International Journal of Health Sciences and Research www.ijhsr.org ISSN: 2249-9571

Original Research Article

Morphometric Evaluation of Anterior Fontanelle: A Fetal Cadaveric Study

Vinodhini Periyasamy, Mamatha H, Suhani, Antony Sylvan D’souza, Prasanna, Keerthana Prasad

Department of Anatomy, Kasturba Medical College, Manipal - 576104.

Corresponding Author: Vinodhini Periyasamy

Received: 11/06//2014 Revised: 04/08/2014 Accepted: 12/08/2014

ABSTRACT

Background: The frontal bone is ossified from two primary centers, each half of the bone ossifies from a single center which appears between 6 and 7 weeks of the fetal life and is situated above the supra orbital margin. At birth the frontal bone is composed of two pieces, separated by the inter frontal suture and also separated from the parietal bones by the diamond-shaped, membrane filled anterior fontanelle that persists until 18 months after birth, which allows development and growth of the brain and the skull. Aim: The study was designed to measure the dimensions & extent of anterior fontanelle in fetal skulls in order to assess the dimensions of the fontanelle and its related clinical significance. Materials &Methods: The anterior fontanelle of 25 fetal skulls was studied, in the Department of Anatomy, Kasturba Medical College, and Manipal. The mean and standard deviation of the morphometric measures were tabulated. Results: In our study, the measurements of the antero posterior & transverse chord length measurements were done both in dry skull & pericranium of the scalp. The mean and standard deviations are determined. 25 dry skulls were placed in the exact environment considering the same distance, light source & angulation and photographed. The photographs were correlated with Digital image analyzer - TISSUE QUANT. The mean total surface area was calculated. Conclusion: Assessment of the tension and size of the anterior fontanelle is important in the routine examination of newborn infants when considering, respectively, possible disturbances of intracranial pressure and disorders of skeletal development. The knowledge of the normal variation in anterior fontanelle size may be of help in the early diagnosis of congenital hypothyroidism or provide a clue to other disorders of skeletal development.

Keywords: Anterior Fontanelle, hydrocephaly, hypothyroidism, tissue quant, Intracranial pressure

INTRODUCTION together with the temporary interfrontal Anterior fontanelles are unpaired, suture, they form the boundaries of a unossified areas located in the vault of the diamond-shaped the anterior fontanelle and fetal skull, allowing the prolific growth of hence rhomboid in shape. (1) the skull. It is situated at the junction of Fontanelles are the fibrous, sagittal, coronal & frontal sutures, membrane-covered gaps formed when more corresponding to bregma. Beneath it lays the than two cranial bones are juxtaposed, as superior sagittal sinus in the fetal skull, opposed to sutures. Examination of a

