Question

spinal nerves and nerve plexuses
the 31 pairs of human spinal nerves are formed by the combination of the ventral and dorsal roots of the spinal cord. although each of the cranial nerves issuing from the (1.) is named specifically, the spinal nerves are named for the region of the cord from which they arise (figure 7.24, p. 259, shows how the nerves are named in this scheme.)
almost immediately after being formed, each spinal nerve divides into the dorsal ramus and ventral ramus (plural rami rami), making each (2.) nerve only about ½ inch long. the rami, like the spinal nerves, contain both motor and sensory fibers. thus, damage to a spinal nerve or either of its rami results both in loss of sensation and in (3.) paralysis of the area of the body served. the smaller dorsal rami serve the skin and muscles of the posterior body trunk. the ventral rami of spinal nerves t1 through t12 form the (4.) nerves, which supply the muscles between the ribs and the skin and muscles of the anterior and lateral trunk. the ventral rami of all other spinal nerves form complex networks of nerves called (5.), which serve the motor and sensory needs of the limbs. (the four nerve plexuses are described in table 7.3, p. 262, three of the four plexuses are shown in figure 7.25, p. 263)

o 1. plexuses 2 brain 3 spinal 4 flaccid 5 intercostal
o 1 spinal 2 flaccid 3 intercostal 4 plexuses 5 brain
o 1 intercostal 2 plexuses 3 brain 4 spinal 5 flaccid
o 1 brain 2 spinal 3 flaccid 4 intercostal 5 plexuses
o 1 flaccid 2 intercostal 3 plexuses 4 brain 5 spinal

Explanation:

Cranial nerves issue from the brain. Spinal nerves are short - about ½ inch long after division. Damage to them causes flaccid paralysis. T1 - T12 ventral rami form intercostal nerves. Other ventral rami form nerve plexuses.

Answer:

1. brain 2. spinal 3. flaccid 4. intercostal 5. plexuses