بسم الله الرحمن الرحيم

1. بسم الله الرحمن الرحيم

2. Chest Wall

3. Objectives • Identify the sternum and ribs with their characteristic features. • Define intercostal space with its contents. • Describe intercostal muscles with their nerve supply and actions. • Enlist the respiratory muscles with their actions. • Explain the Bucket handle and pump handle movements.

4. Thoraciccage

5. THORACIC CAGE • Conical in shape • Formed of: • Sternum & costal cartilages: anteriorly • Twelve pairs of ribs: laterally • Twelve thoracic vertebrae: posteriorly • Has 2 apertures (openings): • Superior (thoracic outlet): narrow, open, continuous with neck • Inferior: wide, closed by diaphragm

6. Articulations Manubriosternal (fibrocartilagenous J.) Small angular Movement possible Costovertebral (Synovial joint) Costochondral (cartilagenous J.) no movements possible Sternocostal (synovial), mobile EXCEPT first, which is cartilagenous & fixed Xiphisternal (fibrocartilagenous J.) no significant movements

7. Thoracic inlet Boundaries: a. Anterior: Supra-sternal notch of the manubrium sterni. b. On each side: First rib. c. Posterior: First thoracic vertebra.

10. Thoracic outlet Boundaries: a. Anterior: Xiphoid process. b. On each side: Lower six costal cartilages & Last two ribs. c. Posterior: Last thoracic vertebra. - It is closed by the diaphragmwhich separates it from the abdominal cavity.

11. Ribs Classification according to their attachments to the sternum: Total number of Ribs: 12 pairs A: True ribs: Upper seven ribs (Directly attached to the sternum). B: False ribs: Lower five ribs (Indirectly attached to the sternum). The lower two ribs (11th & 12th) are called the Floating ribs because they are free anteriorly. Classification of ribs according to their structure: A: Typical: 3rd- 9th ribs. B: Atypical:1st, 2nd, 10th, 11th, and 12th ribs.(first two and last 3) ribs.

12. Typical rib

13. Atypical ribsFirst rib (general features) Shortest C- Shaped Ant end: cup shape. Post end: It has Head, neck and tubercle. Head: One facet Surfaces: Sup. & Inferior Borders: Outer (lateral) & Inner (medial).

14. Second rib -Twice the length of 1st - Head has 2 facets - Surfaces of shaft are in between that of 1st & typical

15. Tenth rib a.Single articular facet on the head.

16. Eleventh rib a.Single articular facet on the head. b.No tubercle.

17. Twelveth rib a.Single articular facet on the head. b.No tubercle. c.No neck. d.No costal groove. e. Large head. f. Tapering anterior end.

18. Sternum

19. Sternum • 3 PARTS: Manubrium, Body * Xiphoid process. • Manubrium: Lies opposite T3,4. • Body: T5 toT8 • Xiphoid T9

20. Intercostal Spaces There are 9 anterior and 11 posterior Each space contains: 1-Intercostal muscles: (External, Internal and transversus thoracicus) 2-An Intercostal nerve. 3-Intercostal vessels: a. Intercostal arteries (Anterior & Posterior) b.Intercostal veins (Anterior & Posterior).

21. Respiratory MovementsA- Movements of Diaphragm Inspiration Contraction (descent) of diaphragm Increase of vertical diameter of thoracic cavity Expiration Relaxation (ascent) of diaphragm)

22. Respiratory MovementsB- Movements of Ribs PUMP HANDLE MOVEMENT Elevation of ribs Increase in antero-posterior diameter of thoracic cavity BUCKET HANDLE MOVEMENT Elevation of ribs Increase in lateral diameter of thoracic cavity

23. Inspiratory Muscles • Diaphragm (most important muscle) • External intercostal muscles Rib elevators: • Accessory muscles (only used during forced inspiration): • Scalene muscles • Pectoralis major • Sternomastoid

24. EXTERNAL INTERCOSTAL • Attachments:from lower border of rib above to upper border of rib below • Direction of fibers: downward & medially • Nerve supply: intercostal nerves • Action: rib elevators (inspiratory)

