Thoracic Wall Flashcards
Thorax is also known as
breast plate or chest
Location of the Thorax
between neck and abdomen
Shape of Thorax
flat in front and back and round at the sides
Boundaries
anterior: sternum and costal cartilages
posterior: thoracic part of vertebral column
superior: communicates with the neck; superior thoracic aperture: T1, R1, manubrium sterni
inferior: separated by diaphragm; inferior thoracic aperture: T12, R12, end of R11, costal margin, xiphoid process of sternum
Functions of the Thorax
houses and protects the lungs and heart
acts as a conduit for structures passing between neck and abdomen
principal role in breathing
provides support for UE
Lines of Orientation
- midsternal line: medial line over sternum
- midclavicular: vertical line from midpoint of clavicle
- anterior axillary line: vertical line at anterior axillary fold
- midaxillary line: line between anterior and posterior axillary fold
- posterior axillary line: vertical line at posterior axillar fold
- vertebral line: vertical line down the vertebral column/ spine
- scapular line: vertical line down on posterior wall of thorax passing through the inferior angle of scapula (T7)
Anterior Spaces
infraclavicular: below
supraclavicular: above
precardia: in front of heart
traube’s: overlying stomach
Posterior Spaces
infrascapular: below
interscapular: between
suprascapular: above
Osteology of Thoracic Wall
thoracic vertebra, ribs, intercostal spaces, sternum, costal cartilages
2 Divisions of the Thoracic Cavity
mediastinum: heart
thoracic pleurae: lungs
Osteology of Thoracic Cage
parietal pleura: inner surface of chest wall
pleural cavity: membranous sac
visceral pleura: covers the lungs
Osteology of Sternum
manubrium
body
xiphoid process
Manubrium
articulates with clavicle (clavicular notch) and costal cartilages (costal notch)
opposite T3-4
Body of Sternum
articulates with 2nd-7th costal cartilages
Xiphoid
hyaline cartilage that becomes ossified
Sternal Angle of Louis
opposite T4
Xiphisternal Joint
opposite T9
Importance of Sternal Angle of Louis
- ribs are counted from this level downwards (2nd rib lies here)
- separates superior and inferior mediastinum
- marks the end of the ascending aorta, the beginning and end of the aortic arch, and the beginning of the descending arch
- trachea divides into 2 principal bronchi at the carina
- azygous vein arches over the roof of right lung and opens in SVC
- pulmonary trunk divides into 2 pulmonary arteries below this level
- thoracic duct crosses from right to left side and reaches left side at the level of the sternal angle
- marks the upper limit of the base of the heart
- cardiac plexus situated at the same level
- found opposite T4-T5
True Ribs
1-7
directly attached to sternum
False Ribs
8-10
indirectly attached to sternum (attach anteriorly to each other and to the 7th rib by the costal cartilages)
Floating Ribs
Rib 11 and 12
no attachment at all
Osteology Typical Ribs
ribs 3-9
superior border: round and smooth
inferior border: sharp and thin with costal groove for neurovascular bundle
anterior end: attachment of costal cartilage
Parts of a Typical Rib
head
neck
tubercle
shaft
costal groove
angle
sternal end
Head
posterior vertebral end
2 articular surfaces separated by a crest
superior surface: articulates with the inferior articular facet on the body of the vertebra above
inferior surface: articulates with the superior articular facet of its own vertebra
Neck of the Rib
flat and slightly constricted
separates head and tubercle
Tubercle
prominence in the outer posterior surface
articular part: medial oval facet for articulation of transverse process of associated vertebra
non-articular part: roughened by ligament
Shaft of Ribs
long, thin, flat, and twisted
superior border: smooth and round
inferior border: sharp and thin
Costal Groove
at the inferior internal surface of the shaft of rib
Angle
where the rib sharply turns
Sternal End
where the costal cartilage is attached
Atypical Ribs
R1,R2,R10,R11,R12
Rib 1
relation to the lower nerves of brachial plexus and subclavian artery and vein
1. attachment to only T1
2. small and flat
3: has a scalene tubercle (separates two smooth grooves crossing the shaft)
- superior: subclavian artery
-inferior: subclavian vein
4. has a subclavian groove: anterior groove- subclavian vein; posterior groove- lower trunk of brachial plexus and subclavian artery
Rib 2
