Lecture 1 - Chest & Lungs Flashcards
What is in the contents of the thorax?
- thoracic wall
- thoracic cavities
- neurovasculature
- lymphatics
- internal organs
- breasts
What are the 2 parts of the thorax?
- superior thoracic aperature (inlet)
- inferior thoracic aperture (outlet)
What makes up the thoracic cage?
- Sternum + 12 pairs of ribs + 12 thoracic vertebrae
How does the ribs articulate with the sternum?
Via the costal cartilages anteriorly and with the thoracic vertebrae posteriorly
What are the 2 openings to thorax?
- Superior thoracic aperature (inlet) - sternum + 1st rib + 1st thoracic vertebrae
- Inferior thoracic aperature (outlet) - Xiphisternal joint + costal cartilage 7th - 10th + 11st-12th ribs ribs + 12th thoracic vertebrae
What does the sternum do?
- lies superficially in the anterior thorax (easily palpable)
- covers and protects the heart and great vessels, as well as the trachea and oesophagus
What are the 3 parts of the thorax?
- Manubrium
- Body
- Xiphoid process
Describe the parts of the thorax from superior to inferior
- Manubrium
- Body
- Xiphoid process
What is the manubrium?
quandrangular, has clavicular and jugular nothches
What is the body of the sternum?
articulates with the manubrium at the sternal angle (at level T3 and 2nd rib)
What is the xiphoid process?
very variable in shape, serves as a point of muscular attachment
What is a true rib?
a rib that has costal cartilage that connects to sternum
What is a false rib?
a rib that has costal cartilage but not attached to anything
What is a floating rib?
no costal cartilage
What is costal cartilage?
Costal cartilage refers to the cartilage that connects the ribs to the sternum (breastbone).
This cartilage allows flexibility and expansion of the rib cage during breathing.
What ribs are true ribs?
True - (1st - 7th)
What ribs are false ribs?
False - (8th - 10th)
What ribs are floating ribs?
Floating - (11th - 12th)
What ribs are typical ribs?
3rd - 9th ribs
What ribs are atypical?
1st, 2nd, 10th-12th
What are the typical rib features?
Head - with superior and inferior facets
Neck
Tubercle - with articular facet
Shaft/body
Costal groove - lower border, for neurovascular bundle
What are features of thoracic vertebrae?
Body - with superior and inferior articular facets
Pedicle
Transverse process (with articular facet)
Lamina
Spinous process
What are the thoracic cage articulations?
- Rib head articulates with adjacent thoracic vertebrae
- Rib tubercle articulates with vertebral transverse process
- Anterior end of rib body articulates with sternum through costal cartilage (except floating ribs)
What are the 3 types of intercostal muscles?
- External
- Internal
- Innermost
What are features of the external intercostal muscles?
Fibres oblique - downwards and forwards
What are features of internal intercostal muscles?
- fibres oblique, downwards & backwards
- fibres at right angle to external intercostal
What are features of innermost intercostal muscles?
fibres run downwards & backwards
Describe the neurovascular bundle
- runs in the internal side of the rib on the costal groove
- between internal & innermost intercostal muscles
What are the 3 parts of the neurovascular bundle?
- Intercostal vein (V)
- Intercostal artery (A)
- Intercostal nerve (N)
What are the different parts of mediastinum?
Everything in the chest but lungs
- heart
- trachea (windpipe)
- esophagus
- major blood vessels
- thymus gland
- lymph nodes
- nerves
What is the superior part of the mediastinum?
- thoracic inlet to sternal angle
- Arch of the aorta, SVC (superior vena cava), trachea and the upper oesophagus
What is the inferior part of the mediastinum?
- sternal angle to thoracic outlet
- divided into anterior, middle and posterior by the heart
What is the pleura?
Serous membrane that originates at the hilum of the lungs. Folds back on itself to form a 2-layered sac
What are the 2 layers of the pleura?
Pariental pleura - lines the thoracic cavity
Visceral pleura - covers the lungs
What is the pleural cavity?
is the space between the pleurae
What is serous fluid?
The fluid within the space which lubricates the pleural space
What are the features of the lungs?
- apex
- base
- fissures
0 lingula
Describe features of the right lung
3 lobes:
- Superior
- Middle
- Inferior
2 Fissures:
- Oblique
- Horizontal
(found at level of 4th)
Describe the features of the left lung
2 lobes:
- Superior
- Inferior
1 fissure:
- oblique
What is the mediastinal surface?
In summary, the mediastinal surface is the side of the lung that faces inward, toward the heart and other central chest structures.
- mediastinal surface has impressions for heart and great vessels
What are the features of the trachea?
- cartilaginous tube from larynx to the bronchi of the lungs
Where does the trachea bifurcate?
Trachea bifurcates into the right and left bronchi at the CARINA - a cartilaginous ridge around the level of the sternal angle
Describe features of the right main (primary) bronchus
- shorter, wider and descends more vertically than the left main bronchus
- divides into 3 lobar bronchi (each lobar bronchi is divided further into segmental bronchi
Describes features of left bronchus
divides into 2 lobar bronchi (each lobar bronchi is divided further into segmental bronchi)
What is the Hilum of the lung (Root of the lung)?
The hilum of the lungs is the area on the medial (inner) surface of each lung where important structures enter and exit the lung.
What are the 3 parts of the Hilum of the lung?
- Bronchus
- Pulmonary artery
- Pulmonary veins
Where does the bronchus lie?
lie posterior to pulmonary artery - accompanied by bronchial vessels
Where does the pulmonary artery lie?
Lie superior to pulmonary veins
What types of pulmonary veins are there?
- superior
- inferior
Describe the innervation of thoracic viscera
- Vagus nerve (CNX - 10th cranial nerve)
- Vagus nerve lies posterior root of the lungs
- Phrenic nerve (C3-C5) lies anterior to the root of the lung
Where are the vagus & phrenic nerve in relation to the root of the lung?
Vagus nerve - posterior to root of the lungs
Phrenic nerve - anterior to the root of the lungs
Describe the thoracic diaphragm
PRIMARY MUSCLE OF RESPIRATION
- innervated by phrenic nerve
- passageway into abdomen for the oesophagus, descending aorta and inferior vena cava
What chest wall changes occurs through respiration?
- vertical
- lateral
- antero-posterior dimension
What occurs to vertical dimensions following contraction of the diaphragm?
Increases the vertical dimensions
- increase in thoracic cavity, which increases the thoracic volume —> air is drawn in
What occurs through inhalation?
- air inhaled
- rib cage expands as rib muscles contract
- INHALATION - diaphragm contracts (moves down)
What occurs through exhalation?
- air exhalated
- rib cage gets smaller as rib muscles relax
- EXHALATION - diaphragm relaxes (moves up)
What occurs through the contraction of the EXTERNAL intercostal muscles?
pulls the ribs up and out increasing the LATERAL diameter. This expands the thoracic cavity, air is drawn into the lungs.
What occurs through the contraction of the INTERNAL intercostal muscles?
pulls the ribs down and in, decreasing the LATERNAL diameter. This decreases the thoracic cavity, air travels out of the lungs
It assists in expiration
Describe the pump handle movement of the chest wall
When the ribs elevate, they move the sternum upwards and forwards (antero-posterior dimension)
Describe the bucket handle movement of the chest wall
When the ribs elevate, the bodies laterally (lateral dimension)
