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Ch. 13 The Spinal Cord, Spinal Nerves, and Spinal Reflexes
Martini - Fundamentals of Anatomy & Physiology 11th Edition
Martini, Nath, Bartholomew11th EditionFundamentals of Anatomy & PhysiologyISBN: 9780136874089Not the one you use?Change textbook
All textbooksMartini, Nath, Bartholomew 11th EditionCh. 13 The Spinal Cord, Spinal Nerves, and Spinal ReflexesProblem 7
Chapter 13, Problem 7

A sensory region monitored by the posterior rami of a single spinal segment is
(a) A ganglion
(b) A fascicle
(c) A dermatome
(d) A ramus

Verified step by step guidance
1
Understand the key terms in the question: a 'sensory region' refers to an area of the body that receives sensory input, and 'posterior rami' are branches of spinal nerves that innervate specific regions.
Recall that each spinal nerve splits into anterior and posterior rami; the posterior rami primarily innervate the muscles and skin of the back.
Recognize that a 'dermatome' is a specific area of skin innervated by sensory fibers from a single spinal nerve segment, which includes the posterior rami.
Eliminate options that do not represent sensory regions: a 'ganglion' is a cluster of nerve cell bodies, a 'fascicle' is a bundle of nerve fibers, and a 'ramus' is a branch of a nerve, not a sensory region itself.
Conclude that the correct term for a sensory region monitored by the posterior rami of a single spinal segment is a 'dermatome'.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Posterior Rami of Spinal Nerves

Posterior rami are branches of spinal nerves that innervate the muscles and skin of the back. Each posterior ramus carries sensory and motor fibers specific to a single spinal segment, providing localized innervation to the dorsal body region.
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Dermatome

A dermatome is an area of skin innervated by sensory fibers from a single spinal nerve segment. It represents the sensory distribution of one spinal nerve, allowing clinicians to map nerve function and diagnose nerve damage.

Spinal Nerve Anatomy and Branches

Spinal nerves split into anterior (ventral) and posterior (dorsal) rami after exiting the spinal cord. Understanding these branches is essential to identify which structures they innervate, such as muscles, skin, or ganglia.
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Related Practice
Textbook Question

The synapsing of several neurons on the same postsynaptic neuron is called

(a) Serial processing

(b) Reverberation

(c) Divergence

(d) Convergence

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Textbook Question

Spinal nerves are called mixed nerves because they

(a) Contain sensory and motor fibers

(b) Exit at intervertebral foramina

(c) Are associated with a pair of spinal ganglia

(d) Are associated with posterior and anterior roots

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Textbook Question

The major nerve of the cervical plexus that innervates the diaphragm is the

(a) Median nerve

(b) Axillary nerve

(c) Phrenic nerve

(d) Common fibular nerve

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Textbook Question

The following are the steps involved in a neural reflex.

1. Activation of a sensory neuron

2. Activation of a motor neuron

3. Response by an effector

4. Arrival of a stimulus and activation of a receptor

5. Information processing

The proper sequence of these steps is

(a) 1, 3, 4, 5, 2

(b) 4, 5, 3, 1, 2

(c) 4, 1, 5, 2, 3

(d) 4, 3, 1, 5, 2

(e) 3, 1, 4, 5, 2

1124
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Textbook Question

The genitofemoral, femoral, and lateral femoral cutaneous nerves are major nerves of the

(a) Lumbar plexus

(b) Sacral plexus

(c) Brachial plexus

(d) Cervical plexus

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Textbook Question

The anterior roots of each spinal segment

(a) Bring sensory information into the spinal cord

(b) Control peripheral effectors

(c) Contain the axons of somatic motor and visceral motor neurons

(d) Do both b and c

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