Anthropometric evaluation of dysmorphology in craniofacial anomalies Treacher Collins syndrome.код для вставкиСкачать
AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 74:441-451(1987) Anthropometric Evaluation of Dysmorphology in Craniofacial Anomalies: Treacher Collins Syndrome J.C. KOLAR, I.R. MUNRO, AND L.G. FARKAS Humana Advanced Surgical Institutes, Medical City, Dallas, Texas 75230 (J.C.K., LR.M.);Department ofsurgery, University of Toronto, and Division ofPlastic Surgery, The Hospital for Sick Children, Toronto, Ontario (L.G.F.) KEY WORDS Anthropometry, Z-score ABSTRACT Advances in surgical techniques for correction of craniofacial anomalies have necessitated the development of objective pre- and postoperative quantitative assessments. Standard anthropometric techniques, supplemented by additional methods oriented to specific clinical problems, have proved useful in defining surface dysmorphology in craniofacial patients. A series of 77 surface measurements of the head and face and 41 proportions were determined in 20 preoperative patients with Treacher Collins syndrome, a rare congenital defect of the first and second branchial arches. To permit comparison with age- and sex-specific data for healthy North American children, the patient data were converted to standard (Z) scores. To test the hypothesis Z = 0, Student’s t-test was performed on all variables. The anthropometric findings verified many of the clinical findings in this syndrome. In addition, a number of previously unreported defects were found. The cranium was low and short with a low, narrow forehead and a narrow cranial base. The face was narrow and shallow, the mandible long and narrow, and the lower face receding. The eye fissures were short with a n antimongoloid inclination, but the orbits were hyperteloric. The nasal root was high and wide, the nasofrontal angle open, and the bridge inclination low. The Iabial fissure was narrow, and the ears were microtic. Except in the nasal root the defects were hypoplastic. Most of these defects were either horizontal or anteroposterior. Recognition of the defective areas and their contribution to disproportions of the head and face is important in the development of surgical strategies. Recent refinements in surgical correction techniques necessitating objective pre- and postoperative assessments have led to a proliferation of applications of quantitative methods to the study of craniofacial anomalies. Anthropometric evaluation is part of the routine craniofacial assessment process at the Humana Advanced Surgical Institutes, Dallas, and the Hospital for Sick Children, Toronto. Gradually, standard anthropometric measurements (Martin, 1914; HrdliEka, 1920) have been augmented to address the specific needs of the reconstructive craniofacia1 surgeon (Farkas, 1981; Farkas and Munro, 1987). The teams’ standard anthropometric evaluation batteries now consist of 142 measurements of the head and face. Control data have been established for North American Caucasians from birth to young adulthood: age- and sex-specific nor@ 1987 ALAN R. LISS, INC ma1 values for 6- to 18-year-oldswere derived from a study of 1,312 Toronto and Montreal schoolchildren (Farkas, 1981); sex-specific control values were developed for young adults in several studies of young Torontonians (Farkas et al., 1984, 1985; Farkas and Munro, 1987) (L.G. Farkas, unpublished data); age- and sex-specific control data for children under 6 years of age, derived from West German norms (HajniB, 1974),were statistically adjusted to the North American population (Csima and Szathmary, 1987). Based on these control data, 56 standard ageand sex-specific proportion indices have been constructed to describe the range of normal relationships among the measurements (Table 1). Received August 19,1986;accepted March 9,1987. 