Ana: Superior And Posterior Mediatinum

Front 1

Boundaries of superior mediastinum

Back 1

Anterior: manubrium
Posterior: bodies of T1-T4
Superior: oblique line passing from jugular notch upward and posteriorly to superior aspect of T1.
Inferior: Transverse plane passing form sternal angel to intervertebral disc b/t T4 and T5
Lateral: mediastinal parts of parietal pleura on either side.

Front 2

Boundaries of posterior mediastinum

Back 2

Anterior: pericardial sac and diaphragm
Posterior:bodies of mid and lower thoracic vertebrae
Superior: transverse plane passing from sternal angel to IV disc b/t T4 T5.
Inferior: diaphragm
Lateral: bordered by mediastinal parts of parietal pleura on either side.

Front 3

content of superior mediastinum
and relationships

Back 3

1. thymus
2. right and left brachiocephalic veins
3. left superior intercostal vein
12. azygos vein
4. superior vena cava
5. arch of the aorta w/ 3 branches
6. trachea
7. esophagus
8. phrnic nerves
9. vagus nerves
10. left recurrent laryngeal nn
11. thracic duct



anterior-posterior
sternum, thymus, brachiocephlic veins, brachiocephalic trunk, trachea, esophagus

Right/ left brachiocephalic veins are lateral to beachiocephlic trunk

R/L phrenic nerves are anterolateralto R/L brachiocephalic veins

Left common carotid artery is post. to left brachiocephalic trunk and anteromedial to left subclavian artery...

right vagus is post. to left vagus nn but parallel to left recurrent laryngeal flanking either side of trachea.

Thoracic duct is post. esophagus and left of azygos.

p. 309

Front 4

content of posterior mediastinum
and relationships

Back 4

1. esophagus and nerve plexuses
2. thoracic aorta
3. azygos system of veins
4 thoracic duct and asso. lymph nodes
5. thoracic splanchnic nerves
*sympathetic trunk are not b/c they lie lateral to the vetebral bodies.

Front 5

Left vagus and laryngeal nerve

Back 5

left vagus nerve gives rise to left recurrent laryngeal nerve at the inferior margin of arch of the aorta lateral to the ligamentum arteriosum
recurrent layrngeal nerve passes under the arch and posterior to ligamentum arteriosum and ascend in a groove b/t trachea and esophaus to enter neck.

Front 6

structures that pass behind the diaphragm

Back 6

T8: IVC (through)
T10: Esophagus (through) & Vagal trunk
T12 Aorta (behind, via aortic hiatus) and Thoracic Duct

Front 7

innervation of the esophagus

Back 7

1. Esophageal plexus:
sensory and motor innervation via vagus and sympathetic chain
L/R nerves mix and travel to abdomen as vagal trunks.

(a) Anterior vagal trunk: anterior to the esophagus (mostly left vagus fibers)
VAL

(b) posterior vagal trunk: posterior to esophagus (mostly fiber from right)

Front 8

branches of the thoracic aorta

Back 8

T4: start
T12: pass through aortic hiatus posterior to diaphragm and become adbominal aorta

1. Pericardial: small vessel to post. surface of pericardial sac.

2. Bronchial: 2 left bronchial arteries (from thoracic aorta) and 1 right bronchial artery (from 3rd post. intercostal artery or upper left bronchial artery).

3. Esophageal: 4 or 5 vessles from anterior thoracic aorta. Form anastomoses:
(a) superiorly: inferior thyroid artery (esophageal branches)
(b) inferiorly: Left inferior phrenic and left gastric arteries (esophageal branches)

4. Mediastinal: small, supplying lymph nodes, vessles, nerves, areolar tissue in post. mediastinum.

5. Post. Intercostal arteries: 9 pairs from posterior surface of thoracic aorta, supply lowe r9 intercostal spaces (first 2 are supplied by supreme intercostal artery, a costo-cervical trunk branch).

