Organization of the Thorax Flashcards
most frequently broken bone in body?
clavicle
angle of louie?
sternal angle
what does sternal angle tell you?
articulation of 2nd costal cartilage
-2nd rib
xiphoid process
ossifies as we age
subcostal angle?
infrasternal angle
AML
anterior median line
intersection of median plane with anterior thoracic wall
MCL
mid-clavicular line
passes through midpoint of clavicle
parallel to AML
AAL
anterior axillary line
runs vertically along anterior axillary fold formed from inferolateral border of pectoralis major
MAL
mid-axillary line
runs from apex of axillary fossa, parallel to AAL
PAL
posterior axillary line
also parallel to AAL
drawn vertically along posterior axillary gold formed by latissimus dorsi and teres major muscles as they span from the back to the humerus
PML
posterior median line
vertical line along the tips of the spinous processes of the vertebrae
SL
scapular line
parallel to PML and intersects inferior angles of scapula
thorax
superior part of trunk lying between root of the neck and thoracic diaphragm
thoracic wall
osteocartilagenous components, muscles, fascia, skin
thoracic cavity
2 pulmonary cavities and central mediastinum
function of thorax
protect underlying viscera, respiration, muscle attachment
how many thoracic vertebrae?
12
have superior and inferior demifacets
-lower vertebrae gives its number
also have costal facets on transverse process
-articulate with rib tubercle
atypical thoracic vertebrae?
1, 10, 11, 12
have single facets for rib head
allows more rotation of rib**
how many and what types of ribs?
1-7 true
8-10 false
11-12 floating
true rib?
attached directly to sternum
false rib?
attach to costal cartilage and form costal margin
floating ribs
not attached to sternum
anteriorly end in muscle
anatomy of rib?
head - proximal end
neck - portion between head and tubercle
tubercle - junction of neck and body, articulate with transverse process of vertebrae
angle - anterolateral angulation of body just lateral to tubercle
shaft - mid and distal portion of rib, inferior portion has concave surface
costal groove - protection for intercostal vein, artery, nerve
costal cartilage - increased elasticity for thoracic wall
atypical ribs?
1, 2, 10, 11, 12
1st rib?
broad horizontal shaft with pronounced curvature
head has single facet - articulates TV1
shaft has grooves for subclavian artery and vein and scalene tubercle
-anterior and middle scalene muscle attachments
2nd rib?
serratus anterior tuberosity on superior surface
and posterior scalene muscle attachment
10th rib?
single articular facet on head for articulation with body of TV10
11th and 12th ribs?
single articular facet on head, absence of neck/tubercle
where do rib fractures occur most often?
near angle (weakest part of rib)
what ribs are more frequently broken?
middle ribs
flail chest?
multiple broken ribs in 2 or more places
-causes loose segment of thoracic wall which moves paradoxically with respiration
suprasternal notch?
anterior to TV2 TV3 intervertebral disc
clavicular notch?
for articulation with clavicle
lateral facets of manubrium?
for articulation with costal cartilage of ribs 1 and 2
manubriosternal joint?
between sternal body and manubrium
symphysis
xiphoid process?
variable in shape
cartilagenous, ossifies with age
lateral demi-facets, articulation with costal cartilage of 7th rib
xiphosternal joint
between sternal body and xiphoid
synchondrosis
transverse thoracic plane
sternal angle to disc between TV4 and TV5
-division between superior and inferior mediastinum
pectus excavatum?
anterior thoracic wall sunken in
-congenital anomaly
can cause respiratory and cardiac problems
pectus carinatum?
anterior thoracic wall protrusion
-congenital anomaly
can cause respiratory and cardiac problems
borders of superior thoracic aperture?
anterior - suprasternal notch of manubrium
lateral - 1st rib
posterior - TV1
extent of superior thoracic aperture?
extends obliquely from TV1 anteroinferiorly to manubrium
- pleural space extends into the neck region
- injury or surgery within this region may affect pleural cavity and lungs (pneumothorax)
borders of inferior thoracic aperture?
