Term
| GENERAL FEATURES OF THORAX |
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Definition
-top of sternum to diaphragm
-thoracic inlet is small and kidney shaped. Boundaries manubrium anteriorly, rib 1 laterally, and thoracic verbrae posteriorly.
-thoracic outlet is large and separated from abdomen by diaphragm. The boundaries xiphoid process anteriorly, costal cartilages 7-10 and rib 12 laterally, and T12 vertebrae posteriorly |
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Term
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Definition
| 12 thoracic vertebrae with facets on bodies (costal facets) for articulation with heads of ribs, facets on transverse processes for articulation with tubercles of rib 9 (except for ribs 11 and 12), and long spinous processes |
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Term
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Definition
12 pairs of ribs articulating with thoracic vertebrae
Rib consists of head, neck, tubercle, and body
Head articulates with body of adjacent thoracic vertebra and intervertebral disc at the costovertebral joint
Tubercle articulates with transverse process of thoracic vertebra at costotransverse joint
True (vertebrosternal) ribs are ribs 1-7 and articulate individually with sternum by costal cartilages
False (vertebrochondral) ribs are ribs 8-12.
8-10 articulate with more superior costal cartilage and form the anterior costal margin
Ribs 11-12 (often called floating ribs) articulate with vertebral bodies but do not articulate with the sternum |
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Term
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Definition
Manubrium forms the jugular notch at superior margin
Has a clavicular notch, which articulates with clavicle at sternoclavicular joint
Articulates with costal cartilages of ribs 1-2 |
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Term
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Definition
Articulates with manubrium at sternal angle of Louis
Articulates with costal cartilages of ribs 2-7
Articulates with xiphoid process at xiphosternal joint |
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Term
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Definition
Articulates with body of sternum
Attaches to diaphragm and abdominal musculature via linea alba |
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Term
| STERNUM: STERNAL ANGLE OF LOUIS |
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Definition
Marks the junction between manubrium and body of the sternum at vertebral level T4
This is site where rib 2 articulates with sternum, aortic arch begins and ends, trachea bifurcates, and superior mediastinum ends |
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Term
| MUSCLES OF THORAX: DIAPHRAGM |
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Definition
Most important muscle of inspiration.
Elevates the ribs and increases the vertical, transverse(bucket handle movement) and anteroposterior (pump handle movement) diameters of thorax. Is innervated by the phrenic nerves (ventral primary rami of C3-5) which provide motor and sensory innervation.
Sensory innervatiion to periphery of diaphgragm is provided by intercostal nerves.
Lesion of phrenic nerve may result in paralysis and paradoxical movement of the diaphragm. The paralyzed dome of the diaphragm does not descend during inspiration and is consequently forced upward due to increased abdominal pressure. |
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Term
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Definition
Thin multiple layers of muscle that occupy the intercostal spaces (1-11).
Keep the intercostal space rigid during inspiration or expiration. |
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Term
| EXTERNAL INTERCOSTAL MUSCLES |
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Definition
Elevate the ribs
Play a role in inspiration during exercise or lung disease |
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Term
| INTERNAL INTERCOSTAL MUSCLES |
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Definition
| Play a role in expiration during exercise or lung disease |
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Term
| INNERMOST INTERCOSTAL MUSCLES |
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Definition
| Presumed to act with the internal intercostal muscles |
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Term
| INTERCOSTAL VEIN, ARTERY, NERVE |
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Definition
| Run between the internal intercostal muscles and innermost intercostal muscles |
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Term
| ADDITONAL MUSCLES OF THE THORAX TO KNOW |
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Definition
Serratus Posterior Superior Muscle
Serratus Posterior Inferior Muscle
Levator Costarum Muscle
Transverse Thoracic Muscle |
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Term
| STERNOCLEIDOMASTOID, PECTORALIS MAJOR AND MINOR, AND SCALENE MUSCLES |
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Definition
| These muscles attach to the ribs and play a role in inspiration during exercise or lung disease. |
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Term
| EXTERNAL OBLIQUE, INTERNAL OBLIQUE, TRANSVERSE ABDOMINAL, AND RECTUS ABDOMINUS MUSCLES |
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Definition
| These abdominal muscles play a role in expiration during exercise, lung disease, or the Valsalva maneuver. |
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Term
| MOVEMENT OF THE THORACIC WALL |
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Definition
Concerned with increasinig or decreasing intrathoracic pressure.
The act of breathing involves changes in intrathoracic pressure and is called inspiration and expiration. |
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Term
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Definition
Inferiorly sloped ribs 1-6 elevate by rotating on the tubercles with the veterbral facets.
