425:
610:
598:
586:
574:
50:
542:
Not all open fontanelles are connected with hydrocephalus. In many young dogs the skull bones are not fused at birth, but instead will close slowly over a three- to six-month period. Occasionally these bones fail to close, but the dog is still healthy. In these cases, however, the dog's owners need
538:
is known as an "open fontanelle", which occurs when the skull bones at the top of the head fail to close. The problem is often found in conjunction with hydrocephalus, which is a condition in which too much fluid is found within and around the brain, placing pressure on the brain and surrounding
539:
tissues. Often the head will appear dome-shaped, and the open fontanelle is noticeable as a "soft spot" on the top of the dog's head. The fluid-filled spaces within the brain, known as ventricles, also become swollen. The increased pressure damages or prevents the development of brain tissue.
346:. This pulsating action is how the soft spot got its name – fontanelle is borrowed from the old French word fontenele, which is a diminutive of fontaine, meaning "spring". It is assumed that the term spring is used because of the analogy of the dent in a rock or earth where a spring arises.
294:
Two smaller fontanelles are located on each side of the head, more anteriorly the sphenoidal or anterolateral fontanelle (between the sphenoid, parietal, temporal, and frontal bones) and more posteriorly the mastoid or posterolateral fontanelle (between the temporal, occipital, and parietal
303:
of the bones of the skull causes the anterior fontanelle to close over by 9 to 18 months. The sphenoidal and posterior fontanelles close during the first few months of life. The closures eventually form the sutures of the neurocranium. Other than the anterior and posterior fontanelles, the
38:
349:
Parents may worry that their infant may be more prone to injury at the fontanelles. In fact, although they may colloquially be called "soft-spots", the membrane covering the fontanelles is extremely tough and difficult to penetrate.
508:
Sometimes there is a third bigger fontanelle other than posterior and anterior ones in a newborn. In one study, the frequency of third fontanelles in an unselected population of newborn infants was 6.3%. It is very common in
278:
is a diamond-shaped membrane-filled space located between the two frontal and two parietal bones of the developing fetal skull. It persists until approximately 18 months after birth. It is at the junction of the
342:
The fontanelle may pulsate, and although the precise cause of this is not known, it is normal and seems to echo the heartbeat, perhaps via the arterial pulse within the brain vasculature, or in the
745:
270:). The posterior fontanelles ossify within 6–8 weeks after birth. This is called intramembranous ossification. The mesenchymal connective tissue turns into bone tissue.
666:
957:
123:
291:, however, it is often late in closing at 8–24 months or may never close. Examination of an infant includes palpating the anterior fontanelle.
543:
to be very careful, since any injury or bumps to the animal's head could cause significant brain damage, as well as conditions like epilepsy.
99:
374:. Increased cranial pressure in infants may cause the fontanelles to bulge or the head to begin to enlarge abnormally. It can occur due to:
950:
559:
357:. Once they are closed, most of the brain is inaccessible to ultrasound imaging, because the bony skull presents an acoustic barrier.
299:
During birth, fontanelles enable the bony plates of the skull to flex, allowing the child's head to pass through the birth canal. The
513:
and some congenital infections. If present, the physician should rule out serious conditions associated with the third fontanelle.
558:
breed standard states that the skull of the
Chihuahua should be domed, with or without the molera being present. However, the
943:
526:
In apes the fontanelles fuse soon after birth. In chimpanzees the anterior fontanelle is fully closed by 3 months of age.
687:"USMLE Step 2: Secrets".editor1=Theodore X. O'Connell.editor2=Adam Brochert.book=USMLE Step 2: Secrets.ed=3rd.page=271
597:
782:
451:
191:
both during birth and later as the brain expands faster than the surrounding bone can grow. Premature complete
437:
The fontanelles may be enlarged, may be slow to close, or may never close, most commonly due to causes like:
118:
662:
482:
20:
487:
1135:
585:
477:
288:
82:
772:
Clinical
Neuroanatomy. 25th ed. New York: Lange Medical /McGraw-Hill, Medical Pub. Division, 2003.
1037:
609:
492:
354:
262:. At birth, the skull features a small posterior fontanelle with an open area covered by a tough
1161:
1027:
130:
106:
94:
1140:
1069:
424:
371:
309:
905:
1171:
1064:
1032:
555:
402:
250:
845:
8:
1130:
1059:
922:
274:
263:
203:
1074:
992:
305:
861:
717:
865:
883:
1017:
980:
857:
378:
267:
231:
196:
176:
832:
812:
705:
1086:
573:
562:(FCI) standard for the Chihuahua lists an open fontanelle as a disqualification.
