Thorax Flashcards
True muscles of the thoracic wall
Serratus posterior. Levatores costarum. Intercostal, subcostal and transverse thoracis.
Serratus posterior superior
Superior attachment: Nuchal ligament, spinous processes of C7 to T3.
Interior attachment: Superior borders of 2nd to 4th ribs.
Innervation: 2nd to 5th intercostal nerves.
Action: Proprioception (Rib elevation)
Serratus posterior inferior
- *Superior attachment:** Spinous processes of T11 to L2.
- *Interior attachment:** Inferior borders of 8th to 12th ribs.
- *Innervation:** Anterior rami to T9 to T12.
- *Action:** Proprioception (Rib depression).
Levator costarum
- *Superior attachment:** Transverse processes of T7-T11.
- *Interior attachment:** Subjacent ribs between tubercle and angle.
- *Innervation:** Posterior primary rami of C8-T11 nerves.
- *Action**: Rib elevation.
External intercostal musces
- *Superior attachment:** Inferior border of ribs.
- *Interior attachment:** Superior border of ribs below.
- *Innervation:** Intercostal nerve.
- Action*: Rib elevation during forced inspiration.
Internal intercostal muscles
Innermost intercostal muscles
- *Superior attachment:** Inferior border of ribs.
- *Interior attachment:** Superior border of ribs below.
Innervation: Intercostal nerves.
Action: Interosseous part: Depresses ribs.*
Interchondral part: Elevates ribs.*
*During active (forced) respiration.
Subcostal muscles
- *Superior attachment:** Internal surface of lower ribs.
- *Interior attachment:** Superior borders of 2nd or 3rd rins below.
- *Innervation:** Intercostal nerve.
- *Action:** Probably act in the same manner as internal intercostal muscles.
Transversus thoracis
- *Superior attachment:** Posterior surface of lower sternum.
- *Interior attachment:** Internal surface of costal cartilages 2-6.
- *Innervation:** Intercostal nerve.
- *Action:** Weakly depress ribs, proprioception.
Posterior intercostal arteries - origin, course, distribution
**Origin:** Superior intercostal artery (IC spaces 1-2). Thoracic aorta (remaining IC spaces).
- *Course:** Pass between internal and innermost intercostal muscles.
- *Distribution:** Intercostal muscles, overlying skin, and parietal pleura.
Anterior intercostal arteries - origin, course, distribution
Origin: Internal thoracic arteries (IC spaces 1-6)
Musculophrenic arteries (IC spaces 7-9)
Course: Pass between internal and innermost intercostal muscles.
Distribution: Intercostal muscles, overlying skin, and parietal pleura.
Internal thoracic artery - origin, course, distribution
- *Origin:** Subclavian artery.
- *Course:** Passes inferiorly and lateral to sternum between costal cartilages and transversus thoracic muscle to divide into superior epigastric and musculophrenic arteries.
- *Distribution:** IC spaces 1-6 and musculophrenic artery (terminal branch).
Subcostal artery - origin, course, distribution
- *Origin:** Thoracic aorta.
- *Course:** Courses along inferior border of 12th rib.
- *Distribution:** Muscles of anterolateral abdominal wall.
Contents of superior mediastinum anterior to posterior
- Thymus
- Great vessels, with the veins (brachiocephalic and SVC anterior to the arteries (arch of aorta and roots of its major branches - the brachiocephalic trunk, left common carotid, and left subclavian), vagus and phrenic nerves and cardiac plexus of nerves.
- Inferior continuation of cervical viscera: Trachea anteriorly and esophagus posteriorly, with related nerves (left recurrent laryngeal nerve).
- Thoracic duct and lymphatic trunks.
Systematic summarization of major structures in superior mediastinum, anterior to posterior.
- Thymus.
- Veins.
- Arteries.
- Airway.
- Alimentary tract.
- Lymphatic trunks.
Arterial, venous and lymphatic supply to thymus.
- *Arterial:** Anterior intercostal and anterior mediastinal branches of the internal thoracic arteries.
- *Venous:** Veins of thymus end in the left brachiocephalic, internal thoracic, and inferior thyroid veins.
- Lymphatic*: Lymphatic vessels of thymus end in the parasternal, brachiocephalic, and tracheobronchial lymph nodes.
Parietal pleura consists of which parts?
Costal, Mediastinal, Diaphragmatic, Cervical.
Which part of parietal pleura is continuous with visceral pleura at the hilum of the lung?
Mediastinal
Pleural cupula is at the level of which rib?
1st rib. (2-3cm superior to medial third of clavicle).
The middle lobe vein of the lung is a tributairy of which vein?
Right superior pulmonary vein.
Right bronchial vein drains into…? Left bronchial vein drains into…?
Right bronchial vein: Azygos vein.
Left bronchial vein: Accessory hemi-azygos vein (or the left superior intercostal vein)
Transverse thoracic plane is at which vertebral level?
IV disc of T4 and T5
Contents of middle mediastinum
Pericardium+contents.
Mediastinum extends..?
Superior thoracic aperture to diaphragm.
Superior mediastinum extends..?
Superior thoracic aperture to transverse thoracic plane
Inferior mediastinum extends..? Divides into?
From transverse thoracic plane and diaphragm. Divides into anterior, middle, and posterior parts.
Sternopericardial ligaments
Attach fibrous pericardium to posterior surface of sternum.
Pericardiophrenic ligament
Site of continuity between fibrous pericardium and central tendon of diaphragm.
Transverse pericardial sinus
Surgical space after pericardial sac has been removed. A finger can be passed through the sinus posterior to the ascending aorta and pulmonary trunk.
Posterior mediastinum is between which vertebral levels?
T5-T12
Anterior mediastinum contains what?
Inferior part of Thymus
Hemi-azygos vein arises from which veins?
Left subcostal and ascending lumbar veins.
Accessory hemi-azygos vein begins at which intercostal space?
4th or 5th IC space, descends down to T8.
