4 HUMAN ANATOMY. 



The short bones, as tarsus or carpus, are small, compact, 

 irregular cubes. 



Flat bones, as those of skull and shoulder-blade, afford 

 extensive surfaces for protection or muscular attachment. 



Under irregular or mixed bones are classed the vertebral, 

 sphenoid, maxillary bones, and such that could not be placed 

 under either of the other heads. 



The surfaces of the bones are marked by certain eminences 

 and depressions, which have received the following names : 



An apophysis is a prominent excrescence formed directly upon 

 a bone, and is distinguished from 



An epiphysis, which has been formed from a distinct centre and 

 separated by cartilage, but afterward united to the bone. 



A head is a rounded, smooth, articular eminence for articulation. 



A condyle is an irregular prominence for muscular attachment. 



A trochanter is a large prominence for the attachment of rotator 

 muscles. 



A tuberosity is a broad, uneven eminence. 



A tubercle is a small tuberosity. 



A spine is a sharp-pointed eminence. 



A line, or ridge, is a rough, narrow elevation, extending some 

 distance. 



Others, from their fancied resemblance to ordinary objects, 

 have received the following names : 



Coronoid, like a crown; coracoid, like a crow's beak; unciform, 

 or hamular, hook-like; malleolar, like a mallet; mastoid, nipple-like; 

 zygoma, yoke-like ; pterygoid, wing-like; odontoid, tooth-like ; spinous, 

 thorn-like; styloid, pen-like; rostrum, a beak; vaginal, ensheathing; 

 squamous, scaly; conoid, cone-like. 



The cavities of bones are divided into the articular and the 

 non-articular. 



The articular are named acetabulum, measure-like ; glenoid, 

 hollow; cotyloid, cup-like; facet, smooth; trochlear, pulley- 

 like; alveolar, socket-like. 



The non-articular cavities are named notches, fissures, 

 grooves, furrows, fossa?, hiatus, foramina, canals, sinuses, aque- 

 ducts, cells, depressions, meatuses, etc. 



Composition of Bone. Adult human bones have a specific 

 gravity of 1.92, and are composed of about one-third (33.30) 

 organic or animal matter, principally gelatin, and two-thirds 

 inorganic or mineral matter, as follows : 



Gelatin and blood-vessels, 33.30; phosphate, carbonate, and 

 fluoride of calcium, 64.34; soda, sodium chloride, and mag- 

 nesium phosphate, 2.36 : total, 100. 



Structure of Bone. In structure they consist of an ivory- 

 like compact substance, inclosing a lamellar, reticular cancellous 

 substance. 