International Journal of Health Sciences & Research (www.ijhsr.org) 107 Vol.4; Issue: 9; September 2014 newborn’s fontanels offers the physician a calipers along the skull surface as in fig1a, window into the infant’s developing brain 2a.The mean and standard deviation of the and general state of health. (1,2) morphometric measures of anterior The normal fontanelle varies largely fontanelle were tabulated. in shape and time of closure. The flat bones Assessment of total surface area was of the skull develop as part of the done using digital morphometric image membranous neuro cranium. During fetal analysis (TISSUE QUANT). It is illustrated and postnatal life, the membranous bones in fig.3. enlarge by resorption centrally and by apposition of new layers at the edges of the RESULTS sutures. (3,4) The word “Anterior fontanelle” Table 1 depicts the measurements done in means little fountain or spring. They persists the dry skull. from18 months till 2 years after birth, Table 2 depicts the measurements done in allowing the development and growth of the the pericranium of fetal scalp: brain and the skull. The eventual closure of DIGITAL MORPHOMETRICS: the fontanelle presumably occurs by All photographs were correlated with transformation of fibroblasts into osteoblasts Digital image analyzer - TISSUE QUANT. by the end of 2 years. (4) The mean total surface area was calculated. Aim TOTAL SUFACE AREA = 5047.3 (no. of The study was designed to measure pixels) the dimensions &extent of anterior Figure 1: Measurements of anterior- fontanelle in fetal skulls in order to assess posterior and transverse chord length the dimensions of the fontanelle and its estimated in the dry skull using Vernier related clinical significance. Calipers Figure 2: Measurements of anterior- MATERIALS & MATHEODS posterior and transverse chord length The anterior fontanelle of 25 fetal estimated in the pericranium of fetal scalp dry skulls & pericranium of the scalp in the using Vernier Calipers spontaneously aborted fetuses, with no Figure 3: Digital Morphometrics: detectable congenital malformations or Comparison of the Original (left) and maternal history of risky pregnancy were numerical model (right). studied, in the Department of Anatomy, TABLE 1: MEASUREMENTS-DRY SKULL: Kasturba Medical College, and Manipal. MEAN STANDARD Calculations of the anteroposterior VALUE DEVIATION ANTERIO- 41.6mm 5.55. and transverse chord length dimensions POSTERIOR CHORD were measured.The antero-posterior chord TRANSVERSE 34.3mm 3.80 length is the distance between the points CHORD respectively the ”anteromost” and the TABLE 2: MEASUREMENTS-PERICRANIUM OF FETAL ”posterior-most” extremities of the SCALP: MEAN STANDARD membranous gap along the axis delimiting VALUE DEVIATION the contact between the right and the left ANTERIO- 39.4mm 4.26 POSTERIOR CHORD halves of the skull. The illustration is given TRANSVERSE 31.2mm 3.22 in Fig. 1, 2. The transverse chord length is CHORD also measured manually using vernier

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MEASUREMENTS - DRY FETAL SKULL BONES

Fig 1,1a; Measurements of anterior-posterior and transverse chord length estimatedusing Vernier Calipers.

MEASUREMENTS - PERICRANIUM OF THE FETAL SCALP

Fig 2,2a; Measurements of anterior-posterior and transverse chord length estimated using Vernier Calipers.

DIGITAL MORPHOMETRICAL ANALYSIS

Fig 3: original (left) and numerical model (right).

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DISCUSSION detect cortical and white-matter The diagnosis of an abnormal abnormalities, such as degenerative diseases, fontanel requires an understanding of the and document the extent of calvarial masses. wide variation of normal. At birth, an infant [5,6] has six fontanels. The anterior fontanel is the Disorders associated with increased largest and most important for clinical intracranial pressure can cause a bulging evaluation. [1,2] anterior fontanel. The most common From our study the dimensions of disorders are meningitis, encephalitis, anterior fontanelle provides valuable hydrocephalus, hypoxic-ischemic injury, information regarding the alterations in the trauma, and intracranial hemorrhage. The size of them during pathological situations. primary cause of a sunken fontanel is An unusually large or small size of fontanel usually the dehydration. [7,8] may be a clue for the identification of From the lateral to the medial edges, intracranial or system disorders. The the bony plates gave way to islands of bone newborn’s skull should be evaluated for and then to aggregates of plump fibroblasts shape, circumference, suture ridges, and size surrounding pink osteoid like material. The of anterior and posterior fontanels. Size is eventual closure of the fontanelle calculated by the average of the presumably occurs by transformation of anteroposterior and transverse dimensions fibroblasts into osteoblasts. These form bony Large fontanelle occurs in a number islands usually joins to the main skull plate. of disorders of skeletal morphogenesis such [9-11] as achondroplasia, hypophosphataemia, Digital anthropology provides osteogenesis imperfecta, and congenital powerful tools for investigations and hypothyroidism. The most common ”revisiting” existing studies and theories on condition associated with enlarged human evolution and in particular on growth fontanelles and delayed closure are due to and development processes. The general increased intracranial pressure, congenital framework of the current research is the hypothyroidism, Down syndrome, Rickets application of the modern medical imaging etc. [3,4] techniques to the geometric morphometric. Palpation of the fontanel in the In a more precise way, we are interested in upright position may reveal a normal, slight retrieval of geometric computer models of pulsation. If the fontanels are closed and anatomical shapes for some collection of intracranial pressure has increased, specimens and the simulation of the percussion produces a “cracked pot” sound geometric morphometric analysis through (dull, lacking resonance), known as digital image processing. [12,13] Macewen’s sign. Bridging of bone over a A new research field, we call digital suture, an indistinct suture, or sclerosis morphometric, could emerge and make along the suture margins indicates fusion of possible to perform morphological studies as the frontal bones. If the anterior fontanel is analysis on different types of supports such open, ultrasonographyis useful to evaluate as collections of specimens, realor synthetic ventricular dilatation. A computed objects or computer geometric models, for tomographic (CT) scan can detect a fused different types of shape features as suture, dilated ventricles, enlarged distances, angles, outlines, landmarks, subarachnoid space, brain size, or surface or volume features, according to anintracranial or extracranial mass. different types of metrics as Euclidean. [13,14] Magnetic resonance imaging (MRI) can International Journal of Health Sciences & Research (www.ijhsr.org) 110 Vol.4; Issue: 9; September 2014

