Respiratory system 1 - Intro to thorax Flashcards
What is the thorax?
superior part of the trunk between the neck and the abdomen
What is the thoracic cavity surrounded by?
thoracic cavity (containing heart, lungs, thymus, distal part of the trachea and most of the oesophagus ) surrounded by thoracic wall (containing skin , fascia, nerves, vessels, muscles, cartilages and bones
What is the function of the thoracic wall?
protects the thoracic and also some of the abdominal organs
helps in respiratory movements
acts as a muscle attachment site for various groups of muscles
What is the thoracic cage?
12 pairs of ribs
12 thoracic vertebra with intervertebral discs
the sternum
Costal cartilage role?
form the anterior continuation of the ribs, providing a flexible attachment at their articulation with the sternum
What are the ribs and their cartilages separated by?
intercostal spaces
What are the intercostal spaces occupied by?
these spaces are occupied by intercostal muscles, vessels and nerves
How does the thoracic cavity communicate with the neck?
through the superior thoracic aperture which is also called anatomical thoracic inlet
How doses thoracic cavity communicate with abdomen?
inferior thoracic aperture which is also called the anatomical thoracic outlet
Describe the boundary of the superior thoracic aperture/anatomical thoracic inlet ?
The first thoracic vertebra (T1) posteriorly.
The first pair of ribs laterally.
The costal cartilage of the first rib and the superior border of the manubrium anteriorly.
Describe the boundary of the The inferior thoracic aperture/thoracic outlet?
12th thoracic vertebra posteriorly.
11th and 12th pairs of ribs laterally.
Costal cartilages of ribs 7 through 10 and xiphisternal joint anteriorly
What are the three parts that the sternum consists of?
manubrium, body and xiphoid process
What is on each side of the manubrium?
clavicular notch
What does the clavicular notch form?
articulates with the sternal end of the clavicle and it forms a saddle joint
just below that point the manubrium articulates with cartilage of the first rib and forms a primary cartilaginous joint
What level is the sternal angle at?
level of the second pair of costal cartilages
lies opposite to the fourth intervertebral disc between T4 and T5 vertebra
What level does the trachea bifurcate?
sternal angle
What are the three kinds of ribs?
true ribs
false ribs
floating ribs
What are true ribs?
first to seventh ribs
they are directly connected to sternum
What are false ribs?
8th to 10 ribs
indirectly connected to the sternum
attach to each others cartilages and form the costal margin anteriorly
What are floating ribs?
11th and 12th ribs
Floating because they are not connected to the sternum
Give characteristics of the first rib?
broad and flat
has two surfaces (inferior and superior)
How is the upper surface of the rib marked?
marked by two shallow grooves
separated by a tubercle ( for attachment of anterior scalene muscle)
What does the anterior groove and posterior groove contain?
anterior groove - subclavian vein
posterior groove- subclavian artery and lowest trunk of the brachial plexus
How many articular facets does the first rib have ?
only one unlike other ribs and for the articulation with the body of the first thoracic vertebra
What are the parts of a typical rib?
head (two articular facets, superior and inferior which articulate with two vertebral bodies)
neck
tubercle - hump at the junction of the neck and the body of the rib
body
What is a costovertebral joint?
The head of the rib articulates with the body of the thoracic vertebra of the same number as well as the body of the vertebra above (i.e., with 2 vertebral bodies) at the costovertebral joints = synovial plane joints.
What does the tubercle of the rib articulate with?
The tubercle of the rib articulates with the with the transverse process of the thoracic vertebra of the same number at the costotransverse joint
Where are the sternocostal joints?
from second to seventh. First is cartilaginous
What type of joints are interchondral joints?
between 6th and 9th ribs
between costal cartilages of adjacent ribs plane synovial joints
Where is the manubriosternal joint and what type of joint is it?
joint between the manubrium and the body of the sternum
secondary cartlaginous
Where are intervertebral joints and what type of joint are they?
joints between the vertebral bodies of adjacent vertebrae in the spine
secondary cartilaginous
Where and what are the costosternal joints ?
joints between the costal cartilages of the ribs and the sternum
primary cartilaginous joint
Where and what is the xiphisternal joint?
joint between the xiphoid process and the body of the sternum
primary cartilaginous
How to differentiate between sternocostal and costosternal?
Both involve the sternum and ribs, but sternocostal joints involve the articulation of the sternum with costal cartilage, while costosternal refers specifically to the ribs’ cartilages and their connection with the sternum.
How to differentiate between Manubriosternal and Xiphisternal?
The manubriosternal joint connects the manubrium with the body of the sternum (higher up on the sternum), while the xiphisternal joint connects the xiphoid process with the body of the sternum (lower down). The manubriosternal joint is a symphysis, and the xiphisternal joint is a synchondrosis.
How to differentiate between intervertebral and other thoracic joints?
