SciELO - Scientific Electronic Library Online

vol.24 número1Impact of oral health care needs on health-related quality of life in adult HIV+ patientsMicroleakage of a self-adhesive resin cement after post cementation índice de autoresíndice de materiabúsqueda de artículos
Home Pagelista alfabética de revistas  

Servicios Personalizados




  • No hay articulos citadosCitado por SciELO

Links relacionados

  • No hay articulos similaresSimilares en SciELO


Acta Odontológica Latinoamericana

versión On-line ISSN 1852-4834

Acta odontol. latinoam. vol.24 no.1 Buenos Aires abr. 2011



Human temporomandibular joint disc: anatomy and measurements in prenatal development


Luis A. Giambartolomei, Mabel N. Brunotto, María E. Gómez de Ferraris

Department of Oral Biology, Faculty of Dentistry, National University of Córdoba, Córdoba, Argentina

CORRESPONDENCE Luis Augusto Giambartolomei Córdoba 287, Villa La Bolsa, Bº El Descanso, Dto. Santa María CP: X5189 – Córdoba – Argentina


The objective of this study was to determine morphological characteristics and measurements of the temporomandibular joint (TMJ) disc in human fetuses between 16 and 20 weeks of intrauterine life, and correlate it with oral-facial neuro-muscular maturing. Scanner images were used to record the length of the disc (D) and the thickness of its anterior, middle and posterior bands in TMJ anteroposterior vertical sections from human fetuses of 16, 18 and 20 weeks of intrauterine life (WIL). Mean disc length was 1.98 mm, 2.69 mm and 2.90 mm at 16, 18 and 20 WIL respectively, and measurements differed significantly between those ages. The thicknesses of the anterior, middle and posterior bands also differed significantly. The results give normal morphological data for D between 16 and 20 WIL. TMJ anatomy and measurements appear to be related and agree with the neuro-muscular maturation time at which sucking and swallowing reflexes begin before birth. It is known that these functions, as well as the neuro-muscular capacity to perform prenatal mandibular movements (opening and closing), begin at 14 to 15 weeks of prenatal development and are fully attained at about 20 weeks of development. Knowledge of this reference pattern may be of major importance to future research, for assessing jaw biomechanics and detecting alterations of TMJ and prenatal development of a vital human function – suckling in preterm infants.

Key words: Temporomandibular joint disc; Morphology; Embryonic development.


Disco de la articulación témporomandibular humana: estudio morfodimensional en período prenatal

El objetivo de este estudio fue determinar las caracteristicas morfologicas y dimensionales del disco de la articulacion temporomandibular (ATM) de fetos humanos entre las 16 y 20 semanas de vida intrauterina y correlacionarla con la maduracion neuro-muscular buco-facial. Mediante un analizador de imagenes se registro la longitud sagittal, el espesor de las bandas anterior, media y posterior del disco (D) en corte vertical anteroposterior de ATM de fetos humanos de 16, 18 y 20 semanas de vida intrauterina (SVI). La longitud promedio del disco fue de 1.98mm, 2.69mm y 2.90mm a las 16, 18 y 20 SVI respectivamente, encontrandose diferencias dimensionales significativas entre aquellas edades. Tambien los espesores anterior, intermedio y posterior de las bandas mostraron diferencias significativas entre los D de las edades estudiadas. Los resultados proporcionan datos morfologicos normales del D entre las 16 y 20 SVI. Los parametros anatomicos y dimensionales de la ATM encontrados, estarian relacionados y coinciden con el tiempo de maduracion neuro-muscular en el cual se inician los actos reflejos de succion y deglucion previa al nacimiento. Como es conocido aquellas funciones se inician entre las 14 o 15 semanas de gestacion, asi como la capacidad neuro-muscular para realizar los movimientos mandibulares prenatales (apertura y cierre) que se alcanzarian alrededor de las 20 semanas de desarrollo. El conocimiento de este patron de referencia puede ser de gran importancia para futuras investigaciones, para valorar la biomecanica mandibular y permitir reconocer alteraciones de la ATM y del desarrollo prenatal en una de las funciones vitales del ser humano, como es la lactancia en recien nacidos prematuros.

Palabras clave: Disco de la articulacion temporomandibular; Morfologia; Desarrollo embriologico.



