Osteology and Joints of the Thorax

Question 1

Brachial plexus passes laterally between__________________muscles, above ________________ rib

Answer 1

Brachial plexus passes laterally between anterior and posterior scalene muscles, above 1st thoracic rib

Question 2

_____________ joint forms the Sternal Angle (Angle of Louis)

Answer 2

Manubriosternal joint

Paralaterally, the costal cartilage of the 2nd rib can be palpated

Question 3

What type of joint is the Sternoclavicular Joint?

What happens in dislocation?

Answer 3

Atypical saddle-shaped synovial joint (fibrocartilaginous disc exists between manubrium and clavicle)

Very stable = joint, often clavicle will fracture rather than dislocate the joint

Anterior dislocation is more common than posterior

Posterior dislocations are an emergency.

Question 4

True Ribs vs. False Ribs vs. Floating Ribs

Answer 4

True ribs are those that articulate directly the sternum anteriorly i.e. Ribs 1-7

False ribs are those that do not articulate directly with the sternum i.e. ribs 8-10 converge to cartilage of rib 7

Floating ribs are those that do not articulate with the sternum i.e. ribs 11-12

Question 5

Typical Ribs?

Answer 5

Typical ribs are ribs 3-9

Question 6

Atypical Ribs?

Answer 6

1, 2, 10, 11, 12

Question 7

Atypical Rib 1

Answer 7

Atypical Features:

• Shortest and most curved rib, flat and broad
• 2 groves across its superior surface for subclavian artery & vein separated by the scalene tubercle
• Single articular facet on its head, articulates with T1 vertebrae only

Question 8

A Typical Rib 2

Answer 8

Atypical Features:

• Rough area on its superior surface, the tuberosity for serratus anterior

Question 9

A Typical Rib 10

Answer 9

Atypical Features:

• 1 articulation on head for articulation with T10 vertebra

Question 10

Atypical RIbs 11/12

Answer 10

Atypical Features:

• These ribs are shorter than the others
• They have no neck or tubercle
• 1 articular facet on head for articulation with T11 / T12 respectively
• No anterior articulation
• Anterior tip is tapered with rudimentary cartilage present on it
• No tubercle for articulation with a transverse process

Question 11

Atypical Thoracic Vertebrae?

Answer 11

Atypical Thoracic Vertebrae:

T1

T9

T10

T11

T12

Question 12

_________________

Circular segment of rib cage broken, move inwards during inspiration, outwards during expiration

Paradoxical movements of the chest wall => opposite direction of expected movement

Answer 12

Flail Chest

Question 13

________________ is a syndrome caused by compression of neurovascular structures between 1st rib and the extra cervical rib

Answer 13

Thoracic outlet syndrome is a syndrome caused by compression of neurovascular structures between 1st rib and the extra cervical rib

Question 14

___________________:

• Usually, asymptomatic. However…
• During exertion, subclavian artery steals reverse blood flow from the vertebrobasilar arterial system
• Results in vertebrobasilar insufficiency (inadequate perfusion of posterior brain regions)

Answer 14

Subclavian Steal Syndrome:

• Usually, asymptomatic. However…
• During exertion, subclavian artery steals reverse blood flow from the vertebrobasilar arterial system
• Results in vertebrobasilar insufficiency (inadequate perfusion of posterior brain regions)