Thoracic Wall, Thoracic Viscera, Serous Membranes

Question 1

What are the skeletal boundaries of the thoracic cavity?

Answer 1

cranial: thoracic inlet
dorsally: the thirteenth thoracic vertebrae
ventrally: the eight sternebrae
laterally: thirteen pairs of ribs (os costae) and costal cartilage
caudally: diaphragm

Question 2

What are the three serous cavities within the thoracic cavity?

Answer 2

(1) right pleural cavity
(2) left pleural cavity
(3) pericardial cavity

space between left and right pleural cavities=mediastinum; continuous with the cervical visceral space*

Question 3

pleural cupula

Answer 3

where the costal and mediastinal pleura come together cranially to form a dome; may extend over first rib or into cervical visceral space

-pleura reflects from costal wall to cranial mediastinum

**located at/near thoracic inlet

• *dog: extends cranially on right side**
• large animal: extends cranially on left side*

Question 4

plica venae cavae

Answer 4

fold of pleura that extends between diaphragm and pericardium; fold of right mediastinal pleura; envelopes caudal vena cava and right phrenic nerve

Question 5

what is the branching of the bronchiole tree?

Answer 5

right and left principal bronchi (formed at carina)–> lobar bronchi–> segmental bronchi (lung parts associated are called bronchopulmonary segments)–> branches of segmental bronchi–> bronchioles

Question 6

functional vs. nutritive blood supply

Answer 6

functional blood supply: pulmonary arteries and veins

nutritive blood supply: bronchoesophageal artery (blood supply to lungs and bronchi) and right azygous vein

Question 7

What are the borders of the costodiaphragmatic recess?

Answer 7

• the basal border of the lung

- diaphragmatic line of pleural reflection

Question 8

diaphragmatic line of pleural reflection

Answer 8

junction between the costal pleura and diaphragmatic pleura

clinical relevance: thoracocentesis, abdominocentesis

Question 9

what arteries make up the brachiocephalic trunk?

Answer 9

(a) left common carotid artery
(b) right common carotid artery
(c) right subclavian artery

Question 10

what are the components of the left and right subclavian artery?

Answer 10

(1) vertebral artery: extends through transverse foramina of cervical vertebrae; supplies blood to brain spinal cord

(2) costocervical trunk:supplies cranial intercostal muscles and spaces of the neck
- supplies first three dorsal intercostal spaces, ventral intercostal arteries of internal thoracic artery, and dorsal cervical musculature (epaxial muscles)

(3) superficial cervical artery: supplies muscles of ventral neck and and cranial shoulder; superficial structures of neck

(4) internal thoracic artery: right ventral intercostal arteries anastomose with dorsal intercostal arteries of the aorta
- branches off to form musculophrenic artery

subclavian arteries eventually become part of axillary arteries

Question 11

pulmonary ligaments

Answer 11

double layers of serous membrane that extend from mediastinal (parietal) pleura to the visceral pleura

Question 12

Where are the phrenic nerves located?

Answer 12

C5, C6, and C7 (cat: C4, C5, C6)

Question 13

what structures are within the mediastinum?

Answer 13

(1) trachea
(2) esophagus
(3) aorta
(4) lymphatic structures (tracheobronchial, mediastinal, and sternal lymph nodes, thoracic duct)
(5) thymus
(6) right and left vagus, recurrent laryngeal, and phrenic nerves

Question 14

How do the branching of the left and right recurrent laryngeal nerves differ?

Answer 14

Both nerves extend from mediastinum

• right branches from right vagus nerve and curves around right subclavian artery
• left branches from left vagus nerve and curves around the ligamentum arteriosum and aortic arch

somatic innervation to larynx