Page 60 - Edited - Webster HEAD AND NECK - part 2-Merge PDF

ΗΝ 254
THE PHARYNX

"Everything could be very nicely arranged, if only we could do things twice over." (Goethe-
Gemischte Epigrammen).

I'm not sure I agree - sounds too much like "the triumph of hope over experience" (Johnson,
as a twice married man, should have known). However, the demiurge, creatorix mundi,
contemplating the pharynx from the Celestial Retirement Home, may well concur:

PITUITARY FOSSA
SCHEMATIC
MEDIAN BODY OF SPHENOID
SECTION NASAL
BASIOCCIPITAL
P

CAVITY

H
PALATE A
TONGUE R

BODIES OF
MANDIBLE CERVICAL
(cut) VERTEBRAE
HYOID
(cut) Y
N
EPIGLOTTIS (cut) X
THYROID
OF CARTILAGE (cut)
LARYNX
(CAVITY OF OESOPHAGUS
LARYNX IS CRICOID
STIPPLED) CARTILAGE
(cut). K.E.W.
TRACHEA

The pharynx of terrestrial vertebrates carries air to the trachea and food and drink to the
oesophagus (see HN 30 et seq.). The design problem, as shown above, is that the two trajectories
cross each other (even when mouth-breathing). Had early vertebrates not opted to have nostrils
above the mouth, or had the primitive teleost fish developed their swim bladder (from which lungs
evolved) from the dorsal (i.e. posterior in humans) rather than the ventral (anterior) side of the
pharynx, all would have been better arranged, since the positions of the trachea and oesophagus
would have been transposed, the pathways from mouth and nose would not cross, and could even
have been completely partitioned from one another... As it was, the dispositions necessitated the
development of a sphincter to prevent food and liquid entering the bronchial tree. This is the
LARYNX, later to become, additionally, a yatter-box... The pharyngeal wall contains SKELETAL
muscle which aids the swallowing of comestibles...

KEW

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