is particular in this, that it contributes to 
form the brachial nerves ; and that the two 
branches of the intercostal which come down 
to the thorax form a considerable ganglion 
with it. 
The sixth lower dorsal nerves give 
branches to tin; diaphragm and abdominal 
muscles. 
The twelfth joins with the first lumbar, 
and bestows nerves on the musculus qua- 
dratus lumborum and illiacus interims. 
May not the communications of all these 
nerves be one reason why the parts they 
serve act so uniformly and conjunctly in 
respiration, and conspire together in the 
convulsive motions of coughing, sneezing, 
&c. ? 
The communications of these lower ones 
with the intercostals, may serve to explain 
the violent efforts of the abdominal muscles 
in a tenesmus, and in childbearing. 
As the intercostal is larger in the thorax 
than any where else, and seems to diminish 
gradually as it ascends and descends, there 
is cause to suspect that this is the trunk from 
which the superior and inferior parts are sent 
as branches. 
The five lumbar nerves on each side, com- 
municate with the intercostal and with each 
other, and give branches backward to the 
loins. 
The first communicates with the last 
dorsal, sends branches to the abdominal 
muscles, to the psoas iliacus, and to the tegu- 
ments and muscles of the fore-parts of the 
thigh ; while its principal branch joins with 
the other nerves, to form the crural nerve. 
The second lumbar nerve passes through 
the psoas muscle, and is distributed nearly 
in the same way as the former; as is also 
the third. 
Branches of the second, third, and fourth, 
make up one trunk which runs along the 
fore part of the pelvis, and passing in the 
notch at the fore part of the great hole, 
common to the os pubis and ischium, is spent 
on the adductor muscles, and on the tegu- 
ments on the inside of the thigh. This 
nerve is called the obturator or posterior 
crural nerve. 
By uniting branches from the second 
third and fourth lumbar nerves, a nerve is 
formed that passes along the psoas muscle, 
to escape with the external iliac vessels out 
of the abdomen, below the tendinous arcade 
of the external oblique muscle. This nerve 
which is named the anterior crural, is dis- 
tributed principally to the muscles and tegu- 
ments of the fore part of the thigh. A branch 
however of this nerve runs down the leg to 
the upper part of the foot, keeping near the 
vena saphena ; in opening of which with a 
lancet at the ankle, the nerve is somewhat 
hurt, and occasions sharp pain at the time 
of operation, and afterwards numbness. 
The remainder of the fourth lumbar and 
the fifth, join in composing the largest nerve 
of the body, which is soon to be described. 
Whoever attends to the course of these 
lumbar nerves, and of the spermatic vessels 
and nerves upon the psoas muscle, with the 
oblique passage of the ureter over that muscle, 
will not be surprised that when a stone is 
passing in this canal, or even when it is 
inflamed, the trunk of the body cannot be 
raised erect without great pain, or that the 
skin of the thigh becomes less sensible, and 
Voi. I. 
ANATOMY. 
the thigh is drawn forward, and that the 
testicle often swells, and is drawn con- 
vulsively towards the ring of the abdominal 
muscles. 
The sixth pair of the false vertebrae consist 
each of small posterior branches sent to the 
hips and large anterior branches. 
