Lecture 11: Thorax I - Wall Flashcards
Define thoracic wall. What is it composed of?
Soft tissues?
Organs?
the muscles, cartilage, bone, and soft tissues (skin, fascia, nerves, and vessels) that surround the thoracic cavity
Surrounds organs located therein (heart, lungs, thymus, trachea, and esophagus)
What are the lateral boundries of the thoracic cavity?
- LATERAL: ribs and contents of
intercostal spaces
Anterior boundry of thoracic wall?
- ANTERIOR: sternum
Posterior boundry of thoracic cavity?
- POSTERIOR: thoracic vertebrae and intervertebral discs
Superior and inferior boundries of Thoracic Wall?
- SUPERIOR: superior thoracic aperture
- INFERIOR: inferior thoracic
aperture
What forms the superior thoracic aperture?
What does it transmit?
- Formed by the T1 vertebra, first ribs, and sternum
- Transmits major vessels (and other soft tissues) between the thoracic cavity, neck, and upper limbs
What forms the inferior thoracic aperature? What attaches to the bottom?
- Formed by the T12 vertebra, ribs 11-12 (and cartilages), costal margin, and the sternum
- The thoraco-abdominal diaphragm attaches along the inferior border of the inferior thoracic aperture
What is anatomical term for this area?
Intercostal Space
Define intercostal space, and where do they extend from and connect to?(origin / insertion)
Intercostal spaces: the spaces between adjacent ribs and costal cartilages
- Extend from the vertebral column (posteriorly) to the sternum (anteriorly)
What does each intercostal space contain?
- Each intercostal space contains: intercostal muscles (three layers), intercostal vessels, and intercostal nerves
Identify these features
What are the 4 major functions of the Thoracic Wall, and some feature of each.
How does thoracic wall contribute to inspiration and expiration?
What produces the changes in thoracic wall dimensions for respiration?
*Changes in thoracic wall dimensions are produced by
coordinated movements of the:
▪ Thoraco-abdominal diaphragm
▪ Ribs and sternum
What does thoraco-abdominal diaphragm contribute to respiration?
What is the bucket handle movement of the ribs and sternum, and how does it contribute to respiration?
What is the pump handle movement of the ribs and sternum? How does it contribute to respiration?
Which muscles contribute to quiet and active inspiration and exhalation?
What types of bones and cartilage is the thoracic wall composed of?
- RIBS & COSTAL CARTILAGE
- THORACIC VERTEBRAE
- STERNUM
How many ribs are there, and what common features do ribs 2-9 contain?
RIBS & COSTAL CARTILAGES
* There are 12 pairs (left/right) of ribs numbered from superior to inferior
- Typical ribs (ribs 2-9) have a head, neck, tubercle, body, and angle
Identify the marked features of the rib.
(posterior view)
Identify marked feature of rib.
(Superior View)
Define the following functions of the rib:
Head, Neck, Angle,Tubercle and Body
Where are the costal cartilages (extend from where to where)? What feature of the thoracic wall do they contribute to?
- Costal cartilages extend from anterior ends of ribs and connect to the sternum; contribute to elasticity of thoracic wall
What are the 3 classes of ribs?
True Ribs
False Ribs
Floating Ribs
Explain location of the three rib classes and which numbers they are?
▪ TRUE RIBS: attach directly to the sternum via their costal cartilages
▪ FALSE RIBS: attach to the sternum via the costal cartilage of the next superior rib
▪ FLOATING RIBS: short ribs with rudimentary cartilages with no attachment to sternum
What is the sternum?
What are the 3 parts to the sternum?
Identify the marked features of the sternum.
Identify marked features of thorax.
Describe location of breast
- The breast is located on the anterior thoracic wall on either side lateral to the sternum
Describe location of the transverse extent and vertical extent of the breast.
What is the Axillary process?
▪ TRANSVERSE EXTENT: from the lateral of the sternum to the anterior border of the axilla
▪ VERTICAL EXTENT: from rib 2 to rib 6
- Axillary process (tail): extension of breast that continues superiorly and laterally
Define nipple.
Define areola.
