GA 4 Mediastinum

Mediastinum

What is described by the central compartment of the thoracic cavity?

mediastinum

Superior boundary of mediastinum is what?

Superior thoracic aperture

Inferior Boundary of mediastinum is what?

Diaphragm or inferior thoracic aperture

Anterior Boundary of mediastinum is what?

Sternum or costal cartilages

Posterior Boundary of mediastinum is what?

T1-T12 vertebrae and related ribs

What divisions of mediastinum are there?

Superior and inferior

What are the anterior, posterior, superior and inferior boundaries of superior mediastinum?

manubrium; T1-T4; sternal angle; thoracic inlet

What compartments are there of the inferior mediastinum?

anterior, middle and posterior

Inferior middle mediastinum contains what?

heart and related structures

Mediastinal pleurae covers what?

lungs

Superior Medianstinum contains what structures?

The lower ends of the neck muscles

Thymic remnants (thymus)

Sympathetic chain, trachea, esophagus and thoracic duct

Superior Medianstinum contains what veins and arteries?

– Internal thoracic arteries and veins

– Brachiocephalic veins and the upper half of the superior vena cava

– Aortic arch and branches off of it

Superior Medianstinum contains what nerves?

right/left vagus n

right/left phrenic n

left recurrent laryngeal n

cardiac n and superifical part of cardiac plexus

Anterior Mediastinum contains what?

Internal thoracic vessels branches

fat

sternopericardial ligaments

What is the broadest part of inferior mediastinum?

middle mediastinum

Middle mediastinum contains what structures?

Pericardium and heart

Ascending aorta

Main bronchi and pulmonary trunk

Middle mediastinum contains which of the following most accurately?

phrenic nerves

Lower half of SVC

Pulmonary veins and arteries

Posterior mediastinum contains VANs?

posterior intercostal VAN

azygos/hemiazygos/accessory hemiazygos v.

Descending aorta, thoracic duct, sympathetic trunk, esophogus belong to what divison of mediastinum?

Inferior posterior mediastinum

Posterior mediastinum contains which nerves?

Splanchnic and vagus nerves

Splanchnic nerve is a branch from what?

paravertebral ganglia

Ascending aorta (middle) ascends from what?

left ventricle

Arch of aorta is part of what mediastinum?

superior mediastinum

Descending aorta has what visceral branches are what?

Esophageal, Pericardial, Bronchial, Mediastinal

Descending aorta parietal (wall) branches are what?

subcostal, superior phrenic, posterior intercostal

What are the veins of thoracic cavity?

SVC, Pulmonary veins (oxygenated blood)

Brachiocephalic vein and azygos are tributaries to what?

superior vena cava

Azygos vein recieves?

Right posterior intercostal veins and right superior intercostal veins

Azygos vein is formed from what?

junction of right subcostal vein and right ascending lumbar veins

The azygos vein communicates with what?

vertebral venous plexuses (drains back, vertebrae, and structures in vertebral canal)

Right posterior costal veins are made up of

veins 5-11

Right superior intercostal veins made up of?

union of 2, 3, and 4th IC veins

Hemiazygos veins formed by what?

junction of left subcostal and left ascending lumbar veins

Hemiazygos veins receives contributions from?

left posterior intercostal veins 9, 10, 11

Left superior intercostal vein drains primarily into what?

left braciocephalic vein

What connects arch of aorta to the pulmonary artery?

Ligamentum Arteriosum

Ligamentum Arteriosum remnant of what?

ductus arteriosus

Right vagus nerves gives what?

Right recurrent laryngeal nerve which goes to thorax

Left vagus nerves gives rise to what?

Left recurrent laryngeal nerve which loops around arch of aorta

Sole nerve for diaphragm is what? What does it run with?

phrenic nerve

runs with pericardiophrenic vessels

Phrenic nerve travels where?

Descends from superior mediastinum into inferior middle

Accessory hemiazygous vein receives from where?

Veins in 4th-8th intercostal space

Azygos vein forms collateral pathway with what?

IVC and SVC

Location of the esophagus is what?

Inferior posterior mediastinum

Esophagus covered by what?

Peritoneum

Bloody supply of esophagus:

Abdominal: left gastric a

Thoracic: esophageal a

Esophageal nerve supply:

Vagus nerve

Sympathetic nerves from T1-T4

Thoracic Duct Action

Return all lymph and chyle from body below diaphragm and left half of body above diaphragm

Thoracic Duct arises from?

Cisterna Chyli and drains 75% of lymph from body

What is described by flattened, pink lobulated structure?

thymus

What is the site of t lymphocyte development?

thymus

Thymus undergoes what until the end of puberty?

growth and then involution

What is chyle?

lymph from gut

Sympathetic fibers to the neck and head from thoracic SP trunk arise from what level?

T1-T2/T3 and ascend as pre-gg fibers which end at cervical ganglion

What is the location of thoracic SP trunk?

runs in inferior posterior mediastinum and on head of ribs

Post-gg fibers of thoracic sympathethetic trunk adhere to?

carotid arteries while some become cardiac nerves

Thoracic splanchnic Nerve arise from what? What type of fibers do they carry?

T1-T4 carry post gg-fibers

Abdominalpelvic splanchnic nerves are what?

pre-gg SP fibers that arise from T5-T12

What are the abdominal splanchnic nerves of the abdomen?

all of the above

What level are the greater splanchnic nerve?

T5-T9

What level are the lesser splanchnic nerve?

T10-T11

What level are the least splanchnic nerve?

T12

Phrenic Nerve arises from

C3-C5 motor