This causes an increase in anteroposterior diameter of the thorax (sternum is pushed forward and upward). This is compared to a "pump handle" movement.
The lower ribs elevate by swinging upward and laterally due to their shape and the limited movement of their tubercles. This causes an increase in the lateral diameter of the thorax, which has been compared to a "bucket handle" movement |
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Term
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Definition
Is predominately passive and depends on the elasticity of the lungs.
In contrast, forced expiration involves contraction of abdominal wall muscles, primarily the external oblique, internal oblique, and transverse abdominal muscles.
This contraction of abdominal muscles pushes against the diaphragm. |
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Term
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Definition
| A branch of the subclavian artery that descends just lateral to the sternum and terminates at intercostal space 6 by dividing into the superior epigastric artery and musculophrenic artery. |
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Term
| ANTERIOR INTERCOSTAL ARTERIES |
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Definition
-intercostal spaces 1-6 are branches of Internal Thoracic Artery
-intercostal spaces 7-9 are branches of musculophrenic artery
-there are 2 ant intercostal arteries w/in each intercostal space that anastomose w/ post intercostal arteries |
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Term
| POSTERIOR INTERCOSTAL ARTERIES |
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Definition
-intercostal spaces 1 and 2 are branches of superior intercostal artery that arises from costocervical trunk of the subclavian
-intercostal spaces 3-11 are branches of thoracic aorta
-all give off post branch, travels w/ dorsal primary ramus to supply spinal cord, vertebral column, back muscles, skin
-anastomose with anterior intercostals |
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Term
| ANTERIOR INTERCOSTAL VEINS |
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Definition
| Drain the anterior thorax and empty into the internal thoracic veins, which then empty into the brachiocephalic veins. |
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Term
| POSTERIOR INTERCOSTAL VEINS |
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Definition
Drain the lateral and posterior thorax and empty into the hemiazygos veins on the left side and azygos vein on the right side.
The hemiazygos veins empty into the asygos vein, which empties into the superior vena cava. |
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Term
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Definition
Are the ventral primary rami of T1-11
Run in the costal groove between internal intercostal muscles and innermost intercostal muscles |
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Term
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Definition
| Is the ventral primary ramus of T12 |
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Term
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Definition
| Evidenced by a sucking in (upon inspiration)and bulging out (upon expiration) of the affected intercostal space |
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Term
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Definition
May compress trachea or tug on trachea with each cardiac systole.
Can be felt by palpating the trachea at sternal notch (T2) |
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Term
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Definition
Result of deceleration injury and aorta tears distal to left of subclavian artery.
Tear is through through tunica intima and media. |
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Term
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Definition
May be result of anomalous cervical rib that compresses lower trunk of brachial plexus, subclavian artery, or both.
Clinical findings: Atrophy of thenar and hypothenar eminences.
Atrophy of interosseous muscles.
Sensory deficits on medial side of forearm and hand.
Diminished radial artery pulse on moving head to opposite side.
Bruit over subclavian artery. |
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Term
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Definition
The space between the pleural cavities in thorax.
Bounded laterally by pleural cavities, anteriorly by sternum, posteriorly by vertebral column.
Divided artificially into superior division and inferior division by line from sternal angle of Louis to T4-5 intervertebral disc.
Inferior division further divided into anterior, middle, and posterior. |
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Term
| SUPERIOR MEDIASTINUM CONTENTS |
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Definition
Includes trachea, esophagus,thymus, phrenic nerves, azygous vein, SVC, brachiocephalic artery and veins,
aortic arch, left common carotid artery, left subclavian artery, thoracic duct.
COMMON PATHOLOGY: Aortic arch aneurysm, esophageal perforation from endoscopy or malignancy, traumatic rupture of trachea. |
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Term
| ANTERIOR MEDIASTINUM CONTENTS |
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Definition
Thymus, fat, lymph nodes, connective tissue.
COMMON PATHOLOGY: Thymoma assoc. with myasthenia gravis and RBC aplasia, thyroid mass, germinal cell neoplasm, lymphomas (Hodgkin or non-Hodgkin) |
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Term
| MIDDLE MEDIASTINUM CONTENTS |
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Definition
Heart, pericardium, phrenic nerves, ascending aorta, SVC, coronary arteries and veins.
COMMON PATHOLOGY: Pericardial cysts, bronchiogenic cysts, sarcoidosis. |
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Term
| POSTERIOR MEDIASTINUM CONTENTS |
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Definition
Descending aorta, esophagus, thoracic duct, azygous vein, splanchnic nerves, vagus nerves (cranial nerve X)
COMMON PATHOLOGY: Ganglioneuromas, neuroblastomas, esophageal diverticula or neoplasms. |
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