thoracic osteology

Question 1

what are the 2 groups of muscles in the thoracic wall?

Answer 1

intrinsic and extrinsic muscles

Question 2

what is the thoracic wall & functions?

Answer 2

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

Question 3

what is the function of the intrinsic muscle group and what are examples of them?

Answer 3

-intrinsic muscle aid with breathing movements through the elevation and depression of the ribcage
-eg serrates anterior, intercostal, subcostal and transversus thoracis muscles

Question 4

what is the function of the extrinsic muscles of the thoracic wall and give examples?

Answer 4

-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

Question 5

what are the ribs?

Answer 5

arc shaped flat bones that protect the thoracic organs eg the heart & lungs

Question 6

how many pairs of ribs are there?

Answer 6

12

Question 7

what are the ‘true ribs’?

Answer 7

the true ribs are the ribs that articulate directly with the sternum through their costal cartilages
- first seven pairs of ribs

Question 8

what are the false ribs?

Answer 8

• the ribs that articulate indirectly with the sternum via the 7th rib

Question 9

which ribs are the floating ribs and why are they called this?

Answer 9

-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

Question 10

what is the intercostal space ?

Answer 10

the space between the ribs

Question 11

List the typical and atypical ribs

Answer 11

typical 3-9
atypical 1,2,10,11,12

Question 12

Describe the basic osteology of a typical rib

Answer 12

-head
-neck
-tubercle
-body
-costal groove (accommodates important arteries, veins and nerves)
-costal cartilage

Question 13

Describe the osteology of rib 1

Answer 13

-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

Question 14

what is different in the structure of the 10th, 11th and 12th rib compared to the others?

Answer 14

they only have 1 facet and neither a neck or tubercle

Question 15

what is the function of the external intercostals muscle?

Answer 15

-elevates the ribs during inspiration to expand the thoracic cavity

Question 16

what is the function of the internal intercostalis muscle?

Answer 16

depress the ribs

Question 17

what part of the rib attaches to the facet on the transverse processes of the thoracic vertebrae?

Answer 17

the tubercle

Question 18

what is the sternum?

Answer 18

-flat, elongated bone located centrally in the anterior thoracic wall

Question 19

what are the 3 main parts of the sternum?

Answer 19

-manubrium
-body
-xiphoid process

Question 20

what bones does the sternum articulate with and as a result what joint is formed?

Answer 20

-clavicles - forming the sternoclavicular joints
-first 7 pairs of ribs - forming the sternocostal joints

Question 21

what are important osteology landmarks on the sternum that can be palpated on a person?

Answer 21

-jugular notch - a visible gap located at the base of the neck just above the top of the sternum
-sternal angle

Question 22

Describe the osteology of the typical thoracic vertebrae

Answer 22

• 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

Question 23

what are the atypical thoracic vertebrae?

Answer 23

-T1
-T10
-T11
-T12

Question 24

Describe the osteology of T1

Answer 24

• 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

Question 25

Describe the osteology of T10-T12

Answer 25

-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

Question 26

what is the superior costotransverse ligament?

Answer 26

this ligament connects the neck of the rib to the transverse process of the vertabra above

Question 27

what 3 arteries does the arterial supply of the thoracic wall come from?

Answer 27

-subclavian artery -axillary artery -thoracic aorta

Question 28

what does the nerve supply of the thoracic wall mainly stem from?

Answer 28

the anterior rami of the spinal nerves T1-T12- aka intercostal nerves

Question 29

what 3 important structures run in the grooves under the ribs?

Answer 29

intercostal vein, artery and nerve VAN

Question 30

what is the diaphragm?

Answer 30

-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

Question 31

what happens to the sternum during respiration?

Answer 31

the sternum moves forward due to the elevation of the ribs

Question 32

what movement occurs in the diaphragm during inspiration?

Answer 32

the diaphragm descends to increase the volume of the thoracic cavity in inspiration

Question 33

what are the intercostal nerves?

Answer 33

-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

Question 34

what are the branches of the subclavian, thoracic aorta and axillary artery that supply the chest wall directly?

Answer 34

- upper 2 posterior intercostal arteries from the subclavian -anterior intercostal artery is from the internal thoracic artery

Question 35

what are the main veins of the chest wall?

Answer 35

-intercostal veins - anterior, posterior and subcostal -internal thoracic veins

Question 36

what happens to the veins in the thoracic wall?

Answer 36

- 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

Question 37

what is the mediastinum?

Answer 37

a compartment of the thorax located in the midline of the body that contains most of the thoracic viscera apart from the lungs

Question 38

what are the divisions of the mediastinum?

Answer 38

-superior -anterior -middle -posterior

Question 39

what is contained in the superior mediastinum? Try To Eat Toast And Vitamins Now Little Oliver

Answer 39

Thymus, trachea, esophagus, thoracic duct (lymph vessel), aortic arch , veins, nerves , lymphatics and other small arteries and veins

Question 40

what is located in the anterior inferior mediastinum?

Answer 40

-the remnants of the thymus -lymph nodes

Question 41

what is located in the middle inferior mediastinum?

Answer 41

-phrenic nerve -heart -pericardium -ascending aorta -pulmonary trunk -superior vena cava

Question 42

what is the thymus gland?

Answer 42

an immune gland located between the lungs and behind the breastbone or sternum

Question 43

what type of joint is the joint between the manubrium and the body of the sternum?

Answer 43

a secondary cartilaginous joint

Question 44

what type of joint is the 1st sternocostal joint (ie rib 1 with sternum)?

Answer 44

a primary cartilaginous joint - no movement

Question 45

what type of joints are the 2nd to 7th sternocostal joints?

Answer 45

synovial joints - they move during respiration

Question 46

what type of joints are the costovertebral joints?

Answer 46

synovial joints - plane/gliding joint

Question 47

what kind of joints are the costotransverse joints?

Answer 47

synovial joints