Diaphragm and the mediastinum Flashcards
Describe the shape of the diaphragm
Dome shaped muscle with a convex superior surface (thoracic side)
Describe the movement of the diaphragm and how this effects respiration
only central portion move, inspiration (contraction) diaphragm drops, expiration (relaxes) diaphragm rises
What is hemidiaphragm
paralysis of half of the diaphragm due to injury of its phrenic nerve, it does not affect the other half because each half has its own innervation
Describe paradoxical movement of the diaphragm
half the dome ascends during inspiration instead of descending as it should
happens because of pressure from descending dome transmits pressure down and abd pressure pushes back up
What are the 2 artificially portions of the mediastinum
superior mediastinum= area behind the manubrium
inferior mediastinum= area inferior to manubrium
From anterior to superior what are the 5 planes of the superior mediastinum and what lies in them
- Glandular=thymus, thyroid
- Venous= vena cava, L+R brachiocephalic vein, arch of the azygos vein
- Arterial-nervous=
- aorta, Brachiocephalic, L common cartoid and subclavian artery
- vagus and phrenic nerves - Visceral nervous=
- trachea, esophagus
- L recurrent laryngeal nerve - Lymphatic =thoracic duct
What does the L recurrent laryngeal nerve innervate, where does it arise and why is it recurrent
- innervates= larynx, muscles of the pharynx, sensory for bronchial tree below the vocal cords
- arises from vagus nerve
- its recurrent because it goes inferiorly then loops back superiorly
What lies in the inferior anterior mediastinum
- connective tissues
- few blood vessels, and lymph nodes
- sometimes lower end of the thymus
What lies in the inferior middle mediastinum
the heart and pericardium
What lies in the inferior posterior mediastinum
- Thoracic aorta
- Thoracic duct
- Thoracic sympathetic trunks
- Thoracic splanchnic nerve
- lymph nodes
- azygos and hemiazygos veins
- esophageal plexus
