L2, L3, L5: Anatomy Of Mediastinum Flashcards

1
Q

Division of mediastinum

A
  1. Superior (Divided at angle of Louis T4, T5)
  2. Inferior
    - Anterior (sternum - pericardium)
    - Middle
    - Posterior (pericardium - vertebral column)
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2
Q

Components of ribs

A
  1. Head (2 facets)
  2. Neck
  3. Tubercle (prominence between head and facet)
  4. Shaft (Costal groove for intercostal VAN)
  5. Angle (downward and anterior)
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3
Q

True ribs and false ribs

A

True: 1-7th
False: 8-10th
Floating: 11-12th

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4
Q

Components of thoracic vertebrae

A
  1. Body
  2. Transverse process
  3. Lamina
  4. Pedicle
  5. Spine
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5
Q

Components of sternum

A
Manubrium (manubriosternal joint)
Body
Xiphoid process (xiphisternal joint)
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6
Q

Sternal angle / Manubriosternal joint / Angle of Louis

A

Attachment of 2nd rib
T4-T5
Level of carina

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7
Q

Cartilaginous joints and synovial joints

A

Cartilaginous: 1st rib
Synovial: 2nd - 7th rib

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8
Q

What is in costal groove

A

Intercostal artery, vein and nerve (VAN)

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9
Q

Where is rib attached to?

A

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

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10
Q

Contents of the intercostal space

A
  1. External IM (hands in pocket, only present in lateral side)
  2. Internal IM (surgeon hand gesture)
  3. Innermost IM (surgeon hand gesture)
  4. Transversus thoracic muscle / Sternocostalis (2-6th rib to posterior of sternum)
  5. Subcostalis
  6. Intercostal VAN (between IM and INM)
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11
Q

Arterial blood flow in thoracic cavity

A

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)

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12
Q

Venous blood flow in thoracic cavity

A

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

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13
Q

Nerve supply of intercostal space

A

Anterior rami of 1-11th spinal nerves (Intercostal nerves within costal groove)

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14
Q

Nerve supply of parietal and visceral pleura

A

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)

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15
Q

Left vs Right bronchus

A

Left: narrower, horizontal, longer
Right: wider, vertical, shorter (短小精悍)

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16
Q

Level of trachea

A

C6 - T4

17
Q

Contents of hilum

A
  1. Pulmonary artery and pulmonary vein
  2. Bronchial artery and bronchial vein (supply bronchi, CT, visceral pleura)
  3. Pulmonary plexus
  4. Bronchus
  5. Lymph nodes
18
Q

Blood supply of pericardium and diaphragm

A

Pericardicophrenic A+V

19
Q

Drainage of lymph vessels

A

Superficial LN (subpleural lymphatic plexus)
—> Deep LN (pulmonary —> bronchopulmonary —> tracheobronchial —> paratracheal)
—> Bronchomediastinal lymphatic trunk
—> Thoracic duct (left) + Right lymphatic duct (right)
—> Brachiocephalic vein
—> SVC

20
Q

Intersection of MAL, MCL, PPL with visceral and parietal pleura respectively

A
MAL + parietal: 10th rib
MAL + visceral: 8th rib
MCL + parietal: 8th rib
MCL + visceral: 6th rib
PPL + parietal: 12th rib
PPL + visceral: 10th rib
21
Q

Location of apex of lung

A

2.5cm above thoracic inlet

22
Q

Two parts of diaphragm

A
  1. Muscular part (peripheral)

2. Central tendon

23
Q

3 openings of diaphragm

A

ACO:

  1. Aortic (T12): Aorta, thoracic duct, Azygous vein
  2. Caval (T8): IVC, phrenic nerve
  3. Oesophageal (T10): Oesphagus, vagus nerve, blood vessels
24
Q

Blood supply of diaphragm

A
  1. Musculophrenic A/V

2. Inferior phrenic A/V

25
Q

Nerve supply of diaphragm

A

Phrenic nerve (C3-C5)

Phrenic nerve: does not belong to ANS but contain somatic, motor and sympathetic (ANS) neurone

26
Q

Diaphragm arises from:

