Thoracic Cage Anatomy Quiz

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Questions and Answers

What structure marks the level of the lower border of the right lung?

7th rib in the midclavicular line (correct)

10th rib adjascent to the vertebral column (correct)

Lobar bronchi

AIveoli

Which type of epithelium is found in the alveolar ducts and alveoli?

Non-ciliated cuboidal epithelium

Ciliated columnar epithelium

Simple squamous epithelium (correct)

Stratified squamous epithelium

Which arteries are responsible for the blood supply to the bronchi?

Intercostal arteries

Right and left bronchial arteries (correct)

Pulmonary arteries

Coronary arteries

What type of nerve supply causes bronchoconstriction?

Vagus nerve Signup and view all the answers

What is the function of surfactant produced by type II pneumocytes?

Reduce surface tension Signup and view all the answers

What is the origin of the diaphragm's sternal part?

Posterior surface of the xiphoid process Signup and view all the answers

Which structures are transmitted through the esophageal opening of the diaphragm?

Esophagus and vagus nerves Signup and view all the answers

What role do the muscle fibers of the right crus play around the esophageal orifice?

They act as a sphincter. Signup and view all the answers

Where is the vena caval opening located?

Level of T8 vertebra Signup and view all the answers

Which blood vessels are transmitted through the greater splanchnic nerve?

Esophageal branches of the left gastric vessels Signup and view all the answers

What is the aortic opening's position relative to the crura?

Anterior to the T12 vertebra Signup and view all the answers

What forms the minor openings in the diaphragm?

Lesser splanchnic nerves Signup and view all the answers

What do the arcuate ligaments form?

Right and left crura Signup and view all the answers

What does the foramen of Morgagni represent?

An enlarged minor opening Signup and view all the answers

Which structure aids in connecting diaphragm actions with the lumbar vertebrae?

Vertebral/lumbar part Signup and view all the answers

What is the primary function of the thoracic cage?

Protect the heart and lungs Signup and view all the answers

Which part is not a component of the sternum?

Clavicular Process Signup and view all the answers

How many pairs of true ribs are there in the human body?

7 pairs Signup and view all the answers

Which characteristic is not associated with typical thoracic vertebrae?

Short spinous processes Signup and view all the answers

Which statement is true regarding the atypical ribs?

The first rib is shorter and flatter Signup and view all the answers

What are the boundaries of the thoracic cage primarily defined by?

Osseo-cartilaginous structures Signup and view all the answers

What feature distinguishes the 10th to 12th ribs?

They are considered floating ribs Signup and view all the answers

Which structure does not traverse through the apertures of the thoracic cage?

The diaphragm Signup and view all the answers

What shape describes the inlet of the thorax?

Kidney shaped Signup and view all the answers

Which structure does NOT pass through the inlet of the thorax?

Aorta Signup and view all the answers

What is the primary function of the diaphragm?

Facilitate breathing Signup and view all the answers

Which of the following is a boundary of the thoracic outlet (inferior aperture)?

Costal margin Signup and view all the answers

Which structure is located posteriorly at the inlet of the thorax?

T1 body Signup and view all the answers

What distinguishes the right cupola of the diaphragm?

It is higher due to the liver. Signup and view all the answers

Which nerve is part of the structures passing through the inlet of the thorax?

Right and left Phrenic nerves Signup and view all the answers

The central part of the diaphragm is primarily made up of what type of tissue?

Tendinous tissue Signup and view all the answers

What is the shape of the inlet of thorax described as?

Kidney-shaped Signup and view all the answers

Which muscle is NOT associated with the structures passing through the inlet of the thorax?

Diaphragm Signup and view all the answers

What is the primary motor nerve supplying the diaphragm?

Phrenic nerve Signup and view all the answers

Which artery is NOT a branch of the internal thoracic artery?

Inferior phrenic artery Signup and view all the answers

What condition is characterized by an inward growth of the ribs and sternum?

Funnel chest Signup and view all the answers

What is the potential consequence of severe funnel chest?

Heart issues Signup and view all the answers

Which of the following nerves provides sensory supply to the peripheral part of the diaphragm?

Lower 6 or 7 intercostal nerves Signup and view all the answers

In case of a deformity known as pigeon chest, what is a common underlying cause?

Rickets Signup and view all the answers

Which of the following vessels correspond with the veins that drain into the systemic veins?

Musculophrenic and pericardiophrenic veins Signup and view all the answers

Which of these is a symptom of severe funnel chest?

Breathlessness Signup and view all the answers

Which artery supplies the diaphragm and is derived from the descending thoracic aorta?

Inferior phrenic artery Signup and view all the answers

What nerve provides sympathetic supply to the diaphragm?

