BONES. 11 



been separate from the bone. Epiphysis, is a process developed as a separate 

 piece and afterwards united to the bone by ossification of the intermediate tissue. 



What other names are given to Bony Prominences ? There are sev- 

 eral adjectives applied to them from their fancied resemblances, such as 

 Azygos, without a fellow; Clinoid, like a bed; Coracoid, like a crow's beak; 

 Coronoid, hooked like a crow's beak ; Hamular, hook-like ; Malleolar, like a 

 mallet ; Mastoid, like a nipple ; Odontoid, tooth-like ; Pterygoid, wing-like ; 

 Rostrum, a beak ; Spinous, thorn-like ; Styloid, pen-like ; Squamous, scaly ; 

 Vaginal, ensheathing, etc. 



Name the Cavities of Bones. Articular cavities are called Cotyloid, cup- 

 like; Glenoid, shallow ; Trochlear, pulley-like ; Facet, if smooth ; Alveolar, or 

 Alveoli, when socket-like. Non-articular cavities are named fossae, sinuses, 

 aqueducts, foramina, canals, fissures, notches, cells, grooves, depressions, etc. 



What is the Composition of Bone ? Organic or animal matter, about ^, 

 consisting of gelatin, vessels and fat. Inorganic, or mineral, about ^, con- 

 sisting of phosphate and carbonate of calcium (62^ per cent.), with fluoride 

 of calcium, phosphates of magnesium, sodium, and chloride of sodium (4^ 

 percent.). Heat will remove the organic matter and leave the inorganic; 

 dilute Nitric or Hydrochloric acid will remove the inorganic, and leave the 

 organic. In old age the inorganic constituents predominate, and the bones 

 are brittle ; in youth the organic predominate, and epiphyseal dislocation is 

 more common than fracture, especially in the long bones of the extremities. 



Describe the Structure of Bone. Bone is composed of an outer compact 

 layer, and an inner cellular or spongy structure. It is surrounded, except at 

 the articular cartilages, by a vascular fibrous membrane, the Periosteum, which 

 receives the insertions of all tendons, ligaments, etc. ; and the central cavity 

 of long bones is lined by a similar structure, the Endosteum. A transverse 

 section of bone, examined microscopically, shows 



Haversian Canals, diameter -^-^ inch, for the passage of vessels. 

 Canaliculi, diameter j^^ inch, radiating from the canals, and connecting 



them with the lacunas. 

 Lacuna, arranged circularly around the canals, and contain the bone-cells, 



appearing as irregular dark spaces. 



Haversian Spaces, connect the canals with the medullary spaces, and divide 

 one Haversian system from another. An Haversian System comprises 

 an Haversian canal with its lamellae, lacunae, and canaliculi. 

 Concentric Lamellce of bone tissue, around the canals. 

 Circumferential Lamellce, are bone layers binding the canals together. 

 Interstitial Lamellce, woven in between the concentric lamellae. 



