1. THORACIC ANATOMY Extramediastinal

2. Boundaries Anterior Posterior Superior Inferior
manubrium, sternum and xiphisternum
Posterior
vertebral column and the ribs
Superior
continuous with the neck
Inferior
diaphragm
Thoracic wall is topographically & developmentally continuous with the abdominal wall

3. Skin & Subcutaneous Tissue
Essentially the same as elsewhere in the body

4. Bones Sternum Vertebral column Scapula & clavicle
manubrium, body and xiphoid process
gives rise to and is the area of attachment
of a number of different muscles
Vertebral column
Scapula & clavicle

5. Bones cont…
Ribs
12 pairs
first seven pairs directly articulate with the sternum
pairs 8-10 articulate with the rib above and then via 7th rib with the sternum
pairs 11&12 are capped with an apex of cartilage but do not articulate with the sternum
atypical: 1st, 11th and 12th
remainder are typical

6. Joints Variety of joints Ribs Sternoclavicular joint
articulations between the ribs and the vertebral column: costovertebral joints
articulation between the ribs and the sternum: costosternal joints
Sternoclavicular joint
synovial joint
medial end of the clavicle and the manubrium

8. Muscles: Outer Layer
Consists of: external intercostals, levator costae and serratus posterior
External intercostals: corresponds to the external oblique in the abdomen
Levator costae: 12 pairs of fan-shaped muscles
Serratus posterior: superior and inferior

9. Muscles: Inner Layer Consists of: internal intercostals
Internal intercostals: corresponds with the internal oblique in the abdomen

10. Muscles: Innermost Layer
Consists of : subcostals, innermost intercostals and tranversus thoracis
Together referred to as the transversus thoracis group
Line the rib cage
subcostals: posteriorly
innermost intercostals: laterally
transversus thoracis: anteriorly

11. Intercostal Spaces Filled with the muscles of the thoracic wall
external/internal/innermost
Neurovascular bundle lies in the plane between the internal and innermost layer
vein, artery and nerve
protected by the lower border of the rib above
Intercostal nerve: anterior ramus of the spinal nerve
segmentally supplies the muscles and skin of the thorax and the abdominal wall

12. Intercostal Spaces cont…
Intercostal arteries: anterior and posterior
branches from the descending thoracic aorta and the internal thoracic artery for all intercostal spaces except for the first two
supplied by the superior intercostal artery
Intercostal veins: more complex
each space has one posterior and two anterior veins
complex drainage pattern

13. Contents: Lungs Surfaces: inferior, mediastinal & costal Hilum
area on the mediastinal surface where structures running to and from the lung enter and leave
different between the right and the left lung

14. Contents: Lungs cont… Structure of the alveolar tree
multiple divisions from the trachea to the respiratory bronchioles
20-25 divisions in total
Relationship of the alveolar tree to vascular supply
pulmonary artery divides alongside the bronchi however, it does not supply it
ultimately ramifies around the walls of
the alveoli and feeds it with deoxygenated
blood
branches of the pulmonary vein drain
the area

15. Contents: Diaphragm Separates the thoracic and abdominal cavities
Arises from within the costal margin: directly from the ribs and via two large crura
Relationships
right dome to the level of 4th ICS on expiration
left dome to the level of the 5th rib
central tendon level with the xiphisternal joint (T8)
Openings
three: aortic, oesophageal and caval

16. Contents: Diaphragm cont…
Nerve supply
sole muscular supply is from the phrenic nerve (C4, 5 & 6)