Chapter 90 Oesophagus Flashcards
At what level does oesophagus regain dorsal position (to trachea)
At tracheal bifurcation
What are the layers of the oesophagus
- Adventitis
- Muscularis
- Submucosa
- Mucosa
N.B. No serosa
What proportion of oesophagus can be resected?
20% of cervical oesophagus
50% of thoracic oesophagus
But in practice excision of >3-5cm –> increased risk of dehisence
What is the distribution of skeletal/smoth muscel in canine oesophagus?
And feline?
In dogs 100% striated
In cats cranial 2/3rds striated, caudal 1/3 smooth muscle (–> herringbone appearance with contrast as caudal 1/3rd has transverse folds, rather than longitudinal)
How is the oesophagus anchored cranially?
Via cricooesophageal tendon to cricoid cartilage
What muscles form the upper oesophageal sphinter?
Thyropharyngeus and cricopharyngeus

What is the main arterial supply to:
- Cervical oesophagus
- Cranial thoracic
- Caudal thoracic
- Terminal oesophagus
- Cervical oesophagus = Cranial and caudal thyroid arteries
- Cranial thoracic (2/3rds) = Bronchooesophageal artery
- Caudal thoracic (1/3rd) = Aorta or dorsal intercostals
- Terminal = Left gastric artery
Which veins drain the oesophagus?
External jugular, azygous and left gastric
Which nerves innervate the oesophagus
Vagus:
- Pharyngo-oesophageal nerves
- Recurrent laryngeal and para-recurrent laryngeal nerves
- Dorsal and ventral vagal branches nerves

Label the diagram


Label the diagram

Left lateral view of the canine thoracic cavity; the lung and much of the pericardium have been removed.
1, Longus colli;
2, left subclavian artery;
3, internal thoracic vessels;
4, thymus;
5, vessels in paraconal interventricular groove;
6, pulmonary trunk;
7, esophagus;
8, pulmonary veins entering left atrium;
9, left principal bronchus and dorsal and ventral vagal trunks;
10, aorta;
11, sympathetic trunk;
12, phrenic nerve;
13, caudal mediastinum;
14, diaphragm.

Label the diagram

Right lateral view of the canine thoracic cavity; the lung and much of the pericardium have been removed.
1, Diaphragm;
2, infracardiac bursa;
3, sympathetic trunk;
4, esophagus;
5, caudal vena cava;
6, plica venae cavae;
7, root of lung and phrenic nerve;
8, right vagus;
9, right azygos vein;
10, cranial vena cava;
11, longus colli;
12, trachea;
13, thymus;
14, internal thoracic vessels;
15, first rib;
16, vagosympathetic trunk.

Name the three phases of swallowing:
-
Oropharyngeal
- Oral
- Pharyngeal
- Cricopharyngeal/pharyngo-oesophageal
-
Oesophageal (if dysfunction, then broken down as follows)
- Mechanical
- Functional
- Inflammatory
- Gastrooesophageal

What nerves co-ordinate swallowing>
V Trigeminal
VII Facial
IX Glossopharyngeal
X Vagus
XII Hypoglossal

On swallow study, a bolus of food stops in front of gastrooesophageal juntion and then enters stomach at next bolus - comment on this
Can be normal
How do oesophageal transit times vary with sternal vs lateral positioning?
Slower in lateral!
(7-9 cm/s in lateral vs 3-4 cm/s in sternal)
N.B. Book misquotes these numbers implying faster in lateral!
List 6 ddx for mechanical oesophageal dysfunction
- VRA
- Mural mass lesion
- Neoplasia
- Duplication cyst
- Paraoesophageal abcess
- Oesophageal diverticula
- Stricture
- FB
- Hiatal hernia
- Gastroesophageal intussusception
What is most common cause for canine megaoesophagus?
Idiopathic
List 5 factors that contribute to higher dehisence rate in oesophagus vs SI
- Lack of serosa
- Lack of omentum
- Segmental blood supply
- Constant movement with peristalisis and respiration
- Less mobile i.e. more tension
In what layer of the oesopagus does the rich intramural plexus of anastomosing vesels sit?
Submucosa
What is the significance of the rich intramural plexus of anastomosing vesels of the oesophagus?
Thoracic oesophageal anastomoses can heal after ligation of thoracic segmental blood supply (however simultaneous ligation of thoracic AND cervical supply –> necrosis).
i.e. ischaemic necrosis usually due to damage to the intramural supply
What are post-op feeding recommendations after oesophageal surgery?
Withhold for 1-7d.
Consider G- or E-tube
What approaches can be performed for cranial thoracic oesophagus
L 3rd or 4th ICT
R 3rd, 4th or 5th ICT
Cranial MS
When performing L ICT for access to cranial oesophagus, what other step is necessary?
And on R?
Left: Ventral retraction of brachiocephalic trunk and subclavian vessels
Right: Ventral retraction of trachea +- retraction/ligation of azygous vein