442 J.C. KOLAR, I.R. MUNRO, AND L.G. FARKAS TABLE 1. Anthropometric evaluation battery Variable and abbreviation' Cranial measurements Maximum cranial breadth (eu-eu) Minimum frontal breadth (ft-ft) Cranial base width (t-t) Calva height (v-tr) Anterior head height (v-n) Special head height (v-en) Auricular head height (right) (v-PO,r) Auricular head height (left) (v-PO,1) Head-upper face height (v-sn) Craniofacial height (v-gn) Forehead height I (tr-g) Forehead height I1 (tr-n) Maximum cranial length (g-op) Head circumference Forehead inclination Proportions Cephalic index (eu-edg-op) Head width-auricular head height index (right) (eu-edv-po,r) Head width-auricular head height index (left) (eu-edv-po, 1) Frontobasal index (ft-ftk-t) Frontozygomatic index (ft-ftizy-zy) Calva-head height index (v-triv-n) Forehead-head height index (tr-dv-n) Head-craniofacial height index (v-dv-gn) Special head-craniofacial height index (v-edv-gn) Facial measurements Maximum facial breadth (bizygomatic breadth) Infants to young adults Age group for control data 6-year-oldsto young adults Young adults X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X (ZY-ZY) Bigonial breadth (go-go) Supraorbital arc (t-g-t) Maxillary arc (t-sn-t) Mandibular arc (t-gn-t) Supraorbital half arc (right) (g-t s, r) Supraorbital half arc (left) (g-t s, 1) Maxillary half arc (right) (sn-t s, r) Maxillary half arc (left) (sn-t s, 1) Lower subnasale-aural surface (right) (sn-obi s, r) Lower subnasale-aural surface (left) (sn-obi s, 1) Labio-aural surface (right) (ch-t s, r) Labio-aural surface (left) (ch-t s, I) Mandibular half arc (right) (gn-t s, r) Mandibular half arc (left) (gn-t s, 1) Lower gnathion-aural surface (right) (gn-obi s, r) Lower gnathion-aural surface (left) (gn-obi s, 1) Supraorbital-aural depth (right)(g-t, r) Supraorbital-aural depth (left) (g-t, 1) Upper face depth (right) (n-t, r) Upper face depth (left) (n-t, 1) Orbito-tragial distance (right) (ex-t, r) Orbito-tragial distance (left) (ex-t, 1) Orbito-gonial distance (right) (ex-go, r) Orbito-gonial distance (left) (ex-go, 1) Middle face depth (right) (sn-t, r) Middle face depth (left) (sn-t, 1) Lower subnasale-aural depth (right) (sn-obi, r) Data for Treacher Collins patients X X X X X X X X X X X X X X X X X X X X X X X X X X X X X (continued) 443 DYSMORPHOLOGY IN TREACHER COLLINS SYNDROME TABLE 1. A nthropometric eualuation battery (continued) Variable and abbreviation Lower subnasale-aural depth (left) (sn-obi, 1) Labio-aural depth (right) (ch-t, r) Labio-aural deDth (left) (ch-t. 1) Lower face depth (right) (gn-t, r) Lower face depth (left) (gn-t, 1) Upper gnathion-aural depth (right) (gn-obs, r) Upper gnathion-aural depth (left) ign-obs, 1) Lower gnathion-aural depth (right) (gn-obi,r) Lower gnathion-aural depth (left) (gn-obi,1) Total face height (tr-gn) Face height (n-gn) Upper face height (n-sto) Lower face height (sn-gn) Mandible height (sto-gn) Upper profile height (tr-prn) Lower profile height (prn-gn) Special upper face height (g-sn) Special face height (en-gn) Chin height (sl-gn) Upper face inclination (g-sn) Leiber inclination (g-1s) Lower face inclination (sn-pg) Lower third face inclination (li-pg) Chin inclination (sl-pg) General face inclination (g-pg) Proportions Facial index (n-gn/zy-zy) Mandibulofacial index (go-go/zy-zy) Upper facial index (n-sto/zy-zy) Mandibular index (sto-gdgo-go) Upper face-face height index (n-stoh-gn) Lower face-face height index (sn-gdn-gn) Mandibulofacial height index (sto-gdn-gn) Upper-middle third face depth index (right) (n-t, r/sn-t, r) Upper-middle third face depth index (left) (n-t, l/sn-t, 1) Middle-lower third face depth index (right) (sn-t, r/gn-t, r) Middle-lower third face depth index (left) (sn-t, Ugn-t, 1) Upper cheek depth-height index (right) (ex-t, r/ex-go, r) Upper cheek depth-height index (left) (ex-t, Uex-go, 1) Mid-cheek-middle third face deDth index (ch-t, I/sn-t, 1) Lower face arcs index (t-sn-t/t-gn-t) Chin-mandible height index (sl-gn/sto-gn) Face-craniofacial height index (n-glv-gn) Lower face-head height index (sn-gn/v-n) Upper-lower profile index (tr-prlprn-gn) Orbital measurements Intercanthal width (en-en) Biocular width (ex-ex) Eye fissure width (right) (ex-en, r) Eye fissure width (left) (ex-en, 1) Eye fissure height (right) (ps-pi, r) Eye fissure height (left) (ps-pi, 1) Infants to young adults Age group for control data 6-year-oldsto young adults Young adults X