Description of thoracic cage

1. THORACIC CAGE
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Maj Dr Rishi Pokhrel
NAIHS

2. 2

3. Learning objectives
• Thoracic inlet and outlet
• Typical intercostal space
– Boundaries and contents
– muscles
• Atypical intercostal space
• Muscles of respiration
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4. 4

5. Thorax - boundaries
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6. Superior Thoracic Aperture
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7. Plane of Inlet
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45°

8. Suprapleural membrane/ Sibson’s fascia
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9. 9
Suprapleural membrane: Relations

10. Inf thoracic aperture-Diaphragm- ant view
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11. Thoracic skeleton ant view
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12. 12
Thoracic skeleton post view

13. Typical rib
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14. 14
Atypical ribs

15. Thoracic vertebrae
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16. Sternum and Joints
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17. 17
Layers in thoracic wall

18. Intercostal muscles
 External
 Internal
 Innermost
 Subcostalis
 Intercostalis intima
 Sternocostalis {transversus thoracis }
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19. 19
Intercostal muscles

20. 20
External and internal intercostal muscles

21. 21
External and internal intercostal muscles

22. 22
External and internal intercostal muscles

23. Subcostalis, Intercostalis intima & Sternocostalis
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24. Intercostal arteries, nerves, and vein
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25. Intercostal nerve
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26. Intercostal nerve & its branches
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27. TYPICAL INTERCOSTAL NERVE
1. Lateral cutaneous with anterior and posterior
branches.
2. Anterior cutaneous nerve with medial and
lateral cutaneous branch.
3. Lie within the intercostal space.
4. Supply structure within its space.
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28. • T1 and T2 give branch to brachial plexus
• T1 has no lat or ant cutaneous branch
• T2 has lateral cutaneous (intercostobrachial)
nerve but no branches
• T7 to T11 cross their corresponding spaces to
supply the anterior abdominal wall.
• Typical : T3 to T6
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TYPICAL INTERCOSTAL NERVE

29. Intercostal Arteries
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30. Intercostal arteries
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31. 31
Anterior
intercostal
Arteries
Absent in 10th
& 11th
space

32. 32
Posterior
intercostal
Arteries

33. Intercostal veins
anterior and posterior
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34. Azygos system
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35. Lymphatic drainage
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36. Atypical intercostal space
• Typical space: typical nerve, rib and vertebra.
• Nerve: T3 - T6
• Ribs: 3 - 9
• Vertebrae: 2 - 8
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37. Typical intercostal space
• 3rd
- 6th
space
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38. MOVEMENTS OF RIB CAGE
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39. Muscles of respiration
Inspiration
• Quiet
– Diaphragm
– External intercostal
• Forceful
– Sternocleidomastoid
– Serratus anterior
– Lattisimus dorsi
Expiration
• Quiet
– Passive recoil of diaphragm
• Forceful
– Rectus abdominis
– Internal intercostal
– Serratus posterior inferior
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40. Applied anatomy
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41. Cervical Rib Syndrome
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42. 44
Gorilla rib

43. Shape
of
chest
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44. Barrel chest
• Large ribcage, round torso
• Increase in the A-P diameter of the chest wall
• Causes
– Normal
– Acromegaly
– Emphysema
– Osteoarthritis of joints of thorax
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45. 47
Barrel chest

46. Pectus excavatum
• Commonest congenital deformity of anterior
chest wall
• Several ribs and the sternum grow
abnormally.
• Caved-in or sunken appearance of the chest
• Aka cobbler's chest, sunken chest, or funnel
chest
• Asymptomatic to severe cardiac / pulmonary
symptoms
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47. 49
Pectus
excavatum

48. Rachitic rosary
• Aka beading of the ribs
• Prominent knobs of bone at the costochondral
joints
• Knobs - beads under the skin of the rib cage,
• Beads of a rosary
• Cause - Rickets
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49. Rachitic rosary
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50. Pectus carinatum
• Opposite of pectus excavatum protrusion of
the sternum and ribs
• Aka pigeon chest
• Overgrowth of cartilage causing the sternum
to protrude forward
• Causes
• During pubertal growth in males
• Congenital ? hereditary
• Post- surgical i.e. median sternal thoracotomy
• Turner syndrome, Marfan syndrome, Ehlers Danlos Syndrome, Morquio syndrome, Noonan syndrome,
Trisomy 18, Trisomy 21, homocystinuria, osteogenesis imperfecta, multiple lentigines syndrome, Sly
syndrome and Scoliosis. 52

51. Pectus carinatum
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52. Applied anatomy
• Thoracotomy – incisions
• Anterolateral
• Posterolateral
• Anterior
• Notching of ribs <– obstruction of aorta
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53. Pleural tap / Paracentesis thoracis
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54. 56
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