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1

The endothoracic fascia creates a natural cleavage plain between which two layers of the thoracic wall?

It separates the parietal pleura from its costal attachments.

2

Thoracic cage

Consists of 12 pairs of ribs and costal cartilages, sternum, 12 thoracic vertebrae and associated intervertebral discs.

3

Rib classification

True ribs (1-7) - articulate with sternum

False ribs (8-10) - articulate with the rib above

Floating ribs (11-12)

 

Also may be classified as:

Typical (3-9)

Atypical (1,2, 10-12)

4

Tubercle of typical rib

 Facet for articulation with transverse process. 

5

Abnormalities of ribs

Abnormalities of ribs are fiarly common:

  • Extra ribs (cervical or lumbar: cervical rib relatively common (0.5-2%) and may affect the brachial plexus and/or subclavian vessels. 
  • Rudimentary 12th rib
  • Congenitally fused ribs

6

Jugular notch

Level of vertebra T2

7

Sternal angle of Louis

Manubriosternal joint. 

  • Site of articulation of second costal cartilage.
    • Level of T4/T5. 
    •  

8

Kyphosis

Anatomically used to describe the natural anteiror concavity of the thoracic spine. 

Clinically is used to describe an excessive anterior concavity which may result from compression fractures of vertebral bodies. 

9

Costovertebral joints

  • Head of rib 'x' and thoracic vertebral bodies 'x' and 'x-1'. 
  • Synovial plane joint. 
  • Ligament: mainly radiate ligament. 
  • Exceptions are irbs 1,11,12 (T1, T11, T12). 

10

Costotransverse joint

  • Tubercle of rib 'x' and transverse process of thoracic vertebra 'x'. 
  • Synovial plane. 
  • Liagment: costotransverse ligament

11

Intervertebral T1-T12

  • Symphysis (secondary cartilaginous) - vertebral bodies covered by hyaline cartilage united by fibrocartilage.
  • Ligaments - anterior and posterior longitudinal. 

12

Joints of the thoracic cage

  • Costovertebral joint
  • Costotransverse joint
  • Intervertebral joints

13

Sternal joints

  • Sternal angle of Louis/manubriosternal joint
  • Sternoclavicular joint
  • Sternocostal joints
  • Costochondral junction
  • Interchondral joint

14

Sternal angle of Louis

Manubriosternal joint. 

  • Symphysis - fibrocaritlage, often ossifies later in life. 

15

Sternoclavicular joint

Synovial saddle

16

Sternocostal joints

Cartilages of ribs 1-7. 

  • First is primary cartilaginous (synchondrosis) usually ossifies in later life. 
  • Ribs 2-7 synovial plane. 

17

Costochondral junction

Not really a joint. Degenerates with age so useful forensically. 

18

Interchondral joint

  • Between cartilages 6-7, 7-8, 8-9.
  • Synovial plane.
  • Ribs 9-10 fibrous. 

19

Boundaries of thorax

  • Superior thoracic aperture: rib 1, manubrium and T1. 
  • Inferiorly enclosed by diaphragm

20

Diaphragm

Most important muscle of respiration. It is a musculotendinous sheet which separates thoracic and abdominal cavities. 

 

Central portion is tendinous (central tendon - dense fibrous CT), outer portions are muscular. 

21

Diaphragm innervation

Phrenic nerve (C3-C5)

22

Diaphragm attachments

  • Ribs 7-12
  • Lumbar vertebrae
  • Xiphoid process
  • Crura (right and left crus)
  • Arcuate ligaments
    • Median
    • Medial
    • Lateral

23

Diaphragm openings

  • IVC at T8
  • Oesophagus and vagal trunks at T10
  • Aorta and thoracic duct as T12

24

External intercostal membranes

External intercostal muscles do not continue all the way to the sternum. 

25

Internal intercostal membrane

Internal intercostal muscles do not continue all the way to the thoracic spine

26

Subcostals

Similar to innermost intercostals except transverse more than one rib

27

Changes upon inspiration

During inspiration:

  • The vertical, lateral and anteroposterior diameters of the thoracic cavity increase. 
  • The upper ribs have a 'pump handle' action which increases A-P diameter. 
  • The lower ribs have a 'bucket handle' action which increases the transverse diameter. 

28

The external intercostals

Mainly inspiration

29

The internal intercostals

Mainly expiration - during normal respiration they mainly increase in tone and only during forced respiration do they create movement. 

30

Innermost intercostals and subcostals actions

 

The innermost intercostals and subcostals probably act similar to internal intercostal muscles and transversus thoracis is probably active in forced expiration and is also involved in proprioception.