X X Data for Treacher Collins patients X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X (continued) 444 J.C. KOLAR, I.R. MUNRO, AND L.G. FARKAS TABLE 1. Anthropometric evaluation battery (continued) Variable and abbreviation Upper lid height (right) (0s-ps, r) Upper lid height (left) (0s-ps, 1) Lower lid height (right) (pi-or, r) Lower lid height (left) (pi-or, I) Orbital-eyebrow height (right) (sci-or, r) Orbital-eyebrow height (left) (sci-or, 1) Eye fissure inclination (right) (ex-en) Eye fissure inclination (left) (ex-en) Orbital rim inclination (right) (0s-or,r) Orbital rim inclination (left) (0s-or, I) Proportions Intercanthal index (en-eiex-ex) Orbital index (ex-en, l/en-en) Eye fissure index (ps-pi, liex-en, 1) Biocular-skull base width index (ex-exit-t) Intercanthoalar index (en-en/al-al) Nasal measurements Nasal root width (mf-mf) Nasal width (al-al) Columella width (sn’-sn’) Ala thickness (right) Ala thickness (left) Nostril floor width (right) (sbal-sn, r) Nostril floor width (left) (sbal-sn, 1) Ala length (right) (ac-prn, r) Ala length (left) (ac-prn, 1) Ala surface length (right) (ac-prn s, r) Ala surface length (left) (ac-prn s, 1) Nose height (n-sn) Bridge length (n-prn) Nasal root height (right) (en-m’ sag, r) Nasal root height (left) (en-m’ sag, 1) Nasal root length (right) (en-m’, r) Nasal root length (left) (en-m’, 1) Columella length (right) (sn-c’, r) Columella length (left) (snc’, 1) Nasal tip protrusion (sn-prn) Nasal bridge inclination Nostril inclination (right) Nostril inclination (left) Bridge deviation (right) Bridge deviation (left) Columella deviation (right) Columella deviation (left) Nasolabial angle Nasofrontal angle Proportions Nasal index (al-alhsn) Nose height-biocular width index (n-siex-ex) Nose height-face width index (n-sdzy-zy) Nasofacial index (n-sn/n-gn) Nasozygomatic index (al-al/zy-ay) Nasal root-nose width index (mf-mf/al-al) Nasal tip protrusion-width index (sn-prial-al) Nasal root depth-intercanthal width index (en-m’ sag, Uen-en) Infants to young adults Age group for control data 6-year-oldsto young adults Young adults Data for Treacher Collins patients X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X (continued) 445 DYSMORPHOLOGY IN TREACHER COLLINS SYNDROME TABLE 1. Anthropometric evaluation battery (continued) Variable and abbreviation Nasal root depth-tip protrusion index (en-m’ sag, lisn-prn) Nasal root-ala length index (en-m‘,liac-prn, 1) Nasal bridge index (n-prin-sn) Orolabial measurements Philtrum width (cph-cph) Mouth width (ch-ch) Labial fissure half length (right) (ch-sto, r) Labial fissure half length (left) (ch-sto, 1) Upper lip height (sn-sto) Cutaneous upper lip height (sn-1s) Cutaneous lateral upper lip height (right) (sbal-ls’, r) Cutaneous lateral upper lip height (left) (sbal-ls’, 1) Upper vermilion height (1s-sto) Lower vermilion height (sto-li) Cutaneous lower lip height (li-sl) Lower lip height (sto-sl) Upper vermilion arc (ch-1s-ch) Lower vermilion arc (ch-li-ch) Upper lip inclination (sn-1s) Lower lip inclination (li-sl) Mouth inclination Proportions Labial index (sn-stoich-ch) Upper lip-nose height index (sn-stoin-sn) Upper lip-mandible height index (sn-stokto-gn) Vermilion height index (1s-stoisto-li) Cheilozygomatic index (ch-chhy-zy) Lower liu index (sto-slich-ch) Vermilion-cutaneous lower lip height index (sto-li/li-sl) Lower-upper lip index (stodsn-sto) Lower lip-mandible height index (sto-slisto-gn) Lower lip-chin height index (sto-slid-gn) Aural measurements Ear length (right) (sa-sba, r) Ear length (left) (sa-sba, 1) Ear width (right) (pra-pa, r) Ear width (left) (pra-pa, 1) Ear insertion height (right) (obs-obi,r) Ear insertion height (left) (obs-obi,1) Ear protrusion (right) Ear protrusion (left) Ear inclination (right) Ear inclination (left) Ear location (right) Ear location (left) Proportions Auricular index (pra-pa, lisa-sba, r) Ear-face height index (sa-sba, lin-gn) Infants to young adults Age group for control data 6-year-oldsto young adults Young adults Data for Treacher Collins patients X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X ‘Landmarks and measurements have