Lecture 6 - Thorax

Question 1

What is the importance of the thorax?

Answer 1

• the protection of organs

Question 2

What are the 2 thoracic apertures?

Answer 2

• superior thoracic aperture
• inferior thoracic aperture

Question 3

What is the superior thoracic aperture?

Answer 3

• allows connection of the anatomic structures of the thorax and the neck
• i.e., rib 1 (x2), T1, & the superior manubrium

Question 4

What is the inferior thoracic aperture?

Answer 4

• formed by T12 behind, by Ribs 11 & 12 at the sides, & in front by the cartilages of ribs 7-10, which ascend on either side and form an angle

Question 5

What is the sternum?

Answer 5

• an elongated bony structure that anchors the anterior thoracic cage

Question 6

What are the 3 parts of the sternum?

Answer 6

• manubrium
• body
• xiphoid process

Question 7

What is the manubrium?

Answer 7

• the wider, superior portion of the sternum
• within the manubrium is jugular/suprasternal notch & the clavicular notches

Question 8

What is the jugular/suprasternal notch

Answer 8

• a shallow notch located on the superior surface of sternal manubrium

Question 9

What are the clavicular notches?

Answer 9

• Paired notches located on the superior-lateral sides of the sternal manubrium for articulation with the clavicle

Question 10

What is the body of the sternum?

Answer 10

• It’s the flat, narrow & the longest part of the sternum
• the centre of the body
• consists of the sternal angle & the costal notches/facets

Question 11

What is the sternal angle?

Answer 11

• the junction line between the manubrium & body of the sternum & the site for attachment of the 2nd rib to the sternum

Question 12

What is the costal notches/facets?

Answer 12

• site on the lateral sides of a thoracic vertebra for articulation with the head of a rib

Question 13

What is the xiphoid process?

Answer 13

• a small process that forms the inferior tip of the sternum

Question 14

How many ribs are there?

Answer 14

• 12 total pairs

Question 15

What are ribs 1-7?

Answer 15

• known as true ribs
• Connect from the thoracic spine to the sternum (via costal cartilage)

Question 16

What are ribs 8-10?

Answer 16

• known as false ribs
• attach to the costal cartilage from the rib above

Question 17

What are ribs 11-12?

Answer 17

• known as floating ribs
• no anterior attachment to anything, embedded in tissue around the abdomen

Question 18

What is supernumerary ribs?

Answer 18

• refers to the presence of more than 12 ribs
• can occur in any region of the vertebral column, however most common as a cervical rib

Question 19

How can you number the ribs?

Answer 19

• Rib # = # of the inferior vertebra that it articulates with on the posterior side
• i.e., Rib 7 articulates with the inferior articular process of T6 and the superior articular process of T7

Question 20

What are the 4 components of a rib?

Answer 20

• head
• neck
• tubercle
• body

Question 21

What is the head of a rib?

Answer 21

• Posterior end of a rib that articulates with the bodies of thoracic vertebrae

Question 22

What is the neck of a rib?

Answer 22

• Narrowed region of a rib, next to the rib head

Question 23

What is the tubercle of a rib?

Answer 23

• small bump on posterior side for articulation with the transverse process of a thoracic vertebra
• smooth articular part, rough non-articular part

Question 24

What is the body of a rib?

Answer 24

• the shaft portion of a rib
• consists of the costal angle & costal groove

Question 25

What is the costal groove?

Answer 25

• part of the body of the rib
• Shallow groove along the inferior margin of a rib that provides passage for blood vessels & a nerve

Question 26

What are the atypical ribs & why?

Answer 26

• Rib 1 = Sharp curve, Single facet - 1 vertebra articulates, 2 grooves - subclavian blood vessels
• Rib 2 = Ridge for scalenes
• Rib 10-12 = Single facet - articulates with 1 vertebra
• Rib 11 & 12 = No neck, Short compared to others

Question 27

What are the 3 joints of the thorax?

Answer 27

• the costovertebral joints
• sternocostal joint
• costochondral joint

Question 28

What are the costovertebral joints?

Answer 28

• the joints between the ribs & the vertebral column
• i.e., the joints of the head & ribs & the costotransverse joint

Question 29

What is the joint of the head & ribs?

Answer 29

• Head of each rib forms a joint with 3 other structures:
• Superior Costal Facet of corresponding (same numbered) vertebra
• Inferior Costal Facet of the superior vertebra
• Adjacent Intervertebral Disc uniting the 2 vertebra

Question 30

What is the costotranservse joint?

Answer 30

• Joins tubercle of a rib to the transverse process of the same number, except for ribs 11 & 12

Question 31

What is the sternocostal joint?

Answer 31

• Between the sternum & costal cartilage
• 1st pair of costal cartilages articulates with manubrium
  - Synarthrosis joint
• 2nd - 7th pairs articulate with sternum
  - Synovial joint

Question 32

What is the costochondral joint?

Answer 32

• Between the ribs and the costal cartilage

Question 33

What are the movements of the thorax?

Answer 33

• Produced by movements of the thoracic wall & the diaphragm
• Inspiration/inhalation
• Expiration/exhalation

Question 34

What is the vertical dimension of thorax movement?

Answer 34

• Contraction/relaxation of diaphragm
• increases superior-inferior

Question 35

What is the anterior-posterior dimension of thorax movement?

Answer 35

• Intercostal muscle contraction/relaxation
• referred to as the “Pump Handle Mechanism”

Question 36

What is the transverse dimension of thorax movement?

Answer 36

• Intercostal muscle contraction/relaxation
• increases laterally
• referred to as the “Bucket Handle Mechanism”