Short Notes: Anatomy of the Thorax

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ANATOMY
Medicine Made Simple

, THORAX

Thoracic cage


Borders
 Anterior-sternum 

 Posterior-12 thoracic vertebrae &
 intervening intervertebral discs 
 On each side- 12 ribs with their
costal cartilages+ intercostal muscles 


Shape
 Adult
Transverse section - kidney shape
Transverse diameter> antero-posterior diameter
Ribs - oblique ribs
Thoracic & abdominal respiration
 Infant
Transverse section – circular
Transverse diameter< antero-posterior diameter
Ribs - horizontal ribs
Purely abdominal respiration


Superior Thoracic Aperture
 Anterior- upper border of manubrium sterni
 Posterior- superior surface of body of 1st
thoracic vertebra (T1)
st
 On each side- 1 rib & cartilage
Inclined at an angle of 45 degrees

*Suprapleural membrane=”Sibson’s fascia”
 Triangular
 Separates thorax from the neck
 Attachments
o apex-tip of the transverse process of C7
st
o Base-inner border of the 1 rib & cartilage

Inferior Thoracic Aperture
 Anterior-infrasternal angle
 Posterior-inferior surface of body of T12
 On each side-costal margin

*Diaphragm separates thorax from abdomen.




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