Mediastinum

Question 1

What divides the mediastinum into superior and inferior segments?

Answer 1

Transthoracic plane (Plane of Ludwig)
Anteriorly: 2nd costal cartilage
Posteriorly: T4/T5 Vertebrae

Question 2

Name the 3 branches of the Aortic Arch:

Answer 2

1. – Brachiocephalic trunk (which branches off into: 
• R subclavian Artery
• R Common Corotid A. 
2. Left Common Carotid A.
3. Left Subclavian A.

Question 3

Name the arteries in the 1st, 2nd and 3rd parts of the Subclavian Artery:

Answer 3

1st part 
– Vertebral Artery
– Internal thoracic Artery
 – Thyrocervical trunk 
2nd part 
– Costocervical trunk 
3rd part 
– ** Dorsal scapular (may arise from 2nd or 3rd part of subclavian artery)

Question 4

Nerves of the superior mediastinum

and locations:

Answer 4

• Vagus nerve
– Travels along the common carotid A

• Recurrent laryngeal nerves
– Left associated with arch of aorta
– Right associated with subclavian artery

Question 5

C-Shaped hyaline cartilage rings held together posteriorly by a band of smooth muscle (Trachealis muscle)

Answer 5

Trachea

Question 6

At what level does the esophagus pass through the diaphragm?

Answer 6

T10

Question 7

At what level does the thoracic aorta pass through the diaphragm?

Answer 7

T12

Question 8

The thoracic duct carries lymph from the entire body except ……

Answer 8

The right head and neck, right upper limb and right thorax

Question 9

Which side of the mediastinum does the following veins run?
Azygus Vein
Hemiazygos Vein
Accessory Hemi-azygos

Answer 9

Azygus Vein- Right Side
Hemiazygos Vein- Left Side
Accessory Hemi-Azygos Vein- Left Side

Question 10

Types of Splanchnic nerves and Functions:

Answer 10

• Greater – T5-9 with some variation
– Enters the abdomen by piercing the diaphragmatic crura
– Joins the celiac ganglion

• Lesser – T10-11 with some variation
– Enters through the diaphragm just lateral to the greater splanchnics
– Joins aorticorenal ganglion

• Least – T12 but not always present
– Joins the renal plexus

Question 11

At what level does the Inferior Vena Cava pass through the diaphragm?

Answer 11

T8

Question 12

Thoracic Outlet Syndrome: Causes

Answer 12

• Caused by
– Extra rib attaching to the 7th Cervical vertebra and rib 1
– Muscular abnormalities
– Injury

Question 13

Thoracic Outlet Syndrome: Symptoms

Answer 13

• Abnormal compression of brachial plexus nerves that pass through the axillary inlet to the upper limb.
• Sensory Deficit in Medial Arm
• Muscle Wasting
• • Pain • Pallor • Paresthesia • Diminished pulse
• Edema due to venous compression