Anatomy of the thorax
(Summary part 1)
1. Surface Anatomy
Key Landmarks:
o Clavicles: Run across the upper chest, easily felt.
o Jugular Notch: Between the medial ends of the clavicles.
o Sternal Angle: Level where rib 2 connects with the sternum
(T4–T5 vertebral level), helpful in rib counting.
o Lines of Reference: Midsternal, midclavicular,
anterior/mid/posterior axillary lines define regions on the chest
and guide in locating internal structures.
2. General Description
The thorax is shaped like a cylinder, open at the top (superior thoracic
aperture) and closed at the bottom by the diaphragm (inferior thoracic
aperture).
Thoracic Cavity Divisions:
o Two pleural cavities (each holding a lung).
o Mediastinum (the central area housing the heart, esophagus,
trachea, and main blood vessels).
3. Component Parts of the Thoracic Wall
Skeletal Components:
o Vertebrae (12 thoracic vertebrae), ribs (12 pairs), and
sternum.
Thoracic Apertures:
o Superior Aperture: Between neck and thorax, bordered by the
first rib, T1 vertebra, and manubrium.
o Inferior Aperture: Closed by the diaphragm, important for
breathing and separating the thorax from the abdomen.
4. Mediastinum
A flexible area extending from the sternum to vertebrae.
Divided by a horizontal plane at the sternal angle into:
o Superior Mediastinum: Above the heart, containing the
trachea, esophagus, and main blood vessels.
o Inferior Mediastinum: Subdivided into anterior, middle (heart
and pericardium), and posterior regions.
5. Pleural Cavities
Lined by Pleura:
o Parietal Pleura: Lines the cavity.
(Summary part 1)
1. Surface Anatomy
Key Landmarks:
o Clavicles: Run across the upper chest, easily felt.
o Jugular Notch: Between the medial ends of the clavicles.
o Sternal Angle: Level where rib 2 connects with the sternum
(T4–T5 vertebral level), helpful in rib counting.
o Lines of Reference: Midsternal, midclavicular,
anterior/mid/posterior axillary lines define regions on the chest
and guide in locating internal structures.
2. General Description
The thorax is shaped like a cylinder, open at the top (superior thoracic
aperture) and closed at the bottom by the diaphragm (inferior thoracic
aperture).
Thoracic Cavity Divisions:
o Two pleural cavities (each holding a lung).
o Mediastinum (the central area housing the heart, esophagus,
trachea, and main blood vessels).
3. Component Parts of the Thoracic Wall
Skeletal Components:
o Vertebrae (12 thoracic vertebrae), ribs (12 pairs), and
sternum.
Thoracic Apertures:
o Superior Aperture: Between neck and thorax, bordered by the
first rib, T1 vertebra, and manubrium.
o Inferior Aperture: Closed by the diaphragm, important for
breathing and separating the thorax from the abdomen.
4. Mediastinum
A flexible area extending from the sternum to vertebrae.
Divided by a horizontal plane at the sternal angle into:
o Superior Mediastinum: Above the heart, containing the
trachea, esophagus, and main blood vessels.
o Inferior Mediastinum: Subdivided into anterior, middle (heart
and pericardium), and posterior regions.
5. Pleural Cavities
Lined by Pleura:
o Parietal Pleura: Lines the cavity.
