HEAD. 
lateral convexities of the head are gently continued by a 
gradual flope into the fides of the neck. 
The head is articulated with the firft vertebra of the 
sane in fuch a manner, that the canal of the {pine corre- 
ds to the foramen magnum of the occipital bone. “And 
the fituation of this articulation is nearly in the centre of the 
$ cranii ; nearly i in the middle of a line, drawn between 
i moft prominent rom or the incifor aan and occi- 
dicularly under the head, the weight of the latter is fuf- 
tained almoft entirely by the former. The head would 
point exactly counterbalanced thofe wh it 
ut the centre of gravity of the whole head — in thet 
of the articulation ; fo that it would incline forwards on 
all extraneous fupport were fuddenly removed. 
This tendency of the parts is refilted partly by a liga- 
ment, which pafles from the vertebra of the neck to the 
occiput, and partly by the — which are placed at 
the back of the articulation 
The ligamentum nuchz, or cer Spee ligament, (ligament 
furépineux cervical of Bichat,) is n fibrous ftratum, 
attached to the {pines of the pave! pete on one fide, 
and to the occiput on the other, and eae oa attachment 
to various mufcles at the back of the nec It has tw 
mufcles; an anterior, a fuperi 
rmer of thefe is affixed to the Hivote gs pro- 
We fhall be 
ligament beft by obferving it in purge aie where the fitu 
ation of the occipital condyles, and the principles on whith 
the head is maintained in its Snttay Se with nea to the 
cpa 5a are t from what we'obferve in 
aisle tha heads t hemp n the ee that 0 ani- 
a In aE He GER € sepia as poor a“ qo 
back in 
adequate notion from co. 
~ human fubje@. If the nee were placed perpendicularly 
Base, < — the head t ea os the Si Bes a in 
which it wo ein pe pio 
be turned backwards, and the mouth gaa sedi te mae 
For the form of the bones, which caine the Foe 
. ‘work of this arti sunt we mult refer to the articles 
t. fuperficial one, narrow, thick, and rounded, defcendi 
© terior femi-circle of a foramen magnum, 
nfiderable ana'ogous part in i 
wium.and Spry.  Thofe articulations of the latter, which 
déviate from the general difpofition, = la rea 
quire feparate mens are efpecially concerned in the mo- 
tions of the : they are, that ° 
They ar 
that ie two joints approach each o 
behind. An anterior and a palenae: panne and a fyno- 
vial membrane at each condyle, ferve to maintain the bones 
in their proper relations to each other, and to facilitate 
their motion 
The anterior ligament is compofed of two. fafciculi : 
ing ‘es 
the bafilary procefs to the tuberele of the anterior arch of 
the atlas; a broader, thin, and flattenened one, attached to 
the occiput between the condyles, and to the atlas between 
its articular hollows. The firft is made up of parallel fibres; 
the fecond, of which the fibrous ftru€ture is not fo difti 
of threads ce purfue various dire¢tion 1” ligament 
fo their juxtapofition correfponds 
mui{cles in ‘front, and behind to the odontoid on gory its 
ligamen 
eThe pe cucthe ligament, broader than the former, confiils 
alfo of two portions, which ar 
The poiterior i is me to the arch of the atlas; and the an 
terior is loft u ura mater, the Ebrous compolition 
of which it atteabics. while the other. has a mee: ba 
This ligament, taken altogether, is broad, and dif- 
tinGly marked ; it correfponds in front to ‘the pF pat 
behind to the potterior rei mufcles, and the fuperior ¢ ob- 
lique ; on the fides to the vertebral arteries, and {ub-occipi~ 
nery 
The enol membrane covers the condyle, and a fall 
the hone in front, on one fide, and, on 
a confiderable portion of cellular sep hee 
the extremity of the tranfverfe ligament, pny Pre 
quires a {mooth furface, and a part of the ae ontoid lige 
ment ; moreover, fome {mall ‘portions of fat a ad i 
wards the j joints, and Forsiexly confidered as glands 3 
Conneétion of the occiput with the axis (articulation o oc 
not here, asim the 
furfaces covered with ratilages 
and conn wee — on each other ; the two bones af - 
held lateral or odontoid 
cipito-axcidienne Chere are 
ments, and b a har ha ior ligamen “ee 
eet or odont nig Tipamentss are two in oumbet “id 
attached to the apex and fides. of the odontos nm procels, a4 
continued upwards and outwards in sa manne 
inferted in the inner part of t rior end of & pie 
dyle. Their fibres are parallel, aid united by falci~ 
tiflue, and they form two thick, rounded and fhort} 2 
culi, They correfpond behi 
and in front to i evliclec = ee “ee furroun 
procefs and favours its ~ ofus,?08 
The potterior ieasear pean collj Higarentl cipite- 
