- Peripheral Nervous System—Upper Extremity 29
Cervical Plexus (Advanced)
■ Th e cervical plexus (C1–C4) innervates the anterior
and posterior cervical triangles and the fl oor of the
mouth.
■ Th e four major sensory nerves of the cervical plexus
are the lesser occipital, greater auricular, and
transverse cervical nerves (C2, C3), and the
supraclavicular nerve (C3, C4).
■ Th e phrenic nerve innervates the diaphragm; it is
supplied by C3 and C4 from the cervical plexus and
C5 from the brachial plexus.
■ Th e cervical spinal ventral rami form the cervical
plexus; the dorsal ramus of C2 supplies the greater
occipital nerve.FIGURE 3-1 Th e brachial plexus. Used with permission from Mendell,
Jerry R., John T. Kissel, and David R. Cornblath. Diagnosis and
Management of Peripheral Nerve Disorders , Contemporary Neurology
Series. Oxford: Oxford University Press, 2001.
FIGURE 3-2 Cervical plexus. Used with permission from Mendell, Jerry
R., John T. Kissel, and David R. Cornblath. Diagnosis and Management of
Peripheral Nerve Disorders , Contemporary Neurology Series. Oxford:
Oxford University Press, 2001.FIGURE 3-3 Th e brachial plexus and the axillary artery.