mkm_contin_sw1 Ultrasound movie. Continuous swallowing of a glass of water through a straw.
Single Swallow 20cc water -made using SURFACES
  1. At first, the bolus depresses the anterior tongue (red). 
  2. The bolus is transported backward.
  3. The tongue elevates A-to-P as the bolus is squeezed backward.

5cc + 20cc Swallows

-from M Noorani MS thesis Dept of Orthodontics 2003

Swallowing patterns were similar for 2 bolus sizes.
ortho_talk_slide_26‌   ortho_talk_slide_27‌ 
The larger bolus depresses more deeply in the front around the bolus (red). Also, the tongue elevates more rapidly to acheive maximum closure.   The 20 ml bolus begins with greater anterior tongue lowering, but both swallows end in the same place,  with full palate contact. Thus pattern differences were primarily scalar.
Unrestrained Jaw vs 10mm Bite Block
The overlay shows the tongue to be anterior and inferior in the BB case.
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The biteblock cause a more anterior tongue initially (blue), a lower depression during propulsion (yellow), and a more anterior final closure(blue).
The initial and final closures were more anterior in BB than unrestrained (red arrows). Perhaps the subject could only reach a more anterior (and lower) part of the palate.