thoracic wall Flashcards
Thoracic wall function and formed by
- thoracic cage is formed by
- 12 thoracic vertebrae posteriorly
- 12 pairs of ribs and their costal cartilages
- sternum anteriorly - protects contents of thoracic cavity and mechanical function of breathing
Superior thoracic aperture (thoracic inlet) description
what passes the inlet?
- access for thoracic cavity to communicate with the neck
- bounded by body of T1
- 1st ribs and costal cartilage
- superior border of manubrium - pass inlet:
- trachea
- esophagus
- common carotid arteries
- jugular veins
- subclavian aa & vv
- vagus & phrenic nerves
- thoracic duct
Inferior thoracic aperture (thoracic outlet)
- access from thoracic cavity to communicate with abdomen
- closed by thoracic diaphragm
- slopes downward and backward
- bounded by T12, 12th rib, costal margins, xiphisternal joint
three parts of sternum
- manubrium-jugular (suprasternal) notch, clavicular notch, manubriosternal joint
- body- costal notches, xiphisternal joint
- xiphoid process
General vertebrae characteristics
- body support weight
- superior/inferior articular facets for articulation with other vertebrae; restrict movement
- transverse process and spinous process for muscle attachments
Thoracic vertebrae (5)
- costal facets on bodies articulate with head of ribs
- costal facets on transverse process articulate with tubercles of ribs
- long, inferiorly-directed spinous processes
- superior articular facets face posteriorly
- inferior articular facets face anteriorly
- true ribs
- false ribs
- floating ribs
- typical ribs
- atypical ribs
- 1-7th vertebrocostal ribs-costal cartilage attaches directly to sternum
- 8-10 vertebrochondral ribs-costal cartilage attaches to costal cartilage of rib 7
- 11 & 12 no attachment to sternum
- 3-9
- 1 & 2, 10-12, 11-12
a. )1st-broad and most curved and shortest- grooves for subclavian vessels
- scalene tubercle
- 1 articular facet
b) 2nd- 2 facets - tubercles for posterior scalene
- serratus anterior
c) 10-12 - only one facet on head
d) 11-12 - short and no neck or tubercles
Three articulations per rib
- inferior costal facet of superior vertebrae (rib 3 with inferior costal facet of T2
- superior costal facet of same number vertebra (rib 3 with superior costal facet of T3)
- costal facet on transverse process of same vertebrae (rib 3 with T3)
Breast: superficial and deep contents
- Superficial
- areola
- niple - deep
- superficial fascia
- mammary lobes
- lactiferous ducts
- lactiferous sinus
- suspensory ligament (Cooper’s)
lactation (3)
- ducts enlarge to form lactiferous sinus which serves as reservoir for milk during lactation
- remaining mass is adipose tissue and suspensory ligaments
- common site of cancer and benign tumors in women
Muscles of thoracic wall
-3 layers intercostal muscles
- external intercostal muscle (superficial); do not extend to the sternum anteriorly
- internal intercostal muscle (middle); does not extend to vertebrae posteriorly
- innermost intercostal muscle (deepest); only present laterally
all innervated by intercostal nerves
Posterior thoracic wall vessels and structures 4
- posterior intercostal vein/artery + intercostal nerve in each intercostal space (VAN)
- posterior intercostal arteries are direct branches of descending aorta
- posterior intercostal veins drain into hemiazygous (Left) nad azygous vein (right)
- vessels and nerve lie between internal and innermost intercostal muscles
Blood supply to thoracic wall anastomosis between posterior and anterior intercostal aa.
-vessels
- descending thoracic aorta
- posterior intercostal a.
- internal thoracic artery (from subclavian artery
- anterior intercostal artery
Nerves of thoracic wall
intercostal nerve are the anterior rami T1-T11
Innervation of muscles nad skin
- dermatone
- myotome
spinal nerves have:
motor-innervate certain muscles
sensory fibers innervate skin
-dermatome-skin area innervated by sensory fibers of single nerve root
-myotome-group of muscles primarily innervated by motor fibers of single nerve root
Thoracic cavity-
1. 3 compartments
- two lateral compartments (R/L pleaural cavities)
- one central compartment=mediastinum
- capacity of thoracic cavity variable allowing lungs to expand/recoil and heart to pump blood.
