Mandibular Condyle : Dimensions , Shapes , Function and Structural adaptation of the condyle

November 11, 2011 | By | Reply More

Mandibular Condyle : Dimensions , Shapes , Function and Structural adaptation of the condyle

Human condyles differ greatly in their shapes and dimen­sions (Solberg et al. 1985, Scapino 1997). From the time of birth to adulthood the medial-lateral dimension of the condyle increases by a factor of 2 to 2.5, while the dimen­sion in the sagittal plane increases only slightly (Nickel et al. 1997). The condyle is markedly more convex in the sagittal plane than in the frontal plane.

image14 Mandibular Condyle : Dimensions , Shapes , Function and Structural adaptation of the condyle

Condyle dimensions

Left: Width of condyle in the frontal plane (Solberg et al. 1985). The av­erage condylar width is significantly greater in men (21.8 mm) than in women (18.7 mm).

Center: Anteroposterior dimension of the central portion shown in the sagittal plane (Oberg et al. 1971; minimum and maximum in paren­theses).

Right: Anteroposterior dimension of the condyle in the horizontal plane. There is no significant differ­ence between men (10.1 mm) and women (9.8 mm).


image18 Mandibular Condyle : Dimensions , Shapes , Function and Structural adaptation of the condyle

Intercondylar distance

Left: Sex-specific data on the dis­tances between pairs of medial poles and lateral poles of the condyle (after Christiansen et al. 1987). The numbers given are aver­age values. A difference of 5-10 mm in the intercondylar dis­tance will have a corresponding ef­fect on the tracings of condylar movements and the accuracy of simulated movements in the articu­lator (see pp. 216 and 243).

Right: Schematic drawing illustrat­ing the intercondylar angle.


image17 Mandibular Condyle : Dimensions , Shapes , Function and Structural adaptation of the condyle

Condylar shapes in the frontal plane

According to Yale et al. (1963) 97.1 % of all condyles fall into one of four groups based upon their frontal profile. These are described as either flat (A), convex (B), angled (C), or round (D). The relative fre­quencies of occurrence are taken from the works of Yale et al. (1963), Solberg et al. (1985), and Chris­tiansen et al. (1987). The condyle form affects the radiographic image of this partofthejointinthe Schuller projection (Bumann et al. 1999) and the loading of the joint surfaces (Nickel and McLachlan 1994).

Function and structural adaptation of the condyle

Summary of the basic anatomical and functional changes in the condylar portion of the joint. In­creased functional loading will stimulate cartilaginous hypertro­phy (= progressive adaptation) that is not noticeable clinically. Continu­ous nonphysiological loading of the condyle can lead to degeneration, deformation, and even ankylosis (Dibbets 1977, Stegenga 1991). These changes may be accompa­nied by pain or, with sufficient adaptation, they may progress painlessly.

 

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Category: Anatomy, Dental, Medical, Oral Anatomy

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