been described previously (Farkas, 1981; Farkas et al., 1984). X X 446 J.C. KOLAR, I.R. MUNRO, AND L.G. FARKAS Fig. 1. Anteroposterior and lateral photographs of a 9-year-old male Treacher Collins patient showing the typical dysmorphology presented in Table 2. The present study is the first in a series describing basic preoperative surface dysmorphology in a number of craniofacial syndromes currently being studied by the craniofacial assessment team. One of the rarest of the anomalies with which the team is concerned is Treacher Collins syndrome, or mandibulofacial dysostosis, a defect of the first and second branchial arches. The anomaly has been recognized for 140 years (Thomson, 1846).The first morphological description was by Berry (18891, who described an affected mother and daughter. The syndome was named for E. Treacher Collins (1900),who identified the marked malar hypoplasia that is one of the major signs of the anomaly (Fig. 1). Research in the past 50 years has greatly extended our knowledge of the craniofacial morphology of this syndrome, based on qualitative studies (Franceschetti, 1944;Franceschetti and Klein, 1949; Klein, 1953; Rogers, 1964; Klimen, 1979; Smith, 1982) and radiographic analyses (Stovin et al., 1960; Garner, 1967; Dahl et al., 1975; Roberts et al., 1975) (Table 2). One detailed cephalometric study has been reported (Dagys, 1977),and a quantitative study of cranial base abnormalities in Treacher Collins and other craniofacial anomalies was published recently (Grayson et al., 1985). TABLE 2. Qualitative signs in Treacher Collins svndrome Malar deficiencies Mandibular hypoplasia Tongue-shaped hair extension onto cheek Antimongoloid eye fissures Lower eyelid coloboma Lower lash deficiency Relatively large nose Open nasofrontal angle Cleft palate Ear defects Malformed auricle External ear canal Conductive deafness Quantitative assessment of craniofacial anomalies is a recent development. So far, four studies reporting such quantitative results in this syndrome have been published (Farkas, 1978a,b; Farkas et al., 1981; Kolar et al., 1985), all presenting only a limited number of variables. This paper presents a detailed statistical analysis of Treacher Collins syndrome based on our standard anthropometric evaluation battery. MATERIALS AND METHODS The study sample consisted of 20 preoperative patients (9 males and 11 females) with I'reacher Collins syndrome, all North Amer- DYSMORPHOLOGYIN TREACHER COLLINS SYNDROME ican Caucasians ranging in age from two to 27 years. To permit comparison of the findings in this small group of patients who have a rare anomaly with the age- and sexspecific normal data, the patient data were converted t o standard (Z) scores. To test the hypothesis Z = 0, Student’s ttest was performed on all variables. Skewness of the Z-score distributions was calculated. Following Kreiborg (1981), a 0.01 confidence level with a Z-score range of k 1.20 was used to define a normal distribution. The metric findings were intrepreted conservatively. This approach was taken for three reasons. First, the patient sample is small. In addition, control data for the standard anthropometric evaluation battery were not available for all variables in all age groups. Finally, not all measurements were taken in all patients for whom normal control data were available, owing mainly to lack of patient cooperation, particularly in the youngest patients. We eliminated from further analysis variables not reported in at least half of the patients. A value of p < 0.01 was taken to indicate significant abnormalities. The abnormal findings were divided into two categories: highly significant (mean Zscore outside the range of +2.58), and significant (mean Z-score within this range but statistically significantly different from normal). Student’s t-test was used to determine whether differences in paired measurements were significant. RESULTS By eliminating variables that were not reported in at least 10 of the 20 patients, we reduced the number from 198 to 118 (77 measurements and 41 proportions). The results of the Z-score analysis are presented in Table 3. Of the 