Table 1.

Detailed review of 27 facial sutures, by region. Abbreviations of the articulations correspond to the labels in Figure 1. Includes timing of closure, notable growth functions, and all documented cases of premature closure in the literature. Abbreviations are as follows: M = metopic, FN = frontonasal, FM = frontomaxillary, FZ = frontozygomatic, FL = frontolacrimal, SZ = sphenozygomatic, FE = frontoethmoidal, LM = lacrimomaxillary, EL = ethmoidolacrimal, EM = ethmoidomaxillary, ZM = zygomaticomaxillary, NM = nasomaxillary, PMx = pterygomaxillary, ZT = zygomaticotemporal, IN = internasal, NE = nasoethmoidal, SV = septovomerine, IMx = intermaxillary, MP = midpalatal, IM = intermandibular, SO = sphenooccipital, SE = sphenoethmoidal, FS = frontosphenoidal, SP = sphenoparietal, SS = sphenosquamosal, PM = parietomastoid, OM = occipitomastoid, CT = computed tomography.

								Clinical Consequences of Premature Closure in Humans
		Type of articulation			Timing of closure			In humans
Region	Articulation	True Suture	Synchondrosis	Symphysis	In humans	In Animal (if limited human studies)	Notable functions of suture growth	Cases of isolated synostosis	Involvement in non-syndromic craniosynostosis	Involvement in syndromic craniosynostosis	Animal models of isolated synostosis
Frontal	M				CT: Starts at 3 months, completes by 9 months		Transverse frontal bone growth, across supraorbital ridge	Non-syndromic trigonocephaly (raised midline ridge, hypotelorism, possible neuropsychologic disturbances)
	FN				Cadaveric: Starts in 40s, completes in 50s		Protrusion of the nasal complex		Calandrelli et al.: Synostosed in 78% of trigonocephaly subjects Udayakumaran et al.: Synostosedin 100% of trigonocephaly subjects. Contributes to metopic angulation Miri et al.: Contributes to facial twist in unilateral coronal synostosis		Nelson & Williams: Hypertelorism, snout shortening, midface hypoplasia (mice) Babler et al.: Midface shortening (rabbits)
	FM				Cadaveric: Does not start until 7th-8th decade		Protrusion of the maxilla		Calandrelli et al.: Synostosed in 70% of trigonocephaly subjects. Synostosis predicts trigonocephaly severity Miri et al.: Contributes to facial twist in unilateral coronal synostosis
	FZ				Cadaveric: Starts in 8th decade, completes in 10th		Inferolateral displacement of the zygoma	Currarino: Frontal flattening, small/round orbit, broadened/shortened lateral orbital rim	Barrabé et al.: Synostosed in some unilateral coronal synostosis cases Genitori et al.: Synostosed in some trigonocephaly cases. May contribute to posterior mispositioning of the zygoma
	FL				Prolonged patency	Ateles monkeys: Closes late in adult life
Orbital	SZ				Cadaveric: Starts in 5th decade, completes in 6th			Currarino: One case of synostosis concomitant with frontozygomatic synostosis. Contributes to lateral orbital wall broadening/shortening	Rogers et al.: Can be synostosed in unilateral frontosphenoidal synostosis. Contributes to plagiocephaly (frontal flattening, orbital rim recession) Genitori et al.: Synostosed in 7% of trigonocephaly subjects	Kreiborg & Bjork: Synostosed in postmortem Crouzon skull. Laterally deviated lateral orbital walls
	FE				Cadaveric: Starts in 40s, completes by early 50s				Hoffman & Mohr: If involved in unilateral coronal synostosis, more severe anterior fossa shortening, pterion thickening, orbital shallowing Genitori et al.: Synostosed in severe trigonocephaly subjects, contributing to hypotelorism	Francel et al.: Synostosed in Apert and Crouzon Runyan et al.: Synostosed in 100% of Pfeiffer and Apert subjects, 33% of Crouzon Calandrelli et al.: Synostosed in 50% of Apert subjects, 78% of Crouzon, 67% of Pfeiffer. Anterior/ middle cranial fossa shortening
	LM				Prolonged patency	Ateles monkeys: Closes late in adult life Presbytis monkeys: Does not close
	EL				Cadaveric: Starts in mid 30s, completes by age 50
	EM				Cadaveric: Starts and completes in late 40s to 50s
Maxillary	ZM				CT: Starts age 10-15 Cadaveric: Some patency through 7th decade		Protrusion of maxilla Inferolateral displacement of the zygoma			Calandrelli et al.: Synostosedin 26% of syndromic infants (4 Crouzon, 1 Pfeiffer). Severe maxillary retrusion and reduced SNA angle. Involvement indicates higher severity facial skeletal deficit, exacerbates maxillary retrusion	Thimaporn et al.: Nasomaxillary complex asymmetry, constrained downward/ forward displacement of the maxilla/ zygoma (guinea pigs)
	NM				Cadaveric: Does not begin until 60s-70s				Miri et al.: Synostosed in 62% of unilateral coronal synostosis subjects. Contributes to facial twist
	PMx				CT: Starts in mid teens		Protrusion of maxilla
Lateral	ZT				Cadaveric: Significant closure does not start until 7th decade			Rogers et al.: Delayed progressive midface/ orbital asymmetry, cranial base angulation, nasal deviation. Maxillary retrusion, thickened lateral orbital wall/zygomatic body (compensatory growth) Sullivan et al.: Progressive unilateral midfacial and frontal retrusion. Nose/chin deviated toward fused suture. Shortening of zygomatic arch, greater sphenoid wing, temporal bone, and frontal bone		Kreiborg & Bjork: Synostosed in postmortem Crouzon skull
