Thoracic Wall Flashcards
Diaphragm Innervation
Phrenic nerve; most peripheral sections via intercostal nerves
Diaphragm Function
Depresses to enable inspiration (inhaling air)
External intercostal muscles innervation
Intercostal nerves
External intercostal muscles function
Elevates ribs to aid forced inspiration
Fibers run posterior to anterior
Pleural Sac Distribution
Surrounds lungs. Transitions between parietal and visceral layer occurs at the hilum of the lung.
Internal intercostal muscles Innervation
Intercostal nerves
Internal intercostal muscles functions
Depresses ribs to aid forced expiration
Fibers run anterior to posterior
Posterior intercostal arteries “arises from/drains
Descending thoracic aorta
Posterior intercostal arteries “Enters/Drains Into”
Thoracic wall
Anastomoses with anterior intercostal arteries
Lies on underside of each rib
Posterior intercostal veins (Arises from/drains)
Azygos vein (right side); Hemiazygos vein or accessory hemiazygos vein (left side of chest)
Internal thoracic artery “arises from/drains
Subclavian artery
Internal thoracic artery “Enters/drains into”
Anterior intercostal arteries
superior epigastric artery
Harvested for coronary artery bypass grafts
Intercostal Nerve Innervates
Skin and muscles of thoracic and abdominal wall
Phrenic Innervates
Parietal pleura along mediastinum and diaphragm, fibrous/parietal pericardial sac, diaphragm
Intercostal nerves
Spinal cord levels: T1-T11 (T12 is subcostal)
Source: Thoracis ventral rami
Destination: Thoracic and abdominal wall
Phrenic Nerve
Spinal cord levels: C3-C5
Source: Cervical plexus (ventral rami of cervical spinal nerves)
Destination: Diaphragm
Sternum
Sternal angle between manubrium/body is level with great vessels when standing
Manubrium
Top part of the sternum
Jugular notch of manubrium
Helpful for feeling aortic pulse in pathologic conditions
Sternal angle
Contact between manubrium and body-useful landmark for great vessels
Body of sternum
Connection between manubrium & body = sternal angle
Xiphoid process
Little bony part at the bottom of the sternum
Ribs
12 pair
7 true, 5 false (incl. 2 floating)
Head of ribs
Contains facets articulating to bodies of thoracic vertebrae