77 measurements evaluated, 46 (59.7%) differed significantly from the controls. Highly significant differences accounted for 27 of the 46 abnormal measurements. Of the 41 proportions examined, 17 (41.5%) differed significantly from normals. Seven differences were highly significant. None of the 118 variables was skewed. Among the cranial variables, 7 of 12 measurements were significantly different from the normal values. One of nine proportion indices was significantly different. In the face, the difference from the controls was significant in 20 of 25 measurements, 447 highly significant in 18 of them, including all 14 paired lateral facial depth measurements. Of 13 proportion indices, five were significantly different, four of them highly so. Six of eight orbital measurements were significantly different from normal, four highly significantly different. Only the heights of the eye fissures were normal. Of five proportion indices, two showed significant differences. In the nose, 8 of 18 measurements differed significantly from normal, but only one difference was highly significant. Seven of 10 proportion indices differed significantly, four highly significantly. Only one of 10 orolabial measurements and one of five porportion indices were significantly different from the control data. Neither difference was highly significant. All four auricular measurements differed highly significantly from the controls. One of the two proportion indices was significantly different. No significant difference was found in any paired measurement. The highly significant differences are shown in Table 4. For the lateral facial depth measurements, the largest Z-score is given. For other paired measurements, the larger of the two Z-scores is shown. The quantitative results are summarized in Table 5. DISCUSSION A comparison of the major qualitative features in Treacher Collins syndrome reported in the clinical literature with our quantitative results indicates that most measureable characteristics are confirmed by the anthropometric data; only the relatively large nose is not apparent in our study. This study also identified many other previously unreported dysmorphologies. Abnormalities such as the hair extension, lower lid defects, cleft palate, and conductive deafness were not amenable to anthropometric analysis. Apart from defects of the external ear canal, the clinical literature does not report any abnormalities of the neurocranium in this syndrome. In a previous study (Kolar et al., 1985), we noted a narrow cranial base width in the majority of these patients. The present study indicates that this is the most defective measurement. However, there are also other slight abnormalities in the width and height of the forehead, anterior cranial height, and craniofacial height and circum- 448 J.C. KOLAR, I.R. MUNRO, AND L.G. FARKAS TABLE 3. Abnormal dimensions and proportions in Treacher Collins syndrome N Mean Z-Score Minimum Maximum Probability 20 18 12 20 11 12 18 -1.88 -1.50 - 1.02 -0.98 -0.96 -0.92 -0.82 -5.30 -2.79 -2.49 -4.10 -2.36 -2.72 -2.42 +LOO +0.87 +0.24 +0.50 +0.27 f0.14 +0.94 0.0001 0.0001 0.01 0.001 0.01 0.01 0.01 18 1-2.51 - 1.66 +5.56 0.0001 20 20 20 11 18 12 -3.35 -3.31 -2.99 -2.88 -1.11 -1.01 -7.23 -5.31 -5.66 -7.69 -3.21 -2.35 -1.30 0.0001 0.0001 0.0001 0.01 0.01 0.01 10 10 12 13 13 12 12 10 13 13 18 18 10 18 -4.30 -4.02 -3.77 -3.77 -3.61 -3.57 -3.53 -3.33 -3.29 -3.23 -3.14 -3.04 -3.03 -2.90 -6.63 -7.48 -5.79 -5.81 -6.02 -6.03 -5.25 -5.21 -5.98 -6.24 -7.81 -6.65 -7.11 -7.46 -2.06 -1.60 -1.53 -1.50 -1.48 -1.02 -1.29 -0.37 +0.19 -0.10 -0.02 -0.62 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.01 0.0001 20 18 20 20 12 +3.05 +3.03 +2.74 +2.04 +1.32 +1.36 -0.05 - 1.00 - 1.67 -0.10 +6.56 +9.56 +7.23 +8.96 +3.00 0.0001 0.001 0.0001 0.01 0.01 13 13 13 13 20 20 -4.02 -3.97 -3.21 -3.20 -1.31 +0.62 -11.94 -11.94 -7.85 -7.08 -3.44 -0.85 -1.41 -1.20 -0.29 -0.29 +0.11 +2.25 0.001 0.001 0.0001 0.0001 0.0001 0.01 13 20 -2.32 +1.91 -4.37 -0.20 -0.36 +4.64 0.0001 0.0001 11 -0.08 12 12 12 12 12 19 +2.70 +2.27 +1.93 +1.88 + 1.57 - 1.43 +1.39 -1.16 +5.04 +4.37 +3.67 +4.27 +4.15 -0.30 +4.08 