OSTEOLOGY. 



THE frame-work of the body is composed of bones, which 

 constitute the skeleton. This in the adult consists of 206 bones, 

 including the ossicula auditus: Excluding the ear ossicles, the 

 number is 200, or excluding also the two patella? and the hyoid 

 bone the number is 197. Spine (including coccyx and sacrum) 

 26, cranium 8, face 14, ribs, sternum, and os hyoides 26, upper 

 extremity 64, lower extremity 62, ear ossicles, 6. 



The bones of the head number 22, consisting of 



Eight cranial bones, the frontal, 2 parietal, occipital, 2 temporal, the 

 sphenoid and ethmoid bones ; 14 facial bones, 2 lachrymal, 2 nasal, 2 malar, 

 2 superior maxillae, 2 palate, 2 turbinal, 1 vomer, and 1 inferior maxilla. 



The bones of the trunk number 52, comprising 



Twenty-six vertebrae, 7 cervical, 12 dorsal, 5 lumbar, 1 sacrum and 



1 coccyx. 



Twenty-six of the thorax, 7 pairs of true ribs, 3 pairs of false ribs, 



2 pairs of floating ribs, the sternum and os hyoides. 



The bones of the skull, face, thorax, and vertebral column 

 are known as the axial skeleton, and consists of 74 segments. 



The bones of the upper extremity number 64, comprising 

 on either side 



Two shoulder, clavicle and scapula ; 1 arm, humerus ; 2 forearm, 

 radius and ulna ; 8 wrist (carpus), scaphoid, semi-lunar, cuneiform, pisi- 

 form, trapezium, trapezoid, os magnum, and unciform ; 19 hand, 5 meta- 

 carpal and 14 phalanges. 



The bones of the lower extremity number 62, comprising 

 on either side 



One hip, divided into 3 portions, the ilium, ischium, and pubes ; 

 1 thigh, the femur; 2 leg, tibia and fibula ; 1 knee, the patella ; 26 foot. 

 7 t irsal bones, the astragalus, os calcis, scaphoid, cuboid, external, middle, 

 and internal cuneiform ; 5 metatarsal bones, and 14 phalanges. 



The bones of the shoulder girdle, upper extermities, pelvic 

 .uirdle, and lower extremities are known as the appendicular 

 skeleton, and consists of 126 segments. They are divided into 

 long, short, flat or tabular, and irregular. 



Long bones, such as femur, humerus, or radius, consist of 

 shaft or diaphvsis, and two extremities or epiphyses. 



The shaft or diaphysis is a cylindrical tube composed ex- 

 ternally of compact tissue and internally of cancellous tissue, the 

 centre being hollowed out by the medullary canal. 



The t'/tifilu/xes, or extremities, are expanded for articulation, 

 and are composed of a mass of solid cancellous tissue with a 

 thin coating of compact tissue. 



(3) 