Celiac plexus Signup and view all the answers

Study Notes

Thoracic Cage

The thoracic cage is the bony framework of the chest
Consists of the vertebral column posteriorly, ribs and intercostal spaces laterally, sternum and costal cartilages anteriorly
Protects heart, lungs and other organs

Bones Forming the Thoracic Cage

Sternum:
Composed of fused sternebrae
Includes manubrium, body, and xiphoid process
Manubrium:
- Contains jugular (sternal) notch
- Articulates with ribs 1 & 2
- Clavicular articular facets
- Sternal angle at the level of the 2nd rib
Body: Articulates with ribs 2-7
Xiphoid process:
- Cartilage that calcifies over time
- Partial attachment of various muscles
Ribs:
12 pairs
7 True ribs: Direct attachment to the sternum
5 False ribs: Indirect or no attachment to the sternum
Floating ribs: Last two false ribs, no ventral attachment
Typical ribs: Ribs 3-9
Atypical ribs: Ribs 1, 2, 10, 11, 12
Rib Anatomy:
- Typical ribs: Head, neck, tubercle, angle, shaft, subcostal groove
- Atypical ribs: First rib is short, flat, wide, and supports subclavian vessels; second rib is long and flat; Ribs 10-12 articulate only with the vertebrae; Ribs 11 & 12 don't articulate with transverse processes posteriorly or sternum anteriorly
Vertebrae:
12 thoracic vertebrae
Identified by:
- Transverse costal facets
- Costal facets on vertebral body
- Long spinous processes pointing inferiorly
- Superior articular facets facing dorsally (posteriorly)
- Inferior articular facets facing ventrally (anteriorly)
- Circular vertebral foramen
- Heart-shaped body

Boundaries of the Openings of the Thoracic Cage

The thoracic cage is osseo-cartilaginous (bony and cartilaginous)
Elastic and allows for respiration
Shapes a truncated cone

Inlet of Thorax (Superior Aperture)

Narrow and kidney shaped
Boundaries:
- Anteriorly: Manubrium sterni
- Posteriorly: T1 body
- Laterally: 1st rib + cartilage
Structures passing:
- Viscera:
  - Trachea
  - Esophagus
  - Lung apices
  - Remnants of the thymus
- Large vessels:
  - Brachiocephalic artery
  - Left common carotid artery
  - Left subclavian artery
  - Right and left brachiocephalic veins
- Muscles:
  - Sternohyoid
  - Sternothyroid
  - Longus colli
- Nerves:
  - Right & left phrenic nerves
  - Right & left vagus nerves
  - Right & left sympathetic trunks
  - Right & left 1st thoracic nerves

Thoracic Outlet (Inferior Aperture)

Presents with the diaphragm
Boundaries:
- Anteriorly: Infrasternal angle
- Posteriorly: T12 body
- Laterally: Costal margin (7th to 12th ribs)

Diaphragm

Dome-shaped musculo-aponeurotic partition between thorax and abdomen
Convex superior surface faces the thorax
Depressed in the middle, summits are called cupolae
Right cupola is higher due to the presence of the liver
Peripheral part is muscular (striated)
Central part is tendinous, occupied by central tendon
Origin:
- Sternal part arises from the posterior surface of the xiphoid process
- Costal part arises from the deep surfaces of the lower six ribs and their costal cartilages, forming the right and left domes
- Vertebral/lumbar part arises from the upper three lumbar vertebrae, forming the right and left crura and the arcuate ligaments (medial & lateral)
Insertion:
- Central tendon. Some right crus muscle fibers pass up to the left, surrounding the esophageal orifice in a sling-like loop, potentially acting as a sphincter to prevent regurgitation
Openings:
- Major openings:
  - Vena Caval opening:
    - Level of T8 vertebra in the central tendon
    - Transmits inferior vena cava & branches of the right phrenic nerve
  - Esophageal opening:
    - Level of T10 vertebra
    - Transmits esophagus, right and left vagus nerves, esophageal branches of the left gastric vessels, and lymph vessels
  - Aortic opening:
    - Anterior to the body of T12 vertebra between the crura
    - Transmits aorta, thoracic duct, and azygos vein
- Minor openings:
  - Space of Larrey: Between sternal origin and 7th costal cartilage, transmits superior epigastric vessels and a few lymphatics from the liver. When enlarged, it's called "foramen of Morgagni"
  - Greater and lesser splanchnic nerves: Right and left crura
  - Left phrenic nerve: Piercing the left cupola
  - Sympathetic trunk, least splanchnic nerve: Medial arcuate ligament
  - Musculophrenic vessels:
  - Subcostal vessels and nerve:
Nerve supply:
- Motor: Phrenic nerve
- Sensory: Central part by phrenic nerve, peripheral part by lower 6 or 7 intercostal nerves
- Sympathetic: Celiac plexus
Blood supply:
- Arteries: Musculophrenic and pericardiophrenic arteries (branches of internal thoracic artery), lower 5 or 6 posterior intercostal arteries, superior phrenic artery (branch of descending thoracic aorta), inferior phrenic artery
- Veins: Corresponding with the arteries, draining into the systemic veins