f0.63 0.001 0.0001 0.0001 0.0001 0.01 0.001 0.01 0.001 13 20 10 12 11 +3.01 +2.72 +2.68 +2.68 +2.56 +6.07 +4.38 +3.88 +5.39 +4.31 0.0001 0.0001 0.0001 0.001 0.0001 Cranial Dimensions t-t ft-ft tr-n g-op v-n "gn Circumference Cranial proportions ft-ft/zy-zy Facial dimensions ZY-ZY t-sn-t t-gn-t Lower face inclination go-go tr-gn Lateral depths gn-obi, r gn-obi, 1 sn-t, r sn-t s, r gn-t s, r n-t, r gn-t, r ch-t, r sn-t s, 1 gn-t s, 1 sn-t, 1 n-t, 1 ch-t, 1 gn-t, 1 Facial proportions n-gnizy-zy sto-gdgo-go n-stolzy-zy sto-gn/n-gn n-gdv-gn Orbital dimensions Eye fissure inclination, r Eye fissure inclination, 1 ex-en, 1 ex-en, r ex-ex en-en Orbital proportions ex-eden-en en-edex-ex Nasal dimensions mf-mf Nasofrontal angle en-m', r en-m', 1 en-m' sag, 1 Nasal bridge inclination en-m' sag, r sn-prn Nasal proportions n-sdzy-zy al-al/zy-zy en-m'/ac-prn en-m' sag, l/sn-prn mf-mf 11 +0.78 +0.56 +0.27 -0.08 -3.38 -0.08 -3.00 t0.02 -0.80 +0.92 +0.10 +0.05 - 1.29 -0.53 +0.24 +LO3 1-0.47 -2.32 - 1.48 (continued) 449 DYSMORPHOLOGY IN TREACHER COLLINS SYNDROME TABLE 3. Abnormal dimensions and proportions in Treacher Collins syndrome (continued) n-sdex-ex sn-prdal-a1 Orolabial dimension ch-ch Orolabial proportion ch-clwzy-zy Ear dimensions sa-sba, r pra-pa, r pra-pa, 1 sa-sba, 1 Ear proportion sa-sbdn-gn N Mean Z-Score Minimum Maximum Probability 13 19 + 1.40 -0.94 +0.03 -2.78 +3.85 +1.48 0.001 0.01 20 -0.89 -2.21 +1.76 0.01 20 +1.33 -1.15 +3.89 0.01 19 19 19 19 -3.17 -3.04 -2.91 -2.70 -7.15 -11.35 - 10.24 -6.42 -0.22 +1.71 +0.72 -0.41 0.0001 0.01 0.01 0.0001 19 -2.47 -5.25 +0.36 0.0001 TABLE 4. The most significant dysmorphologies in Treacher Collins syndrome Variable Measurements Lateral facial depths Eye fissure inclination ZY -ZY t-sn-t ex-en sa-sba pra-pa t-gr-t Lower face inclination mf-mf Proportions n-gnizy-zy sto-gdgo-go n-snlzy-zy n-stolzy-zy al-allzy-zy en-m'lac-prn en-m' sag/sn-prn Mean Z score -4.30 -4.02 -3.35 -3.31 -3.21 -3.17 -3.04 -2.99 -2.88 +2.70 +3.05 +3.03 +3.01 +2.74 +2.72 +2.68 +2.68 ference, all being below average. The discrepancy between the short anterior head height and normal auricular head height most probably reflects the abnormal cranial base flexion reported in the cephalometric analysis (Grayson et al., 1985). The disproportion between the forehead and face widths demonstrates that the hypoplasia of the malar region is relatively greater than the narrowness of the forehead, although both measurements are significantly below average. Clinical reports of Treacher Collins syndrome emphasize the deficiency of the malar region. This defect is evident from the highly TABLE 5. Quantitative abnormalities in Treacher Collins syndrome Head Low, short cranium Narrow, low forehead Narrow cranial base Face Shallow facial depth Narrow face Long, narrow mandible Receding lower face Orbits Short, antimongoloid eye fissures Hyperteloric orbits Nose High, wide nasal root Open nasofrontal angle Low nasal bridge inclination Low nasal tip Lips and Mouth Narrow labial fissure Ears Microtic ears significant reduction of the maximum facial breadth in these patients. Apart from the lateral facial depths, this is the most damaged measurement in the face. The other clinically evident facial feature, mandibular hypoplasia, is reflected in the small mandibular arc, subnormal inclination of the lower face owing to the receding chin, and narrow mandible. Also, the mandible height tends to be increased (although only at the level of p < 0.05) because of recession of the chin point in the hypoplastic mandible. In addition to mandibular hypoplasia, our patients also exhibit maxillary hypoplasia, 450 J.C. KOLAR, I.R. MUNRO, AND L.G. FARKAS as shown in the short maxillary arc and middle third face depths. The short total face height reflects the short forehead previously noted. The paired lateral facial depth measurements are unusual. As Table 3 indicates, all of these measurements are strikingly abnormal. They are the most damaged measurements in the entire craniofacial complex. Other than one middle-third face-depth measurement in one patient, every lateral depth distance in our patient sample