Anatomy of esophagus and Physiology of swallowing in brief

1. ANATOMY OF
ESOPHAGUS
AND
PHYSIOLOGY
OF
SWALLOWING

2. ANATOMY OF ESOPHAGUS
– C6 TO T11
– Total length of 25 cm
– Esophagus is the narrowest region of Digestive tract
– Has 3 constrictions
– 15 cm from the incissors
– 23 cm
– 40 cm

3. Esophageal wall
– 4 layers
– Mucosa
– Submucosa
– Muscularis propria
– Upper 1/3 striated
– Lower 1/3 smooth
– Adventitia

4. Nerve supply of Esophagus
– Straited muscle is supplied by recurrent laryngeal nerve.
– Smooth muscle is supplied by parasympathetic fibres from the vagus.
– They form two plexus
– Myenteric plexus and Messners plexus.
– Sympathetic supply comes from Cardiac plexus.
Afferent fibres for temperature sentivity is carried along these same fibres.

5. Blood supply
– Cervical esophagus- inferior Thyroid artery and left subclavian artery.
– Thoracic part has segmental supply from descending aorta and branches of
bronchial and intercostal arteries.
– Abdominal part is supplied by left gastric artery and left phrenic artery.
– Venous drainage is to both systemic as well as portal venous system.

6. – Lymphatic supply:
Cervical Part drains to lower deep cervical and paratracheal
Thoracic part drains into Posterior mediastinal and Tracheobronchial
group of lymph nodes
Abdominal part drains into left gastric nodes

7. Relationships of Esophagus

8. Physiology of Swallowing
– Eating and swallowing are complex behaviors that include volitional and
reflexive activities involving more than 30 nerves and muscles
– The basic musculature of swallowing controls the jaw, the tongue, the degree of
constriction and length of the pharynx and closure of the laryngeal inlet

9. THE SEQUENCE OF EVENTS IN
THE NORMAL SWALLOW
– 1. Oral
– 2. Pharyngeal
– 3. Oesophageal

10. ORAL PHASE
– Food is readied for swallowing by reducing and mixing it with saliva by the
muscles of the jaw and oral cavity.
– Again divided into two
– Preparatory phase
– Oral phase proper

11. Oral Preparatory Phase of the
Swallow
– The food is manipulated (masticated if a solid) into a cohesive unit (referred to as a
bolus) in preparation for the remaining phases of the swallow
– Food is chewed and mixed with saliva to form a bolus
– Bolus is positioned on the tongue for transport
– “Chipmunk Swallow or Pocketing”, when a large bolus is partially held in the cheeks
and the patient then swallows several times to clear the oral cavity-food left in the
cheek is a sign of weak musculature

13. Oral phase proper
– The food is moved back through the mouth with a front-to-back squeezing
action
– Performed primarily by the tongue

15. PHARYNGEAL PHASE
– As the bolus is moved back by the tongue to enter the pharynx, a sequence of
events is initiated that ensures that the airways are protected during bolus
transport
– Firstly, diaphragmatic contraction is inhibited making simultaneous breathing
and swallowing impossible under normal circumstances. At the same time, the
soft palate is elevated to ensure a sphincteric closure of the nasopharynx.
– Finally, the vocal cords start to close to protect the airways.

17. ESOPHAGEAL PHASE:
– The cricopharyngeus relaxes
– The bolus passes through the sphincter and moves along the oesophagus by
peristalsis

18. Neural control
– Neural control of the complex activity of healthy swallowing involves a number of
different regions of the central nervous system (CNS).
– Consists mainly 4 components
1. The efferent nervous system (motor nerve fibres- Cranial nerve and Ansa cervicalis)
2. The afferent nervous system (Sensory nerve fibres- Cranial Nerve)
3. The Midbrain and cerebral synaptic nerve fibres that connects to swallowing centres
4. The paired swallowing centres in brainstem

19. Afferent
Nerve
Fibres
Brainstem
swallowing
centre
Cerebral
cortex
centre
Efferent
nerve fibres

21. – The major sensory stimuli needed to elicit swallowing are thought to originate
from the fauces, pharynx, and posterior larynx

22. Brain stem swallow Centers
– The swallow centers are not discrete focal areas, but consist of ill-defined broad
zones.
– Located lateral to the midline and ventral to the caudal portion of the fourth
ventricle, which incorporate the nucleus tractus solitarius (NTS) and the
ventromedial reticular formation (VMRF).

23. RESPIRATION AND SWALLOWING
– Respiration and swallowing are inextricably linked as they use the same
structures and thus the two processes must be finely coordinated
– Swallowing tends to occur during the expiration phase of respiration. Expiration
occurs after 80–100 percent of healthy swallows. This is likely to be a protective
mechanism: material left in the laryngeal vestibule post swallow will be moved
to the pharynx rather than sucked into the lungs.
–

24. TESTING OF ESOPHAGUS

25. Radiological Evaluation

26. Pathological findings

31. Killian–Jamieson diverticula
and pouches
– NOT TO BE CONFUSED WITH KILLIANS DEHISENCE
– The Killian –Jamieson space is a triangular area of weakness in the upper
anterolateral cervical esophagus.
– The Killian –Jamieson space is bounded superiorly by the inferior border of the
cricopharyngeus, anteriorly by the cricoid cartilage, and inferomedially by the
suspensory ligament of the esophagus.

32. – Transient – pouches
– Permanent- Diverticula

35. Cervical Esophageal Web
• Predominantly from the anterior wall
• 3 –8% of patients who undergo upper gastrointestinal
barium studies and in 16% of patients at autopsy
A web appears on barium studies as a radiolucent bar in the
barium pool.
50% - Dysphagia
Jet phenomenon