A
  1. Medial arcuate ligament

2. Lateral arcuate ligament

27
Q
Muscle contraction in:
Passive inspiration
Active inspiration
Passive expiration
Active expiration
A

Passive inspiration:
Diaphragm + External IM

Active inspiration:
Diaphragm + External IM + Scalene (fix 1st rib) + Pectoralis (major&minor) + Serratus

Passive expiration:
Diaphragm (relaxation) + Internal IM + Inn IM + Lung recoil

Active expiration:
Diaphragm (relaxation) + Internal IM + Inn IM + Abdominal + Latissimus dorsi + Quadratus lumborum (fix 12th rib)

28
Q

Components of thoracic cavity

A
  1. Mediastinum
  2. Lungs
  3. Pleura
29
Q

What is mediastinum

A
  • Space located between the lung
  • extending to the root of the neck
  • below to the diaphragm
30
Q

Actions of diaphragm

A
  1. Respiration (increase vertical diameter)

2. Valsalva’s maneuver

31
Q

Contents of mediastinum

A

Superior: Great vessels, Phrenic nerve, Vagus nerve, Sympathetic trunks, Plexus, Trachea, Oesophagus

Anterior: Lymph nodes, remnants of thymus gland, Sternopericardial ligament

Middle: Pericardium, Heart, Trachea

Posterior: Aorta, Azygous, Sympathetic trunks, Splanchnic nerve, Vagus nerve, Thoracic duct, Oesophagus

32
Q

Classification of nervous system

A

Anatomically: Central vs Peripheral

  1. Central: Brain + Spinal cord
  2. Peripheral: Cranial nerve (12 pairs) + Spinal nerve (31 pairs)

Functionally: Somatic vs Autonomic

  1. Somatic: Sensory + Motor
  2. Autonomic: Sympathetic + Parasympathetic
33
Q

Sympathetic vs Parasympathetic NS

A
  1. Function
    SNS: Flight or fight, prepare for emergency
    PNS: Conserves and restores energy
  2. Anatomical outflow
    SNS: T1-L2
    PNS: CN3,7,9,10 + S2-S4
  3. Preganglionic fibre
    Both: myelinated + ACh as transmitter
  4. Ganglia
    SNS: paravertebral + prevertebral
    PNS: small ganglia close to viscera
  5. Postganglionic fibre
    SNS: Long, non-myelinated (NE most, ACh very few)
    PNS: Short, non-myelinated (ACh)
  6. Activity
    SNS: widespread + NE&E from adrenal medulla
    PNS: discrete due to few postganglionic fibre
  7. Higher control
    Both: hypothalamus
34
Q

5 plexus and their nerve supply

A
  1. Cardiac plexus
    Vagus (CN10) + T2-T5
  2. Pulmonary plexus
    Vagus + T2-T5
  3. Aortic plexus
    Vagus + T5-T11
  4. Renal plexus
    Vagus + T12
  5. Hypogastric plexus
    S2-S4 (pelvic splanchnic nerve) + L1-L2
35
Q

Nerve supply of eye, lacrimal gland, submandibular + sublingual, parotid gland (less important)

A

Eye:
CN3 + T1-T2

Lacrimal gland:
CN7 + T1-T2

Submandibular + sublingual:
CN7 + T1-T2

Parotid gland:
CN9 + T1-T2

36
Q

Sympathetic afferent and efferent pathway

A

Afferent:
Myelinated fibres from viscera through sympathetic ganglion (without synapsing) —> white rami communicantes —> Posterior ganglionic root —> Higher centre / reflex arc

Efferent:
Lateral column (anterior horn) —> white rami communicantes —> paravertebral ganglion —> sympathetic trunk
37
Q

Parasympathetic afferent and efferent pathway

A

Afferent:
From target organ (without synapsing) —> white rami communicantes —> Posterior ganglionic root / CNS —> Higher centre / reflex arc

Efferent:
Anterior horn —> Plexuses —> Post-ganglionic neurone

38
Q

Lymphatic drainage of trunk

A

Left:
Left side: bronchomediastinal, jugular, subclavian trunk (left) —> Thoracic duct
Below diaphragm: Intestinal + lumbar trunk —> Cisterna chyli —> Thoracic duct

Right:
Right upper side (head, thorax, limb) —> bronchomediastinal, jugular, subclavian trunk (right) —> Right lymphatic duct

Thoracic duct + Right lymphatic duct —> Brachiocephalic vein —> SVC