Description--Skull long (GSL: 19.9 mm) and narrow; lambdoidal and sagittal crests poorly developed; braincase rounded and narrow (BBC: 8.2 mm); mastoid processes poorly developed (MAB: 9.6 mm); rostrum long and narrow; postorbital region constricted, measuring about 3.4 mm; internal margin of the upper internal incisors united from the bases to the apices; two upper premolars, P3 alveolus smaller than P4; M3 alveolus much smaller than the M1 and M2.
Description--Skull small (GLS: 13.8 mm) and delicate; braincase narrow (BBC: 6.6 mm) and elevated in lateral view; rostrum short (LNR: 5.6 mm); postorbital region depressed; sagittal and lambdoidal crests poorly developed; premaxillae completely separated; upper incisors and canines separated by a short diastema; upper canines with a well developed external cingulum; P2 and P3 united and separated from P4 by a short diastema; P3 alveoli less than P2 and smaller than half the size of P4; P4 antero-posteriorly expanded; molars ectolophs W-shaped; M2 larger than M1 and M3; premolars forming a continuous row from the canine to the molar.
Description--Skull short (GLS: 16.3 to 17.1 mm); braincase laterally expanded (BBC: 8.7 mm); rostrum short (LNR: 6.7 mm), robust and heavy; postorbital region very constricted (INC: 4.1 to 4.5 mm); mastoidal processes pointed (MAB: 10.3 mm); well developed sagittal crest, extending from the posterior end of the nasals to the lambdoidal crest, being highest in the region of the postorbital constriction; upper incisors completely fill the space between the canines; canines with external cingulum very developed; P4 broad, in occlusal view almost as broad as M1; molars broad, ectolophs of M1 and M2 W-shaped; M3 smaller than the M1 and M2, with the talon very reduced, having a V-shape.
In synostosis, the skull is somewhat brachycephalic with prominent ridging over the lambdoidal sutures.
Initial evaluation of patients with flattening of the posterior occipital parietal skull should include close assessment of the ear and palpation of the lambdoidal suture.