The temporomandibular joint (TMJ) is one of the most complex joints in the human body. It connects the jaw to the cranium, enabling the jaw to move and fulfill a vital human function: suckling and feeding in newborn infants. Its alteration involves nutritional, neurological, sensorial, immunological and affective deficiencies, and affects normal oralmaxillofacial development. Early detection of dysfunctions that alter or prevent vital functions in the newborn infant is therefore needed in order to prevent these growth and development disorders1, 2. Many newborn infants do not start suckling, or do so in an uncoordinated, deficient way, due to various etiologies. There are many factors that may prevent a newborn infant from latching on to the nipple (breast or bottle), such as oral-maxillofacial anatomical and functional alterations, metabolic or central nervous system alterations and some first arch syndromes2-9.
Knowledge of the histology, anatomy and measurements of the TMJ, including embryological development, provides significant support to the understanding of the etiopathogenesis and physiopathogenesis of damaging dysfunctions. The subject has therefore been studied by many researchers, particularly from physiological and clinical standpoints, mainly during the post-natal period in humans3, 9-11. The morphology and measurements of the articular disc (D) during prenatal development have not been described in available literature, nor has a pattern of normality been determined for the articular disc during the prenatal stage. The formation of the articular disc is identified at the end of the embryonic period (twelve weeks). It develops from both blastemas – condylar and glenoid – (upper and lower portions of the disc respectively) showing its close relationship to the superior lateral pterygoid muscle and Meckel’s cartilage which gives rise to the malleus10,12.
It has been suggested that the oral-facial neuromuscular maturation needed for acquiring the sucking and swallowing reflexes before birth begins at 14 or 15 weeks gestation and is complete at about 20 weeks4,13. The formation and maturation of the condylar process at the expense of the secondary cartilage (condylar cartilage) and the neuromuscular capacity to perform the prenatal mandibular movements (opening and closing) are probably attained at approximately 20 weeks of development. Both mechanisms are essential to the development of reflex actions for feeding14,15. It should be noted that there is partial or global alteration of these functions in preterm infants, depending directly on gestational age1,6,7. Thus, these biomechanical functions may be altered in full-term and/or preterm infants. Based on this background, it could be determined whether TMJ anatomy and measurements are correlated to embryonic age, specifically, whether the TMJ is prepared for the biomechanical movement that results from the sucking and swallowing reflexes beginning approximately at the abovementioned age. This would allow resulting alterations to be identified, rehabilitated and/or prevented.


For the study of articular disc morphology and measurements, human fetuses fixed in 10% formalin were used (without apparent macroscopic anomalies), at gestational ages of 16, 18 and 20 weeks. These fetuses were from spontaneous abortions and were provided by the anatomic pathology service at Hospital Materno Neonatal (Ministry of Health of Cordoba Province, Argentina), unclaimed by their progenitors, with legal authorization for use in study purposes at the abovementioned service. Gestational age was determined for each specimen according to cephalocaudal length (Fig. 1), using the human development table16 (Table 1).

Fig. 1:
Fetus, gestational age 16 weeks. Cephalocaudal length 155 mm.

Table 1: Criterion for calculating gestational age – (Keith L. Moore, Clinical Embryology).

To dissect the TMJ area, a vertical preauricular incision was made between an upper semicircular, concave-up incision and a lower horizontal incision following the lower edge of the mandibular branch and body (Fig. 2).

Fig. 2:
Lateral view of head of fetus, gestational age 16 weeks, on which an H-shaped incision has been made to reach the temporal, masseter and TMJ regions.

The skin and subcutaneous cellular tissue were peeled back to expose the temporal and masseter muscles, which were also dissected to the articular capsule, but without touching it. At 1.5 centimeters peripheral to the TMJ, a cut at a depth of approximately 2 cm was performed above, below, in front of and behind it. The block was then moved in order to reach and release its medial wall using scissors, and finally the complete joint was removed as a block (articular eminence and temporal mandibular or articular fossa, mandibular condyle and all components of the soft tissues), fixed in 10% formalin and labeled (Fig. 3). A scalpel was then used to make an anteroposterior vertical cut (Fig. 4) under a stereoscopic microscope, beside and parallel to the squama temporalis, just above the superior wall of the joint where the zygomatic process begins, thus standardizing the sections so that they would be reproducible and errors minimized (Fig. 4). It is important to note that in fetuses and infants the mandibular fossa is not placed horizontally, but obliquely, running from lateral to medial and superior to inferior.

Fig. 3:
Front, right of figure: cutaneous and subcutaneous tissues (Ж) peeled back, allowing view and access to temporal, masseter and articular (TMJ) regions.

Fig. 4:
Picture of a frontal section of TMJ from a fetus 18 WIL, showing the vertical anteroposterior cut line (dotted line – cut line) that the sections were cut along for the morphological study of the articular disc. The right side of the figure is the medial side, and the left is the lateral.

All samples were examined under stereoscopic microscope at 2x magnification. Screening criteria were having an undamaged bilaminar zone, and a sharp, clear image of the anterior edge of the section and its three bands, with no tears. Samples should be precise enough for the anterior and posterior edges of the disc (D) and the edges of each band thickness to be seen clearly. The anterior edge was taken as the vertex of the angle formed by the bifurcation of the anterior capsule fibers. The posterior edge was taken as the vertex of the angle formed by the bifurcation of the bilaminar area (Fig. 5).