Define mammary gland: Type of gland / what happens during pregnancy?
- Mammary gland: modified sweat gland that produces milk; consists of glandular tissue surrounded by adipose
- Typically, well-developed in females only; enlarge during
pregnancy (new glandular tissue forms)
What are mammory gland lobules, and how many does each breast contain?
- Each breast contains 15-20 mammary gland lobules, which comprise the functional part of the mammary gland
What are the mammary gland lobules supported by?
- Mammary gland lobules are supported by suspensory
ligaments which anchor mammary glands to skin
What is each lobule drained by, and where do they lead?
Each lobule is drained by a lactiferous duct, which opens independently onto the nipple
What is the lactiferous sinus?
- Each lactiferous duct has a lactiferous sinus—i.e., a dilated portion just deep to the nipple
Identify indicated structures of the breast. (unable to include lactiferous sinus and nipple so dont forget them)
What are the 2 costovertebral joints, and their functions?
Identify the joint
What is the location of the sternocostal joints, costochondral joints and interchondral joints?
Is there movement / what do they increase?
Identify the indicated joints
What are the intercostal muscles, and where do they attach?
What is their overall function?
INTERCOSTAL MUSCLES: three layers of muscles spanning the intercostal spaces; attached to superior and inferior borders of consecutive ribs
FUNCTION: elevate/depress ribs during respiration
Describe external intercostal muscles: layer / fiber orientation / prevalence
- External intercostal muscles: most superficial; fibers oriented inferiorly and anteriorly; most prevalent posteriorly
Describe internal intercostal muscles: layer / fiber orientation / prevalence
- Internal intercostal muscles: intermediate depth; fibers oriented inferiorly and posteriorly; most prevalent anteriorly
Describe innermost intercostal muscles: layer / fiber orientation / prevalence
- Innermost intercostal muscles: deepest; fibers oriented inferiorly and posteriorly; only present laterally
Identify the indicated muscles and structures
Name 2 additional muscles of the thoracic wall, and their overall function.
Transversus Thoracis
Subcostal
these muscles also primarily function in moving the ribs during respiration
Anatomical position of transversus thoracis muscle?
which ribs does it attach to?
Transversus thoracis muscle:
attached to the posterior surface of the sternum and the costal
ribs 2-6
Anatomical location of subcostal muscle
Which ribs?
Subcostal muscle: attached superiorly to the angles of the inferior most ribs and inferiorly to the superior surfaces of ribs 2-3. Located posteriorly on ribcage
What is the Thoraco-Abdominal Diaphragm?
Thin skeletal muscle forming the partition between the thoracic and abdominal cavities
Describe the shape of the Thoraco-Abdominal Diaphragm from the anterior and lateral views.
Anterior view: dome-shaped from R to L (R side higher due to liver)
Lateral View: dome-shaped from anterior to posterior
What is the central tendon?
Aponeurosis that serves as a point of attachment for diaphragm.
Where does the diaphragm originate from? Name the 3 different origins?
Originates from boundries of inferior thoracic aperture.
Sternal Origin
Costal Origin
Vertebral Origin
What is the sternal origin of the diaphragm?
- STERNAL ORIGIN: from xiphoid process
Costal origin of diaphragm
Which costal cartilages and ribs?
- COSTAL ORIGIN: from lower six costal cartilages and lower two
ribs
Left Crus and Right Crus of vertebral origin of diaphragm
which vertebrae / which is larger / smaller
- VERTEBRAL ORIGIN:
Right crus: arises from the vertebral bodies and discs of L1-L3; usually larger
Left crus: arises from vertebral bodies and discs of L1-L2; usually smaller
What causes inspiration and expiration?
Inspiration: Contraction of the diaphragm
Expiration: Relaxation of the diaphragm
How does the contraction of the diaphragm affect the following features of the thoracic cavity:
* Vertical dimensions
* Volume
* Lung Pressure
How does the relaxation of the diaphragm affect the following features of the thoracic cavity:
* Vertical dimensions
* Volume
* Lung Pressure
Describe shape of diaphragm during inspiration and expiration
What 3 structure pass through the diaphragm, and where?
Identify the indicated structures