thoracic osteology Flashcards
what are the 2 groups of muscles in the thoracic wall?
intrinsic and extrinsic muscles
what is the thoracic wall & functions?
The thoracic wall is formed by 12 ribs, 12 thoracic vertebrae, cartilage, sternum, and five muscles.
- functions in movement, respiration and protection of thoracic cavity
what is the function of the intrinsic muscle group and what are examples of them?
-intrinsic muscle aid with breathing movements through the elevation and depression of the ribcage
-eg serrates anterior, intercostal, subcostal and transversus thoracis muscles
what is the function of the extrinsic muscles of the thoracic wall and give examples?
-functionally related to the neck, abdomen, back or upper limbs
-examples include subclavian, pec major and minor muscles and inferior portion of serrates anterior muscle
what are the ribs?
arc shaped flat bones that protect the thoracic organs eg the heart & lungs
how many pairs of ribs are there?
12
what are the ‘true ribs’?
the true ribs are the ribs that articulate directly with the sternum through their costal cartilages
- first seven pairs of ribs
what are the false ribs?
- the ribs that articulate indirectly with the sternum via the 7th rib
which ribs are the floating ribs and why are they called this?
-ribs 11 + 12
-they are called this because they do not attach to the sternum in any manner and are short and have no necks or tubercles
what is the intercostal space ?
the space between the ribs
List the typical and atypical ribs
typical 3-9
atypical 1,2,10,11,12
Describe the basic osteology of a typical rib
-head
-neck
-tubercle
-body
-costal groove (accommodates important arteries, veins and nerves)
-costal cartilage
Describe the osteology of rib 1
-widest and shortest rib
-has the sharpest curve and only 1 articular surface
-scalene tubercle - where scale muscle attaches to
-contains 2 grooves for the subclavian vessels
what is different in the structure of the 10th, 11th and 12th rib compared to the others?
they only have 1 facet and neither a neck or tubercle
what is the function of the external intercostals muscle?
-elevates the ribs during inspiration to expand the thoracic cavity
what is the function of the internal intercostalis muscle?
depress the ribs
what part of the rib attaches to the facet on the transverse processes of the thoracic vertebrae?
the tubercle
what is the sternum?
-flat, elongated bone located centrally in the anterior thoracic wall
what are the 3 main parts of the sternum?
-manubrium
-body
-xiphoid process
what bones does the sternum articulate with and as a result what joint is formed?
-clavicles - forming the sternoclavicular joints
-first 7 pairs of ribs - forming the sternocostal joints
what are important osteology landmarks on the sternum that can be palpated on a person?
-jugular notch - a visible gap located at the base of the neck just above the top of the sternum
-sternal angle
Describe the osteology of the typical thoracic vertebrae
- vertebral body is heart shaped with costal facets
-veretbral canal is round
-spinous process slopes inferiorly
-costal facets - to articulate with ribs
-transverse process have facets to articulate with the tubercle of the rib
what are the atypical thoracic vertebrae?
-T1
-T10
-T11
-T12
Describe the osteology of T1
- has 1/2 facets on the body of articulation with the head of the ribs
-full superior facet on body for 1st rib and inferior demi-facet on body
rib 1 articulates with T1
Describe the osteology of T10-T12
-single facet on the side of the vertebral body of T10-T12
-these ribs only articulate with their own vertebrae
no facet on transverse process of T11 and T12
what is the superior costotransverse ligament?
this ligament connects the neck of the rib to the transverse process of the vertabra above
what 3 arteries does the arterial supply of the thoracic wall come from?
-subclavian artery
-axillary artery
-thoracic aorta
what does the nerve supply of the thoracic wall mainly stem from?
the anterior rami of the spinal nerves T1-T12- aka intercostal nerves
what 3 important structures run in the grooves under the ribs?
intercostal vein, artery and nerve
VAN
what is the diaphragm?
-a muscle located on the inferior end of the rib cage
-undergoes contraction and relaxation which alters the volume of the thoracic cavity - causing inspiration and expiration
what happens to the sternum during respiration?
the sternum moves forward due to the elevation of the ribs
what movement occurs in the diaphragm during inspiration?
the diaphragm descends to increase the volume of the thoracic cavity in inspiration
what are the intercostal nerves?
-they are mixed nerves that originate from the anterior rami of the spinal nerves T1-T11
- carry motor and sensory fibres
- main function is to provide supply to structures of the thoracic wall and abdominal wall as well as motor innervation to the intercostal muscles snd muscles of anterior ab wall
what are the branches of the subclavian, thoracic aorta and axillary artery that supply the chest wall directly?
- upper 2 posterior intercostal arteries from the subclavian
-anterior intercostal artery is from the internal thoracic artery
what are the main veins of the chest wall?
-intercostal veins - anterior, posterior and subcostal
-internal thoracic veins
what happens to the veins in the thoracic wall?
- these veins eventually unite to drain into the right atrium either indirectly by the azygous and homozygous or brachiocephalic veins (which drain into the superior vena cava) or directly by the superior vena cava
what is the mediastinum?
a compartment of the thorax located in the midline of the body that contains most of the thoracic viscera apart from the lungs
what are the divisions of the mediastinum?
-superior
-anterior
-middle
-posterior
what is contained in the superior mediastinum?
Try To Eat Toast And Vitamins Now Little Oliver
Thymus, trachea, esophagus, thoracic duct (lymph vessel), aortic arch , veins, nerves , lymphatics and other small arteries and veins
what is located in the anterior inferior mediastinum?
-the remnants of the thymus
-lymph nodes
what is located in the middle inferior mediastinum?
-phrenic nerve
-heart
-pericardium
-ascending aorta
-pulmonary trunk
-superior vena cava
what is the thymus gland?
an immune gland located between the lungs and behind the breastbone or sternum
what type of joint is the joint between the manubrium and the body of the sternum?
a secondary cartilaginous joint
what type of joint is the 1st sternocostal joint (ie rib 1 with sternum)?
a primary cartilaginous joint - no movement
what type of joints are the 2nd to 7th sternocostal joints?
synovial joints - they move during respiration
what type of joints are the costovertebral joints?
synovial joints - plane/gliding joint
what kind of joints are the costotransverse joints?
synovial joints