flat but twice as long as first rib (shorter and thinner)
articulates with the vertebral column in a way similar to typical ribs
Rib 10
single facet for articulation to T10
Rib 11 to 12
articulates with the bodies of their own only (T11 and T12)
no tubercles or necks
short, little curve, pointed anteriorly
Costal Cartilage
hyaline cartilage connecting upper seven ribs to the sternum and 8th to 10th ribs to the cartilage immediately above
cartilages of 11th to 12th rib end at the abdominal wall
helps in elasticity and mobility of the wall
Facets of the Thoracic Vertebrae
transverse costal facets: articulation with tubercle of rib
costal facts: posterolateral aspect of the body; also called demifacets
Joints in the Thoracic Region
sternal joint
xiphisternal joint
costosternal joint
costovertebral joint
Sternal Joint/ Manubriosternal Joint
cartilaginous
T4-T5
attachment of 2nd costal cartilage
separates superior and inferior mediastinum
Xiphisternal Joint
cartilaginous
T9
Costovertebral Joint
synovial plane joint
single synovial plane joint: rib 1,10-12
Joint of Tubercle and Rib
tubercle and transverse process
synovial
absent in 11th-12th rib
Rib to Costal Cartilage
cartilaginous
Costal Cartilage to Sternum
1st rib: cartilaginous
2nd-7th: synovial
6th to 10th: synovial (articulates with each other)
Thoracic Outlet/ Superior Thoracic Aperture Boundaries
communicates with root of the neck
T1, medial edges of rib 1 and costal cartilage, superior margin of manubrium sterni
Thoracic Outlet Structures that Pass
Esophagus
Trachea
Vessels and Nerves
Apices of the Lungs and Pleurae
Inferior Thoracic Aperture Boundaries
large and expandible
communicates with the abdomen
closed by diaphragm
anterior: xiphisternal joint
posterior: 12th thoracic vertebrae
laterally: costal margin
Thoracic Outlet Syndrome
compression of lower nerves of brachial plexus (C8 and T1), and subclavian artery and vein
Causes
- cervical rib: extra
- scalene syndrome: between anterior and middle scalene
- costoclavicular syndrome: between 1st rib and clavicle
- hyperabduction syndrome: beneath pectoralis minor
Allen’s Test
flex elbow at 90 degrees, extend horizontally, rotated laterally
palpate for radial pulse while turning head opposite tested hand
Adson’s Test
abduction, extension, and external rotation
rotate head toward involved side and take deep breath and hold it while palpating for radial pulse
Costoclavicular Maneuver
shoulder down and back and exaggerated “at attention” posture
backpack or heavy jacket syndrome
Intercostal Space
between adjacent ribs
costal groove lies the intercostal VAN
Structures most pronounced in lateral aspect of thoracic wall in the Intercostal Space (superficial to deep)
skin
superficial fascia
deep fascia
intercostal membrane
endothoracic fascia
extrapleural fatty layer
parietal pleura
pleural cavity
visceral pleura
lungs
Muscles of Respiration
external intercostals: most superficial; downward and forward
internal intercostals: intermediate; downward and back
innermost intercostal: deepest layer; incomplete muscle layer; related to endothoracic fascia and parietal pleura
Action of Intercostal Muscles
prevent sucking in or blowing out of the lungs during changes in the intrathoracic pressure
Inspiration
1st rib is fixed by scaleni muscle
2nd to 12th rib elevates towards 1st by intercostal muscles
Expiration
12th rib is fixed by quadratus lumborum and oblique muscle of the abdomen
1st to 11th rib depresses by intercostal muscles
Pump Handle Effect
1st to 7th rib
sternum raises; increases diameter
ribs depresses; decreases diameter
increases anteroposterior diameter
Bucket Handle Effect
8th to 10th rib
increases transverse diameter in the frontal plane
Caliper Motion
11th to 12th rib
increases inferior vertical diameter
Piston Action
diaphragm
increases vertical diameter
External Intercostals (11)
superior attachment: inferior margin of the rib above
inferior margin: superior margin of the rib below
nerve: intercostal nerves
action: stabilize rib cage; active during inspiration; supports intercostal space; moves ribs superiorly when 1st rib is fixed (increases anteroposterior and transverse diameter)
Internal Intercostals (11)
superior attachment: lateral edge of the costal groove of the rib above
inferior attachment: superior margin or rib below deep to attachment of related eternal intercostal
nerve: intercostal nerves