The first, second, and third, after coming 
through the three upper holes of the os 
sacrum, join together with the fourth and 
fifth of the loins, to form the largest nerve 
of the body, which is well known by the name 
of schiatic or ischiatic nerve : this, after send- 
ing large nerves to the different parts of the 
pelvis, and to the external parts of gene- 
ration and the povex, as also to the muscles 
of the hips, passes behind the great tuber of 
the os ischium, and then over the quadri- 
gemini muscles to run down near to the bone 
of the thigh at its back part, giving off 
nerves to the neighbouring muscles and tegu- 
ments some way above the ham, where it has 
the name of popliteus nerve, it sends off 
a large branch that passes over the fibula, 
and sinking, among the muscles on the an- 
terior external part of the leg, runs down to 
the foot to be lost in the upper part of the 
larger toes, supplying the neighbouring 
muscles and teguments every where in its 
passage. The larger branch of the schiatic, 
after giving branches to the muscles and 
teguments above the ham and knee, and 
sending a large cutaneous nerve down the 
calf of the leg to be lost at last on the outside 
of the foot, and the upper part of the lesser 
toes, sinks below the gemellus muscle, and 
distributes nerves to the muscle on the back 
of the leg, among which it continues its 
course till passing behind the malleolus in- 
ternal, and in the internal hollow of the os 
calcis, it divides into the two external and 
internal plantar nerves. The internal is 
distributed to the toes in the same manner 
that the radial nerve of the hand serves the 
concave side of the thumb and fingers ; and 
the external plantar is divided and distributed 
to the sole of the foot and toes, nearly as the 
ulnar nerve is in the palm of the hand, and 
in the concave part of the fingers. 
Several branches of these nerves that 
serve the inferior extremities, pierce through 
muscles. 
The fourth, which with the two following, 
is much smaller than the three superior, soon 
is lost in the vesica urinaria and intestinum 
rectum. 
The fifth comes forward to the extremity 
of the os sacrum and coccygis to be distri- 
buted principally to the levatores ani. 
The sixth may be considered as the termi- 
nation of a substance called ligamentum den- 
ticulatum. For the uses of the various 
parts of the human body, see the article 
Physiology. See also Comparative 
Anatomy. 
EXPLANATION OF THE ANATO- 
MICAL PLATES. 
EXPLANATIONS OF THE BONES. 
Fig. 1. 
1. The Cranium. 
2. The Cervical Vertebrae. 
3. The Clavicles. 
4. The Acroniums. 
6. The Humerus. 
7. The Radius. 
105 
9. The Ulna. 
9. The Carpus. 
10. The Metacarpus. 
It, 12. The Sternum. 
13. The Ribs. 
а. The true Ribs. 
c. The false Ribs. 
c. The transverse processes of the Lumbar 
Vertebral. 
1 4. The Lumbar Vertebra. 
15. The os Sacrum. 
16. The os Innomin&ta. 
17. The ossa Ilii. 
18. The ossa Pubis. 
19- The ossa Ischii. 
r. The brim of the Pelvis. 
s. The foramen Thyroideum. 
t. The trochanter Major. 
u. The trochanter Minor. 
20. The Femur. 
21. The Patella. 
22. The Tibia. 
23. The inner Ancle. 
24. The Fibula. 
25. The Astragabes. 
26. 27, 28, 29- The Tarsu3. 
30. The Metatarsus. 
Fig. II. 
1. The Cranium. 
2. The os occipitis. 
4. The os Temporis. 
5. The os Sphenoidesv 
б. The Scapula. 
7. Its Spine. 
8. The Humerus. 
9- The Radius. 
10. The Ulna. 
11. The Olecranon. 
12. The Carpus. 
13. The Metacarpus. 
14. The cervical Vertebra. 
15. The Clavicles. 
a. a. 'Phe Spines of the cervical Vertebra. 
р. The Ribs. 
1 6. The lumbar Vertebra. 
17. The ossa Innominata. 
18. Their Spines. 
19. The ossa Pubis. 
20. The os Sacrum. 
22. The Femur. 
24. The trochanter Minor. 
25. The Patella. 
26. The Tibia. 
27. Fibula. 
28. The os Calcis. 
a, b, c, d, e. The bones of the Foot 
EXPLANATIONS OF THE MUSCLES. 
Fig. 1. Superficial Muscles. 
a. Platystica Myoides. 
b. Deltoides. 
с. Biceps. 
d. Pro vat or Teres. 
e. Supinator Longus. 
f Flexor Radialis. 
g. Palmaris Longus. 
h. Flexor Ulnaris. 
i. Pectoralis Major. 
k. Obliquus Externus. 
l. Linea Semilunaris. 
m. Linea Alba. 
7i. Abdominal Ring. 
o. Sartorius. 
p. Tensor Femoris Vaginae. 
q. Long head of the Triceps. 
