Thorax Respiratory Flashcards
External abdominal oblique m.
Action:
• Unilateral: rotation of trunk
• Bilateral: flexion of trunk (sit-ups)
• Compression of anterior abdominal wall and viscera (increases intra-abdominal pressure)
Innervation:
• Ventral rami of T8-L1 spinal nerves
Comment:
• Important in “straining” (e.g., lifting, defecation, urination, child-birth)
• Functions in respiration (“abdominal breathing”)
• At right angle to internal abdominal oblique (strengthens abdominal wall)
Internal intercostal m.
Action:
• Muscle of respiration
• Depression of ribs during forced exhalation to decrease transverse dimensions (anterior-posterior, medial-lateral) of thoracic cavity
Innervation:
• Intercostal nerves (ventral rami of T1-11 spinal nerves)
Costal cartilages
Description:
• Attaches rib to sternum
• True ribs (ribs 1-7): attached directly to sternum by costal cartilages
• False ribs (ribs 8-10): attach indirectly to sternum via a shared costal cartilage
• Costal margin created by costal cartilages of ribs 7-10
Comment:
• All ribs: articulate with thoracic vertebrae
• Floating ribs (ribs 11-12): not attached to sternum
External intercostal m. and membrane
Action:
• Muscle of respiration
• Elevation of ribs during inhalation to increase transverse dimensions (anterior-posterior, medial-lateral) of thoracic cavity
Innervation:
• Intercostal nerves (ventral rami of T1-11 spinal nerves)
Comment:
• External intercostal muscle continuous with external intercostal membrane near sternum
Right lung
Location:
• Pulmonary cavity (in lateral thoracic cavity)
• Surrounded by pleural cavity
Description:
• Three lobes: upper (or superior), middle, and lower (or inferior), separated by two fissures - oblique and horizontal
• Medial surface has hilum with airway and pulmonary vessels
• Surface of lung covered with visceral pleura
Function:
• Primary organ of respiration
Comment:
• Thoracic cavity divided into three parts: mediastinum, and right and left pulmonary cavities
Horizontal fissure of right lung
Location:
• Lung (right)
Description:
• Short, deep cleft
• Separates upper and middle lobes
• Joins oblique fissure laterally (at midaxillary line)
• Surface projection: right 4th rib and costal cartilage
Left lung
Location:
• Pulmonary cavity (in lateral thoracic cavity)
• Surrounded by pleural cavity
Description:
• Two lobes: upper (or superior) and lower (or inferior), separated by oblique fissure
• Medial surface has hilum with airway and pulmonary vessels
• Surface of lung covered with visceral pleura
Function:
• Primary organ of respiration
Cardiac notch
Location:
• Left lung (upper lobe)
Description:
• Anterior, indented region of upper lobe
• Adjacent to left side of heart
Oblique fissure of right lung
- Deep, narrow cleft
- Separates upper from lower lobe
- Separates middle from lower lobe
- Passes through hilum
Oblique fissure of left lung
Description:
• Deep, narrow cleft
• Separates upper and lower lobes
• Passes through hilum
Comment:
• Surface projection follows line connecting spinous process of T2 (posteriorly) with left 6th costal cartilage (anteriorly)
Carina
Location:
• Trachea (bifurcation)
Description:
• Midline, internal ridge
• Formed by cartilage
Segmental bronchus and branches
Location:
• Lung
Description:
• Segmental bronchus is a branch of lobar (secondary) bronchus
• Each supplies one bronchopulmonary segment
Comment:
• Segmental bronchus also known as tertiary bronchus
Lobar Bronchus
Location:
• Lung
Description:
• Branch of main bronchus to lobes of lungs
• Left lung has two lobar bronchi
• Right lung has three lobar bronchi
Also known as:
• Secondary bronchus
