Thoracic wall/cavity/mediastinum Flashcards
(33 cards)
Sternal angle
manubriosternal joint
articulation with rib 2
creates Transverse Thoracic Plane which crosses thru the disc b/w TV4 and TV4
–>divides superior and inferior mediastinum
Thoracic Inlet
1st TV
1st rib
manubrium
Oblique and anterior-inferiorally from TV1–>manubrium
need to be aware of pleura in this area during surgery or injury
Thoracic outlet (inferior aperture)
12th TV 11th and 12th ribs costal margin xiphisternal joint Closed by diaphragm oblique and anterior-superior need to be aware of pleura in this area during surgery or injury
ribs
true=1-7
false=8-10
floating= 11-12
3-9 are typical
1st Rib
no angle
lies in a more transverse
tubercles for scalene muscles
grooves for subclavian a. and v.
2nd rib
serratus anterior tuberosity on superior surface
10th rib
single articular facet for the body of TV10
11th and 12th rib
single articular facet on head, no neck or tubercle (don’t articulate with TP of TV 11 and 12)
Sternocostal joint
articulation b/w costal cartilage and sternum
supported by anterior and posterior radiate ligaments
1st SC joint is synchondrosis—>no movement
2-7 are synovial plane
Costochondral joints
articulation b/w rib and costal cartilage
synchondroses, **frequently dislocated, even in minor trauma
Costovertebral joint
b/w rib head and vertebral bodies/IV discs
synovial plane
radiate ligaments support capsule
Costotransverse joint
b/w rib and vertebral transverse process
synovial joints
not on 11 and 12
supported by superior costotransverse ligament
Pump handle motion
increase AP diameter
rotation at costotransverse joint elevates anterior part of ribs
**first rib is fixed
Bucket handle motion
gliding at posterior costovertebral and costotransverse) cases elevation of lateral portion of ribs
increases the transverse diameter of thoracic wall
Thoracic diaphragm
contraction–> increase in vertical diameter
n=Phrenic (C345)
rest–>4th ICS
rest= TV8
Deep inspiration= TV11
Deep expiration= TV4
forced inspiration lowers it 2 vertebral bodies
Intercostal nn.
11 pairs + 1 pair of subcostal
formed by ventral rami of thoracic spinal nn.
1) Motor innervation to thoracic wall muscles
2) preganglionic SNS via 14 pairs of white rami to the sympathetic chain
3) Postganglionic SNS via 31 pairs of grey rami to glands, smooth muscles, arrector pili etc
Dermatomes of thoracic wall
T4=Nipple
T6=Xiphoid
T10= Umbilicus***
note that C4 (shoulder) abuts T2 due to the brachial plexus.
Anterior IC arteries
9 pairs arise from
1) Internal thoracic –>1-6
2) Musculophrenic a. (branch of internal thoracic) –>lower ICS
anastomose with posterior
Posterior IC arteries
11 pairs
arise from
1) Thoracic (descending) aorta–>3-11
2) Costocervical trunk–>1-2
higher pressure system
Internal thoracic a.
branch of subclavian gives off 1) anterior IC a. 1-6 2) Musculophrenic a. -->IC a. 7-9 3) Superior epigastric a.
Superior Intercostal vein
gets drainage from 1-3rd intercostal veins
drains into azygous (R) or brachiocephalic (L)
Azygos vein
from right ascending lumbar v and right subcostal vv.
tributaries: R posterior intercostal veins, hemiazygos, and accessory hemiazygous….plus tributaries from IVC
at TV4 it enters the SVC
**collateral circulation b/w SVC and IVC
Hemiazygous
gets blood from inferior 3 posterior IC veins
joins azygos at TV9
Accessory hemiazygos
drains left posterior IC veins 4-8
