L2, L3, L5: Anatomy Of Mediastinum Flashcards
Division of mediastinum
- Superior (Divided at angle of Louis T4, T5)
- Inferior
- Anterior (sternum - pericardium)
- Middle
- Posterior (pericardium - vertebral column)
Components of ribs
- Head (2 facets)
- Neck
- Tubercle (prominence between head and facet)
- Shaft (Costal groove for intercostal VAN)
- Angle (downward and anterior)
True ribs and false ribs
True: 1-7th
False: 8-10th
Floating: 11-12th
Components of thoracic vertebrae
- Body
- Transverse process
- Lamina
- Pedicle
- Spine
Components of sternum
Manubrium (manubriosternal joint) Body Xiphoid process (xiphisternal joint)
Sternal angle / Manubriosternal joint / Angle of Louis
Attachment of 2nd rib
T4-T5
Level of carina
Cartilaginous joints and synovial joints
Cartilaginous: 1st rib
Synovial: 2nd - 7th rib
What is in costal groove
Intercostal artery, vein and nerve (VAN)
Where is rib attached to?
Posterior: Body (costovertebral joint, intra-articular ligament) + transverse process (costotransverse joint, costotransverse ) of thoracic vertebrae
Anterior: costal cartilage —> sternum
Both costovertebral and costotransverse joints are synovial joints
Contents of the intercostal space
- External IM (hands in pocket, only present in lateral side)
- Internal IM (surgeon hand gesture)
- Innermost IM (surgeon hand gesture)
- Transversus thoracic muscle / Sternocostalis (2-6th rib to posterior of sternum)
- Subcostalis
- Intercostal VAN (between IM and INM)
Arterial blood flow in thoracic cavity
All starts from aorta
Posterior:
Thoracic aorta —> Posterior intercostal artery (only 1) —> 3-11th posterior ICS
Subclavian artery —> Costocervical trunk —> Superior intercostal artery —> 1-2nd posterior ICS
Anterior:
Subclavian artery —> Internal thoracic artery —> Anterior intercostal artery (1-6th anterior ICS) + Musculophrenic artery (7-9th anterior ICS + diaphragm) + Superior epigastric artery (Rectus abdominis)
Subcostal artery and nerve = below 12th rib (T12)
Venous blood flow in thoracic cavity
Posterior:
Right: 1-2nd ICS —> Right superior intercostal vein —> Azygos —> SVC
Left: 1-2nd ICS —> Left superior intercostal vein —> Accessory hemiazygos —> Azygos —> SVC
Right: 3-11th ICS —> Posterior intercostal vein —> Azygos —> SVC
Left: 3-11th ICS —> Hemiazygos —> Azygos —> SVC
Anterior:
Anterior chest wall —> Anterior intercostal vein —> Internal thoracic vein —> Left brachiocephalic vein
Nerve supply of intercostal space
Anterior rami of 1-11th spinal nerves (Intercostal nerves within costal groove)
Nerve supply of parietal and visceral pleura
Parietal:
Costal pleura + peripheral diaphragmatic pleura: Intercostal nerve
Central diaphragmatic pleura: Phrenic nerve (C3-C5)
Mediastinal pleura: Phrenic nerve (C3-C5)
Visceral: Pulmonary plexus (T2-T5; Vagus nerve)
Left vs Right bronchus
Left: narrower, horizontal, longer
Right: wider, vertical, shorter (短小精悍)