Lecture 19

Question 1

Thorax

Answer 1

Supported by thoracic cage constructed of horizontally positioned ribs articulating with the vertically positioned sternum and thoracic vertebrae. Spaces between ribs are filled with tissue which contribute to the thoracic wall.

Question 2

thorax function

Answer 2

Protects thoracic and abdominal organs.

Conduit for structures passing from head/neck to abdomen

provides machinery needed for manoeuvres for inspiration/expiration for gas exchange

Question 3

Pulmonary cavities

Answer 3

Two lateral compartments. Contains lungs. Lined by parietal pleura which is divided into cervical, mediastinal, costal and diaphragmatic

Question 4

Mediastinum

Answer 4

Centrally located incl. heart, vessels, nerves, trachea, bronchi, oesophagus, lymphatics. Divided by pericardium.

Question 5

Thoracic cage components

Answer 5

1x sternum

12x thoracic vertebrae
intervertebral discs

12x pairs of ribs

12x pairs of associated costal cartilage which caps ribs

Question 6

Manubrium

Answer 6

Joins body of sternum creating the manubriosternal joint which forms sternal angle at T4/T5

Question 7

Sternum of body

Answer 7

Joins manubrium creating MBS and Xiphoid process creating Xiphisternal joint

Question 8

Xiphoid process

Answer 8

Joins body via XSJ which is an important midline marker for the inferior limit of thoracic cavity and heart boarder, superior limit of liver and central tendon of diaphragm.

Question 9

Manubrium articulation

Answer 9

1x suprasternal notch, 2x clavicular notch, 2x synchrondroses of 1st ribs, 2x half costal notch of 2nd ribs.

Question 10

Body articulations

Answer 10

2x half notch of 2nd ribs (other halves), 2x costal notches for 3rd-6th ribs, 2x half notch for 7th ribs

Question 11

Xiphoid process articulations

Answer 11

2x half notch for 7th ribs (inferior half)

Question 12

Unique feature of vertebral body

Answer 12

Heart-shaped vertebral body. Has costal facets on the sides for rib head articulation. These costal facets are only found in thoracic vertebrae (cervical and lumbar vertebrae don’t have them). This is where the head of the rib attaches.

Question 13

Transverse process

Answer 13

Wing shape with costal facets for rib articulation with rib tubercle.

Question 14

spinal process

Answer 14

long and slopes downwards

Question 15

vertebral canal

Answer 15

contains spinal cord

Question 16

Pedicles

Answer 16

Wall attaching lamina to vertebral body

Question 17

Intervertebral foramen

Answer 17

Where spinal nerves come out

Question 18

Zygapophysial joint

Answer 18

superior articular process plus inferior articular process between vertebrae

Question 19

vertebrae articulation and cartilage

Answer 19

Can articulate with ribs, costal facets where rib articulates, cartilage lined (synovial). Can be intervertebral

Question 20

Components of vertebrae

Answer 20

spinous process x1, transverse process x 2, superior articular process x 2, inferior articular cartilage x2.

Question 21

benefits of the Position on rib and vertebrae articulations

Answer 21

These articulations position the ribs so that, when the joints move during inspiration, the ribs elevate and flare outward, which widens the thoracic cavity. This expansion decreases intrathoracic pressure, allowing air to flow into the lungs.

Question 22

ribs

Answer 22

posterior position articulates with vertebrae while anterior/sternal end joins with cartilage connecting to it.

Question 23

Determining LHS and RHS

Answer 23

Costal groove is always inferior which is good for identifying whether LHS or RHS

Question 24

Body/shaft

Answer 24

Rib smoothens and continues anteriorly.

Question 25

Costal groove

Answer 25

For neurovascular bundle

Question 26

anterior end of ribs

Answer 26

little fossa for costal cartilage

Question 27

typical ribs

Answer 27

Ribs 3-9. Have head, neck, tubercle, angle, body

Question 28

Atypical rib

Answer 28

Ribs 1,2,10-12. Have variations in rib structure.