action: most active during inspiration; stabilize rib cage; depresses ribs when lower ribs are fixed
Innermost Intercostal (incomplete layer)
superior layer: medial edge of the costal groove of the rib above
inferior layer: internal aspect of the superior margin of the rib below
nerve: intercostal nerves
Action: assists internal and external intercostals
Subcostales
superior attachment: internal surface (near angle) or the lower ribs
inferior attachment: internal surface of 2nd or 3rd rib below
action: depresses ribs
Transversus Thoracis
superior attachment: inferior margin and internal surfaces of the costal cartilages of the 2nd and 6th rib
inferior attachment: internal aspect of the deep surfaces of body of sternum, xiphoid, and costal cartilages of 4th-7th rib
action: depresses costal cartilages; holds internal thoracic vessels to the walls
Diaphragm
superior attachment: xiphoid, costal cartilages of lower 6 ribs, 1st to 3rd lumbar vertebrae
inferior attachment: central tendon
nerve: phrenic nerve
action: most important in respiration, assists in pulling ribs downward, increases vertical diameter by pulling down central tendon, abdominal strain in weightlifting
Levatores Costarum
origin: tip of transverse process of C7 to T11
insertion: rib below (vertebra of origin) near the tubercle
nerve: posterior rami of thoracic spinal nerves
action: raises ribs
Serratus Posterior Superior
origin: lower cervical and upper thoracic spines
insertion: upper ribs
nerve: intercostal nerves
action: proprioception; raises ribs (inspiratory muscle)
Serratus Posterior Inferior
origin: lower thoracic and upper lumbar spines
insertion: lower ribs
nerve: intercostal nerve
action: proprioception; depresses ribs (expiratory)
Diaphragm Attachments
xiphoid process
costal margin
ends of ribs 11 and 12
lumbar vertebrae
ligaments that span across structures of the posterior abdominal wall
3 Main Parts of the Diaphragm
- sternal part: arising from xiphoid process
2: costal part: arising from deep surfaces of lower six ribs and costal cartilages
3: vertebral part: arising from vertebral column
Right and Left Parts of the Diaphragm
right crus: comes from L1-L3
left crus: comes from L1-L2
right diaphragm: reaches upper border of 5th rib
left diaphragm: reaches lower border of 5th rib
Central Tendon
muscle fibers of the diaphragm converge in the center
where the pericardium is situated
at the level of xiphisternal joint (T9)
Openings of the Diaphragm
caval opening
esophageal opening
aortic opening
Caval Opening
central tendon
inferior vena cava
terminal branches of right phrenic nerve
at T8
Aortic Opening
abdominal aorta
thoracic duct
azygous vein
anterior of 12
Esophageal Opening
esophagus
vagus nerve
esophageal branch of left gastric vessel
lymphatics from lower esophagus
at the level of T10
Other openings of the Diaphragm
crura: greater, lesser, and lowest splanchnic nerves
medial arcuate ligament: sympathetic trunk
between sternal and costal margin: superior epigastric vessel
left dome: left phrenic nerve
Nerve Supply and Action of Diaphragm
phrenic nerve (C3-5)
muscle of inspiration
increases intra abdominal pressure
acts as thoracic pump
Arterial Supply of Diaphragm
branches of internal thoracic arteries: pericardiophrenic and musculophrenic arteries
thoracic aorta: superior phrenic
abdominal aorta: inferior phrenic
Venous Supply of Diaphragm
brachiocephalic
azygos system
abdominal veins
Neurovascular Bundle
vein, artery, and nerves (superior to inferior)
found between middle and innermost layer
Venous Drainage of Neurovascular Bundle
right: superior intercostal azygous vein
left: superior thoracic brachiocephalic
Arterial Supply of the Neurovascular Bundle
anterior intercostal arteries from lateral branches of internal thoracic artery
Intercostal Nerves
posterior rami of T1-T11
carries somatic motor innervation to thoracic wall, sensory innervation to skin and parietal pleura, and post ganglionic sympathetic fibers to the periphery
Subcostal Nerve
anterior rami of T12
Innervating Regions of Intercostal Nerve
anterior ramus of T1: brachial plexus
lateral cutaneous branch of 2nd intercostal: sensation to upper arm
lower intercostal nerve: muscle, skin, peritoneum of abdominal wall
RATPLANTS
rib (2nd)
aorta (arch)
trachea (bifurcation)
pulmonary trunk (bifurcation)
left recurrent laryngeal
azygous vein
nerves - cardiac plexus
thoracic duct
separation of inferior and superior mediastinum
