Essentials of Anatomy and Physiology

173

Spinal cord

Phrenic nerve

Intercostal nerves

Radial nerve

Median nerve

Ulnar nerve

Cauda equina

Femoral nerve

Sciatic nerve

Cervical plexus

Brachial plexus

Lumbar plexus

Sacral plexus

C1

C2

C3

C4

C5

C6

C7

C8

T1

T2

T3

T4

T5

T6

T7

T8

T9

T10

T11

T12

L1

L2

L3

L4

L5

S1

S2

S3

S4

S5

CO1

Figure 8–4. The spinal cord
and spinal nerves. The distribu-
tion of spinal nerves is shown
only on the left side. The nerve
plexuses are labeled on the
right side. A nerve plexus is a
network of neurons from sev-
eral segments of the spinal cord
that combine to form nerves to
specific parts of the body. For
example, the radial and ulnar
nerves to the arm emerge from
the brachial plexus (see also
Table 8–3).
QUESTION: Where does the
spinal cord end? Why is this
important clinically?