Thoracic Wall and Pleural Cavities Anatomy Flashcards
Describe the Thorax.
Region b/w the neck and abdomen (including heart, lungs, and diaphragm)
Shape = truncated cone with Superior Thoracic Aperture (inlet) and Inferior Thoracic Aperture (outlet)
Bony Thorax = 12 vertebrae, 12 pairs of ribs + cartilages, and sternum
What are the boundaries of the Superior Thoracic Aperture?
Posterior = Body of 1st thoracic vertebra Anterior = Manubrium Lateral = 1st pair of costae (ribs + costal cartilage)
What are the boundaries of the Inferior Thoracic Aperture?
Posterior = Body of 12th thoracic vertebra Anterior = Xiphoid process and costal cartilages 7-10 Lateral = 11th and 12th costae
Describe the respiratory diaphragm.
Closes of the Inferior Thoracic Aperture separating the thorax from the abdomen
Dome will rise to 5th intercostal space on the right side and 6th intercostal space on left providing some protection to thoracic and abdominal viscera
What are the 3 parts of the Sternum?
Manubrium, Body of the Sternum, Xiphoid process
What structures does the manubrium articulate with?
Clavicle @ sternoclavicular joint
1st pair of ribs
2nd pair of ribs and Body of sternum @ sternal angle
What is manubriosternal joint? What is its classification and action?
The articulation between Manubrium and Body of Sternum at the sternal angle.
It is a secondary cartilaginous joint (symphysis) with a hinge-like movement both anteriorly and posteriorly.
Allows for increased respiration by expansion of the thoracic cavity.
What structures does the manubrium articulate with?
Manubrium - Manubriosternal joint
Costal cartilages 2-7
Xiphoid process - Xiphisternal joint (T8 level)
What are the 3 type of Ribs?
True Ribs (1-7) False Ribs (8-10) Floating Ribs (11-12)
Describe True Ribs.
Ribs 1-7
They have costal cartilages attached DIRECTLY to sternum.
Describe False Ribs.
Ribs 8-10
They have costal cartilages attached INDIRECTLY to sternum, attached to the 7th costal cartilage.
Describe Floating Ribs.
Ribs 11-12
They have no attachment to sternum.
Describe External Intercostal Ms.
Origin: Tubercles of Ribs Insertion: Junction of costal cartilage with bony rib
Runs Inferomedially - Ribs elevated upon contraction Action = inspiration
Where is the External Intercostal membrane located?
The membrane passes from the anterior margin of EI Ms. to lateral border of sternum
Describe Internal Intercostal Ms.
Origin: Sternum
Insertion: Mid-axillary line
Runs Inferolaterally - Ribs depressed upon contraction
Action = expiration
Where is the Internal Intercostal membrane located?
The membrane passes from lateral margin of II Ms. to fuse with superior costotransverse L. (on vertebral column)
Describe Innermost Intercostal Ms.
Origin: Angle of Ribs Insertion: Anterior mid-axillary line
Same orientation and function of Internal Intercostals.
Where is the Innermost Intercostal membrane located?
Membrane passes from Anterior border of Innermost Intercostals to lateral border of Transverse Thoracis Ms.
Describe Transverse Thoracis Ms.
Origin: Posterior surface of lower half of body of sternum and xiphoid process
Insertion: costochondral junction of ribs 3-6
Function = depress ribs
What is the innervation of the intercostals and TT?
Intercostal Nerves = Ventral Primary Rami of T1-T11
Motor branches innervate muscles
Cutaneous branches innervate lateral and anterior skin of thorax and provide sensory info
What arteries supply blood to the intercostals and TT?
Supreme Thoracic A. Supreme Intercostal A. Posterior Intercostal As. Anterior Intercostal As. Musculophrenic A.
Describe the Supreme Thoracic A.
Branch of the Axillary A.
Supplies intercostal spaces 1-2
Describe the Supreme Intercostal A.
Branch of the costocervical trunk
Supplies intercostal spaces 1-2
Describe the Posterior Intercostal As.
Branches of the descending aorta located between 2 deepest layers of intercostals in spaces 3-11
Supply intercostals, pectorals, serratus anterior
Spaces 3-5 = supply breasts in females
Describe the Anterior Intercostal As.
Branches of Internal Thoracic A., spaces 1-6
Supplies skin, intercostals, breasts, thymus (anterior mediastinum)
Describe the Musculophrenic A.
Terminal branch of Internal Thoracic A.
Provides anterior intercostal as. to spaces 7-9
What is the mediastinum?
3D space between the 2 pleural cavities
What are the 2 types of Pleura?
Parietal and Visceral
What is visceral pleura?
Pleura that covers the surface of lungs
Viscera = organ
What is parietal pleura? Parts of this pleura?
It lines the pleural cavity
Costal pleura = most lateral, attaches to ribs and intercostal spaces
Mediastinal pleura = adheres to mediastinum
Diaphragmatic = adheres to superior surface of respiratory diaphragm
Cervical = lines pleural cavity above level of 1st ribs in root of neck
What are the 3 lines of reflection? Describe them.
Vertebral Reflection = costal and mediastinal pleura become continuous posteriorly
Sternal Reflection = costal and mediastinal pleura become continuous anteriorly
Costal Reflection = costal and diaphragmatic pleura become continuous inferiorly
What are pleural recesses? Locations?
Where 2 layers of parietal pleura form an acute angle and are in direct contact with each other
Can fill with pus and fluid
Locations:
- Right AND Left Costodiaphragmatic recess
- LEFT Costomediastinal recess
What is a Pleural Cavity? Contents?
Space between the parietal and visceral pleura (aka Pleural space)
Contents = pleural fluid
What is a Pleural Sac?
LUNGS are found in the pleural SAC, NOT CAVITY.
It is the space contained within the visceral pleura.
Describe the Sensory Innervation of the Parietal Pleura.
Intercostal nerves = costal pleura + periphery of the respiratory diaphragm
Phrenic nerves = mediastinal pleura + diaphragmatic pleura
How would you classify the Xiphisternal joint?
Primary cartilaginous joint - Synchondrosis
Permanent, but can ossify
What are other thoracic wall muscles?
Subcostal Ms.
Transverse more than 1 intercostal space posteriorly