Fig. 5: Vertical anteroposterior section of TMJ. Accurate sectioning of the sample allowed the following to be identified and recorded: (D: disc; A: anterior band; M: middle band; P: posterior band; s: superior; a: anterior; p: posterior) (fetus 18 WIL).

Two samples were taken from each of the 36 fetuses in the sampling universe, adding up to 72. They were documented with digital photographs at 2x magnification under a stereoscopic microscope, and only 36 samples (one from each fetus) were selected for the corresponding analysis of measurements according to the aims established in the study. The same stereoscopic microscope was used to make a digital image of a millimeter caliper gage to be used as a reference for measurements. The images were processed with special software (Image Pro-Plus) for different types of measuring. A measurement pattern was created, according to which all the measurements of the anatomical samples were recorded; following exactly the same sequence to ensure it was reproducible and to evaluate all samples under the same conditions, thus minimizing the margin of error. The measurements considered for the study were: 1: length of articular disc, for which the image processor was used to draw an anteroposterior line between the anterior and posterior edges described above, maintaining equal distance from the upper and lower edges, 2: the anterior band of the disc was measured from its upper to its lower edge in a line perpendicular to the one drawn to measure its length, and the software determined its thickest part, 3: the middle band was measured in the same way but the software determined the thinnest part, and 4: the posterior band, in the same way as the others, at its thickest part.
The samples were grouped according to different gestational ages (Table 2). Group I (GI): was made up of 9 (nine) TMJ samples from fetuses at 16 weeks of intrauterine life (WIL). Group II (GII): made up of 12 (twelve) TMJ samples from fetuses at 18 WIL, and Group III (GIII): made up of 15 (fifteen) TMJ samples from fetuses at 20 WIL.

Table 2: Groups according to gestational age.


The aim of analyzing the morphometric data of the articular disc was to relate the different measurements at the three gestational ages. The results from the 36 samples that were selected and processed are shown in Tables 3, 4, 5, 6, Fig. 6. The data showed homoscedasticty (homogeneity of variance, i.e. the variability in the response in each specimen is almost the same between samples) and normality, so an analysis of variance test (ANOVA) considering statistically significant differences with a value p<0.05 was performed for each characteristic (length of disc and thickness of anterior, middle and posterior bands).

Table 3: Comparison of anterior band thickness in the three groups.

Table 4: Comparison of middle band thickness in the three groups.

Table 5: Comparison of posterior band thickness in the three groups.

Table 6: Comparison of disc length in the three groups.

Fig. 6:
Mean value and standard deviation for each measurement of the articular disc in the three age groups.

For all measurements, statistically significant differences were found when GII and GIII were compared to GI. There was no difference between the two latter times (GII and GIII, i.e. between 18 and 20 weeks gestation). Figure 6 shows the arithmetical mean values of each measurement of the articular disc for the three age groups and relationship between median and the values that are not among the most frequent (but not rare). Table 7 summarizes the results for the different groups.

Table 7: Measurements of the articular disc of the temporomandibular joint in human fetuses.


On the sagittal plane, according to its thickness, the articular disc is divided into three bands17, 18. There is noticeable similarity between the thickness values at 18 and 20 WIL for the anterior and middle bands, interpreted as a plateau in growth during that stage of development, at least regarding the TMJ disc. On the coronal plane, in adults there is a disc eminence on the superior face and posterior band of the disc18, which is not present on the disc of 16 to 20 WIL fetuses (Fig. 5) because the function of the jaw is also different, joint movements that are generated by the action of associated muscles of mastication and driven and coordinated by the nervous system 19- 22. In other words, the joint biomechanics at five months’ development does not require the morphological configuration of an adult.
When a fetus and/or preterm or full-term infant performs sucking action, the mandibular condyle moves with the disc in posterior-anterior direction without any modification of the route from the mandibular fossa (MF) to the articular eminence (AE), which are almost flat in sagittal direction. In other words, the topography of the TMJ is directly related to the presence or absence of teeth and the mandibular function, and there is correlation between gestational age and the start of biomechanics, driven by sucking and swallowing reflexes in the embryonic stage at 20 WIL. Further research monitoring the mandibular/articular movement at that age, possibly during pregnancy, by means of ultrasonography, would complement this study.
Knowledge of joint morphology and biomechanics at 20 WIL and in infants would allow alterations of TMJ and its associated structures to be identified, preventing future dysfunction and post-natal anomalies in growth and development, and the implementation of appropriate therapies, enabling the infant to feed normally again. This means that it is important to include a dentist in the interdisciplinary health team so that in case of a joint disease, specific, biologically adequate treatment may be provided. To sum up, the measurements of the disc at 16, 18 and 20 WIL are significant in that they would allow pre-natal diagnosis of future TMJ alterations.


