Thoracic Walls and Airways Flashcards
How many pairs of ribs are there?
12
How many thoracic vertebrae are there?
12
Where do ribs 1-7 join and with what?
Join at the sternum with cartilage end points
Where do ribs 8-10 join and what do they combine with?
Join at the sternum with combined cartilage at 7th rib
What to ribs 11-12 attach to anteriorly?
They have no anterior attachment
What are the three main points of the sternum?
Manubrium (Jugular notch)
Body
Xiphiod
What does the manubrium join to?
Clavicle and 1st rib
What is the sternal angle?
Junction of the manubrium with the sternal body- attachment of 2nd rib
What is the thoracic cage made up of?
Sternum
Ribs
Thoracic vertebrae
It has a narrow inlet and a wide outlet
What is the thoracic inlet?
The superior opening of the thoracic cage
What are the three boundaries of the thoracic inlet?
Anterior- suprasternal notch of the manubrium sterni
On each side- the first rib
Posterior- First thoracic vertebra
What is the thoracic outlet?
The inferior opening of the thoracic cage?
What are the boundaries of the thoracic outlet?
Anterior- Xiphoid process
On each side- lower six costal cartilages + last two ribs
Posterior- last thoracic vertebra
What closes the thoracic outlet?
Diaphragm which separates it from the abdominal cavity
What is the origin of the external intercostal muscles?
Inferior border of rib
What is the insertion of the external intercostal muscles/
Superior border of rib below
What direction do the fibres of the external intercostal muscles run?
Fibres run oblique (down and forward)
What is the role of the external intercostal muscles?
To aid in inspiration -lift ribcage and increase the dimensions
What is the role of the internal intercostal muscles?
Aid in forced expiration and depresses the ribcage and decreases the dimensions
What is the origin of the internal intercostal muscles?
Superior border of rib below
What is the insertion of the internal intercostal muscles?
Inferior border of the rib above
What direction do the fibres of the internal intercostal muscles run?
Fibres run at right angles to external intercostals
What neurovascular structures are located in the intercostal muscles and where are they located?
Intercostal vein
Intercostal artery
Intercostal nerve
Sit in Subcostal groove between the internal intercostal and innermost intercostal layer
What is the major muscle of inspiration?
Diaphragm
What are the muscles of active expiration?
Internal intercostal muscles
Abdominal muscles
What are the accessory muscles of inspiration?
Sternocleidomastoid
Scalenus
Describe what happens during inspiration
the diaphragm descends on contraction, increasing the vertical dimension of the thoracic cavity. Contraction of the external intercostal muscles elevates the ribs and subsequently the sternum to enlarge the thoracic cavity from front to back and from side to side.
Describe what happens during passive expiration
during which the diaphragm relaxes, reducing the volume of the thoracic cavity from its peak inspiratory size. As the external intercostal muscles relax, the elevated rib cage falls because of the force of gravity. This also reduces the volume of the thoracic cavity.
What happens during active expiration
during which contraction of the abdominal muscles increases the intra-abdominal pressure, exerting an upward force on the diaphragm. This reduces the vertical dimension of the thoracic cavity further than it is reduced during quiet passive expiration. Contraction of the internal intercostal muscles decreases the front-to-back and side-to-side dimensions by flattening the ribs and sternum.
What are the ribs from the 3-9 called?
Typical ribs
What features indicate a typical rib?
Head Neck Tubercle Angle Shaft Subcostal Groove
Describe the first rib
Shortest C- shaped
Anterior end is cup shaped
Posterior end has a head neck and tubercle
Head is one facet
Surfaces -superior + inferior
Borders- Outer (lateral) & inner (medial)
Describe the 2nd rib
Twice the length of the 1st
Head has 2 facet
Surfaces or shaft are in between that of 1st & typical
What vertebrae are typical?
2-9
Describe the characteristics pf a typical vertebrae
Body- heart shape & carries 2 demi-facet at its side
Transverse process- has a facet for rib tubercle of the same number
Spine - long, pointed & directed downward and backward
Vertebral foramen- small & circular
What is significant about T1?
Has a full facet for the first rib
What is significant about T10- T12?
Have a single facet
What is significant about T11 and T12?
No costal facet
What direction does the superior articular facets point?
Posteriorly
What direction do the inferior articular processes point?
anteriorly
What does the position and direction of the facets and processes allow?
Allows rotation and some lateral flexion
What is the trachea
Hollow and cartilage supported structure
How long to the bronchi extend for on RHS and LHS?
3 cm
Where do the bronchi enter?
enter lungs at pulmonary hilum
Where do the pulmonary arteries and veins enter?
Pulmonary hilum
What happens to the bronchi?
Further subdivide and terminate as alveoli
basic unit of structure and function in the lungs - have a single cell membrane
How many lobes are on the right lung?
3 lobes
How many lobes are on the left lung?
2 lobes
What are the two types of pleura
Visceral pleura
Parietal pleura
What is the function of visceral pleura?
Cover the lungs
What is the function of parietal pleura?
Lines inside of thoracic cavity
What is the pleural space?
Potential space
Serous (pleural) fluid within
What is the role of the pleural fluid?
Lubricates & permits ease of expansion
What is air in the pleural space known as?
Pneumothorax
What is air in the pleural space?
Haemothorax
Surface projections of the pleural fluid?
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What separates the three lobes on the right?
Horizontal and oblique fissures
What is the cardiac notch?
An indent in the superior lobe on the LHS forming the lingula that wraps arounf the apex of the heart