Nasal	IN				Cadaveric: Starts in 20s, completes after age 30				Udayakumaran et al.: Synostosed in all trigonocephaly subjects. Contributes to metopic angulation and hypotelorism Calandrelli et al.: Synostosed in 78% of metopic synostosis subjects
	NE				Patent through mid-teens at least (based on critical growth roles through adolescence)		Nose and nasal airway development through the mid-teens Septovomerine may also contribute to maxillary protrusion
	SV							Haug & Foss: Deep facial trauma can cause premature ossification of the septovomerine and consequent midface growth disruption. Also asymmetric nasal deformity, septal deviation, obstructed airway
Palatal	IMx				Cadaveric: Mostly closed by age 18, variable patency in 20s		Transverse maxillary growth	Transverse maxillary hypoplasia, possible severe malocclusion
	MP				CT and cadaveric: Starts in teens, completion varies considerably					Kreiborg & Bjork: Synostosed in postmortem Crouzon skull. Hypoplastic maxilla in vertical and transverse dimensions
Mandibular	IM				Cadaveric: Ossifies by 7-8 months, completely closed by 12 months						Wang et al.: Narrowed mandible with missing mandibular teeth (mice exposed to all-trans retinoic acid)
Basal	SO				CT: Starts at age ~12, completes at ~15 in females CT: Starts at ~13, completes at ~17 in males		Midfacial growth, cranial base lengthening			Goldstein et al.: Significantly premature closure in Apert, Crouzon, and Pfeiffer patients (average of fusion is 3.5 years) Tahiri et al.: Premature closure in Crouzon. Midface deficit McGrath et al.: Significantly premature closure in Apert. Not premature in Muenke	Rosenberg et al.: Severe midface retrusion (rabbit)
	SE				CT: Starts at age 2, completes by age 15			Burdi et al.: Isolated fusion in warfarin-exposed fetus. Severe exorbitism	Rogers et al.: Involved in one case of unilateral frontosphenoidal synostosis. Frontal flattening, orbital rim depression/recession	Runyan et al.: Synostosed in 75% of Pfeiffer subjects, 50% of Apert subjects. Not synostosed in Crouzon Calandrelli et al.: Synostosed in 50% of Apert subjects, 11% of Crouzon, 67% of Saethre-Chotzen. Variable middle cranial fossa shortening. Not synostosed in Pfeiffer
Circummeatal	FS				CT: Starts at age 5, completes by age 15		Anteroposterior lengthening of cranial base from birth to age 7	Francel et al: Frontal plagiocephaly phenotype Rogers et al.: Ipsilateral flattening, contralateral bossing, orbital rim depression/recession Puente-Espel et al.: Ipsilateral frontal flattening/ retrusion, inferolateral positioning of ipsilateral orbit with compensatory medial elongation	Showalter et al.: If synostosis occurs in unilateral coronal synostosis, it blunts the harlequin orbital deformity and can delay diagnosis	Kreiborg et al.: Bilateral synostosis in Apert skull. May contribute to cranial base shortening Kreiborg & Bjork: Synostosed in Crouzon skull Seeger & Gabrielsen: In Apert and Crouzon. Frontal shortening, anterior cranial fossa shortening, orbital shallowing Runyan et al.: Synostosed in 50% of Pfeiffer and Apert subjects. Not synostosed in Crouzon Calandrelli et al.: Synostosed in 100% of Apert and Saethre-Chotzen subjects, 44% of Crouzon, 33% of Pfeiffer. Variable middle cranial fossa shortening
	SP				CT: Starts before age 7, completes during teen				Lambert & Wineski: Can be involved in scaphocephaly with sagittal synostosis	Cohen & Kreiborg: In Apert, retrusion/ elevation of the supraorbital wings. Disrupted eyebrows, forehead skin wrinkling Runyan et al.: Synostosed in 100% of Pfeiffer subjects, 33% of Crouzon, and 50% of Apert Calandrelli et al.: Synostosed in 50% of Apert subjects, 56% of Crouzon, and 67% of Pfeiffer and Saethre-Chotzen. Variable anterior/ middle cranial base shortening
Circummeatal	SS				CT: Starts at age 2, completes by age 6				Sakamoto et al.: Suture growth is arrested in unilateral coronal synostosis. Shortened sphenoid greater wing and temporal bone	Kreiborg & Bjork: Synostosed in Crouzon skull. Laterally deviated lateral orbital walls Runyan et al.: Synostosed in 100% of Pfeiffer subjects, 67% of Crouzon, and 50% of Apert Calandrelli et al.: Synostosed in 50% of Apert subjects, 78% of Crouzon, and 67% of Pfeiffer. Variable anterior/ middle cranial base shortening
	PM				CT: Starts in 40s-50s, completes after age 70				Jimenez et al.: Unilateral posterior plagiocephaly without lambdoid synostosis, but with parietomastoid and occipitomastoid synostosis. Anterior displacement of ear. Compensatory frontal bossing, malar protrusion	Runyan et al.: Synostosed in 100% of Pfeiffer subjects, 67% of Crouzon, and 50% of Apert Calandrelli et al.: Synostosed in 100% of Apert and Crouzon subjects, 67% of Saethre-Chotzen, and 33% of Pfeiffer. Variable anterior/ middle cranial base shortening
	OM				CT: Partially patent through late teens					Coll et al.: Synostosis in Crouzon starting at age 2 Runyan et al.: Synostosed in 75% of Pfeiffer subjects, 67% of Crouzon, and 50% of Apert Calandrelli et al.: Synostosed in 50% of Apert subjects, 67% of Crouzon, and 33% of Pfeiffer. Variable anterior cranial base shortening