***anatomy-exam 6- ch 17- spinal cord & spinal nerves

Name the four plexuses and give the general distribution of each.

1) Cervical plexus: skin and muscles of the head and neck, superior portion of the shoulders and chest, diaphragm. 2) Brachial plexus: shoulders and upper limbs. 3) Lumbar plexus: anterolateral abdominal wall, external genitalia, and parts of the lower limbs. 4) Sacral plexus: buttocks, perineum, lower limbs

The femoral nerve is a branch of the sciatic nerve.

FALSE

Complete paralysis of the diaphragm occurs if the spinal cord is crushed or destroyed just below the C5 region.

FALSE (c1-c4 bc phrenic nerve innervates the diaphragm)

The anterior median fissure of the spinal cord is shallower and narrower than the posterior median sulcus.

FALSE (fissures are deeper than sulci)

Which of the following is NOT a correct description of the location of the lumbar plexus? a) lateral to the first four lumbar vertebrae b) posterior to the quadratus lumborum muscle c) between the two heads of the psoas major muscle d) None of these choices

b) posterior to the quadratus lumborum muscle

From which plexus does the iliohypogastric nerve arise?

lumbar

Select the structure(s) served by the supraclavicular nerve.

skin of superior portion of the chest & shoulder

Cerebrospinal fluid is found between two layers of the meninges, in a space called the _____.

subarachnoid space

Describe, in order, from superficial (outermost) to deep (innermost), the structures, tissues, and fluids that provide protection for the spinal cord.

1. vertebral column, 2. vertebral ligaments, 3. epidural space with adipose tissue, 4. dura mater of dense irregular connective tissue, 5. subdural space with interstitial fluid, 6. arachnoid mater of collagen and elastic fibers, 7. subarachnoid space with cerebrospinal fluid, 8. denticulate ligaments, extensions of pia mater, attach cord to dura mater, 9. pia mater of thin fibrous connective tissue.

The roots of which spinal nerves make up the cauda equina? 1. Thoracic 2. Lumbar 3. Sacral 4. Coccygeal

2. Lumbar 3. Sacral 4. Coccygeal

A typical reflex arc involves the following components: 1. sensory neuron 2. motor neuron 3. sensory receptor 4. integrating center 5. effector The correct order is:

3. sensory receptor 1. sensory neuron 4. integrating center 2. motor neuron 5. effector

There are _____ pairs of spinal nerves, consisting of the following groups: _____ pairs of cervical, _____ pairs of thoracic, _____ pairs of lumbar, _____ pairs of sacral, and _____ pair of coccygeal spinal nerves.

31; 8; 12; 5; 5; 1

All segments of the spinal cord contain lateral, posterior (dorsal), and anterior (ventral) gray horns.

FALSE (lateral horns are only found in the thoracic, upper lumbar, and sacral segments of the spinal cord)

Complete anesthesia of a dermatome typically requires blocking of only one pair of spinal nerves because there is never overlap between neighboring dermatomes.

FALSE (there is some overlapping)

A dermatome is an area of skin that provides sensory input to the CNS via one pair of spinal nerves or the trigeminal (V) nerve.

TRUE

Cell bodies of motor neurons that supply smooth muscle, cardiac muscle, or glands via the autonomic nervous system can be found in the lateral gray horns of the spinal cord.

TRUE

Except for T2-T12, all anterior (ventral) rami form nerve plexuses.

TRUE

The denticulate ligaments and the filum terminale are both structures that help to anchor the spinal cord and protect it against sudden displacement.

TRUE

The epidural space found between the dura mater and the wall of the vertebral canal contains a protective cushion of fat and connective tissue.

TRUE

The thin transparent spinal meninx called pia mater separates the spinal cord from the surrounding cerebrospinal fluid.

TRUE

Describe the anatomy of a spinal nerve from the point where it is attached to the spinal cord to where it divides into branches. Name the roots and branches and describe in general the regions served by each branch.

The nerve is attached to the cord by the anterior (ventral) root (contains axons of motor neurons) and the posterior (dorsal) root (which contains the sensory neurons' cell bodies in a posterior (dorsal) root ganglion). The two roots merge to form a single spinal nerve, which passes through an intervertebral foramen. The spinal nerve then divides laterally into: 1. the anterior (ventral) ramus, which serves the upper and lower limbs and lateral and anterior trunk, 2. the posterior (dorsal) ramus, which serves the posterior region of the trunk, 3. the meningeal branch, which reenters the spinal canal to serve the meninges, vertebrae, vertebral ligaments, and blood vessels of the spinal cord, and 4. rami communicantes, which contain components of autonomic nerve pathways.

Which of the following is FALSE regarding the sciatic nerve? It: a) arises from the lumbar plexus. b) splits at about the level of the knee into tibial and common fibular nerves. c) is the largest nerve in the body. d) sends branches to the hamstring muscles.

a) arises from the lumbar plexus

Which of the following is NOT a correct description of the location of the brachial plexus? a) on the neck alongside the first four cervical vertebrae b) passes above the first rib posterior to the clavicle c) extends inferiorly and laterally on either side of the last few cervical and first thoracic vertebrae d) enters the axilla

a) on the neck alongside the first 4 cervical vertebrae

Select the muscle(s) served by the obturator nerve.

adductor muscles of thigh

The gray matter of the spinal cord: a) is subdivided into regions called horns. b) is surrounded by white matter. c) contains neuronal cell bodies. d) all of these choices

all of these choices: a) is subdivided into regions called horns. b) is surrounded by white matter. c) contains neuronal cell bodies.