Morphometric data measurements The results indicate that the aplanation are performed according to a chosen principle as used by the Hewlett Packard protocol using chosen metrics and applied transducer maybe used to measure on chosen shape features of the computer intracranial pressure without puncture in geometric model. The correlation with age is infants. [23-25] not so high; the closure of the anterior An elaborate physical examination fontanelle was used, along with the feature helps the physician determine which of the inner ear, to estimate the age of death imaging modality, such as plain films, of the validation of the object reconstruction ultrasonography, computed tomographic is determined on the ability to perform scan, or magnetic resonance imaging, to use reliable morphometric measures. [14,15] for diagnosis, for interpretation of the root The present study contributes to both cause to provide the earliest interventional digital image processing and digital therapy. anthropology. The diagnosis of an abnormally large or small anterior fontanelle CONCLUSION at birth presumes the knowledge of normal The knowledge of size of anterior variations in its size, possible variations in fontanelle is useful in evaluating the size of the anterior fontanelle in relation to abnormal situations of failure of calvarial gestational age and intrauterine growth. In and brain growth. Assessment of the tension the absence of raised intracranial pressure and size of the anterior fontanelle is the most important reason for assessing important in the routine examination of anterior fontanelle size in the neonate is the newborn infants when considering, possible early diagnosis of congenital disturbances of intracranial pressure and hypothyroidism, since its early detection and disorders of skeletal development. The treatment has an important bearing on diagnosis of an abnormally large or small ultimate mental progress. [16-18] anterior fontanelle at birth, possess an The closure of the fontanelle must be alarming threat to the clinicians for largely dependent on the growth of the interventional therapies. bones bordering on it. The anterior Knowledge of the normal variation fontanelle closed earlier in the male than in in anterior fontanelle size helps in the early the female. This distinguishes fontanelle diagnosis of congenital hypothyroidism or closure from skeletal maturation in which provides a significant factor for disorders of the female lead is well known. [19, 20] skeletal development. A simple method is It is suggested that non-invasive described for measuring the area of the techniques for measuring intracranial anterior fontanelle at birth. Normal values in pressure should be suitable for use in the preterm and term infants suggest unsedated infant and should be capable of enlargement of the fontanelle with measuring pressure continuously. The gestational age. tension of a membrane containing a fluid is Considerable skeletal growth determined by the pressure of the contained retardation undoubtedly occurs in many fluid and the elasticity of the membrane. small-for-dates babies, so that it is likely that [21,22] large fontanelle size in these infants is a Use of aplanation transducer, APT- further manifestation of intrauterine growth 16transducer (Hewlett Packard) uses a retardation suggesting of a delay in osseous modification of the aplanation principle and maturation of the skull bones. was evaluated for use as a 'fontanometer'. International Journal of Health Sciences & Research (www.ijhsr.org) 111 Vol.4; Issue: 9; September 2014

