Thorax

Question 1

What is the thoracic cage part of?

Answer 1

The axial skeleton

Question 2

What are the articulations of the thorax?

Answer 2

1. the sternoclavicular joint (which is a saddle-type synovial joint with an articular disc)
2. the sternocostal joints (which are synchondroses)
3. the costochondral joints (which are primarily cartilaginous joints).

Question 3

What is the opening at the top of the thoracic cage?

Answer 3

Superior thoracic aperture

Question 4

What is the opening at the bottom of the cage?

Answer 4

the opening at the bottom of the cage is the inferior thoracic aperture, which is closed by the abdominal diaphragm

Question 5

What are rib fractures?

Answer 5

• Thoracic cage injuries result from trauma and often involve rib fractures
• Ribs 1, 11, and 12 are the least fractured ribs.

Question 6

What direction will rib fractures usually occur?

Answer 6

Rib fractures may occur in a transverse plane or an oblique plane or at multiple sites on the same rib, resulting in a free-floating segment (stove-in, or flail chest, injury)

Question 7

Why are rib fractures really painful?

Answer 7

The pain is intense because of the continued expansion and contraction of the rib cage necessary during respiration

Question 8

What dot he superior and inferior articular processes (facets) articulate and form?

Answer 8

plane synovial joints (zygapophysial joints)

Question 9

What is each articulation surrounded by?

Answer 9

Each articulation is surrounded by a thin capsule

Question 10

What do accessory ligaments do?

Answer 10

Accessory ligaments unite the laminae, transverse processes, and spinous processes

Question 11

What do these articulations allow?

Answer 11

These articulations permit some gliding movements between adjacent vertebrae during flexion, extension, and limited lateral bending

Question 12

What type of joints are costovertebral joints?

Answer 12

Costovertebral joints are plane synovial joints that occur between the head of a rib and the costal facets of a vertebra

Question 13

Where do costotransverse plane synovial joints occur?

Answer 13

1. Costotransverse plane synovial joints (ribs 1-10) occur between a tubercle of a rib and a transverse process of a vertebra
2. Gliding movements occur at these joints.

Question 14

Where could osteoarthritis affect?

Answer 14

Osteoarthritis is the most common type of arthritis and often involves erosion of the articular cartilage of weight-bearing joints, including the facet (zygapophysial) joints

Question 15

Where do the external intercostal muscles arise from?

Answer 15

Each muscle arises from the lower border of a rib

Question 16

Where do the external intercostal muscles insert?

Answer 16

Each muscle attaches to the upper border of the rib below its origin

Question 17

What is the action of external intercostal muscles?

Answer 17

It is generally accepted that the external intercostal muscles are active during inspiration and that they elevate the ribs

Question 18

What is the innervation of external intercostal muscles

Answer 18

• Muscles are innervated by intercostal nerves, which are numbered sequentially according to the intercostal interspace.
• The 4th intercostal nerve supplies muscles that occupy the 4th intercostal space, between the 4th and 5th ribs.

Question 19

How many external intercostal muscles are there?

Answer 19

Because these muscles fill the intercostal spaces, there are 11 external intercostal muscles on each side of the thorax

Question 20

What do the intercostal muscles do?

Answer 20

All of the intercostal muscles keep the intercostal spaces rigid, preventing them from bulging out during expiration and being drawn in during inspiration

Question 21

Can the intercostal muscles assist the diaphragm?

Answer 21

1. Whereas the diaphragm is the primary muscle of respiration (used almost exclusively in neonates and during quiet respiration)
2. the intercostals do assist the diaphragm and, along with other accessory muscles of respiration (e.g., the scalene muscles)
3. can become hypertrophied if a respiratory pathologic process occurs (e.g., in a chronic obstructive pulmonary disease such as emphysema).

Question 22

Where do the internal intercostal muscles arise from?

Answer 22

arise from a ridge on the inner surface of the inferior aspect of each rib and from the corresponding costal cartilage

Question 23

Where do the internal intercostal muscles insert?

Answer 23

Each muscle attaches to the upper border of the rib below its origin

Question 24

What is the action of the internal intercostal muscles?

Answer 24

1. The portions of the upper 4 or 5 internal intercostal muscles that interconnect with the costal cartilages may elevate the ribs.
2. The more lateral and posterior portions of the muscles, where the fibers run more obliquely, depress the ribs and are active during expiration

Question 25

What is the innervation of the internal intercostal muscles?

Answer 25

Intercostal nerves.

