Unit 3 – Thorax & Lungs / Heart & Mediastinum – Vocabulary Flashcards

Vocabulary flashcards covering major anatomical structures, functions, and clinical correlations from Unit 3 lectures on the thorax, lungs, heart, and mediastinum.

Thoracic cage

Bony framework formed by sternum, ribs, and thoracic vertebrae (clavicle is NOT included).

Costovertebral joint

Articulation between a rib and a thoracic vertebral body/transverse process.

Manubrium

The broad, superior portion of the sternum.

Typical rib

A rib that articulates posteriorly with thoracic vertebrae and anteriorly (via costal cartilage) with the sternum.

Head of a rib

Posterior end of rib that articulates with the bodies of thoracic vertebrae.

External intercostal muscles

Elevate the ribs during inspiration.

Intercostal muscle layers

Three layers—external, internal, and innermost intercostals.

Internal intercostal muscles

Depress the ribs to aid in exhalation.

Innermost intercostal muscles

Deepest intercostal layer; closely associated with the thoracic neurovascular bundle.

Intercostal neurovascular bundle

Vein, artery, and nerve located between internal and innermost intercostal muscles in the costal groove.

Intercostal arteries

Primary arterial supply of the thoracic wall.

Azygos venous system

Receives intercostal veins and drains them into the superior vena cava.

Intercostal veins

Course superior to the corresponding intercostal arteries within the costal groove.

Internal thoracic artery

Branch of the subclavian artery that descends along the inner anterior chest wall.

Intercostal nerve

Somatic nerve within each intercostal space, part of neurovascular bundle.

Horizontal fissure (right lung)

Separates the superior and middle lobes of the right lung.

Hilum of lung

Medial region where bronchi, vessels, and nerves enter or leave the lung.

Trachea

Airway that constitutes the beginning of the bronchial tree.

Pulmonary arteries

Carry oxygen-poor blood from the right ventricle to the lungs.

Parasympathetic lung input

Vagus-mediated bronchoconstriction of airways.

Right main bronchus

Wider, shorter, and more vertical bronchus; most common site for aspirated objects.

Reason for right-sided aspiration

Right main bronchus is shorter and more vertical than the left.

Collapsed lung finding

Diminished or absent breath sounds on the affected side.

Lobar obstruction pattern

Right middle and inferior lobes are most often affected by aspirated foreign bodies.

Respiratory distress sign (child)

Combination of cough and dyspnea indicating compromised breathing.

Apex of the heart

Located in the left 5th intercostal space at the mid-clavicular line.

Tricuspid valve

Valve between the right atrium and right ventricle.

Mitral (bicuspid) valve

Valve between the left atrium and left ventricle.

Semilunar valves

Aortic and pulmonic valves guarding the great vessel outflow tracts.

Pulmonary veins

Vessels that return oxygenated blood from the lungs to the left atrium.

SA node

Pacemaker of the heart located in the right atrium.

AV node

Electrical relay node at the base of the right atrium.

Purkinje fibers

Terminal conduction fibers that trigger ventricular contraction.

Heart sounds ("lub-dub")

Produced by closing of the atrioventricular valves (S1) and semilunar valves (S2).

Vagus nerve passage

Vagus nerves accompany the esophagus through the T10 (esophageal) hiatus of the diaphragm.

Cardiac referred pain distribution

Pain perceived in the left arm and chest (sometimes neck) during myocardial ischemia.

Mechanism of referred pain

Visceral and somatic afferents share spinal cord segments, creating a shared nerve pathway.

Visceral cardiac pain fibers

Travel back to the spinal cord alongside sympathetic fibers.

Cardiac referred pain levels

Arise from spinal segments T1–T4.

ABCs of superior mediastinum

Arch of Aorta, Brachiocephalic trunk, left Common carotid artery.

Caval (T8) hiatus

Diaphragmatic opening for the inferior vena cava.

Thoracic duct drainage

Empties into the left subclavian vein (near its junction with the internal jugular).

Aortic hiatus (T12)

Diaphragmatic opening transmitting the aorta (and thoracic duct, azygos vein).

Coronary sinus

Main venous channel returning deoxygenated blood from the myocardium to the right atrium.