1134 



THE ORGANS OF SPECIAL SENSE 



horizontal, averaging on the right side 50 degrees and on the left side 45 degrees 

 (Spalteholz). Internally the handle is covered by the mucous membrane of the 

 tympanum. On the inner side, near its upper end, is a slight projection, into 

 which the tendon of the Tensor tympani is inserted (Fig. 838). 



The processus gracilis (processus anterior [Folii]) is a long and delicate process, 

 which springs from the eminence below the neck and is directed forward and 

 outward to the Glaserian fissure, to which it is connected by ligamentous fibres. 

 In the fetus this is the longest process of the malleolus, and is in direct continuity 

 with the cartilage of Meckel. 



SHORT 

 PROCESS 



LONG 

 PROCESS 



INSERTION 



OF TENSOR 



TYMPANI 



MUSCLE 



AURICULAR 

 SURFACE 

 FOR BODY 

 OF INCUS 



INSERTION OF 

 EXTERNAL 

 LIGAMENT 

 OF MALLEUS 



SHORT 

 PROCESS 



MANUBRIUM 



FIG. 841. Viewed from in front. FIG. 842. Viewed from behind. (Spalteholz.? 



FIGS. 841 and 842. The right malleus (enlarged). 



The processus brevis (processus lateralis) is a slight conical projection, which 

 springs from the root of the manubrium; it is directed outward and is attached 

 to the upper part of the tympanic membrane by cartilage and to the margins of 

 the notch of Rivinus by the two tympanomalleolar folds. 



The Incus (Figs. 843 and 844) has received its name from its supposed 

 resemblance to an anvil, but it is more like a bicuspid tooth with two roots, 



ARTICULAR SURFACE 

 FOR HEAD OF MALLEUS 



ARTICULAR 

 SURFACE FOR 

 HEAD OF 

 MALLEUS 



LONG 

 PROCESS 



LENTICULAR 

 PROCESS 



FIG. 843. Lateral view. FIG. 844. Medial and front view. (Spalteholz.) 



FIGS. 843 and 844. The right incus (enlarged). 



which differ in length, and are widely separated from each other. It consists of 

 a body and two processes. The body and the short process are placed in the 

 epitympanic recess (Fig. 840). 



The body (corpus incudis} is somewhat quadrilateral, but compressed laterally. 

 On its anterior surface is a deeply concavo-convex facet, which articulates with 

 the head of the malleus, and the lower part is hollowed for the spur of the malleus. 



The two processes diverge from each other at an angle of from 90 to 100 degrees. 