Clinical Significance of Sternum

Preferred site for bone marrow aspiration because it's subcutaneous and readily accessible
Funnel chest (pectus excavatum):
- Abnormality in the shape of the chest wall
- Also known as sunken chest or funnel chest
- Ribs and sternum grow inward, forming a dent in the chest. Can be mild or severe, and severe cases can impact the heart/lungs
Pigeon chest (pectus carinatum):
- Abnormality in the shape of the chest wall
- Congenital deformation of the anterior chest wall
- Presents with an outward protrusion of the sternum or rib cage
- Also called "pigeon breast" when the sternal manubrium is prominent
- Might be caused by Rickets due to unmineralized osteoid deposition

Thoracic Viscera: Pulmonary Cavities and Mediastinum

Pulmonary cavities: Spaces within the thorax containing the lungs
Mediastinum: Central compartment of the thorax, located between the two pulmonary cavities, containing heart, great vessels, trachea, esophagus, thymus, and other structures

Anatomy of the Pleura and Pleural Cavity

Pleura: Serous membrane that lines the thoracic cavity and covers the lungs
Parietal pleura: Lines the thoracic cavity
Visceral pleura: Covers the lungs
Pleural cavity: Potential space between the parietal and visceral pleura, containing a small amount of lubricating fluid that reduces friction during lung movements
Pleural fluid: Lubricates the pleural surfaces, allowing smooth gliding during respiration

Lungs

Structure:
- Parenchyma: Functional tissue of the lungs, responsible for gas exchange
- Bronchial tree: System of branching airways that conduct air to and from the alveoli
  - Trachea: Main airway, dividing at level of 5th thoracic vertebra
  - Bronchi: Main branches of the trachea, transporting air to each lung
    - Right bronchus: Wider, shorter, more vertical, and more likely to be obstructed by inhaled objects
    - Left bronchus: Longer, narrower, and more oblique
  - Lobar bronchi: Branches of the bronchi, supplying each lobe of the lung
    - Right bronchus: Divides into 3 lobar bronchi
    - Left bronchus: Divides into 2 lobar bronchi
  - Segmental bronchi: Subdivisions of the lobar bronchi, supplying specific lung segments
  - Bronchioles: Smallest airways, leading to the alveoli
  - Terminal bronchioles: Last conducting airways before the respiratory bronchioles
  - Respiratory bronchioles: Begin gas exchange, connecting to alveolar ducts
  - Alveolar ducts: Small air passages with alveoli along their walls
  - Alveoli: Tiny air sacs where gas exchange occurs
Blood supply:
- Pulmonary arteries: Transport deoxygenated blood from the heart to the lungs for oxygenation
- Pulmonary veins: Carry oxygenated blood from the lungs back to the heart
Nerve supply:
- Parasympathetic nerves: From the vagus nerve, cause bronchoconstriction
- Sympathetic nerves: From the sympathetic trunk, cause bronchodilation
Function:
- Gas exchange: Primarily oxygen uptake and carbon dioxide removal
- Defense: Protective cells within the lung tissue, like plasma cells, macrophages, and lymphocytes, defend against microbes in the distal air passages
- Regulation:
  - pH regulation: Lungs help regulate blood pH by removing carbon dioxide, a major contributor to acidity in the body
  - Regulation of blood pressure: Lungs produce ACE (angiotensin-converting enzyme), which plays a role in blood pressure regulation

Respiratory Bronchioles and Alveoli

Each lung is further divided into lobules by fine sheets of connective tissue
Airway wall becomes thinner as it divides and becomes smaller, with a gradual decrease in smooth muscle and connective tissue
Alveolar ducts and alveoli have a single layer of squamous epithelium
Elastic fibers support these distal passages
Dense network of capillaries surround the alveoli
Respiratory membrane: Thin membrane between the alveoli and capillaries, where gas exchange occurs
Septal cells (Type II pneumocytes): Located between squamous cells, producing surfactant
Surfactant: Reduces surface tension, aiding in lung inflation and preventing alveolar collapse. Production begins between the 24th and 35th week of fetal life
Nerve supply:
- Parasympathetic: Vagal nerve, triggers bronchoconstriction
- Sympathetic: Causes bronchodilation
Function:
- Defense against microbes relies on protective cells like plasma cells, macrophages, and lymphocytes in the distal air passages

Blood supply

Pulmonary arteries: Transport deoxygenated blood from the heart to the lungs.
Pulmonary veins: Transport oxygenated blood from the lungs back to the heart.

Venous Drainage

Right side: Empties into the azygos vein
Left side: Empties into the superior intercostal vein

Nerve Supply

Vagus nerve: Bronchoconstriction
Sympathetic nerves: Bronchodilation.

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Description

Test your knowledge on the thoracic cage and its components, including the sternum and ribs. Explore the anatomy of the bony framework that protects vital organs such as the heart and lungs. This quiz will cover the details of rib structure, types, and articulations.