Resp anatomy part 2

Rib-age
True: attached to sternum
False: Not

  • Jugular notch
  • Clavicular notch
  • Sternum
  • Intercostal spaces
  • Costal cartilage
  • Costal margun
  • Floating ribs
  • True ribs (1-7)
  • False ribs (8-12)

Sternum

Intercostal

  • Manubrium
  • Sternal angle: fibrocartilage joint
  • Body
  • Xiphsternal joint
  • Xiphoid process
  • Intercostal vein, nerve (least protected) and artery
  • Internal intercostal
  • Innermost intercostal
  • Costal groove
  • Endothoracic fascia
  • Parietal pleura
  • Collateral branches

Blood supply ❌

Supreme intercostal- 1+2 intercostal arteries

  • Superior (accessory) hemiazygous Vein
    (receives 4-8th left posterior intercostal veins)
  • Azygous Vein
    (receives lower 8 right posterior intercostal veins, right superior intercostal vein and hemiazygous veins, drain into superior vena cava
  • Inferior hemiazygous Vein
    Receives lowest 4-5 left posterior intercostal veins

Inspiration
T8: vena cava
T10: Oesophagus
T12: Aortic hiatus

  • Passive
  • Main: Diaphragm
  • Innervation C3,4,5 - PHRENIC nerve

Attaches to:

  • Xiphoid process
  • Spine via arcuate ligament + Crua -
    Left = L1-3
    Right = L1-2
    Deep surface of lower 6 ribs
  • Midline - arch over aorta (median arcuate ligament)
  • Lateral to this, fibres pass over psoas major (paired medial arcuate ligaments) to transverse processes of L1
  • From here they arch over quadratus lumborum (paired lateral arcuate ligaments) to tip of 12th rib

Accessory Resp muscles

Forced Expiration

Forced inspiration

  • Pectoralis Major and minor, serratus anterior, scalene group of muscles and sternocleidomastoid
  • Abdo.muscles - Rectus abdominous, internal + External oblique
  • Internal intercostals
  • Anterior and superior movement of sternum
  • Elevation of lateral aspect rib shaft
  • Diaphragm descends

Pleural cavity

  • Serous membrane: mesothelium (simple squamous lining) - secretes fluid into cavity
  • Visceral (splanchnic mesenchyme) + parietal pleura (somatic mesoderm) continuous with eachother + at root of lung/hilum
  • Neg pressure within pleura cavity: Lungs and thoracic wall constantly opposing eachother
  • Costmediastinal recess: allows space for beating heart
  • Costodiaphragmatic recess: Only filled withh lung in deep inspiration + potential areas of fluid collection
    (costophrenic angle)

Regions

  • Cervical
  • Costal
  • Diaphragmatic
  • Mediastinal
  • Pulmonary ligament: Allows increased mobility during respiration

Innervation

Somatic innervation - parietal

  • Costal + peripheral pleura - intercostal nerves
  • Medistinal + central diaphragmatic pleura - phrenic nerve (referred pain shoulder tip)
  • Touch
  • Temp
  • Pain/pressure

Lungs and visceral pleura:

  • Supplied by visceral sensory nerves (sympathetic trunk + vagus nerve):
  • Travels to CNS in nerves that also carry sympathetic +/ parasymp fibers
  • Visceral pain vague + only detects stretch

Embryology
Formation lung beds ❌

  • Development of lung buds start 4th week development
  • Out pouching caudal (tail) end of embryological pharynx/foregut
    between 6th pharyngeal arches
  • Laryngeal groove form (outpouching occurs from)
  • End 4th week laryngo-tracheal (respiratory) diverticulum formed
  • Diverticulum: form everything from trachea downwards (trachea + trachea-bronchiole tree)
  • Diverticulum: forms two primary bronchiole buds
    (Buds grow into primordial pleura)
  • Each primary bud: divides into secondary + tertiary buds
    Secondary + tertiary buds diff into main bronchi
  • End 5th week: trachea + bronchi fully formed

Lung dev

Canalicular stage (16-26)

Terminal sac stage (26-brith)

Pseduo glandular (6-16weeks)

Alveolar stage (32-8)

  • Lungs resemble exocrine glands
  • Tubes lined with cuboidal epithelia
  • No exchange
  • Vascularisation
  • Dev up till terminal bronchioles and primordial sacs
  • First surfactant production: glucocorticoids stimulate production
  • Terminal sacs devlop )thinner epithelium)
  • Surfactant production + increased vascularisation
  • Epithelial becomes thin squamous
  • Newborn lungs denser: more alveolar sacs added

Lymphatics

Changes after birth

Lungs gas exchange organs, not secretory

Pressure decreases in lungs as they inflate

  • Right side blood of right side heart redirected to pulmn artery

Production surfactant

  • Ant thoracic wall drain parasternal nodes + diaphragmatic nodes
  • Post thoracic wall drain intercostal nodes around head + neck ribs
  • Lungs drain tracheobronchial nodes
  • Thoracic duct: major lymph vessel body: begins cisterna chyli: behind arch of aorta enter left brachiocephallic vein