6. Sup. phrenic arteries: small, supply posterior part of superior surface of diaphragm, anastomose with musculophernic and percardiacophrenic arteries.

Front 9

blood supply and venous drainage of posterior thoracic wall

Back 9

Azygos system
(a)longitudinal vessels on each side of by that drain blood from body wall and return it to superior vena cava

(b) anastomose with abdominal veins and return blood from lower body if IVC is blocked.

(c) azygos (right) and hemiazygos and accessory hemiazygos (left).

Front 10

course of thoracic duct in posterior mediastinu and relationships

Back 10

(a) Start in cisterna chyli in abdomen (LII) and extend into neck
(b) enter thorax through aortic hiatus of diaphragm (posteriot to aorta)
(c) In posterior mediastinum: right of midline b/t thoracic aorta on the left and azygos vein on the right, posterior to diaphagm and esophagus and anteiror to vertebra.
(d) At TV, moves to left of midline, through superior mediastinum into neck.
(b) empties into junction of left subclavian and internal jugular veins.

Front 11

Contents of each portion of the mediastinum and structures common to more than one portion

Back 11

Thymus: S, A
Trachea: S.
Esophagus: S, P
Thoracic duct: S, P


Phrenic nn: S, M
Vagus nn: S, P
Splanchnic nn: P

Azygos vv: S, P,
Brachiocephalic vv: S

Brachiocephalic artery: S
Left common carotid artery: S
Left subclavian artery: S

Pericardial ligaments (attach to sternum): A
Pericardium and Heart: M

Ascending aorta: M
Descending aorta: P
Aortic arch: S
Pulmonary Arteries: M
Pulmonary Veins: M
IVC: M
SVC: S, M

Front 12

Lymphatics of the thoracic regions

Back 12

DRAINAGE:
1. Anterior thoracic wall & breast
(a) 75% axillary nodes
(b) parasternal nodes

2. Deep structures:
(a) Right: R. Bronchomediastinal -> R. Lymph duct
(b) Left: L. bronchomediastinal -> Thoracic duct

3. Lungs
(a) R: bronchomediastinal nodes and trunk
(b) L: bronchomediatinal nodes and trunk (lower lobe into right)

STRUCTURES:
1. R/L bonchomediastinal Lymph trunks: cource along sides of trachea
2. R lymphatic duct: empties into junction of R. subclavian and R internal jugular vv.
3. Thoracic duct: empties into L. subclavian and L. internal jugular vv.
4. R/L parasternal nodes and trunks: along the internal thoracic vessels empty into R/L bronchomedistinal lymph trunks

Front 13

relationships

Back 13

Pulmonary trunk is anterior to bronchi branches which are anteior to eosophagus

Aorta loops from in right anterior of pul trunk to left posterior to esophagus. (Under arch are left bronchi and pul artery)

Internal thoracic artery connects to subclavian posterior to brachiocephci veins - otherwise it's anterior to brachiocephalic veins.

Going down, esophacus moves from right side of aorta to in front of it and immediately behind left atrium.

Throacic duct is behind esophagus, above TV it is left below TV it is right of midline, (left of azygos and right of aorta)

Structures other than the thoracic duct posterior to the esophagus include portions of the hemiazygos veins, the right posterior intercostal vessels, and, near the diaphragm, the thoracic aorta

Front 14

What drains into parasternal nodes and trunks, directly into thoracic duct, and bronchomedistinal nodes and trunk.

Back 14

1. parastneral nodes
(a) anterior thoracic wall
(b) breast
(c) parietal pleura
(d) diagphragm
(e) upper abdominal wall

2. thoracic duct
(a) diaphragm
(b) post. thoracic wall
(c) post. mediastinum

3. bronchomeditinal nodes/trunks
(a) superior, middle, post. mediastina
(b) heart
(c) parietal pleaura
(d) esophagus (thoracic), upper (cervical nodes), lower (gastric nodes)