551:
284:
259:
255:
87:
333:
The anterior fontanelle is generally the last to close between 12 and 18 months.
1166:
1125:
1120:
1044:
935:
769:
472:
467:
280:
227:
172:
634:
1155:
1049:
1022:
510:
457:
446:
441:
390:
223:
111:
972:
418:
384:
327:
The sphenoidal fontanelle is the next to close around 6 months after birth;
300:
219:
192:
188:
869:
827:
807:
700:
414:
242:
239:
164:
19:
This article is about the human anatomical feature. For other uses, see
1002:
396:
330:
The mastoid fontanelle closes next from 6 to 18 months after birth; and
235:
160:
136:
985:
387:– swelling (inflammation) of the brain, most often due to infections
324:
The posterior fontanelle generally closes 2 to 3 months after birth;
287:. The fetal anterior fontanelle may be palpated until 18 months. In
343:
168:
42:
The skull at birth, showing the anterior and posterior fontanelles
1115:
997:
535:
497:
266:, where the two parietal bones adjoin the occipital bone (at the
822:
820:
1099:
1094:
1012:
695:
693:
547:
207:
184:
1007:
817:
370:
A very tense or bulging anterior fontanelle indicates raised
320:
In humans, the sequence of fontanelle closure is as follows:
180:
70:
690:
884:"Open Skull Bones May, May Not Be Sign of Deadly Disorder"
187:. Fontanelles allow for stretching and deformation of the
49:
37:
667:
Center for
Academic Research and Training in Anthropogeny
413:
A sunken (also called "depressed") fontanelle indicates
254:
is triangle-shaped. It lies at the junction between the
353:
Fontanelles allow the infant brain to be imaged using
218:An infant's skull consists of five main bones: two
54:
The skull at birth, showing the lateral fontanelles
906:"American Kennel Club – Chihuahua breed standard"
534:One of the more serious problems that can affect
1153:
965:
627:
399:– infection of the membranes covering the brain
843:
951:
175:) between the cranial bones that make up the
876:
16:Anatomical feature of the infant human skull
740:
738:
428:Anterior fontanelle of a 1-month-old infant
958:
944:
48:
36:
663:"Age of Closure of Fontanelles / Sutures"
381:– premature fusion of the cranial sutures
735:
423:
337:
234:, which allow movement that facilitates
844:Chemke, Juan; Robinson, Arthur (1969).
656:
654:
652:
603:Cranial sutures shown from top of head.
1154:
939:
560:Fédération Cynologique Internationale
393:– a buildup of fluid inside the skull
649:
565:
660:
13:
14:
1183:
550:, is a recognized feature of the
608:
596:
584:
572:
516:
915:
898:
837:
546:An open fontanelle, known as a
452:Intrauterine growth restriction
923:"FCI Chihuahua breed standard"
800:
775:
763:
710:
681:
230:. These are joined by fibrous
1:
862:10.1016/S0022-3476(69)80457-9
718:"Online Etymology Dictionary"
620:
966:Compound structures of skull
360:
213:
7:
521:
432:
21:Fontanelle (disambiguation)
10:
1188:
365:
315:
18:
1108:
1085:
971:
850:The Journal of Pediatrics
408:
195:of the sutures is called
129:
117:
105:
93:
81:
69:
64:
59:
47:
35:
30:
1136:pterygomaxillary fissure
828:MedlinePlus Encyclopedia
808:MedlinePlus Encyclopedia
701:MedlinePlus Encyclopedia
503:
478:Cleidocranial dysostosis
289:cleidocranial dysostosis
787:www.hopkinsmedicine.org
529:
493:Osteogenesis imperfecta
488:Neonatal hypothyroidism
846:"The third fontanelle"
833:Fontanelles – enlarged
463:Rarer causes include:
429:
312:are also significant.
131:Anatomical terminology
1141:pterygopalatine fossa
706:Fontanelles – bulging
427:
372:intracranial pressure
338:Clinical significance
310:sphenoidal fontanelle
813:Fontanelles – sunken
591:Anterior fontanelle.
556:American Kennel Club
403:Shaken baby syndrome
251:Posterior fontanelle
1131:infratemporal fossa
637:. TheFreeDictionary
275:Anterior fontanelle
204:anterior fontanelle
202:After infancy, the
886:. Terrificpets.com
783:"Craniosynostosis"
770:Waxman, Stephen G.
