e _tendo Achillis_. It forms a high relief with a
shallow depression on each side of it. Behind both the inner and outer
ankle several tendons can be felt. Over the front of the ankle, when the
muscles are in action, we can see and feel several tendons. They start up
like cords when the action is resisted. They are kept in their proper
relative position by strong pulleys formed by the annular ligament. Most
of these tendons can be best seen by stand a model on one foot, _i.e._ in
unstable equilibrium.

III. Landmarks of the Heart.

To have a general idea of the form and position of the _heart_, map its
outline with colored pencils or crayon on the chest wall itself, or on
some piece of clean, white cloth, tightly pinned over the clothing. A
pattern of the heart may be cut out of pasteboard, painted red, or papered
with red paper, and pinned in position outside the clothing. The apex of
the heart is at a point about two inches below the left nipple and one
inch to its sternal side. This point will be between the fifth and sixth
ribs, and can generally be determined by feeling the apex beat.

IV. Landmarks of a Few Arteries.

The pulsation of the _temporal_ artery can be felt in front of the ear,
between the zygoma and the ear. The _facial_ artery can be distinctly felt
as it passes over the upper jaw at the front edge of the masseter muscle.
The pulse of a sleeping child can often be counted at the anterior
fontanelle by the eye alone.

About one inch above the clavicle, near the outer border of the
sterno-mastoid, we can feel the pulsation of the great _subclavian_
artery. At the back of the knee the _popliteal_ artery can be felt
beating. The _dorsal_ artery of the foot can be felt beating on a line
from the middle of the ankle to the interval between the first and second
metatarsal bones.

When the arm is raised to a right angle with the body, the _axillary_
artery can be plainly felt beating in the axilla. Extend the arm with palm
upwards and the _brachial_ artery can be felt close to the inner side of
the biceps. The position of the _radial_ artery is described in Experiment
102.

Glossary.

Abdomen (Lat. _abdo_, _abdere_, to conceal). The largest cavity of the
body, containing the liver, stomach, intestines, and other organs.

Abductor (Lat. _abduco_, to draw from). A muscle which draws a limb from
the middle line of the body, or a finger or toe from the middle line of
the foot or