Question 29

True ribs

Answer 29

1st-7th. Costal cartilages attach DIRECTLY to ribs

Question 29

False ribs

Answer 29

8th-10th costal cartilage attach to sternum via cartilage of superior rib

Question 30

Floating ribs

Answer 30

Ribs 11-12 have caps but do not join to sternum in any way

Question 31

sternocostal joints

Answer 31

Between sternum and costal cartilage of ribs

Question 32

costovertebral joints

Answer 32

between posterior rib and thoracic vertebrae

Question 33

costocorporeal joint

Answer 33

the head of a typical rib articulates with the inferior costal facet of the vertebra above, and the superior costal facet of the vertebra of the same number as the rib.

Question 34

costotransverse joint

Answer 34

between rib tubercle and transverse process

Question 35

Intercostal spaces

Answer 35

Spaces between ribs. Labelled according to the superior rib number. Occupied by the constituents of the thoracic wall incl. muscles, membranes, vasculature and nerves.

Question 36

Location of thoracic wall

Answer 36

skin to endothoracic fascia (superior to pleura)

Question 37

Intercostal muscles

Answer 37

Fills ICS and provides structural support. Makes ribs move and cooperate to produce breathing manoeuvres. Pulls rib below upwards due to synchondrosis of 1st rib. Resists paradoxical movement of thoracic wall during breathing i.e when we increase thoracic volume, you decrease pressure without sucking the wall in. Sandwich also protects neurovascular bundle.

Question 38

External intercostal muscles

Answer 38

Most superficial. Fibres go L to R

Question 39

Internal intercostal muscles

Answer 39

Fibres go R to L. Layer of sandwich.

Question 40

Inntermost intercostal muscles

Answer 40

Fibres go R to L. Layer of sandwich.

Question 41

Neurovascular bundle

Answer 41

Artery drains into aorta, veins drain into azygous vein and anterior ramus of spinal nerve. NVB nestled in costal groove on inferior boarders of ribs. Give off collateral branches. Order is VAN (vein, artery and nerve)

Question 42

Azygous vein

Answer 42

Last vein that peripheral veins drain into before reaching superior VC and RV.

Question 43

Thorax boundaries

Answer 43

Extends between neck and abdomen. Superior portion doesn't change shape while inferior portion does change shape.

Question 44

Thoracic inlet

Answer 44

Bound by superior boarders of anterior manubrium, 1st ribs and cartilage laterally and posterior presence of T1. Filled with vessels, nerves, trachea and oesophagus.

Question 45

Thoracic outlet

Answer 45

Anteriorly bound by xiphisternal joint, laterally bound by costal cartilage of ribs 7-10, ends of ribs 11 and posteriorly bound by boarder of 12th rib. Filled with diaphragm and punctured by inferior VC, oesophagus, aorta.

Question 46

Thoracic inlet contents

Answer 46

Listed from anterior to posterior L and R: brachiocephalic veins subclavian vein internal jugular vagus nerves common carotid artery phrenic nerve subclavian arteries Trachea apex of L and R lungs oesophagus

Question 47

Thoracic outlet contents

Answer 47

filled with diaphragm

Question 48

Diaphragm

Answer 48

Thin, domed musculotendinous sheet that attaches to inferior margin of thoracic cage and lumbar vertebrae to separate thorax from abdomen.

Question 49

Diaphragm attachments

Answer 49

The diaphragm is the chief muscle of respiration, with a fixed peripheral muscular attachment and a central tendon that moves during breathing. During inspiration, the diaphragm contracts actively, pressing down on the abdominal viscera and causing the central tendon to descend, increasing thoracic volume. Expiration is passive, as the diaphragm relaxes and the central tendon rises. Several important structures pass between the thorax and abdomen via or behind the diaphragm. The inferior vena cava pierces the central tendon at around the T8 level. The oesophagus passes through the muscular portion of the diaphragm, just posterior to the central tendon, at T10. The descending aorta passes behind the diaphragm at T12, where it becomes the abdominal aorta.