Abdomen 1 - Oesophagus & Tongue Flashcards
what type of sphincter is the lower oesophageal sphincter - anatomical or physiological?
physiological (functional sphincter without a distinct thickening of muscle, relying on surrounding structures)
angle of His between the cardiac orifice of the stomach & oesophagus acts as a physiological sphincter
what does the Z-line in the oesophagus signify? when is this clinically significant?
Z-line marks a distinct change between oesophageal (squamous) and gastric (columnar) epithelium
clinical: blurry Z-line suggests chronic GERD (acid reflux) = risk of Barrett’s oesophagus & oesophageal cancer
how is the structure of the oesophagus adapted to prevent refleux?
lower oesophageal sphincter = physiological sphincter; high resting muscle tone prevents reflux
angle of His = sharp angle prevents reflux
diaphragmatic crura (right crus) = acts as a functional sphincter & contracts oesophagus during inspiration
describe the change in muscle composition o the oesophagus from upper to lower 1/3s
upper 1/3 = purely skeletal muscle (under voluntary control)
middle 1/3 = mixed skeletal & smooth muscle (transition zone)
lower 1/3 = smooth muscle (involuntary control)
what structures compress the oesophagus? (ABCD)
aortic arch (T4)
left main bronchus (T5)
cricoid cartilage (C6)
diaphragm (T10)
course of the oesophagus?
starts at C6 (where the laryngopharynx ends) - travels through posterior mediastinum & through diaphragm at T10
ends at cardiac orifice of the stomach
at what vertebral level is the cardiac orifice of the stomach?
T11
what passes through the oesophageal hiatus at T10 along with the oesophagus?
right & left vagus nerves
- right vagus nerve becomes posterior vagal trunk
- left vagus nerve becomes anterior vagal trunk
what arteries supply the upper, middle & lower 1/3s of the oesophagus?
upper = inferior thyroid artery (branch of external carotid)
middle = oesophageal branches (directly from thoracic aorta)
lower = left gastric artery (from coeliac trunk)
what are the 3 oesophageal constrictions visible via a barium swallow?
- cervical (C6) - by cricoid cartilage
- thoracic - by aortic arch + left bronchus
- diaphragmatic (T10) - oesophageal hiatus
clinical importance of a barium swallow & oesophageal constrictions?
important landmarks for dysphagia, stricture, achalasia, or during endoscopy
the tongue consists of intrinsic & extrinsic muscles - what do these groups do?
intrinsic = change shape of tongue
extrinsic = move tongue position (e.g. protrude, retract, elevate, depress)
innervation to tongue muscles (extrinsic & intrinsic)? which muscle is the exception - what innervates it?
hypoglossal nerve (CN12)
exception: palatoglossus; by vagus nerve (CN10)
What structure divides the anterior and posterior tongue?
terminal sulcus (different embryological origins of each part)
anterior 2/3 of tongue - general sense & special sense innervation?
general sense = CNV3 (mandibular branch) via lingual nerve
special sense = CN7 (facial nerve; via chorda tympani)
posterior 1/3 of tongue - general sense & special sense innervation?
glossopharyngeal nerve (CN9) for both