Question 26

What are the fibres like in the internal intercostal muscles?

Answer 26

- In general, the fibers of the internal intercostals are roughly perpendicular to those of the external intercostal muscles - There are 11 pairs of internal intercostal muscles

Question 27

When will intercostal muscles hypertrophy?

Answer 27

1. The intercostal muscles assist in respiration 2. can hypertrophy if a respiratory pathologic process develops (e.g., in a chronic obstructive pulmonary disease such as asthma or emphysema).

Question 28

Where does each innermost intercostal arise from?

Answer 28

- arises from the lower border of a rib - The innermost intercostal muscles frequently are poorly developed and may be fused to the overlying internal intercostals - They are most prominent on the lateral thoracic wall.

Question 29

Where does the transverses throacis arise from?

Answer 29

arises from the posterior surface of the lower portion of the body of the sternum and the xiphoid process

Question 30

Where does each innermost intercostal attach?

Answer 30

to the upper border of the rib below its origin

Question 31

Where does the transversus thoracis attach?

Answer 31

- attaches to the inner surfaces of costal cartilages 2-6 | - The transversus thoracis muscle is variable in its attachments

Question 32

What does the innermost intercostals do?

Answer 32

The action of the innermost intercostals is controversial, but these muscles are thought to depress the ribs

Question 33

What do the transversus thoracis do?

Answer 33

The transversus thoracis muscle depresses the ribs

Question 34

What is the innervation of the innermost intercostals and transversus thoracis?

Answer 34

Intercostal nerves

Question 35

Where do you inject a local anaesthetic for chest trauma?

Answer 35

1. Chest trauma can lead to very painful breathing 2. Injection of a local anesthetic agent into the intercostal space (intercostal nerve block) can relieve this pain 3. The intercostal neurovascular bundles course between the internal and innermost intercostal muscles in the costal groove of the ribs.

Question 36

Where does the serratus anterior muscle arise from?

Answer 36

arises by fleshy digitations from the outer surfaces and superior borders of the first 8 to 9 ribs

Question 37

Where do the serratus anterior muscle insert?

Answer 37

The serratus anterior muscle fibers pass backward, closely apply themselves to the chest wall, and insert on the ventral aspect of the vertebral (medial) border of the scapula

Question 38

What is the action of the serratus anterior muscle?

Answer 38

1. Muscle pulls the medial border of the scapula anteriorly toward the thoracic wall (protraction) 2. Preventing the bone from protruding (winging) 3. Its fibers also rotate the scapula upward by laterally rotating the inferior angle 4. This action helps abduct the arm at the shoulder 5. Abduction above (above the horizontal) can be accomplished only by lateral rotation of the inferior angle of the scapula.

Question 39

What is the innervation of the serratus anterior muscle?

Answer 39

Long thoracic nerve (C5, C6, and C7)

Question 40

What is the serratus anterior particularly important in?

Answer 40

- in rotation of the scapula so the deltoid muscle may fully abduct the arm - also is important in keeping the scapula flush against the thoracic wall.

Question 41

What could damage to the long thoracic nerve result in?

Answer 41

- may lead to "winging" of the scapula, most evident when a patient pushes forward with the upper limb against resistance - In particular, the inferior angle of the scapula is elevated away from the thoracic wall - This type of nerve injury may occur from trauma to the lateral thoracic wall or from lateral flexion of the neck to the opposite side, causing a stretch injury to the nerve.

Question 42

What is the length of the oesophagus?

Answer 42

The esophagus is a muscular canal that extends from the pharynx to the stomach. Its muscular coat is organized into 2 planes

Question 43

What are the two planes in the oesophagus?

Answer 43

1. an external plane of longitudinal fibers | 2. an internal plane of circular fibers

Question 44

What muscle transitions are in the oesophagus?

Answer 44

transitions from skeletal to smooth muscle as it descends from the pharynx to the stomach

Question 45

Where are the 4 narrowed regions along its length where a swallowed object may become lodged or erode the mucosa as it passes?

Answer 45

1. the pharynx becomes continuous with the proximal esophagus 2. the aortic arch crosses the esophagus 3. the esophagus is compressed by the left main bronchus 4. the esophagus passes through the diaphragm (esophageal hiatus)

Question 46

What is GERD?

Answer 46

Gastroesophageal reflux disease (GERD) may occur at the level of the lower esophagus and present as dyspepsia, gas, heartburn, dysphagia, bronchospasm, or asthma