722:www.etymonline.com
661:Beasley, Melanie.
483:Congenital rubella
430:
306:mastoid fontanelle
161:anatomical feature
1149:
1148:
566:Additional images
155:) (colloquially,
145:
144:
140:
1179:
960:
953:
946:
937:
936:
930:
929:
927:
919:
913:
912:
910:
902:
896:
895:
893:
891:
880:
874:
873:
841:
835:
824:
815:
804:
798:
797:
795:
793:
779:
773:
767:
761:
760:
758:
756:
742:
733:
732:
730:
728:
714:
708:
697:
688:
685:
679:
678:
676:
674:
658:
647:
646:
644:
642:
631:
612:
600:
588:
576:
379:Craniosynostosis
206:is known as the
197:craniosynostosis
167:comprising soft
137:edit on Wikidata
134:
76:fonticuli cranii
52:
40:
28:
27:
1187:
1186:
1182:
1181:
1180:
1178:
1177:
1176:
1152:
1151:
1150:
1145:
1104:
1087:Facial skeleton
1081:
967:
964:
934:
933:
925:
921:
920:
916:
908:
904:
903:
899:
889:
887:
882:
881:
877:
842:
838:
825:
818:
805:
801:
791:
789:
781:
780:
776:
768:
764:
754:
752:
744:
743:
736:
726:
724:
716:
715:
711:
698:
691:
686:
682:
672:
670:
659:
650:
640:
638:
633:
632:
628:
623:
616:
613:
604:
601:
592:
589:
580:
577:
568:
532:
524:
519:
506:
458:Premature birth
435:
411:
368:
363:
355:ultrasonography
340:
318:
285:sagittal suture
260:lambdoid suture
256:sagittal suture
216:
141:
55:
43:
24:
17:
12:
11:
5:
1185:
1175:
1174:
1169:
1164:
1147:
1146:
1144:
1143:
1138:
1133:
1128:
1126:temporal fossa
1123:
1121:zygomatic arch
1118:
1112:
1110:
1106:
1105:
1103:
1102:
1097:
1091:
1089:
1083:
1082:
1080:
1079:
1078:
1077:
1072:
1067:
1062:
1052:
1047:
1045:cranial cavity
1042:
1041:
1040:
1035:
1030:
1020:
1015:
1010:
1005:
1000:
995:
990:
989:
988:
977:
975:
969:
968:
963:
962:
955:
948:
940:
932:
931:
914:
897:
875:
856:(4): 617–622.
836:
816:
799:
774:
762:
734:
709:
689:
680:
648:
625:
624:
622:
619:
618:
617:
614:
607:
605:
602:
595:
593:
590:
583:
581:
578:
571:
567:
564:
531:
528:
523:
520:
518:
515:
505:
502:
501:
500:
495:
490:
485:
480:
475:
473:Apert syndrome
470:
468:Achondroplasia
461:
460:
455:
449:
444:
434:
431:
410:
407:
406:
405:
400:
394:
388:
382:
367:
364:
362:
359:
339:
336:
335:
334:
331:
328:
325:
317:
314:
297:
296:
292:
281:coronal suture
271:
228:occipital bone
224:parietal bones
215:
212:
163:of the infant
143:
142:
133:
127:
126:
121:
115:
114:
109:
103:
102:
97:
91:
90:
85:
79:
78:
73:
67:
66:
62:
61:
57:
56:
53:
45:
44:
41:
33:
32:
15:
9:
6:
4:
3:
2:
1184:
1173:
1170:
1168:
1165:
1163:
1162:Human anatomy
1160:
1159:
1157:
1142:
1139:
1137:
1134:
1132:
1129:
1127:
1124:
1122:
1119:
1117:
1114:
1113:
1111:
1107:
1101:
1098:
1096:
1093:
1092:
1090:
1088:
1084:
1076:
1073:
1071:
1068:
1066:
1063:
1061:
1058:
1057:
1056:
1053:
1051:
1050:Base of skull
1048:
1046:
1043:
1039:
1036:
1034:
1031:
1029:
1026:
1025:
1024:
1021:
1019:
1016:
1014:
1011:
1009:
1006:
1004:
1001:
999:
996:
994:
991:
987:
984:
983:
982:
979:
978:
976:
974:
970:
961:
956:
954:
949:
947:
942:
941:
938:
924:
918:
907:
901:
885:
879:
871:
867:
863:
859:
855:
851:
847:
840:
834:
830:
829:
823:
821:
814:
810:
809:
803:
788:
784:
778:
771:
766:
751:
747:
741:
739:
723:
719:
713:
707:
703:
702:
696:
694:
684:
668:
664:
657:
655:
653:
636:
630:
626:
615:infant skull.