The spinal cord is protected by which of the following? a) vertebral column b) meninges c) cerebrospinal fluid d) All of these choices

all of these choices: a) vertebral column b) meninges c) cerebrospinal fluid

The part of the spinal cord indicated by the line is the _____. (The structure composed of axons of motor (efferent) neurons that emerges from the anterior aspect of the spinal cord and extends laterally to join a posterior root, forming a spinal nerve)

anterior (ventral) root

Motor neurons that supply skeletal muscles have cell bodies in _____ gray horns of the spinal cord, and their axons exit the cord via a/an _____ root.

anterior (ventral); anterior (ventral)

The meninx indicated by the line is the _____. (middle layer)

arachnoid mater

What is the best description of the subarachnoid space?

between arachnoid mater & pia mater

From which plexus does the axillary nerve arise?

brachial

From which plexus does the long thoracic nerve arise?

brachial

From which plexus does the ulnar nerve arise?

brachial

From which plexus does the great auricular nerve arise?

cervical

From which plexus does the phrenic nerve arise?

cervical

The _____ plexus serves the skin and muscles of the head, neck, and superior part of the shoulders and chest.

cervical

The main plexuses formed by the anterior (ventral) rami of spinal nerves are:

cervical, brachial, lumbar, & sacral

What is the best description of the arachnoid mater?

consists of collagen & elastic fiber network; has no blood vessels

What is the best description of the epidural space?

contains a protective cushion of fat & connective tissue

The white matter of the spinal cord:

contains ascending (sensory) and descending (motor) tracts

What is the best description of the pia mater?

contains blood vessels that supply O2 & nutrients to the spinal cord

which of the following statements is FALSE for spinal nerves? a) The two largest branches of a spinal nerve are the anterior (ventral) ramus and the posterior (dorsal) ramus. b) All spinal nerves are mixed nerves. c) The outer covering of a spinal nerve is the epineurium. d) Every pair of spinal nerves exits through the intervertebral foramina above the vertebra that has the same name and number as the nerves.

d) Every pair of spinal nerves exits through the intervertebral foramina above the vertebra that has the same name and number as the nerves.

Select the structure(s) served by the axillary nerve.

deltoid muscle

Select the structure(s) served by the phrenic nerve.

diaphragm

The two main routes for motor information traveling down the spinal cord are _____ pathways and _____ pathways.

direct; indirect

The two main routes for sensory information traveling up the spinal cord to the brain are _____ tracts and _____ columns.

direct; indirect

The meninx indicated by the line is the _____. (most superficial layer)

dura mater

Select the muscle(s) served by the femoral nerve.

extensor muscles of knee joint

The inferior extension of the pia mater that anchors the spinal cord to the coccyx is called the _____.

film terminale

Select the structure(s) served by the median nerve.

flexors of the wrist

Select the muscle(s) served by the tibial nerve.

gastrocnemius & soleus muscles

Select the muscle(s) served by the inferior gluteal nerve.

gluteus maximus

The central canal of the spinal cord is located in the center of the:

gray commissure

Motor impulses that help maintain muscle tone and posture are conveyed from the brain through the spinal cord by the:

indirect pathways

Which peripheral nerves are responsible for cutaneous sensation from the skin of the anterior abdominal wall as well as motor innervation to anterior abdominal wall muscles?

intercostal (thoracic) nerves

Which of the following is NOT a branch of a spinal nerve?

lateral ramus

The senses of pain and temperature are conveyed to the brain by:

lateral spinothalamic tracts

From which plexus does the femoral nerve arise?

lumbar

The adult spinal cord extends from the _____ of the brain inferiorly to the superior border of the _____ lumbar vertebra.

medulla oblongata; second

What is the best description of the dura mater?

meninx closest to the bone of the vertebral column

The meninx indicated by the line is the _____. ( most deep layer)

pia mater

Which of the following contain cell bodies of interneurons?

posterior (dorsal) gray horns

The part of the spinal cord indicated by the line is the _____. (The structure composed of sensory axons lying between a spinal nerve and the dorsolateral aspect of the spinal cord.)

posterior (dorsal) root

Which of the following contains sensory information ONLY?

posterior (dorsal) root

Which of the following contain cell bodies of sensory neurons?

posterior (dorsal) root ganglia

The structure(s) indicated by the lines is/are the _____. (Branches of a spinal nerve that are components of the autonomic nervous system)

rami communicantes

From which plexus does the pudendal nerve arise?

sacral

From which plexus does the superior gluteal nerve arise?

sacral

Which of the following could serve as an effector for a somatic reflex?

skeletal muscle

Spinal nerves T2-T12 differ from all other spinal nerves in that:

the anterior (ventral) rami do not contribute to a plexus

The conus medullaris is:

the tapering end of the spinal cord inferior to the lumbar enlargement

Lateral gray horns are present in ALL segments of the _____ region of the spinal cord.

thoracic

Select the muscle(s) served by the common fibular nerve.

tibialis anterior & fibulas (peroneal) muscles

Select the structure(s) served by the radial nerve.

triceps brachii