anterior - xiphosternal joint
lateral - costal margin
posterior - TV12 and ribs 11 and 12
extent of inferior thoracic aperture?
obliquely from TV12 anterosuperiorly to xiphosternal joint
- pleural space extends inferiorly to lie posterior to the abdominal region
- injury or surgery may affect pleural cavity and lungs (pneumothorax)
sternocostal joint?
articulation between costal cartilages and sternum
7 pairs
1st sternocostal joint?
synchondrosis - no movement
2-7 sternocostal joints?
synovial plane joints
support of sternocostal joint?
anterior and posterior radiate ligaments
costochondral joints?
articulation between rib and costal cartilage
most likely location of rib separation
synchondrosis - very little movement
interchondral joint?
articulation between costal cartilages of ribs 8-10 with costal cartilage above
costovertebral joint?
articulation between head of rib with vertebral bodies, IV disc
synovial plane joint
ribs 2-9?
articulate with adjacent vertebral bodies and IV discs
-intra-articular ligament extends from crest of head to IV disc limiting movement of this joint
what supports joint capsule of costovertebral joint?
radiate ligament
costotransverse joint?
articulation between rib tubercle and vertebral transverse process
synovial joint
not on rib 11 or 12**
ligaments of costotransverse joint?
lateral, superior costotransverse ligaments
attachments of external intercostal muscle?
origin:
inferior border of rib above (1-11)
insertion:
superior border of rib belw (2-12)
fiber direction - superoposterior >inferoanterior
action of external intercostal muscle?
maintain intercostal space during respiration
-elevate ribs (inspiration)
innervation of external intercostal muscle?
intercostal nerve
attachments of internal internalcostal muscle?
origin:
superior border of rib below (2-12)
insertion:
inferior border of rib above (1-11)
fiber direction - inferoposterior > superoanterior
action of internal intercostal muscle?
maintain intercostal space during respiration
-depress ribs (expiration)
innervation of internal intercostal muscle?
intercostal nerves
attachments of innermost intercostal?
origin:
superior border of rib below (2-12)
insertion:
inferior order of rib above (1-11)
action of innermost intercostal?
maintain intercostal space during respiration
-depresses ribs (expiration)
innervation of innermost intercostal?
intercostal nerves
attachments of subcostal muscle?
origin:
superior border of rib near angle
insertion:
inferior border of rib 2 or 3 intercostal spaces higher
action of subcostal muscle?
depress ribs (expiration)
innervation of subcostal muscle?
intercostal nerves
attachments of transverse thoracic muscle?
origin:
internal surface of inferior ternum
insertion:
inferior border of ribs 2-6
action of transverse thoracic muscle?
depress ribs (expiration)
innervation of transverse thoracic muscle?
intercostal nerves 2-6
attachments of levator costarum muscle?
origin:
transverse proces of CV7-TV11
insertion:
superior border of ribs near tubercle
action of levator costarum muscle?
assist with elevating ribs during forced inspiration
innervation of levator costarum muscle?
ventral rami C8-T11
attachments of serratus posterior superior?
origin:
nuchal ligament and spinous process of CV7-TV3
insertion:
ribs 2-5 superior border near angle
action of serratus posteror superior?
assist in elevation of ribs during forced inspiration
innervation of serratus posterior superior?
intercostal nerves 1-4
attachments of serratus posterior inferior?
origin:
spinous process of TV11-LV2
insertion:
ribs 9-12, inferior border near angle
action of serratus posterior inferior?
assist with forced inspiration
depress lower ribs to oppose superior movement of diaphragm
innervation of serratus posterior inferior?
intercostal nerves 9-12
external intercostal membrane?
continuation of external intercostal muscle anteriorly
internal intercostal membrane?
continuation of internal intercostal muscle posteriorly
innermost intercostals?
discontinuous sheet of muscle
transversus thoracis anteriorly
innermost intercostal laterally
subcostalis posteriorly
neurovascular bundle course?
