1 - Thoracic Wall Flashcards
Posterior Thoracic Wall?
Anterior Thoracic Wall (rib count, palpable structures)
12 Thoracic Vertebrae
12 Pair of ribs
True Ribs: 1-7
False Ribs: 8-12
Floating Ribs: 11-12 (in abdominal muscles)
Palpable Structures: Rib 2, Jugular/Suprasternal Notch, Manubrium, Sternal Angle, Costal Cartilage, Body of Sternum, Xiphoid Process, Costal Margin
What does the Plane of Sternal Angle serve as a landmark for?
(2x)
- Rib 2 articulates with sternum
- Intervertebral Disc T4-T5
Naming convention for Intercostal Space?
Named according to the rib forming the superior border
Nipple as landmark?
What ribs does this lie between based on naming convention?
Intercostal Space 4
Sits between ribs 4 and 5
Innervation of Intercostal Muscles?
Ventral Rami of T1-T11
Layers of Intercostal Muscles?
What lies on the outside of the external?
- External (most superficial)
- Internal
- Innermost
- - -
Serratus Anterior
External Intercostal Muscle
Action?
Inn?
Orientation?
A: Moves ribs superiorly during INSPIRATION
I: Ventral Rami of T1-T11
O: Anterior-Inferiorly Fibers
Internal Intercostal Muscle
Action?
Inn?
Orientation?
Action: Moves ribs inferiorly during EXPIRATION
I: Ventral Rami of T1-T11
O: Postero-Inferiorly Fibers (right angle to External)
Innermost Intercostal Muscle
Action?
Inn?
Orientation?
A: Act with internal intercostals (move ribs inferiorly, expiration)
I: Ventral Rami of T1-T11
O: Postero-Inferior (same as Internal)
What happns to the External Intercostal Muscles near the sternum and costal margins?
What happens to the Internal Intercostal Muscles from the angle of the ribs to vertebral column?
Replaced by aponeurosis called External Intercostal Membrane
Replaced by aponeurosis called Internal Intercostal Membrane
Other Intercostal Muscles: Transversus Thoracis Muscles
Location?
Action?
L: Deep surface of anterior thoracic wall, attach posterior surace of lower sternum to ribs 3-6
A: Depress costal cartilage
Other Intercostal Muscles: Subcostal Muscles
Location?
Action?
L: Lower region of posterior thoracic wall–span MULTIPLE ribs
A: Depress ribs
What is the orientation/location of the Intercostal Neurovascular Bundle?
Clinical implications of location?
Superior to Inferior:
Vein - Artery - Nerve (VAN)
Run on inferior or rib, between Internal/Innermost Muscle Layer
If inserting chest tube, insert along superior border of rib to avoid this bundle
Clinical: Thoracostomy
Purpose?
Position?
Insertion of a chest tube through thoracic wall and into the pleural cavity that surround lungs
Drain abnormal fluid or air from pleural cavity
Between the Anterior Axillary and Mid-Axillary Lines at the 4th or 5th Intercostal space on the superior border of the rib
