Theme 1: Lecture 5 - Applied Anatomical Concepts Flashcards
What are the areas of breathing?
Thoracic and Abdominal
What are the types of breathing?
Quiet and forced
Boyles law
- Decrease in volume leads to an increase in pressure
- Increase in volume leads to a decrease in pressure
What are the pressure changes in inspiration?
Increase in intrathoracic volume and decrease in intrathoracic pressure
What happens in inspiration?
- Parietal pleura is pulled with the movement of the ribs and diaphragm
- Visceral pleura moves with parietal pleura (surface tension)
- Lung volume increases
- Air moves into lungs towards lower pressure
What are the pressure changes in expiration?
Decreased intrathoracic volume and higher intrathoracic pressure
What happens in expiration?
- Visceral pleura moves with elastic recoil of lungs
- Parietal pleura moves with the ribs and diaphragm as they return to rest
- Surface tension between parietal and visceral pleura prevents lung from collapsing
- Lung volume decreases
- Air moves out of the lungs towards lower pressure
What are the dimension changes in thoracic breathing?
- Transverse/lateral diameter
- Anteroposterior diameter
What are the dimension changes in abdominal breathing?
- Transverse/lateral diameter
- Anteroposterior diameter
- Vertical diameter
How does the lateral diameter of the thorax change in breathing?
- Lateral edges of ribs are elevated supero-laterally during inspiration and the lateral diameter of thoracic cavity increases
- Results in an increase in the transverse or lateral diameter of chest cavity
- AKA bucket handle movement
How does the anteroposterior diameter of the thorax change in breathing?
- Anterior ends of ribs are raised in inspiration
- Elevation causes sternum to also be raised
- Movement is facilitated by costal cartilages
- Results in an increase in anteroposterior diameter of chest cavity
- AKA pump handle movement
Origin of diaphragm
- Sternal (xiphoid process)
- Costal (costal cartilages of ribs 7-10, ribs 11 and 12)
- Lumbar (medial and lateral arcuate ligaments and lumbar vertebral bodies)
Insertion of diaphragm
Central tendon
How does the vertical diameter of the thorax change in abdominal breathing?
- Via diaphragm which forms the floor of the thoracic cavity
- Resting position of diaphragm is domed
- Upon contraction the diaphragm descends 5 -10 cm compressing abdominal organs
- Increases vertical diameter of thorax
Which muscles are involved in quiet inspiration?
- External intercostals
- Scalene muscles
- Diaphragm
Which muscles are involved in quiet expiration?
Normally a passive process. Elastic recoil of lungs expels air and chest wall falls back into resting position
What are the scalene muscles?
- They are 3 pairs of muscles, anterior, middle and posterior
- They come from the cervical spine
- Anterior and middle scalenes insert into the first rib whereas the posterior inserts into the second
Which muscles are involved in forced inspiration?
- The muscles used in quiet inspiration plus:
- Pectoral muscles
- Sternocleidomastoid (SCM)
- Latissimus dorsi
Origin and insertion of sternocleidomastoid
Origin: Sternum and clavicle
Insertion: Mastoid process (prominence behind the ear)
Latissimus dorsi
A large muscle of the back that wraps up and around and inserts into the upper limb
Which muscles are involved in forced expiration?
- Internal intercostals
- Oblique and transverse abdominal muscles
- Quadratus lumborum
Describe the diaphragm
- Sheet of skeletal muscle with a central tendon
- Pericardium attached to middle of tendon on its superior surface
- Diaphragmatic (parietal) pleura lines its superior surface
What are the openings of the diaphragm and what levels are they at?
-Opening for Inferior Vena Cava (T8)
-Oesophageal hiatus (T10)
-Aortic hiatus (T12)
The thoracic duct and azygos vein also pass through the aortic hiatus
What is the blood supply to the diaphragm?
Superior and inferior phrenic arteries
