Thorax anatomy Flashcards
What anatomical landmark splits the mediastinum into superior and inferior?
Sternal angle (angle of Louis)
Found at L4/L5
How is the inferior mediastinum further divided?
Anterior mediastinum
Middle mediastinum
Posterior mediastinum
What structures are found in the Superior mediastinum?
There are 10
- SVC
- Brachiocephalic vein
- Arch of aorta
- Thoracic duct
- Trachea
- Oesophagus
- Thymus
- Vagus nerve (CNX)
- Phrenic nerve
- Left recurrent laryngeal nerve
What are the 3 structures that lie in the Anterior mediastinum
Thymic remnants
Lymph nodes
Fat
What are the structures found in the middle mediastinum?
- Pericardium
- Heart
- Aortic root
- Arch of azygos vein
- Main bronchi
What structures are found in the Posterior mediastinum?
V DATES
V DATES
- Vagus nerve
- Descending aorta (Thoracic aorta)
- Azygos vein
- Thoracic duct
- Esophagus
- Sympathetic nerve trunks / Splanchic nerves
What is the posterior boundary of the posterior mediastinum?
Last 8 thoracic vertebra
T5-T12
What are the anterior and lateral borders of the posterior mediastinum?
Anteriorly: Heart + Pericardium
Laterally: Lung pleura
If a patient had a stab wound to the sternal angle (L4-L5), what structure is most at risk of injury?
Arch of the aorta
What anatomical structures are found beneath the upper part of the manubrium?
- Left common carotid
- Left brachiocephalic vein
- Left subclavian artery
- Brachiocephalic artery
Which rib is found at the sternal angle?
2nd rib
What is the most common site for injury of the Thoracic duct?
When crossing to the midline at the sternal angle
During an oesophagectomy, where would the chyle accumulate if the thoracic duct is injured?
Posterior mediastinum
At what levels of the vertebrae does trachea begin and end?
C6 - T5 (upper border)
What is the arterial supply and venous drainage of the trachea?
Inferior thyroid arteries
Thyroid venous plexus
What lies posterior to the trachea?
Oesophagus and vagus nerve
What structures lie anterior to the trachea?
- Isthmus of thyroid
- Inferior thyroid veins
- Sternothyroid
- Sternohyoid
- Cervical fascia
- Anastomosing branches of the anterior jugular veins
What structures run laterally to the trachea?
Common carotids
Right and Left thyroid lobes
Inferior thyroid arteries
Recurrent laryngeal nerves
At which levels does the oesophagus begin and end?
C6 - T11
Pierces the diaphragm at T10
What kind of epithelium is found in the oesophagus?
Non-keratinised stratified squamous epithelium
It has no serosa and so holds sutures poorly
Where are the 4 areas of constriction of the oesophagus and distance from front incisors?
Cricoid cartilage: 15cm
Arch of the aorta: 22.5cm
Left principal bronchus: 27cm
Diaphragmatic hiatus: 40cm
How is the oesophagus divided?
Divided into Upper (cervical), Middle (thoracic) and Lower (abdominal) thirds
What is the blood supply of the upper third of the oesophagus and its lymphatic drainage?
Arterial: Inferior thyroid artery
Venous: Inferior thyroid vein
Lymphs: Deep cervical
What is the blood supply of the middle third of the oesophagus?
Arterial: Aortic branches
Venous: Azygos branches
Lymphs: Mediastinal
What is the blood supply to and from the lower third of the oesophagus?
Arterial: Left gastric
Venous: Left gastric vein
Lymph: Gastric
In which part of the oesophagus do oesophageal varies arise?
Lower third
What is the nerve supply of the oesophagus?
Upper half: Recurrent laryngeal nerve
Lower half: Vagus (oesophageal plexus)
How many lobes are there in the left and right lung?
Left: 2
Right: 3
What is found above the hilum of the right lung?
Azygos vein and groove for the SVC
Where does the oesophagus lie in relation to the hilum of the right lung?
The oesophagus sits in a vertical groove posterior to the hilum
What structure lies anterior to the hilum of the left lung?
- Phrenic nerve
- Vagus nerve (which then arches backwards superior to the root of the left bronchus to give off the Recurrent Laryngeal nerve
What structure is found superior to the hilum of the left lung?
Aortic arch and more superiorly, the groove accommodating the left subclavian artery
What structure runs posterior to the hilum of the left lung?
Descending aorta
What is the posterior border of the lung cavity?
Transverse process of C7 - T10
At what costal level is the cardiac notch found?
Left lung deviates laterally from the sternum at the 4th costal cartilage to form the cardiac notch