25. Is partly traversed by the nerve & vessels, which splits each muscle into 2 parts: Outer: Internal Intercostal (proper) Inner: Innermost Intercostal (In the middle of the space) Transversusthoracicus The most inner layer of thoracic wall It is formed of 3 muscles 1- Innermost Intercostal. 2- Sternocostalis. 3- Subcostalis Internal Intercostal

26. RIB DEPRESSORS 1. Internal intercostal 2. Innermost intercostal Direction: upward & medially 3. Subcostal 4. Transversus thoracis Nerve supply: intercostal nerves (ventral rami of T1-T11) 3 1 2 4

28. 4 to 5 slips which arise from inner surface of lower part of body of sternum and costal cartilages Inserted into inner surface of costal cartilages from 2 to 6. Thin bands of muscle fibers. Mainly in lower 6 spaces. Only in post. part of spaces. Origin: Inner surface & lower border of rib above. Insertion: Upper border of 2nd or 3rd rib below. Sternocostalis Subcostalis muscle

29. Expiratory Muscles • Act only during forced expiration • Rib depressors: • Internal intercostal • Innermost intercostal • Subcostals • Transversus thoracis • Anterior abdominal wall muscles: • External oblique • Internal oblique • Transversus abdominis • Rectusabdominis

30. Intercostal Spaces It contains: 1- Intercostal muscles. 2- Intercostal nerves. 3- Intercostal arteries. 4- Intercostal veins.

31. Intercostal muscles I. Outer layer: External intercostal muscle II. Intermediate layer: Internal intercostal muscle III. Inner layer: Transversus thoracis group:subdivided into: a. Innermost inter-costalis b. Sterno-costalis c. Sub-costalis

34. Transversus thoracis group Arrangements and extension of the muscles

36. Intercostal Arteries Intercostal Arteries:  1- Anterior Intercostal Arteries. 2- Posterior Intercostal Arteries.

37. Anterior Intercostal Arteries • Each anterior intercostal space contains two anterior intercostal arteries (except in the lower two inter-costal spaces). • The upper 6 pairs arise from the internal thoracic artery. • b. The 7th, 8th, and 9thpairs arise from the musculo-phrenic artery.

38. Posterior Intercostal Arteries - Each posterior intercostal space contains oneposterior intercostal artery which runs in the costal groove . *The upper two posterior intercostal arteries superior intercostal artery (from the costo-cervical trunk)  Subclavian artery. * From 3 - 11 posterior intercostal arteries and subcostal artery descending thoracic aorta.

39. Intercostal Nerves • There are 11 intercostal nerves in the upper 11 intercostal spaces and a subcostal nerve (12th ) below the last rib (on each side). - Each intercostal nerve arises from the corresponding thoracic nerve.

40. Typical Intercostal Nerves

41. Intercostal Veins I. Anterior intercostal veins: - They correspond to the anterior intercostal arteries. - They drain into the venae comitantes of the musculophrenicand internal thoracic arteries.

42. II. Posterior Intercostal Veins Right side: • 1st +2nd + 3rd post. intercostal veins unite to form the right superior intercostal vein azygos vein. -4th - 11th post. intercostal veins azygos vein -Subcostal vein Azygos Vein

43. II. Posterior Intercostal Veins Left side: - 1stpost. intercostal veinleft innominate vein. • 2nd + 3rd post. intercostal veins unite to form the superior intercostal vein - 4th–8th post. intercostal veinssuperior hemiazygos. - 9th – 11th post. intercostal veininferior hemiazygos vein. - Subcostal veininferior hemiazygos vein.

44. Arrangement of intercostal nerve and vessels in the costal groove

45. Branches: White & grey rami (1) communicans with sympathetic ganglion Collateral branch to Intercostals(2) Lateral cutaenous branch to skin (3) Anterior cutaenous(4) Muscular branches Pleural sensory branches peritoneal branches (5) Articular branches.

46. Applied anatomy: Needles introduced into the intercostal spaces (to remove collection in the pleura) Site:They are done in the lateral part of the chest wall. Cause:To avoid injury of the posterio intercostal nerve and vessels. (It is also better to be introduced near the rib below).

47. Thank you