284 SPECIAL HISTOLOGY. 



bones of the extremities, and in the scapula and os innoniinatum, occur- 

 ring apparently in variable number in the bones of the face.* 



§ 94. Connections of the Bones. — A. synarthrosis, connection Avithout 

 articulation. 



1. By suture. In this mode of connection, the bones are united by 

 an extremely thin, membranous, whitish streak, to which authors have 

 incorrectly given the name of sutural cartilage. It is composed merely 

 of connective tissue, which, like that of the ligaments, extends, in short, 

 parallel fasciculi, from the border of one bone to that of the other, and 

 is characterized solely by the presence of numerous, short, unequal-sized, 

 usually elongated nuclei. This sutural ligament, as it may be termed, 

 is very evident as long as the cranial bones are still growing, at the same 

 time, that it is softer and differently constituted [vide infra). As the 

 growth of the cranium approaches its completion, this tissue gradually 

 disappears, becomes firmer, and, in old age, seems, in many places, 

 especially on the inner part of the sutures, and even before their com- 

 plete obliteration, to be entirely removed. 



2. Connection hy ligament, syndesmosis, is effected by means o? fibrous 

 and elastic ligaments. The fibrous ligaments, constituting the majority 

 of the ligaments, are white and glistening, corresponding in their struc- 

 ture, partly with the aponeuroses and ligaments of the muscles, and 

 partly with the true tendons. 



Elastic ligaments (Fig. 121), are, the ligamenta flava, between the 

 arches of the vertebrae, and the ligamentum nuchse, which, however, is 

 not nearly so well developed in man, as in some others of the Mammalia. 

 The ligamenta flava are yellowish, highly elastic, strong ligaments, the 

 elastic elements of which, in the form of roundish polygonal fibres, 0-0015 

 -0-004 of a line thick, united into a dense network, run parallel with the 

 long axis of the vertebral column, and give the longitudinal, fibrillar 

 aspect to the ligaments. Between these fibres, which are not collected 

 either into fasciculi or lamellce, but are continuously connected through- 

 out the entire thickness of each yellow ligament, there is interposed some 

 connective tissue, upon the whole in small quantity, but demonstrable in 

 every preparation, and occurring in the form of lax undulating fasciculi, 



* [These nucleated medulla-cells exist in great number in the superior maxillary bone of 

 Man and of many of the Vertebrata. Several of them are sometimes enclosed in a common 

 cell-wall, forming a variety of cell, frequently seen in pathological formations, viz. the 

 parent-cell of the German authors, the plaque k noyaux multiples of Robin. 



The occurrence of nucleated cells in the normal medulla of the bones of the face has been 

 mostly overlooked, and has hence given rise to many errors on the part of pathologists. In 

 the description of morbid changes of the bones of the face, especially in those of the superior 

 maxillary bone, representations are frequently given of small cancer-cells or nuclei, taken 

 from the interior of the bone, virhich are but the normal nucleated cells of the medulla. 

 Many tumors of the upper jaw have thus been pronounced cancerous, which were simply 

 non-malignant hypertrophies of the bone. — DaC] 



