Thoracic wall

Question 1

borders of the superior thoracic aperture

Answer 1

T1
1st rib
manubrium of the sternum

Question 2

borders of the inferior thoracic aperture

Answer 2

T12
ribs 11 and 12
costal margin
xiphoid process of sternum

Question 3

What structures pass near the superior thoracic aperture to get to the arm?

Answer 3

subclavian/axillary artery/vein
brachial plexus, long thoracic nerve

Question 4

true ribs

Answer 4

a rib attaching directly to the sternum via its own costal cartilage
1-7

Question 5

false rib

Answer 5

a rib that indirectly articulates with the sternum by connecting to the common seventh costal cartilage
8-10

Question 6

typical ribs

Answer 6

3-9
articular facet to articulate with transverse process
costal groove for neurovascular bundle

Question 7

atypical ribs

Answer 7

1-2, 10-12

Question 8

floating ribs

Answer 8

not connected to the sternum

Question 9

distinct features of rib 1

Answer 9

wide/flat
shortest rib
articulates with only one vertebrae, T1
scalene tubercle for middle scalene attachment
subclavian/axillary a./v.

Question 10

distinct characteristics of rib 2

Answer 10

flat, not as wide as 1
tuberosity for SA muscle on this rib only

Question 11

distinct characteristics of rib 10

Answer 11

head has a single articulation with its own vertebrae

Question 12

distinct characteristics of rib 11/12

Answer 12

articulate with only bodies of their own vertabrae, no tubercles
short ribs, not much curve
point anteriorly
no articulation with sternum

Question 13

three parts of the sternum

Answer 13

manubrium, body, xiphoid process

Question 14

sternocostal joint

Answer 14

articulation between costal cartilage and sternum

Question 15

Which costal cartilage articulation is not synovial? Why?

Answer 15

rib 1 and manubrium is fibrocartilaginous
don’t want movement to avoid compression of superior thoracic aperture structures

Question 16

sternal angle

Answer 16

angle between the 2nd costal cartilage and the sternum

Question 17

clinical significance of the sternal angle

Answer 17

T4/T5 disc level
divides mediastinum into sup/inf
overlies aortic arch on left and SVC on right
pericardium just superior
bifurcation of trachea
tracheal carina deep to sternal angle
level of pulmonary trunk bifurcation

Question 18

What do the intercostal nerves pass between?

Answer 18

internal intercostals and innermost intercostals

Question 19

external intercostal

Answer 19

origin: inf margin of sup rib
insertion: sup margin of inf rib
innervation: intercostal nerves
action: active in inspiration, support intercostal space, move ribs superiorly

Question 20

internal intercostal

Answer 20

origin: lateral edge costal groove of rib above
insertion: superior margin of inf rib
innervation: intercostal nerves
action: most active in expiration, support intercostal space, move ribs inferiorly

Question 21

innermost intercostal

Answer 21

origin: medial edge costal groove of rib above
insertion: internal aspect of superior margin of rib below
innervation: intercostal nerves
action: acts with internal intercostal muscles

Question 22

subcostal muscle

Answer 22

origin: internal surface near angle of lower ribs
insertion: internal surface of every second or third rib
innervation: related intercostal nerves
action: depress ribs

Question 23

transversus thoracic

Answer 23

origin: inferior margins and internal surfaces of costal cartilages of 2nd - 6th ribs
insertion: inferior aspect, deep surface of body of sternum, xiphoid process, costal cartilages ribs 4-7
innervation: related intercostal nerves
action: depress costal cartilage, favoring expiration

Question 24

internal thoracic artery

Answer 24

branches into anterior intercostal arteries
comes off the subclavian
also know as the mammary a.
lateral to the sternum BL

Question 25

Where do the first intercostal arteries come from?

Answer 25

subclavian - costocervical trunk - to supreme intercostal artery to first intercostal artery

Question 26

Where do all the intercostal arteries come from, except the first?

Answer 26

from the descending abdominal aorta posteriorly and the internal thoracic artery anteriorly
these anastomoses

Question 27

azygous vein

Answer 27

asymmetrical, present only on the right side of the posterior thoracic wall, receiving the intercostal veins

Question 28

accessory azygous vein

Answer 28

upper intercostal veins drain into this, which drains into the azygous vein
only present on the left side

Question 29

hemiazygous vein

Answer 29

lower intercostal veins drain into this, which drains into the azygous vein
only present on the left side

Question 30

intercostal nerves

Answer 30

anterior rami of spinal nerves running with artery and vein
sensory/motor
innervate intercostal space muscles, parietal pleura, overlying skin

Question 31

T12 innervation

Answer 31

anterior ramus spinal nerve T12, inferior to rib 12, innervates the abdominal wall