax features a well-designed framework that includes the costal arch for flexibility, intercostal spaces to facilitate rib movement, and the infrasternal angle as a key anatomical landmark
  • These structures work together to protect vital organs and support efficient respiration through the expansion and contraction of the thoracic wall

Thoracic Skeleton

Bones of the thorax 360-degree viewer showing thoracic vertebrae, twelve pairs of ribs, and sternum
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  • Comprises the bones forming the thorax
  • Bones of the Thorax:
    • Includes thoracic vertebrae, ribs, and sternum
  • Ribs:
    • Twelve pairs of elastic, curved bones
    • Attach posteriorly to the vertebral column and anteriorly to the sternum via costal cartilages
    • Functions: provide structural support, protect thoracic organs, enable respiration through mobility
  • Sternum:
    • Long, flat bone in the center of the anterior thoracic wall
    • Provides structural support
    • Articulates with clavicles (collarbones) and first seven pairs of ribs via costal cartilages

Infrasternal Angle

Infrasternal angle 360-degree viewer showing angle formed at xiphoid process where lower rib cage edges meet
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Infrasternal Angle, Preview from the app. Download 3D OSTEOLOGY for full 3D control—multiple views, x-ray mode, and unlimited zoom.

  • Angle formed at the xiphoid process where the lower rib cage edges meet
  • Serves as an anatomical landmark for diaphragm access

Costal Cartilages

Costal cartilages showing hyaline cartilage connecting ribs to sternum providing flexibility to thoracic wall
Costal Cartilages - Sourced from the app 3D OSTEOLOGY
  • Hyaline cartilage connecting ribs to the sternum or each other
  • Provides flexibility to the thoracic wall for respiration

Intercostal Spaces

Intercostal spaces showing eleven spaces between adjacent ribs containing intercostal muscles and neurovascular bundles
Intercostal Spaces - Sourced from the app 3D OSTEOLOGY
  • Spaces between adjacent ribs and their costal cartilages
  • Eleven spaces on each side
  • Contents:
    • Intercostal muscles
    • Membranes
    • Neurovascular bundles
  • Function:
    • Allows rib movement during respiration
    • Aids in thoracic cavity expansion and contraction

BIBLIOGRAPHY

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

QUICK FACTS: THORACIC SKELETON

Key questions answered about this anatomy topic

Q: Which structures form the thoracic cage?

Answer: Ribs, thoracic vertebrae, and sternum. The thoracic cage is formed by the ribs, thoracic vertebrae, and sternum, which together create a flexible yet sturdy framework.

Q: What is the primary function of the thoracic cage?

Answer: Protection of the heart, lungs, and great vessels. The thoracic cage plays a vital role in protecting thoracic organs like the heart, lungs, and great vessels while also providing structural support for breathing.

Q: What structure forms the posterior boundary of the superior thoracic aperture?

Answer: First thoracic vertebra. The superior thoracic aperture is bounded posteriorly by the first thoracic vertebra, anteriorly by the manubrium of the sternum, and laterally by the first ribs.

Q: What structures pass through the superior thoracic aperture?

Answer: Trachea, esophagus, and major blood vessels. The superior thoracic aperture allows passage of the trachea, esophagus, and major blood vessels between the neck and thoracic cavity.

Q: What structure seals the inferior thoracic aperture?

Answer: Diaphragm. The inferior thoracic aperture is sealed by the diaphragm, which separates the thoracic cavity from the abdominal cavity.

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