ACKNOWLEDGEMENTS fontanel. Childs Nerv Syst. 1997;13: Our sincere thanks to Mrs. Keerthana 626-8. Prasad, Assistant Professor, Manipal center 12. Green M. Pediatric Diagnosis: for information sciences, Manipal for her Interpretation of symptoms and signs help and the support for our project. in children and adolescents. 6th ed. Philadelphia: Saunders, 1998. REFERENCES 13. Mackenzie A, Shann F, Barnes G. 1. Susan Standring. Gray's Anatomy Clinical signs of dehydration in The anatomical basis of clinical children. Lancet 1989;2:1529-30. practice, 40th Edition, 14. Desbarats,P, Gueorguieva, al, Digital spain.Churchill Livingstone; Anthropology for effective retrieval Elsevier,2008,416-418.. of the Anterior fontanelle,. Image 2. Richard S Snell, Clinical Neuro Anal Stereol - Sep 2009, volume: 1- Anatomy,7th edition,Wolter Kluwer 5. (India) pvt ltd, New Delhi,2010,46- 15. Hildebrandt K, Polthier K, 467. Wardetzky M (2005). On the 3. Adeyemo AA, Omotade OO. convergence of metric and geometric Variation in fontanelle size with properties of polyhedral surfaces. In: gestational age. Early Hum Dev Research Report 05-24. 1999;54: 207-14. 16. Mehta A, Wright BM, Short C. 4. Joseph Kiesler, The Abnormal Clinical fontanometry in the Fontanel ,American family physician newborn. Lancet 1988:754-6. 2547 June 15, 2003 ,no 12,vol 17. L. Crome , Peter E. S, 67,2540-2552.. (Hydrencephaly). Sept 30, 1957.235- 5. M Sundaresan, M Wright, Anatomy 246. and development of the fontanelle. 18. Smith DW, Popich GA. Large August 20, 2012. 386-389. fontanels in congenital 6. Sarla Mattur,Ram Kumar et al, hypothyroidism: A potential clue Anterior fontanel size, Indian towards its recognition. J Pediatr pediatiucs Vol 31-Feb 1994. 1972, 80: 753. 7. Sadler TW, Langman J. Langman’s 19. Scammon RE. The geometric Medical embryology. 8th ed. relationships of the anterior Philadelphia: Lippincott Williams & fontanelle in infancy. Anat Rec Wilkins, 2000,173-175. 1930;46: 349-63. 8. Duc G, Largo RH. Anterior fontanel: 20. Kirkpatrick, H Engleman, Symptoms size and closure in term and preterm and signs of progressive infants. Pediatrics 1986; 78: 904-8. hydrocephalus, Department of 9. Popich GA, Smith DW. Fontanels: Neurology, Royal Hospital for Sick Range of normal size. J Pediatr 1972, Children, Edinburgh, 1989, 64, 124- 80:749-752 128. 10. Indira Bai K, Subrahmanyam MVG. 21. Robinson DC, Hall R, Munro DS. Fontanels: Range of normal size. Grave's disease an unusual Indian Pediatr 1973, 10: 667-670. complication: Raised intracranial 11. Martinez-lage JF, Torroba A,. pressure due to premature fusion of Cranial fasciitis of the Anterior skull sutures. Arch Dis Child 1962, 44: 252. International Journal of Health Sciences & Research (www.ijhsr.org) 112 Vol.4; Issue: 9; September 2014

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How to cite this article: Periyasamy V, Mamatha H, Suhani et. al. Morphometric evaluation of anterior fontanelle a fetal cadaveric study. Int J Health Sci Res. 2014;4(9):107-113.

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