Lecture 6 - The Thorax

Question 1

What is the Thorax?

Answer 1

• defines the chest cavity
• protects the vital organs
• supports bone & muscles of the posterior girdle & shoulder

Question 2

What are thoracic apertures ?

Answer 2

• apertures = openings
• there is a superior boundary & an inferior boundary

Question 3

What are the 3 parts of the sternum?

Answer 3

• manubrium
• body
• xiphoid process

Question 4

What is the manubrium of the sternum?

Answer 4

• the most superior part of the sternum
• includes the jugular notch, which has a pair of clavicular notches for articulation of the clavicles
• also has attachment points for cartilage of 1 rib

Question 5

What is the body of the sternum?

Answer 5

• a long flat bone
• includes the sternal angle which has facets for the costal cartilage of either 2nd rib to articulate with the sternum

Question 6

What is the xiphoid process of the sternum?

Answer 6

• serves as an attachment point for muscles
• ends at the T10 vertebrae

Question 7

How many ribs are there?

Answer 7

• 12 total pairs

Question 8

Which ribs are true ribs?

Answer 8

• ribs 1-7
• They articulate directly with the sternum

Question 9

What ribs are false ribs?

Answer 9

• ribs 8-10
• First 3 pairs join anteriorly to the costal cartilage of the rib above, but not directly with the sternum

Question 10

What ribs are floating ribs

Answer 10

• ribs 11 & 12
• they do not have an anterior attachment point

Question 11

What are supernumerary ribs?

Answer 11

• Means you have extra ribs
• Can occur in any region of the vertebral column, however most common from the cervical or lumbar
• Can be bilateral or unilateral

Question 12

What are the components of a rib?

Answer 12

• head
• neck
• tubercle
• body

Question 13

What is the head of a rib?

Answer 13

• Two facets separated by a crest, one articulates with corresponding vertebra and the other with the superior vertebra

Question 14

What is the neck of a rib?

Answer 14

• connects the head with the body

Question 15

What is the tubercle of a rib?

Answer 15

• located at the junction of the neck & body
• has a smooth Articular part & a Rough non-Articular part
• the point of articulation with the transverse costal facet

Question 16

What is an atypical rib & which ones are they?

Answer 16

• these ribs have features that are not common to all the other ribs
• the atypical ribs are ribs 1, 2, 10, 11, 12

Question 17

Why is rib 1 atypical?

Answer 17

• it is shorter & wider
• has a single facet on the head for articulation with T1 vertebra, Two grooves for subclavian blood vessels, & a ridge for attachment of scalene muscles
• also has a different groove

Question 18

Why is rib 2 atypical?

Answer 18

• it is thin & long
• has a rough area on anterior surface for muscle attachment

Question 19

Why is rib 10 atypical?

Answer 19

• it only has one facet & articulates with only a single vertebra

Question 20

Why are ribs 11 & 12 atypical?

Answer 20

• they are short & have no neck
• do not have an anterior attachment end

Question 21

What is costal cartilage?

Answer 21

• provides structural strength & flexibility
• its an anchor point of ribs anteriorly
• contribute to elasticity of the thorax
• connection point between ribs & sternum

Question 22

What are intercostal spaces ?

Answer 22

• Separate ribs and costal cartilages from each other
• As we travel posteriorly, the ribs get narrower & Widens further with inspiration

Question 23

Joints of the Thorax

Answer 23

• they are part of the synovial plane
• have small range of motion (ROM)
• they are associated with normal respiration

Question 24

What are the 4 joints of the Thorax?

Answer 24

• costovertebral joints
• costotransverse joints
• sternocostal joints
• costochondral joint

Question 25

What is the costovertebral Joint?

Answer 25

• Joints at head of the ribs; posteriorly
• Head of each rib forms a joint with 3 other structures:

1. Superior costal facet of corresponding (same numbered) vertebra
2. Inferior costal facet of the superior vertebra; Solid attachment point posteriorly
3. Adjacent intervertebral disc uniting the two vertebrae

Question 26

What is the costotransverse joint?

Answer 26

• Joins the tubercle of a rib to the transverse process of the same number
• allows only gliding movement
• present in all ribs except for ribs 11 & 12

Question 27

What is the sternocostal joint?

Answer 27

• First attachments to the sternum
• 2nd-7th pairs articulate with sternum
• helps increase the anteroposterior diameter of the thorax during inspiration

Question 28

What is the costochondral joint?

Answer 28

• they are a hyaline cartilaginous Joint
• Provides flexibility but no movement
• Located between the ribs & costal cartilage in front of the rib cage

Question 29

What are the movements of the thorax? And what produces these movements?

Answer 29

• inspiration/inhalation
• expiration/exhalation
• movements are produced by the thoracic wall & diaphragm

Question 30

What is the diaphragm?

Answer 30

• a thin dome-shaped muscle attached to the sternum that helps you inhale/exhale

Question 31

What is vertical dimension?

Answer 31

• refers to contraction/relaxation of the diaphragm
• Contraction causes the dome to be pulled inferiorly
• Relaxation of the dome returns to its resting position superiorly

Question 32

What is the pump handle mechanism?

Answer 32

• it is intercostal muscle contraction/relaxation that changes in anterior-posterior diameter
• increase interiorly/posteriorly diameter

Question 33

What is the bucket handle mechanism

Answer 33

• it is intercostal muscle contraction/relaxation that changes in transverse diameter
• Lateral-most (middle) parts of the ribs are raised, especially lower ones
• increases lateral diameter