1044 



Head 



tition by the Salpingopharyngeus and Dilatator tubse. The latter arises from the 

 hook of the cartilage and from the membranous part of the tube, and blends below 

 with the Tensor veli palatini. 



The Auditory Ossicles (Ossicula Auditus). 



The tympanic cavity contains a chain of three movable ossicles, the mal 

 incus, and stapes. The first is attached to the tympanic membrane, the last to 

 the circumference of the fenestra vestibuli, the incus being placed between and 

 connected to both by delicate articulations. 



The Malleus (Fig. 916), so named from its fancied resemblance to a hammer, 

 consists of a head, neck, and three processes, viz., the manubrium, the anterior and 

 lateral processes. 



The head (capitulum mallei) is the large upper extremity of the bone; it is oval 

 in shape, and articulates posteriorly with the incus, being free in the rest of its 



extent. The facet for articu- 

 lation with the incus is con- 

 stricted near the middle, and 

 consists of an upper larger and 

 lower smaller part, which form 

 nearly a right angle with each 



other - Opposite the constric- 

 tion the lower margin o f the 



facet projects in the form of a 

 process, the cog-tooth or spur oi 

 the malleus. 



The neck (collum mallei) is 

 the narrow contracted part just 

 beneath the head ; below it, is a 

 a prominence, to which the 

 various processes are attached. 



The manubrium mallei (handle) is connected by its lateral margin with the tym- 

 panic membrane. It is directed downward, medialward, and backward ; it decreases 

 in size toward its free end, which is curved slightly forward, and flattened trans- 

 versely. On its medial side, near its upper end, is a sli'ght projection, into which 

 the tendon of the Tensor tympani is inserted. 



The anterior process (processus anterior [Folii]; processus gracilis) is a delicate 

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

 to the petrotympanic fissure, to which it is connected by ligamentous fibers. In 

 the fetus this is the longest process of the malleus, and is in direct continuity with 

 the cartilage of Meckel. 



The lateral process (processus lateralis; processus brevis) is a slight conical projec- 

 tion, w r hich springs from the root of the manubrium; it is directed laterally, and is 

 attached to the upper part of the tympanic membrane and, by means of the ante- 

 rior and posterior malleolar folds, to the extremities of the notch of Rivinus. 



The Incus (Fig. 917) has received its name from its supposed resemblance to 

 an anvil, but it is more like a premolar tooth, with two roots, which differ in 

 length, and are widely separated from each other. It consists of a body and two 

 crura. 



The body (corpus incudis) is somewhat cubical but compressed transversely. 

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

 the head of the malleus. 



The two crura diverge from one another nearly at right angles. 

 The short crus (crus breve; short process), somewhat conical in shape, projects 



FIG. 916. Left malleus. A. From behind. B. From within. 



