Thoracic Wall Flashcards
Which is the longest rib?
7th Rib
Length increases from 1-7, then gradually decreases.
Which rib has the greatest lateral projection?
8th Rib
Transverse diameter increases from 1-8
How are ribs classified according to features?
Typical ribs : 3-9
- have the same general features
Atypical ribs : 1, 2, 10-12
- have differentiating features
How are ribs classified according to relation with sternum?
True Ribs : 1-7
- articulate with the sternum anteriorly
False Ribs : 8-12
- do not articulate with the sternum
How are ribs classified according to articulation?
Vertebrosternal ribs : 1-7
- articulate anteriorly with sternum
Vertebrochondral ribs : 8-10
- articulate anteriorly with the cartilage of the above rib
Floating ribs : 11-12
- anterior end is free
What features are present on anterior end of rib?
A small concave depression
What features are present on posterior end of rib?
Head
Neck
Tubercle - on outer surface
What are the features of a typical rib head?
(A) a lower articular facet and a smaller (B) upper articular facet, separated by (C) a crest.
What does the lower articular facet articulate with?
body of the numerically corresponding vertebrae
what does the upper articular facet articulate with?
Next higher vertebrae
How is a rib tubercle divided?
(a) medial articular part
(b) lateral non-articular part
What is the difference between articular part and non-articular part of rib tubercle?
Articular part
- Bears an oval facet
Non-Articular part
- rough
- pierced by foramina
What does the oval facet articulate with?
transverse process of corresponding vertebrae
Describe the superior border of a rib shaft.
Is thick and rounded
Has an outer lip to which the external intercostal muscle attaches.
Has a inner lip to which the internal intercostal & intercostalis intimus muscles attach.
Describe the lower border of a rib shaft.
Is sharp
Forms lower border of costal groove.
Which muscle attaches to lower border of rib shaft?
External intercostal muscles
Describe the outer surface of rib shaft.
Smooth and convex
Describe the inner surface of rib shaft?
Smooth and concave
Presents costal groove near lower border
What sits within the costal groove?
Intercostal VAN
What are the distinguishing features of 1st rib head?
- Small
- Rounded
- Bears single circular articular facet
What are the distinguishing features of 1st rib shaft?
- Slopes obliquely upwards, backwards and forwards to its sternal end
- No costal groove
What are the distinguishing features of 1st rib neck?
- rounded
- elongated
- directed upwards, backwards and laterally.
What are the features rib 1s upper surface?
Presents a scalene tubercle about its middle
Two oblique grooves separated by ridge:
(a) anterior groove
(b) posterior groove
What attaches to the scalene tubercle?
Scalenus anterior muscle
List the muscles attaching to rib I
Scalenus medius - area behind posterior groove
Scalenus anterior - Scalene tubercle
Subclavius - area anterior to anterior groove
Costoclavicular L. - area anterior to anterior groove
What lodges within anterior and posterior groove of Rib I?
Anterior - subclavian vein
Posterior - subclavian artery & lower trunk of brachial plexus
At what level is the manubrium situated?
T3 - T4
