1. Ribs & Sternum

Question 1

What is the function of the sternum?

Answer 1

Anchors anterior ends of ribs 1-7

Protects cardiorespiratory organs

Question 2

What are the 3 parts of the sternum?

Answer 2

Manubrium
Mesosternum
Xiphoid process

Question 3

Where does the clavicle articulate with the sternum?

Answer 3

Clavicular notch

Question 4

Where do the ribs articulate with the sternum?

Answer 4

Costal notches

Question 5

What is the sternal angle?

Answer 5

Joint formed by articulation of the manubrium and mesosternum

Question 6

What are the transverse processes?

Answer 6

Raised ridges running laterally across mesosternum between costal notches

Question 7

What muscles attach to the manubrium?

Answer 7

Sternoclediomastoid (goes to temporal bone)

Sternohyoid (goes to hyoid bone)

Question 8

Action of SCM?

Answer 8

head rotation and flexion

Question 9

Action of sternohyoid?

Answer 9

Depression of hyoid

Question 10

What muscles connects to the manubrium and the mesosternum?

Answer 10

Pectoralis major (goes to the humerus)

Question 11

Action of pec major?

Answer 11

Adduction, medial rotation and flexion of arm

Question 12

Examples of non-metric traits of the sternum?

Answer 12

Sternal foramen
Synostosis
Bifid/trifid xiphoid process

Question 13

What is pectus excavatum?

Answer 13

Failure in fusion of sternal plates
Causes compression of thoracic viscera
More common in males than females (3:1)
Indent of the chest

Question 14

What is pectus carinatum?

Answer 14

Overgrowth of costal cartilages which force sternal plates into bowed arrangement
Can cause difficulties in breathing
Outgrowth of the chest

Question 15

Which ribs are false ribs and why?

Answer 15

8-10

articulate with the costal margin

Question 16

Which ribs are floating ribs and why?

Answer 16

11-12
do not connect to sternum or costal cartilages
end in abdominal musculature

Question 17

Which ribs are true ribs and why?

Answer 17

1-7

Articulate directly with sternum via costal cartilages

Question 18

What is the pattern of length of ribs?

Answer 18

Increase 1-7, decrease 7-12

Question 19

What vertebrae do ribs articulate with?

Answer 19

Thoracic vertebrae

Question 20

Characteristics of Rib 1?

Answer 20

Rougher superior (grooves for vascular structures - subclavian vein and artery)
Scalene tubercle for anterior scalene msucle
Oriented in transverse plane, no angle
Single whole articular facet on head

Question 21

Characteristics of Rib 2?

Answer 21

Starts to deviate inferiorly

Ridge for posterior scalene muscle

Question 22

Characteristics of Rib 11?

Answer 22

Singular articular facet on head
Lacks tubercle
Slight angle
Shallow costal groove

Question 23

Characteristics of Rib 12?

Answer 23

Similar to rib 11 but shorter with no angle

Shaft tapers to point

Question 24

Examples of non-metric traits of ribs?

Answer 24

Extra cervical and lumbar ribs

Bifid ribs - sternal end may be congenitally split

Question 25

What are costal cartilages?

Answer 25

Persistent, unossified extensions of cartilaginous models that preceded the fully ossified ribs Flat bars of hyaline cartilage

Question 26

What do costal cartilages contribute to?

Answer 26

Mobility and elasticity of the thorax

Question 27

What is the costochondral junction?

Answer 27

Where rib and cartilage merge together with convex tip of cartilage being received by concave end of rib No movement across joint

Question 28

Properties of 1st costosternal joint?

Answer 28

Between costal cartilage 1 and manubrium Primary cartilaginous Potential to synostose with age

Question 29

What type of joints are costosternal joints 2-7/8?

Answer 29

Synovial

Question 30

What type of joints are costosternal joints 9&10?

Answer 30

Rarely synovial | Joint cavity may be absent

Question 31

How does ossification in a ventral direction occur?

Answer 31

Morphological alteration of ventral/sternal rib end OR Direct ossification of the costal cartilages

Question 32

What problems does the Iscan et al (1984) method suffer from?

Answer 32

Depends on preservation and positive identification of 4th rib Criteria used for method do not allow consistent application between examiners Separate standards for race and sex Estimated age ranges provided do not equate to 2SD as normally expected

Question 33

What 3 age related changes did Iscal et al (1984) describe?

Answer 33

Pit depth Pit shape Rim and wall configuration ...at the end of the 4th rib