Lecture 2 - Thorax, Lungs, Mediastinum & Heart

Question-and-answer flashcards covering breast anatomy, thoracic wall, respiratory structures, pleurae, lungs, diaphragm, and mediastinum from the provided lecture notes.

Which tissues make up the bulk of the female breast?

Glandular (mammary) tissue, supportive fibrous connective tissue, fat, blood vessels, lymphatics, and nerves.

Where are the mammary glands located?

Within subcutaneous tissue overlying the pectoralis major and minor muscles.

Between what landmarks does the bed of the breast extend transversely?

From the lateral border of the sternum to the mid-axillary line.

Vertically, the breast extends between which ribs?

2nd-6th rib.

What is the retromammary space?

between the breast and pectoral fascia, allowing some breast movement.

_____ of the bed of breast is formed by pectoral fascia; _____ is formed by serratus anterior fascia

2/3; 1/3

Name the three main arterial supplies to the breast.

Medial mammary branches (internal thoracic a.), lateral mammary branches (lateral thoracic a.), posterior mammary branches (posterior intercostal aa. in 2nd–4th spaces).

What is the primary vein draining the breast?

Axillary vein (with secondary drainage to the internal thoracic vein).

Where do the apical axillary lymph nodes drain to?

The subclavian trunk then into respective thoracic duct

Which nerves innervate the breast skin and gland?

Anterior and lateral cutaneous branches of the 4th–6th intercostal nerves.

Approximately 75–90 % of breast lymph drains first to which nodes?

Ipsilateral axillary lymph nodes.

List the six major axillary lymph-node groups that receive breast lymph.

Anterior (pectoral), posterior (subscapular), lateral (humeral), central, apical (subclavicular), and interpectoral (Rotter’s)

What lymph-node group drains nipple and areola?

Subareolar plexus (of Sappey).

What lymph-node group drains deep/medial breast tissue?

Parasternal (internal mammary) lymph nodes

What is the thorax formed by?

12 pairs of ribs, 12 thoracic vertebrae, sternum, and costal cartilage

Define true, false, and floating ribs.

True (1–7) attach directly to sternum via own cartilage; false (8–10) attach via cartilage of rib above; floating (11–12) have no anterior cartilage attachment.

Typical ribs (3-9) articulate with how many vertebral bodies?

Two (corresponding vertebra and the one above).

List the contents of the thoracic cavity

two pleural cavities and the mediastinum

Which ribs are considered atypical

1, 2, 10-12

What unique features distinguish the 1st rib?

Broadest, shortest, most curved, single facet on head (T1), and a scalene tubercle for anterior scalene attachment.

Which muscle attaches to the tubercle of the 2nd rib?

Serratus anterior.

Ribs 11–12 lack which two bony parts?

Necks and tubercles.

Name the three parts of the sternum.

Manubrium, body, and xiphoid process.

Which vertebral level corresponds to the jugular (suprasternal) notch?

T3/T4 level.

Give the six key landmarks that lie at the sternal angle (manubriosternal junction).

2nd rib articulation, T4–T5 intervertebral level, border between superior & inferior mediastinum, start/end of aortic arch, tracheal bifurcation, left recurrent laryngeal nerve wraps around aorta to head proximally back to larynx

What is the principal action of the external intercostal muscles?

Elevation of ribs during inspiration.

Orientation of external vs internal intercostal fibers?

External run inferior-anterior, internal run inferior-posterior

What muscle is considered the muscle of expiration?

Internal intercostal

How many pairs of nerves are located in the thoracic wall?

12

What makes up the 12 intercostal nerves?

The ventral rami of T1-12

List the only ventral rami with a name

T12 - subcostal nerve

What does the dorsal rami supply?

Bones, joints, muscle and skin of the posterior thorax

Which nerve supplies the diaphragm?

Phrenic nerve (C3–C5).

Which arteries supply the anterior intercostal spaces?

Anterior intercostal arteries from the internal thoracic artery (subclavian origin).

Upper vs lower respiratory tract anatomical limits.

Upper: nose to superior mediastinum border; lower: trachea (at T1 level) downward through lungs.

Intercostal vessels and nerve pass between what?

Internal and innermost intercostal muscles

The intercostal arteries run ______ to the intercostal nerve, but ______ to the intercostal vein.

superior; inferior

List the structures found in the upper respiratory system.

Nose, nasal cavity, mouth, pharynx, and larynx

List the structures found in the lower respiratory system

Trachea, bronchii, bronchioles, and alveoli

At what vertebral level does the trachea bifurcate?

Inferior border of T4 (sternal angle).

Why do aspirated objects more often lodge in the right primary bronchus?

It is shorter, wider, and more vertical than the left primary bronchus.

Order of airway branching beyond primary bronchi.

Primary (main) → secondary (lobar) → tertiary (segmental) bronchi → terminal bronchioles → respiratory bronchioles → alveolar ducts → alveolar sacs/alveoli.

Where does gas exchange occur in the lungs?

Across alveolar walls in the alveoli.

Differentiate visceral and parietal pleura in terms of pain sensation.

Parietal pleura is highly pain-sensitive (somatic), whereas visceral pleura is not (autonomic).

Define pneumothorax, hemothorax, and chylothorax.

Air, blood, and lymph within the pleural cavity

Typical chest-tube insertion site to drain pleural fluid.

Mid-axillary line between ribs 8–10 (usually over rib 9) into costodiaphragmatic recess.

List the lobes and fissures of the right lung.

Superior, middle, inferior lobes; separated by oblique and horizontal fissures.

Which lung has a lingula and why?

Left lung; a tongue-like projection of the superior lobe that overlaps the heart.

Name the three structures found in each lung root and their usual relative positions.

Bronchus (posterior, thick-walled), pulmonary artery (superior), pulmonary veins (inferior).

What happens to thoracic volume when the diaphragm contracts?

It flattens, increasing vertical thoracic dimension and causing inspiration.

Define mediastinum.

Central thoracic compartment between pleural cavities, extending from sternum to vertebral column and thoracic inlet to diaphragm.

Major divisions of the mediastinum.

Superior; and inferior, which subdivides into anterior, middle, and posterior parts.

Anterior and posterior borders of the superior mediastinum.

Posterior surface of manubrium (anterior) and anterior surfaces of T1–T4 vertebral bodies (posterior).

What imaginary plane separates the superior and inferior mediastinum?

A line from the sternal angle to the T4–T5 intervertebral disc.

Five principal content categories of the superior mediastinum.

Veins (SVC & brachiocephalic), arteries (aortic arch & branches), nerves (vagus, phrenic, left recurrent laryngeal, cardiac plexus), “tubes” (trachea, esophagus), lymphatics (thoracic duct, thymic remnants).

Into what three parts is the inferior mediastinum subdivided?

Anterior, middle, and posterior mediastinum.