Pulmonary cavities contents
- lungs-essential organ of respiration
2. pleurae-serous pleural sac consisting of two membrane that are continuous at hilum
Parietal pleura functions and parts
- outer lining, adhered to inner surface of the thoracic wall and mediastinum
- 4 parts: costal, diaphragmatic, mediastinal, cervical
Visceral pleura
pleural cavity
- inner lining, adhered to lung tissue
- potential space btw visceral and parietal pleura, filled with pleural fluid, acts as lubricant, lung expands into space during inspiration
lungs (4)
know surface structures
- attached to pulmonary vessels & trachea
- apex-blunt superior end
- divided into lobes and fissures
- in life-normally light, soft, spongy
Trachea location and characteristics
function
- . begins at cricoid cartilage
- 16-20 incomplete hyaline cartilaginious rings
- divides into R/L primary bronchi at sternal angle
- carina division point:
1. keel like projection on inside
2. most sensitive area of trachea
3. last line of defense; carcinomatous lymph nodes widen the carina - trachealis muscle
- constrict the trachea allow higher velocity of air during coughing
R/L bronchi
R: wider, shorter, more vertical, food enters more often
L: difficult surgically, closer to pulmonary trunk and aorta
-both divides into secondary lobar bronchi and into tertiary segmental bronchi
pulmonary circulation
each segmental bronchus is accompanied by segmental artery and vein for gas exchange. Thus each bronchopulmonary segment operates independently and can be surgically removed if diseased.
Diaphragm structure (3)
- it is a musculo-tendinous structure and chief muscle of inspiration
- dome-shaped; closes inferior thoracic aperture
- separates thoracic cavity from abdominal cavity
actions of diaphragm (4)
- contraction moves dome inferiorly
- pushes abd viscera inferiorly
- increases vol of thoracic cavity
- allows air to be taken into the lungs
- diaphragm important in circulation of blood in abd staining (micturition, defecation, and parturition) in weight lifting
Normal inspiration, structure involve 5
-diaphragm
-external intercostals
-internal intercostals (medial)
-sternocleidomastoid
scalenes
Actions during inspiration
- diaphragm
- ribs
- lungs
- abd pressure
- diaphragm contracts- dome pulls inferiorly
vertical height thorax increase
intrathoracic pressure decrease - ribs elevated
passively during relaxed inspiration
actively during forced inspiration - pleural cavities and lungs enlarge
air rushes passively into lungs (not pumped in) - abdmoninal pressure increases due to decreased abdominal volume
Normal and forced expiration structures
normal: elastic recoil of lungs forced: -rectus abdominus -internal inercostals (lateral) -external oblique -internal oblique -transversus abdominus
Expiration actions
- diaphragm and intercostal
- lungs
- ribs
- abdominal
- diaphragm & intercostal muscles relax
- thoracic volume decreases
- intrathoracic pressure increases
- stretch elastic tissue of lungs recoils like an inflated balloon releasing its air -air expelled
- ribs depressed
- abdominal pressure decreased
nerves of respiration (somatic innervation of diaphragm)
- arise from ventral rami of C3-C5
- descend through thorax passing anterior to root of lung
- Right/left phrenic nerve (C3, 4, 5)
pulmonary circulation
each segmental bronchus is accompanied by segmental artery and vein for gas exchange. Thus each bronchopulmonary segment operates independently and can be surgically removed if diseased.
Diaphragm structure (3)
- it is a musculo-tendinous structure and chief muscle of inspiration
- dome-shaped; closes inferior thoracic aperture
- separates thoracic cavity from abdominal cavity
actions of diaphragm (4)
- contraction moves dome inferiorly
- pushes abd viscera inferiorly
- increases vol of thoracic cavity
- allows air to be taken into the lungs
- diaphragm important in circulation of blood in abd staining (micturition, defecation, and parturition) in weight lifting
Normal inspiration, structure involve 5
-diaphragm
-external intercostals
-internal intercostals (medial)
-sternocleidomastoid
scalenes
Actions during inspiration
- diaphragm
- ribs
- lungs
- abd pressure
- diaphragm contracts- dome pulls inferiorly
vertical height thorax increase
intrathoracic pressure decrease - ribs elevated
passively during relaxed inspiration
actively during forced inspiration - pleural cavities and lungs enlarge
air rushes passively into lungs (not pumped in) - abdmoninal pressure increases due to decreased abdominal volume
Normal and forced expiration structures
normal: elastic recoil of lungs forced: -rectus abdominus -internal inercostals (lateral) -external oblique -internal oblique -transversus abdominus
Expiration actions
- diaphragm and intercostal
- lungs
- ribs
- abdominal
- diaphragm & intercostal muscles relax
- thoracic volume decreases
- intrathoracic pressure increases
- stretch elastic tissue of lungs recoils like an inflated balloon releasing its air -air expelled
- ribs depressed
- abdominal pressure decreased
nerves of respiration (somatic innervation of diaphragm)
- arise from ventral rami of C3-C5
- descend through thorax passing anterior to root of lung
- Right/left phrenic nerve (C3, 4, 5)