Intervertebral joints are between vertebrae and are not directly involved in the rib cage, unlike the other joints which are part of the rib cage system. Intervertebral joints are also cartilaginous, while most of the rib-related joints are synovial or cartilaginous depending on the articulation type.
Describe the movement of the thoracic cage and the diaphragm during inspiration?
increases the intrathoracic diameter and volume of thorax
decreases the intrathoracic pressure
What is happening during forced expiration?
abdominal muscles and internal intercostal muscles are involved and this decreases the diameter of the thoracic cage
What happens during forceful inspiration?
increase the anteroposterior and transverse diameter of the thoracic cage
Describe inspiration in terms of bucket handle motion?
the lateral most part of the rib gets elevated and therefore the transverse diameter of the thoracic cage will be increased - happens at the lower ribs
Describe inspiration in terms of the ‘pump handle’ motion?
elevates the sternum and the anterior end of the ribs and it causes an increase in the anterior-posterior diameter of thoracic cage
What is the middle of the intercostal muscles?
internal intercostal muscles- inferoposterior direction
What is the superficial layer of the intercostal muscles?
external intercostal muscles
direction towards your hand
What is the least superficial intercostal muscle?
innermost intercostal muscle- inferoposterior direction
What do the neurovascular bundles consist of?
intercostal vein
intercostal artery
intercostal nerve
Superior to inferior: VAN
Where does VAN lie?
between internal intercostal and innermost intercostal muscles
What do external intercostal muscles become anteriorly?
becomes membrane called external intercostal membrane
What do the innermost intercostal muscles become posteriorly?
internal intercostal membranes
What is the arterial supply of the thoracic wall?
posterior intercostal arteries (branch of mainly descending thoracic aorta)
anterior intercostal arteries (branch of internal thoracic artery)- which are branch of the subclavian artery
branches of axillary arteries
What is the venous drainage of the thoracic wall?
Azygos vein - drains into the superior vena cava
accessory hemiazygos vein- drain into azygos vein
internal thoracic veins- drains into subclavian vein and ultimately all goes the vena cava superior to the right atrium
What is the lymphatic drainage of the thoracic wall?
Left side of chest wall drains to thoracic duct to left subclavian vein
Right side of chest wall drains to right lymphatic duct to right subclavian vein
Breast lymphatics have a majority of them draining into the axillary lymph node
Some part of the medial part of breast drains into the para sternal lymph nodes
Lower part of breast will be draining into the abdominal lymph nodes
What is a dermatome?
area of the skin supplied by a single spinal nerve.
Extending from the posteromedial line to the anteromedial line
What is a myotome?
defined as a group of muscles which is innervated by single spinal nerve root
compartments of the thoracic cavity?
Pulmonary cavities- lungs and pleura
Mediastinum (central compartment in middle) - heart and the great vessels. Also has oesophagus, thymus and lymph nodes
If divided the mediastinum with imaginary line through the sternal angle- superior and inferior mediastinum
Extends from the superior thoracic aperture to the diaphram
highly mobile
Superior
Inferior mediastinum:
anterior - infront of pericardial sac
middle
posterior - behind pericardial sac
What are the three peripheral attachments and central of the diaphragm?
-lumbar vertebra
-costal cartilages from ribs 7-12
-xiphoid process of the sternum
One central attachment: central tendon of the diaphragm
What are the right and left crura?
part of diaphragm that arises from the vertebra
Right crus – Arises from L1-L3. Some fibres from the right crus surround the oesophageal opening and help prevent reflux of gastric contents back into the oesophagus.
Left crus – Arises from L1-L2 and their intervertebral discs.
What is the function of the diaphragm?
prime muscle of inspiration
What are the three important openings of the diaphragm?
T8: The caval opening passes through the central tendon of the diaphragm. It transmits the inferior vena cava.
T10: The oesophageal hiatus is located through the muscular sling of the right crus. It transmits the oesophagus and both vagus nerves.
T12: The aortic hiatus is between the left and right crus.
It transmits the aorta, the azygos vein, the hemiazygos vein, and the thoracic duct.
What is the diaphragm innervated by?
the phrenic nerve
two phrenic nerves that pass in front of the root of the hilum or the sides of the heart
Why is phrenic nerve a mixed nerve?
both motor and sensory
Where does phrenic nerve originate from (anterior rami)?
c3 to c5 spinal nerves in the neck
What are the motor and sensory functions of the phrenic nerve?
Motor: Pierces and innervates thediaphragm.
Sensory: Supplies the central part of the diaphragm.
(The peripheral portions of the diaphragm are also innervated by sensory fibres of intercostal nerves, T7-T12).
What will happen if there is injury in one of phrenic nerves?
if right phrenic nerve damaged- right dome paralysed.
Going upward instead because the active part will contract and go down and will compress abdominal viscera which will push to the other side.
Paralysed part goes higher