runs between 2nd and 3rd layers
-between internal intercostal and innermost intercostal muscles
VAN - superior-inferior
vein artery nerve
endothoracic fascia?
connective tissue lining entire surface of internal thoracic wall and superior surface of diaphragm
thickens superiorly
simpsons fascia
function of endothoracic fascia?
provides a cleavage plane between thoracic wall and pleura
-important for surgeries requiring access to thoracic cavity
pump handle motion?
increase in AP diameter
-rotational movement at costotransverse joint causes elevation and depression of most distal portion of upper ribs
first rib is fixed***
bucket handle motion?
increase in transverse diameter
-gliding movement at posterior (costovertebral and costotransverse) joints causes elevation and depression of lateral most portions of ribs
what causes increase in vertical diameter of thoracic cavity?
contraction of diaphragm
innervation of thoracic diaphragm?
phrenic nerve - C3,4,5
action of thoracic diaphragm?
flattens during contraction to increase intrathoracic volume
during deep expiration
diaphragm extends to 4th intercostal space
during forced inspiration?
can move down 10cm
-about 2 vertebral bodies
sternocleidomastoid?
inspiration
scalene?
inspiration
serratus anterior?
inspiration
quadratus lumborum?
inspiration
pectoralis major?
inspiration
pectoralis minor?
inspiration
anterolateral abdominal wall muscles?
expiration
muscles of abdominal wall?
external intercostal > external abdominal oblique
internal intercostal > internal abdominal oblique
innermost intercostal > transversus abdominus
where to put needle into thorax?
roll it over top of the rib
intercostal nerve?
ventral ramus
innervation of thoracic wall?
11 intercostal pairs
1 subcostal pair
travel in costal groove inferior margin of rib
preganglionic sympathetic nerve cell processes?
via 14 pair white rami communicantes
postganglionic sympathetic nerve cell processes?
31 pair of gray rami communicantes
course of intercostal nerves?
first - within endothoracic fascia
near rib angle - pass between 2nd and 3rd muscle layers (internal and innermost intercostal muscles)
lateral perforating branches?
given off near MAL
pierces lateral body wall
-divides to anterior and posterior cutaneous branches
anterior perforating branches?
given off near lateral border of sternum
pierce anterior body wall
-divide into medial and lateral cutaneous branches
ventral rami of T1?
divides into large superior trunk that goes to brachial plexus and small inferior trunk (1st intercostal nerve)
intercostal nerve 1?
no cutaneous branches
-T1 dermatome not represented on thoracic wall
lateral cutaneous branch of intercostal nerve 2
forms intercostobrachial cutaneous nerve, supplying skin and subQ of axilla and medial brachial area
thoracoabdominal nerves
continuation of the intercostal and subcostal nerves
innervate skin and muscles of abdominal wall
nipple dermatome?
in males T4
xiphoid dermatome?
T6
umbilicus dermatome?
T10 - key dermatome
anterior intercostal arteries?
9 pairs
originate from internal thoracic artery (branch of subclavian)
descend along internal surface of anterior thoracic wall, lateral to sternum
division of anterior intercostal artery?
near 6th or 7th intercostal cartilage, divide:
- musculophrenic
- epigastric arteries
directly provides anterior intercostal arteries 1-6
musculophrenic artery?
follows costal arch and provides anterior intercostal arteries to lower intercostal spaces
how many anterior intercostal arteries per intercostal space?
2
-anastomose with posterior intercostal arteries
posterior intercostal arteries?
11 pairs (and 1 subcostal artery)
originate from thoracic aorta
-provides 3-11 and subcostal
originate from costocervical trunk (subclavian branch)
-provides supreme intercostal artery - 1st and 2nd intercostal spaces
1-3 posterior intercostal veins?
unite to form superior intercostal vein
right - drain to azygous
left - drain to brachiocephalic
anterior intercostal veins?
drain to internal thoracic veins
posterior intercostal veins?
drain to azygous system
