Thorax, Pleura And Mediastinum wk6 Flashcards
What are the bones of the thorax?
- True Ribs = ribs 1-7 (attached to sternum)
- False ribs = ribs 8-10 (dont join sternum - join off of rib 7
- Floating ribs = ribs 11-12 (come from back, half the size)
What are chest joins used for?
Indications - pneumothorax - pleural effusion - perioperative e.g. after heart surgery Preparation - ultrasound - consent - aseptic technique - local anaesthetic
What is the position of chest drains?
- 5th intercostal space - midaxillary line
- in ‘safe triangle’ bordered by latissimus dorsi, pectoralis major, and a horizontal line level with nipple
- over the rib, to avoid intercostal vessels and nerve
- aspiration of fluid or air
- then secure drain with suture
- attach to drainage system
- dressing over drain site
- repeat x-ray
- analgesia as required
What is the gross anatomy of the thoracic cavity?
• It is conceptually divided into 3 separate anatomical compartments
• Demarcations of the fibrous pericardium form boundaries of compartments of the thoracic cavity
• The 3 compartments, from left to right are as follows:
• Left Pulmonary Cavity
– The anatomical space to the left of the mediastinum – Occupied by the left lung
• The Mediastinum
– Occupies the centre of the thoracic cavity
– It is the compartment within the boundaries
created by the fibrous pericardium
• Right Pulmonary Cavity
– The anatomical space to the right of the
mediastinum
– Occupied by the right lung
What are the tissue layers of pulmonary cavities?
– From outside-to-inside – Endothoracic Fascia – Parietal Pleura – Pleural Cavity • Filled with Pleural Fluid – Visceral Pleura – Outer Surface of lung – Parenchyma of the lung • Alveoli
What is the mediastinum?
• It is thus, the central compartment of the chest • It lies behind the sternum • Its boundaries are defined by outlines of the fibrous pericardium • The main contents of the mediastinum are as follows: – Heart – Membranous linings of the heart – Connective tissue sac of the heart – Great vessels connected to the heart
What are the tissue layers of the mediastinum?
From outside-to-inside – Fibrous Pericardium – Parietal Layers of Serous Pericardium – PericardialCavity • Filled with serous fluid – Visceral Layer of Serous Pericardium • Also known as Epicardium – Myocardium • Variable thickness depending on chambers of the heart – Endocardium
What is the pericardial sac?
• It is a double walled sac containing the heart & great vessels
• The outermost layer is the fibrous pericardium
• The innermost layer is the serous pericardium
• The serous pericardium is further sub-divided into
– Parietal pericardium
– Visceral pericardium
What are pericardial sinuses?
• The lines of reflection between visceral and parietal layers of serous pericardium form two pericardial sinuses
– Transverse pericardial sinus
– Oblique pericardial sinus
What is the transverse pericardial sinuses?
– Lies anterior to the superior vena cava (SVC)
– Also lies posterior to the ascending aorta and pulmonary trunk
• By placing a finger in the transverse pericardial sinus, it is possible to examine relationships of structures
• A tourniquet placed in this sinus is used as a ligature in major surgery of the heart
What is an oblique pericardial sinus?
- It is a cul-de-sac formed by reflections of the serous pericardium lining the venous structures of the embryonic heart tube
- It lies posterior to the heart in the pericardial sac
What is the presentation of the heart in-vivo?
• It is located within the thoracic cavity
• We need to know as to which compartment of the thoracic cavity it is found in
• It sits in relation to the following structures:
– Behind
• the sternum with a slight shift to the left
• Thymus in children
– Encased within the pericardial sac
• Serous pericardium
• Fibrous pericardium
– In front of:
• The trachea
• oesophagus
• Descending Aorta
– Rests on the diaphragm
• Above its central tendon
What is the heart?
• It is a four chambered, hollow muscular organ • It is designed as a double pump • Approximately the size of a person’s clenched fist • It is located in the thorax • Within the mediastinum • Its anatomical relations are: – Superior to superior surface of diaphragm – Left of the midline – Anterior to the vertebral column – Posterior to the sternum
What is the gross anatomy of pulmonary cavity?
• There are two pulmonary cavities – Left Pulmonary Cavity – Right Pulmonary Cavity • They are separated by the mediastinum • They are occupied by their respective lungs – Left Lung – Right Lung
What is the gross anatomy of lungs?
• Each lung has an opening on its medial surface • This is the hilum of the lung • It is attached as follows: • The trachea – via the main bronchus • Heart – via Pulmonary vessels • Each lung is divided into: – Lobes • Major divisions of the lungs • Divided by fissures – Segments: • Minor divisions of the lungs • Secondary lobules