611:
606:
599:
594:
587:
582:
575:
570:
569:
563:
561:
557:
553:
549:
544:
540:
537:
527:
517:Other animals
514:
512:
511:Down syndrome
499:
496:
494:
491:
489:
486:
484:
481:
479:
476:
474:
471:
469:
466:
465:
464:
459:
456:
453:
450:
448:
447:Hydrocephalus
445:
443:
442:Down syndrome
440:
439:
438:
426:
422:
420:
416:
404:
401:
398:
395:
392:
391:Hydrocephalus
389:
386:
383:
380:
377:
376:
375:
373:
358:
356:
351:
347:
345:
332:
329:
326:
323:
322:
321:
313:
311:
307:
302:
293:
290:
286:
282:
277:
276:
272:
269:
265:
261:
257:
253:
252:
248:
247:
246:
244:
241:
237:
233:
229:
225:
221:
220:frontal bones
211:
209:
205:
200:
198:
194:
190:
186:
182:
178:
174:
170:
166:
162:
158:
154:
150:
138:
132:
128:
125:
122:
120:
116:
113:
110:
108:
104:
101:
98:
96:
92:
89:
86:
84:
80:
77:
74:
72:
68:
63:
58:
51:
46:
39:
34:
29:
26:
22:
1054:
973:Neurocranium
917:
900:
888:. Retrieved
878:
853:
849:
839:
826:
806:
802:
790:. Retrieved
786:
777:
765:
753:. Retrieved
749:
725:. Retrieved
721:
712:
699:
683:
671:. Retrieved
639:. Retrieved
635:"fontanelle"
629:
545:
541:
533:
525:
507:
462:
436:
419:malnutrition
412:
385:Encephalitis
369:
352:
348:
341:
319:
301:ossification
298:
273:
249:
217:
201:
193:ossification
189:neurocranium
156:
152:
148:
146:
100:A02.1.00.027
75:
25:
1172:Neonatology
746:"Fontanels"
579:Fontanelle.
554:breed. The
415:dehydration
165:human skull
65:Identifiers
1156:Categories
1070:sphenoidal
1055:Fontanelle
1003:Stephanion
890:24 October
621:References
397:Meningitis
236:childbirth
226:, and one
169:membranous
149:fontanelle
31:Fontanelle
1065:posterior
1038:posterior
792:4 October
755:3 October
750:Boundless
552:Chihuahua
361:Disorders
214:Structure
157:soft spot
1060:anterior
1028:anterior
993:Asterion
981:Calvaria
673:24 April
641:24 April
522:Primates
433:Enlarged
344:meninges
308:and the
264:membrane
177:calvaria
159:) is an
153:fontanel
1116:dacryon
1075:mastoid
998:Pterion
870:4241462
727:2 April
669:(CARTA)
536:canines
498:Rickets
366:Bulging
316:Closure
295:bones).
232:sutures
173:sutures
88:D055762
60:Details
1100:Gonion
1095:Nasion
1033:middle
1023:Fossae
1018:Lambda
1013:Bregma
986:Diploë
868:
548:molera
454:(IUGR)
409:Sunken
268:lambda
243:growth
222:, two
208:bregma
185:infant
183:or an
171:gaps (
1167:Skull
1008:Inion
926:(PDF)
909:(PDF)
504:Third
240:brain
181:fetus
179:of a
135:[
124:75437
71:Latin
1109:Both
892:2012
866:PMID
794:2022
757:2016
729:2016
675:2013
643:2013
530:Dogs
283:and
258:and
238:and
151:(or
95:TA98
83:MeSH
858:doi
417:or
119:FMA
112:431
107:TA2
1158::
864:.
854:75
852:.
848:.
831::
819:^
811::
785:.
748:.
737:^
720:.
704::
692:^
665:.
651:^
421:.
245:.
210:.
199:.
147:A
959:e
952:t
945:v
928:.
911:.
894:.
872:.
860::
796:.
759:.
731:.
677:.
645:.
139:]
23:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
