BIO 476 Week 1 Pre-Lab: Structures of the Thorax - Flashcards

Question-and-answer flashcards covering thoracic anatomy from Week 1 Pre-Lab notes. Topics include bones, vertebrae, ribs, sternum, intercostal muscles, mediastinum, vessels, lungs, pleura, and related structures.

What bones make up the thoracic wall?

Ribs, sternum, and thoracic vertebrae; the vertebrae form the posterior wall and the ribs attach to them, wrapping anteriorly to interact with the sternum.

Two articulation points of a typical thoracic rib

The head articulates with the body of a thoracic vertebra; the tubercle articulates with the transverse process of a thoracic vertebra.

What is the subcostal groove?

A groove on the inferior edge of a rib where the intercostal vein, artery, and nerve (intercostal bundle) run.

Which ribs attach only to vertebrae and not to the sternum?

Ribs 11 and 12 (floating ribs).

Parts of the sternum and their rib connections

Manubrium (top; connects to ribs 1–2), body (major portion; connects to ribs 2–10 via costal cartilage), and xiphoid process (inferior tip).

Intercostal muscles and fiber directions

External intercostals (superficial; fibers run superior-lateral to inferior-medial), Internal intercostals (middle; fibers run superior-medial to inferior-lateral), Innermost intercostals (deepest; fibers run generally superior to inferior).

What is Transversus thoracis?

Maple-leaf shaped muscle with projections from the posterior surface of the sternum to the ribs.

Internal thoracic vessels along the sternum

Internal thoracic artery and vein run along the inner surface of the sternum; they give rise to and drain the anterior intercostal arteries and veins; the artery branches from the subclavian artery and veins drain to brachiocephalic veins (leading to the SVC).

What is the mediastinum?

The space between the two lungs within the thorax that contains the heart and major structures (aorta, superior/inferior vena cavae, phrenic nerve, etc.).

Aorta in the thorax

Largest artery; travels along the left side of the thoracic cavity, arching within the mediastinum; often cut in cadavers with the heart removed.

Phrenic nerve

Innervates the diaphragm; runs laterally to the heart outside the pericardial sac; there are two phrenic nerves (left and right) and they are often encased in fat.

Inferior vena cava and its relation to the heart

Attaches to the right and inferior aspect of the heart inside the pericardial sac.

Intercostal bundle and its order

Intercostal vein, artery, and nerve running together along the subcostal groove; order from superior to inferior is VAN (vein, artery, nerve).

Azygous vein

Drains blood from the thoracic cavity and connects to the posterior intercostal veins; drains into the superior vena cava.

Hilum of the lung

Medial region where blood vessels and air passages enter and exit the lung; contents lie on the medial surface and are encountered when removing the lung.

Lung lobes and fissures

Right lung: upper, middle, lower lobes separated by oblique fissure and a horizontal fissure; Left lung: upper and lower lobes separated by the oblique fissure (no middle lobe due to the heart).

Pleura types and their placement

Visceral pleura lines the lungs; parietal pleura lines the body wall; pleura reduce friction and allow the lungs to slide in the thoracic cavity.

Apex and diaphragmatic surface of the lung

Apex is the superior-most point of the lung; diaphragmatic surface is the flat, most inferior surface that contacts the diaphragm.

Trachea and bronchi branching

Trachea divides into bronchi, which subdivide into lobar bronchi to supply lung lobes; walls contain cartilage in the bronchi.

Intervertebral foramina

Openings created when two vertebrae are stacked; spinal nerves exit through these foramina to innervate different body regions.