is below average. Even the paired lateral measurements excluded from this study because of small sample sizes show the same trend. Tensor analysis of the cranial base suggests an explanation for this phenomenon. The abnormal kyphosis of the cranial base in Treacher Collins syndrome reported by Grayson et al. (1985) shifts the entire face posteriorly, bringing it closer to the tragi, reducing the measurements taken from the tragi t o the facial midline. The facial and upper facial indices reflect the hypoplastic malar measurements in the presence of normal vertical measurements. The mandible is long relative to its width and for the face length, but it is not absolutely long at the level of p < 0.01. The face is long relative to the craniofacial height, because of the short anterior head height. In the orbital region, the defects of the lengths and inclinations of the eye fissures are highly significant. The eye fissures are short and have a subnormal, or antimongoloid, inclination. The biocular distance is significantly shorter than in controls, while the intercanthal distance is above average. This combination produces a disproportionately wide space between the eyes, or hypertelorism. The eye fissures also are short relative to the intercanthal distance. Except for a mildly, but significantly, reduced nasal tip protrusion, the defects in the nose are concentrated in the nasal root, which is high and wide with long sides. The high nasal root results in an open nasofrontal angle, as reported in the clinical literature. Combined with the below-average nasal tip protrusion, the high nasal root produces a low nasal bridge inclination. The relatively large nose indicated in the clinial literature is not evident in our quantitative findings. The apparent nasal disproportions are due mainly to defects in other regions, such as the malar hypoplasia or narrow biocular distance. However, the nasal root is relatively high and wide for the soft nose. The appearance of a large nose is accentuated by the lack of a clear separation between the nose and the forehead, resulting from the open nasofrontal angle produced by the high nasal root. The only abnormal measurement in the orolabial region is a narrower than average labial fissure. The proportion between the mouth width and maximum facial breadth again indicates the severe hypoplasia of the malar region. The ears are microtic in all our Treacher Collins patients. The reductions in length and width are proportionate, although the Zscore ranges indicate greater variability in ear width than ear length. The ear rudiments were short relative to the face length. In the 13 paired measurements the average measurements were shorter in the right side than the left side, but there was no significant difference. These results reflect only the normal asymmetry of the face (Farkas and Cheung, 1981). With one exception, the defects in Treacher Collins syndrome are the result of hypoplastic development of the head and face. As Table 3 demonstrates, the mean Z-scores for significantly differing measurements are negative, except in the area of the nasal root, including the intercanthal distance. In most cases, even the maximum Z-score for a hypoplastic measurement is below average. In addition, the data indicate that most of these defects are oriented either horizontally or anteroposteriorly (including lateral depth measurements). The only vertical defects are the microtic ears and the short forehead. Anthropometric analysis is a valuable tool in our understanding of craniofacial anomalies. It can identify defective areas not immediately apparent from qualitative observation. As one of a variety of quantitative methods, including cephalometry, biostereometrics, three-dimensional computer imaging, and others, it offers the clinician objective information about the nature and extent of craniofacial defects that is necessary in the planning of corrective treatment. ACKNOWLEDGMENTS We thank the Medical Publications Department, The Hospital for Sick Children, for their assistance in editing the manuscript. 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