The Collaborative International Dictionary of English v.0.48:

Distend \Dis*tend"\, v. i.
   To become expanded or inflated; to swell. "His heart distends
   with pride." --Milton.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Distend \Dis*tend"\, v. t. [imp. & p. p. Distended; p. pr. &
   vb. n. Distending.] [L. distendere, distentum, distensum;
   dis- + tendere to stretch, stretch out: cf. F. distendre to
   distend, d['e]tendre to unbend. See Tend, and cf.
   Detent.]
   1. To extend in some one direction; to lengthen out; to
      stretch. [R.]
      [1913 Webster]

            But say, what mean those colored streaks in heaven
            Distended as the brow of God appeased? --Milton.
      [1913 Webster]

   2. To stretch out or extend in all directions; to dilate; to
      enlarge, as by elasticity of parts; to inflate so as to
      produce tension; to cause to swell; as, to distend a
      bladder, the stomach, etc.
      [1913 Webster]

            The warmth distends the chinks.       --Dryden.

   Syn: To dilate; expand; enlarge; swell; inflate.
        [1913 Webster]

WordNet (r) 3.0 (2006):

distend
    v 1: become wider; "His pupils were dilated" [syn: dilate,
         distend]
    2: cause to expand as it by internal pressure; "The gas
       distended the animal's body"
    3: swell from or as if from internal pressure; "The distended
       bellies of the starving cows"