Overview Of The Thorax

Question 1

Name the boundaries and general contents of the thoracic cavity, including compartments.

Answer 1

Anterior: sternum
Posterior: vertebral column
Inferior: diaphragm
Superior: superior thoracic aperture

R/L pleural cavities
Superior/Inferior mediastinum’s

Question 2

Describe the components and functions of the thoracic wall.

Answer 2

Components: skin, subcutaneous tissue, ribs, intercostal mm. And cc.
Function: protection, respiration, muscle attachment

Question 3

Identify the three different ribs.

Answer 3

True (1-7): direct cartilagenous attachment to the sternum
False (8-10): indirect cartilagenous attachment to the sternum
Floating (11-12): no attachment to the sternum

Question 4

Describe the general structure of a rib.

Answer 4

Head is most medial and then neck.
Distal to neck is the costal tubercle.
Costal angle to shaft of rib.
Rib to sternum.

Question 5

Name the three rib joints and give their synovial classification.

Answer 5

Costovertebral: head of rib to vertebral body.
Costotransverse: costal tubercle to transverse process
Sternocostal: sternum to costal cc.
* all joints are plane

Question 6

Explain the unique landmarks of the first rib and sternum.

Answer 6

1st Rib:

• scalene tubercle (comes from attachment of anterior scalene mm. - boundary between two grooves)
• grooves for subclavian a. and v. (Posterior: artery, anterior: vein)
• Subclavian v. Is anterior to subclavian a. and anterior scalene mm is anterior to subclavian a.

Sternum:
Manubrium: jugular notch, clavicular notch
Body: sternal angle (joint between manubrium and body where the 2nd rib attaches), costal notch
Xiphoid Process

Question 7

List the muscles of the thoracic cage.

Answer 7

External intercostals, internal & innermost intercostals, transverse thoracic, diaphragm

Question 8

Describe the action and segmental and peripheral nerve innervation of the diaphragm.

Answer 8

Action: inspiration (negative thoracic pressure by inferior displacement)
Innervation: phrenic nn. (C3-C5) - one nerve does half and vice versa

Question 9

Describe the naming convention of the intercostal nerves (T1-T12).

Answer 9

Intercostal nn. (T1-T6) - upper intercostal nn.
Thoracoabdominal nn. (T7-T11) AKA Lower Intercostal nn.
Subcostal n. (T12)

Question 10

Identify the major landmarks of the innervation of the thoracic wall.

Answer 10

Dermatomes

Question 11

Draw the thoracic arterial supply.

Answer 11

See drawing 17

Question 12

Draw the venous drainage of the thorax.

Answer 12

See drawing 18

Question 13

Draw the lymphatic drainage of the thorax and describe the territory each group drains and the typical pattern of drainage.

Answer 13

See drawing 19
Structure Information
PARIETAL
Parasternal: drain medial aspect of breast, upper abdominal wall, anterior pleura & part of liver
Diaphragmatic: drain liver, pleura & diaphragm
Intercostal: drain lateral & posterior thoracic wall
Posterior Mediastinal: drain pleura & esophagus
VISCERAL
Pulmonary: drain lung
Bronchopulmonary: drain pulmonary nodes & bronchi
Tracheobronchial: drain bronchopulmonary & posteiror mediastinal nodes, trachea, and heart
Paratracheal: drain tracheobronchial nodes

Question 14

List the attachments, innervation, and actions for the external intercostal mm.

Answer 14

Attachments: from rib to rib, oriented from superior-lateral to inferior-medial
Actions: elevation of the ribs
Innervation: intercostal nerve (segmental)

Question 15

List the attachments, innervation, and actions for the internal and innermost intercostal mm.

Answer 15

Attachments: from rib to rib, oriented superior-medial to inferior-lateral
Actions: depression of ribs
Innervation: intercostal nn. (Segmental)

Question 16

List the attachments, innervation, and actions for the transversus thoracis m.

Answer 16

Attachments: from posterior sternum to costal cc.
Actions: depress ribs
Innervation: intercostal nerves (segmental)

Question 17

List the attachments, innervation, and actions for the diaphragm.

Answer 17

C3-C5
Attachments: from xiphoid process, inner surface of the lower ribs & costal cc., lumbar vertebrae via the crura to the central tendon
Actions: inspiration (negative thoracic pressure by inferior displacement)
Innervation: phrenic n. (Motor and postganglionic sympathetic)