aganglionicadj.
/ˌeɪɡaŋɡlɪˈɒnɪk/, U.S. /ˌeɪɡæŋɡliˈɑnɪk/ 1. Anatomy and Zoology. Lacking a ganglion or ganglia (cf. ganglion n. 2); = ganglionless adj.
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1837 M. Hall Mem. Nerv. Syst. ii. 50 The aganglionic nerves are purely motor, as Prof. Grant first conjectured, and direct in their mode of action.
1884 J. McFadyean Anat. Horse 140 The inferior, motor, or aganglionic root consists of fibres detached from the cord along its infero-lateral fissure.
1946 Physiol. Zool. 19 331/2 Whereas the nervous system of echinoderms, coelenterates, etc., is undoubtedly diffuse, it does not seem quite correct to designate it as aganglionic.
1989 R. W. Hill & G. A. Wyse Animal Physiol. (ed. 2) xvi. 388/2 There are two major forms of organization of central nervous systems in higher phyla: ganglionic central nervous systems characteristic of protostomes and aganglionic nervous systems characteristic of deuterostomes.
2. Pathology. Of a part of the gastrointestinal tract: lacking ganglion cells normally present within the wall.
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1949 Proc. Royal Soc. Med. 42 225 Complete absence of parasympathetic ganglion cells was noted throughout the entire narrow segments... Moreover, this aganglionic segment extended beyond the narrow bowel into the hypertrophied and dilated part for a distance of 1–5 cm.
1968 New Eng. Jrnl. Med. 25 Jan. 188/1 The dilated bowel proximal to this aganglionic segment is normally innervated.
2002 A. M. Brown & B. R. Ransom in V. S. Ramachandran Encycl. Human Brain III. 490/2 In these mice, the terminal colon is aganglionic because it is not infiltrated by enteric glial precursors from the neural crest.
2009 M. D. Gershon in G. Lemke Developmental Neurobiol. 346/1 Hirschsprung's disease occurs when a variable length (long segment or short segment) of terminal bowel is aganglionic.
This entry has been updated (OED Third Edition, September 2012; most recently modified version published online June 2022).
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adj.1837