SKELETON. 



The latter of 



2 offa maxillaria fuperiora, 



2 olTa palatina, 



2 offa malarum, or zygomatica, 



2 offa nafi, 



2 ofla lacrymalia, 



2 offa turbinata inferiors, 



I vomer, 



1 maxilla inferior, 

 32 teeth. 



The whole amount of bones of the head is 59 or 60. The 

 five pieces of the os hyoides added to thefe, make 64 or 65. 



II. The Trunk, comprehending the fpine, cheil, and 

 pelvis, confifts ©f 



7 cervical 1 

 1 2 dorfal > vertebrcE, 

 ^ lumbar J 



2 or 3 bones of the ftemum, 

 24 ribs, 



1 facrura, 



4 o(ia coccygis, 



2 ofla innominata. 



57 csS 



III. The Extremities. 

 The upper contain 



2 clavicles, 

 2 fcapulx-. 

 2 humeri. 



In the fhouldert, i 



In the arms. 



In the fore-arras, < 



In the wrifts, 



In the metacarpi, 

 In the fingers. 



2 radii, 



2 ulnae. 



2 ofla navicularia or fcaphoidea, 



2 ofla lunaria, 



2 ofla cuneiformia, 



2 ofla pififormia, or orbicularia, 



2 ofla trapezia, or multangula majors, 



2 ofla trapezoidea, or multangula mi- 

 nora, 



2 ofla capitata, 



2 ofla unciformia, or hamata. 



10 ofl^a metacarpi. 



10 firft or metacarpal phalanges, 



8 middle or fccond phalanges, 



10 third or unguinal phalanges, 



8 fefamoid boies. 



7» 



The lower extremities contain. 



Brought over 

 In the metatarfi. 



In the toes, 



ofl'a metatarfi. 



firll or metatarfal phalanges, 

 middle or fecond phalanges, 

 third or unguinal phalanges, 

 fefamoid bones. 



66 



The whole number of bones will be 259 or 261. There 

 is frequently a fmall bone of the fefamoid kind in the tendon 

 of the external head of the galtrocnemius : and a'roundifli 

 bit in the hyo-thyrcid ligament. If both thefe lliould exitt, 

 we mufl; add four to the preceding number. 



A complete dry natural (keleton of a male fubjeft of the 

 middle fize, weighs from 150 to 200 ounces ; that of a fe- 

 male, from 100 to 1 60 ounces. 



Of the bones juft; enumerated, the frontal, fpheno-occi- 

 pital, vomer, lower jaw, vertcbrie, facrum, coccyx, ilernum, 

 and OS linguale medium, are Angle (imparia), and, being 

 placed on the middle line of the body, fymmctrical ; all the 

 others are double, or in pairs (paria) ; each pair being 

 compofed of a right and left correfponding bone. Hence 

 the ftrufture of the whole fl-celeton is fymmetrical ; that is, 

 if we imagine a perpendicular line to be drawn through the 

 whole body, from before backwards, it will divide the 

 Ikeleton into two correfponding halves, a right and left ; 

 the fingle bones having their right and left fides exaftly alike. 



This obfervation, however, of the fymmetry of the 

 /keleton, is not to be underftood rigoroufly ; fince the right 

 and left of the double bones, or the right and left fides of the 

 fingle ones, are not accurately alike. The right or left 

 bone, or the right or left fide of a bone, may be longer or 

 fliorter, broader or narrower, &c. &c. than the other. 

 The vomer is generally bent to one fide ; the internal fur- 

 face of the fl<ull feldom fymmetrical." The laft; rib is often 

 an inch longer on one fide than on the other. The iternum 

 is feldom fymmetrical ; and the cartilages of the ribs are not 

 fixed to it exaftly oppofite to each other. The articulationg 

 of the ribs with the fpine often differ confiderably on the 

 two fides. But the fymmetry of the external form is not 

 dilturbed by thefe diff^erences. If the right fide of a ver- 

 tebra is more elevated than the left, the correfponding part 

 of the neighbouring bone, or of the intervertebral cartilage, 

 is accommodated to the deviation ; fo that the perpendicular 

 line of the fpinat column is not impaired, &c. &c. 



The fingle bones may be regarded as the media of union 

 of the two lateral halves, which conltitute the flccletoH ; 

 they join together thefe two halves into one folid whole. 

 In this refpeft there is a marked difference between the 

 bones and the other organic inllruments of locomotion, the 

 mufcles. The diaphragm is the only mufcle placed on the 

 median line, and its llrufture is not fymmetrical : it belongs 

 in great meafure to the internal or organic life, and corre- 

 fponds, in its want of fymmetry, to the arrangements of the 

 internal organs. The ikeleton, being the baiis or point of 

 fupport of the mufcles, as well as of all the other organs, 

 conllitutes an entire and firm fabric ; an attribute which it 

 derives from the fingle bones, which may be regarded as the 

 key-ftoncs of the building. The mufcles, not contributing 

 to the folidity of the animal llrufture, are not united into 

 fuch a fingle and firm aflemblage. 



The mode in which the different pieces of the fl<clcton are 

 joined to each other, is confidcred under tiie article Joi.NT ; 

 to which, and to that of Membranf, Synovia/, we refer for 

 the details regarding the anatomic.il llrufture of thefe con- 

 Rcflions. 



N TLf 



