CPR02

The upper respiratory tract consists of

Nose, pharynx, larynx

The lower respiratory tract consists of

Trachea, bronchi, lungs

Functions of thoracic cage

1. protect internal organs (e.g. lungs, heart, great vessels)

2. attachment of muscles

   a. ICM intercostal muscles —> muscles between ribs

   b. PJ pectoralis major PM pectoralis minor—> attached to the upper limb and scapula

   c. SM scalene muscles—> attached on the surface of the first rib to the cervical vertebrae (neck region)

What does sternum consist of

Manubrium, body, xiphoid process

What does manubrium consist of

attachment site for clavicle, cartilaginous joint for 1st rib attachment, facets for attachment of 2nd rib

Body of sternum consist of

articulate facets for 2nd - 7th rib

synovial joint for attachment of costal cartilage connecting to 2nd -7th rib

What is sternal angle

Manubrium and the body forms an angle

Also called manubriosternal joint, Angle of Louis

Ribs are classified into

True ribs: 1-7( attach to corresponding cartilage)

False ribs: 8-10( costal cartilage attaching to 7)

Floating ribs: 11-12( no attachment to sternum)

What does typical ribs consist of

1. Head with two articular facets

   • demifacets on vertebral body

   • corresponding vertebral body and one level above

2. Neck

3. Tubercle

4. Angle

5. Body

6. Costal groove, contains intercostal VAN

What does thoracic vertebrae consist of

Synovial joints to allow free movement

What does the movement of chest wall do

• anterior posterior diameter AP, as rib is attached anteriorly to the sternum, it results in the increase in the anterior posterior diameter of the chest thoracic cavity

• Transverse diameter, as rib is attached posteriorly to the vertebrae, anterior to sternum, movement expands the chest wall

What do thoracic muscles do

Elevate or depress the thoracic cage

external intercostal muscles EIM

internal intercostal muscles IIM

innermost intercostal muscles InIM

respective roles, action on ribs

Most active during inspiration, elevates ribs

Most active during expiration, depress ribs

Not confined within intercostal space, depress ribs

How is the neurovascular structure in thoracic cage

Arranged according to intercostal VAN

run along the costal groove of ribs

Which blood vessel posterior intercostal artery originate from

subclavian artery SA —> costocervical trunk CT —> supreme intercostal artery SIA —> 1st and. 2nd posterior intercostal artery

thoracic aorta —> 3rd-11th posterior intercostal artery

Which blood vessel anterior intercostal artery originate from

subclavian artery SA —> internal thoracic artery ITA —> 1st-6th anterior intercostal artery

internal thoracic artery —> musculophrenic branch MA—> 7th-9th anterior intercostal artery

What are other accessory muscles

Transversus thoracis/ sternocostalis, depress ribs

Subcostalis, depress ribs

Levator costarum, elevate ribs

Serratus posterior superior, elevate ribs

Serratus posterior inferior, depress ribs

Venous drainage of posterior intercostal veins

1st posterior intercostal vein —> brachiocephalic vein

Right 2-11 posterior intercostal vein —> azygous vein

Left 2-3 posterior intercostal vein —> superior intercostal vein —> left brachiocephalic vein

Left 4th-11th posterior intercostal vein —> hemiazygous vein

Venous drainage of anterior intercostal vein

1-6 anterior intercostal vein —> internal thoracic vein —> subclavian artery

7-9 anterior intercostal vein —> musculophrenic branch —> internal thoracic artery