46 SPECIAL ANATOMY. 



2. Inlet, sinus, a cavity with a narrow opening, e. g., sinus Maxillaris ; cells, 

 ccllulcR, similar, but smaller. 



3. Grooves, sulcus. 



4. Incision, incisura, notch (on the edges). 



5. Impression, impressio. 



4. Perforations: 



1. Hole, foramen hiatus (small). 



2. Fissures, fissura (long and narrow). 



3. Canals, carialis, ductus. 



45, Conjunction of the Bones. 



I. Immoveable conjunction, synarthrosis. The edges of the 

 bones rest against each other, and are joined by sutures. The 

 edges grasping one another from opposite sides by indentations, 

 form a true, but when merely overlying each other, a false suture. 



a. True suture, sutura vera. We distinguish : 



1. S. dentata, where the indentations are simple, long and vertical, like 

 teeth ; e. g., the sagittal suture. 



2. S. serrata, when they are simple but oblique, like a saw; e. g., the 

 coronal suture. 



3. 8. limbosa, when the principal indentations are provided with small 

 lateral ones ; e. g., the lambdoidal suture. 



b. False suture, sutura spuria. 



1 . S. Squamosa, scale suture ; the rough edge of one bone overlying that 

 of the other. 



2. Harmonia ; the rough edges merely meeting together. 



Gomphosis is that conjunction in which the teeth extend in a wedge-like 

 manner into the cavities of the indented edge. 



II. Moveable conjunction. 



a. Close conjunction amphiarthrosis. The bones coming immediately in 

 contact or connected by ligaments, can only glide a little on one another, e. g., 

 the carpal and tarsal bones. The junction at the pubes, called symphysis, is 

 effected by cartilage and ligaments ; the union of the hip bones, synchondro&is, 

 by the interposition of cartilage alone. 



b. Peculiar articular conjunction, diarthrosis, articulatia. 



1. Hinge, angular joint, ginglymus. Formed by two (long) bones placed 

 at an angle, the one describing with the other an obtuse, right, or acute 

 angle. 



2. Rolling or rotatory joint, rotatio, s. trochaides. One bone moving upon a 

 surface lying parallel to it in a semicircle or less, e. g., radius and atlas. 



3. Ball and socket joint, enarthrosis. The movement is free in all di- 

 rections, circular ; e. g., hip joint. 



4. Free joint, arthrodia. The articular head is not deeply fixed in the 

 articular cavity, as in the one above, but moves upon the articular sur- 

 face ; e. g., shoulder joint, thumb. 



