Flashcards in Lecture 4 RH Deck (40)
What are the basic components of the diaphragm?
diaphragm contains a central tendon with muscle fibers around it attach to.
How many domes does the diaphragm contain?
diaphragm is made up of 3 domes; the left dome which projects lower than the right dome due to the heart's positiion in the thorax.
Where does the diaphragm attach to the rest of the body?
Costal margin at the inferior 6 ribs. at the back end it only gets a few attachments to ribs. This is due to other muscles that attach at that location. For this reason, the diaphragm also attaches to continuous connective tissue posteriorly. These tissue are the arcuate ligaments
2 attachments to the lumbar spine at the crura.
What are the 3 types of arcuate ligaments present in the thorax?
Median arcuate ligament (arches over descending aorta)
Medial arcuate ligament (over psoas major)
Lateral arcuate ligament (over quadratus lumborum)
Where do the crura attach?
right crus at L1-3/4
Left crus at L1-2.3
Where does the IVC penetrate the diaphragm?
T8 slightly to the right
Where does the oesophagus penetrate the diaphragm?
T10 (posteriorly in the muscular part of the diaphragm)
Where does the aorta pass through the diaphragm?
T12 and passes behind the median arcuate ligament between the crura
How does the diaphragm assist IVC in venous return?
IVC uses contraction of the diaphragm to move blood towards the heart. The diaphragm's contraction widens IVC and simultaneously causes lower pressure in the abdomen forcing blood upwards.
What is the functional significance of the oesophagus's position?
Diaphragm forms a functional sphincter around the oesophagus. When the diaphragm contracts the oesophagus is closed up to prevent stomach content reflux.
Where does the right phrenic nerve penetrate the diaphragm?
Right phrenic nerve penetrates the right side of the diaphragm at the central tendon.
Where does the left phrenic nerve penetrate the diaphragm?
Left phrenic nerve penetrates diaphragm at the muscular part of the diaphragm.
How do the azygous veins enter the diaphragm from the thorax?
azygous system of veins penetrates diaphragm through slings of the crura.
How does the sympathetic trunk penetrate the diaphragm to go from the thorax to the lower abdomen?
sympathetic trunk enters the abdomen under medial arcuate ligament
What nerves innervate the diaphragm?
mostly the phrenic nerve which supplies motor innervation to the whole diaphragm. Also some sensory innervation to central diaphragm and pericardium.
Lower intercostal nerves are sensory to the periphery of the diaphragm.
Where is pain referred to from the diaphragm?
C3, 4, 5 roots cause pain to be referred to the upper limb and neck.
How do the lungs expand during inspiration?
parietal pleura is attached to the thoracic walls and visceral pleura to the viscera directly. when thoracic cage expands the lungs expand allowing inspiration.
What is the main respiratory muscle involved in quiet respiration?
How does expiration take place?
relaxation of muscle and elasticity of lung allow expiration to take place.
What is the mechanism of pump handle action?
When intercostal muscles contract the rib is raised upwards and for this reason the antero-posterior dimensions of the rib cage are increased.
What is the mechanism of bucket-handle action?
bucket handle action causes an increase in the inferior dimensions and as a result expands the rib cage inferiorly.
What causes the different movements observed in the rib cage during breathing?
The shape of the ribs and how they are influenced by being pulled upwards.
Which intercostal muscles assist in inspiration?
External intercostals elevate the ribs and assist in inspiration
Which intercostal muscles assist in expiration?
Internal intercostal muscles help collapse the rib cage (assist in expiration)
What is the function of the scalenes?
Scalene muscles attach to first and second ribs and act as accessory respiratory muscles.
How do abdominal muscles assist respiration?
abdominal muscles assist forced expiration.
How do pec major and minor influence respiration?
pec major and pec minor assist inspiration. This is because when they attach to a fixed humurous causing the thoracic cage to open
What are hiccups and what causes it?
hiccups are caused by spasmodic contractions of the diaphragm. It is hypothesized to be initiated by neurons in phrenic nerve, daphragm muscle itself, and respiratory centers in the brainstem.
What is the location of the mammary gland relative to internal structures?
mammary glands sit on fascia superficial to the pectoralis major. And space known as retromammary space.