This work was supported by a grant from National University of Cordoba: SeCyT - Res. Nº 1657. The authors would like to thank the Anatomic Pathology Service at Hospital Materno Neonatal (Ministry of Health, Córdoba Province) for authorizing (allowing) the use of study materials and their facilities.


1. Daniels H, Devlieger H, Casaer P, Callens M, Eggermont E. Nutritive and non-nutritive sucking in preterm infants. J Dev Physiol 1986;8:117-121.         [ Links ]

2. Desarrollo neurologico del recien nacido a termino y prematuro; Saint-Anne S.;1977; Ed. Medica Panamericana.         [ Links ]

3. Medicina Bucal. Vol. II; Bermejo Fenoll A; Editorial Sintesis; 1998.         [ Links ]

4. Embriologia Humana y Biologia del Desarrollo. Capitulo 8; Carlson B; 2000; Editorial Harcourt.         [ Links ]

5. Crecimiento Maxilofacial; Enlow DH; 1998; Editorial Interamericana-Mcgaw-Hill.         [ Links ]

6. Neonatology pathophysiology and management of the newborn; Gordon B, Avery MD; 1981; Editorial: JB Lippincott Company.         [ Links ]

7. Hanlon MB, Tripp JH, Ellis RE, Flack FC, Selley WG, Shoesmith HJ. Deglutition apnoea as indicator of maturation of suckle feeding in bottle-fed preterm infants. Dev Med Child Neurol 1997; 39:534-542.         [ Links ]

8. Manual de Ortodoncia. Capitulo: Crecimiento y desarrollo facial; Moyers RE; 1992; Editorial Medica Panamericana.         [ Links ]

9. Pillemer FG, Masek BJ, Kaban L. Temporomandibular joint dysfunction and facial pain in children: an approach to diagnosis and treatment; Pediatrics 1987; 80: 565-570        [ Links ]

10. Histologia y Embriologia Bucodental. Capitulo 7: Articulacion Temporomandibular; Gomez de Ferraris ME, Campos Munoz A; 2000; Editorial Medica Panamericana.         [ Links ]

11. Pelegano JP, Nowysz S, Goepferd S. Temporomandibular joint contracture in spastic quadriplegia: effect on oralmotor skills Dev Med Child Neurol. 1994; 36:487-494.         [ Links ]

12. Dominguez M, Taramasso F, Rossano A, Manchini T, Gutierrez J. Conexiones ligamentosas entre la articulacion temporomandibular y el oido medio en el feto a termino. AOU 1999;67:13-18.         [ Links ]

13. Bosna J, Hepburn L, Josell S, Baker K. Ultrasound demonstration of tongue motions during suckle feeding. Dev Med Chid Neurol, 1990. 32: 223-229.         [ Links ]

14. Carranza M. Ferraris ME. Actis A. Simbron A. Diferenciacion Anatomica e Histologia de los componentes tisulares de la ATM. Acta Odontol Venez 1997 35: 41-45.         [ Links ]

15. Carranza M, Ferraris ME, Actis A, Simbron A. Gestational Tissular Changes of Human Temporomandibular Joint (TMJ). J Dent. Res1998; 77: 1119.         [ Links ]

16. Embriologia Clinica. Capitulo 6: Periodo fetal; Moore Keith L; 1975; Ed: Interamericana.         [ Links ]

17. Anatomia del Complejo Articular Craneomandibular – ATM; Giambartolomei LA; 2003; Publicaciones Universidad Nacional de Cordoba. Cordoba..

18. Anatomia Humana. Capitulo: Articulacion de la mandibula inferior con el craneo o articulacion temporomaxilar; Testut L, Latarjet A; 1954 Editorial Salvat.         [ Links ]

19. Lindblom G. On the anatomy and function of the temporomandibular joint. Acta Odontol Scand 1960;17: 7287 supp 28.         [ Links ]

20. Anatomia Odontologica Funcional y Aplicada. Capitulo 2; Figun ME, Garino RR; 1984; Editorial El Ateneo.         [ Links ]

21. Anatomia con Orientacion Clinica. Capitulo 7; Moore Keith L; 1996; Editorial Panamericana.         [ Links ]

22. Anatomia de la cabeza con enfoque odontoestomatologico. Capitulo 5: Articulacion temporomandibular; Velayos JL, Santana HD; 2001; Editorial Medica Panamericana. España.         [ Links ]

Creative Commons License Todo el contenido de esta revista, excepto dónde está identificado, está bajo una Licencia Creative Commons