human anatomy chapter 14 part 2
College: First year
Spinal meninges
Function (3)
1. Provide protection
2. physical stability
3. shock absorption
Spinal Meninges
1. Denticulate ligaments
help anchor the spinal cord in position
Spinal Meninges
1. Dura mater
2. Arachnoid mater
3. pia mater
1. tough, fibrous outermost layer
2. middle layer
3. innermost layer

1. white matter 2. grey matter
3. ventral root 4. dorsal root
5. spinal nerve 6. dorsal root ganglion
7. pia mater 8. arachnoid mater
9. dura mater
Spinal cord grey matter
sectional anatomy (2)
1. Central canal
2. consists of somas (cell bodies) surrounding the central canal
Spinal cord White matter
sectional anatomy (3)
1. consists of axons
2. nerves organized into tracts or columns
3. located outside grey matter area
Spinal cord Grey matter
Organization
1. Somas are organized into groups called...
2. include (2)
1. nuclei
2. A. sensory nuclei
B. motor nuclei
Spinal cord Gray matter Organization
1. Posterior Gray horns
2. Lateral Gray horns
3. Anterior gray horns
4. Gray Commissure
1. somatic sensory and visceral nuclei
2. visceral motor nuclei
3. somatic motor nuclei
4. consists of axons crossing from one side to the other

1. posterior gray horn 2. posterior median sulcus
3. posterior gray commissure 4. lateral gray horn
5. anterior gray horn 6. anterior median fissure
7. somatic 8. visceral
9. sensory nuclei 10. visceral
11. somatic 12. motor nuclei
13. to ventral root 14. from dorsal root
Spinal cord White matter Organization
1. consists of...
2. _A_ convey either: (2)
1. columns of nerves (fascicles
2. A. Columns
B. sensory tracts (ascending tracts)
C. motor tracts (descending tracts)
Spinal nerves
1. There are ___ pairs of spinal nerves
2. __ cervical nerves
3. __ thoracic nerves
4. __ lumbar nerves
5. __ sacral nerves
6. __ coccygeal nerves
1. 31
2. 8
3. 12
4. 5
5. 5.
6. 1

1. cervical spinal N. 2. Thoracic Spinal N
3. Lumbar spinal N 4. Sacral Spinal N
5. Coccygeal N 6. Cervical Enlargement
7.posterior median sulcus 8.lumbosacral enlargement
9. conus medullaris 10. inferior tip of spinal C
11. cuada equina 12. fillum terminale
Spinal Nerves (consists of)
1. Epineurium
2. Perineurium
3. Endoneurium
1. outer layer- becomes continuous with dura mater
2. layer surrounding a fassicle (bundle of axons)
3. layer surrounding a single axon

1. epineurium
2. perineurium
3. endoneurium
Peripheral distribution of spinal nerves : branches
1. white ramus (rami communicates)/
2. gray ramus (rami communicates)
3. dorsal ramus
4. ventral ramus
1./2. A. innervates smooth muscles, glands, and organs
B. motor impulses leave the spinal cord through the ventral root to the spinal nerve
3. innervates skeletal mucles of the neck and back
4. innervates skeletal muscles of the limbs

1. Motor Commands
2. Postganglionic fibers to smooth muscles, glands, etc. of back
3. to skeletal muscles of back
4. to skeletal muscles of body wall, limbs
5. postganglionic fibers to smooth muscles, glands, etc of body wall, limbs
6. postganglionic fibers to smooth muscles, glands, visceral organs in thoracic cavity
7. preganglionic fibers to sympathetic ganglia innervating abdominopelvic viscera
8. somatic motor commants
9. visceral motor commands

1. Dorsal Ramus 2. Ventral ramus
3. grey ramus (postganglionic)
4. white ramus (preganglionic)5. Rami communicantes
6. sympathetic nerve 7. dorsal root ganglion
8. dorsal root 9. visceral motor
10. somatic motor 11. ventral root
12. Spinal Nerve 13. Sympathetic ganglion
Sensory impulses associated with the spinal nerves
sensory impulses travel in the spinal nerve through the dorsal root to the spinal cord

1. Sensory information
2. from interoceptors of back
3. from exteroceptors, proprioceptors of back
4. from exteroceptors, proprioceptors of body wall, libms
5. from interoceptors of body wall, limbs
6. from interoceptors of visceral organs
7. somatic sensations
9. visceral sensations

1. dorsal ramus 2. ventral ramus
3. rami communicantes 4. ventral root
5. dorsal root ganglion 6. dorsal root
7. somatic sensory 8. visceral sensory
Spinal Nerves
1. Dermatomes
2. importance...
1. A sensory region monitored by the dorsal rami of a single spinal segment
2. clinically important areas regarding surgery
Nerve Plexuses
1. Cervical Plexus
2. Bracial Plexus
3. Lumbar Plexus
4. Sacral Plexus
5. Lumbosacral Plexus
1. C1-C5
2. C4-T1
3. T12-L4
4. L4-S4
5. sometimes lumbar and sacral are combined T12-S4

1. Cervical Plexus 2. Brachial plexus
3. Lumbar Plexus 4. Sacral Plexus
5. phrenic N 6. Axillary N
7. Musculocutaneous N 8. Radial N
9. Ulner N 10. Median N
11. Digital N

1. Iliohypogastric N 2. Ilioinguinal
3. Genitofemoral N 4. lateral femoral cutaneousN
5. Femoral N 6. obturator N
7. Saphenous N 8. Superior Gluteal N
9. Inferior Gluteal N
10. posterior femoral cutaneous M
11. Perineal Branches

1. Sciatic N 2. Tibial N
3. Sural N 4. Common fibular(peroneal)N
5. Pudendal N 6. Perineal Branch
7. Hemorrhoidal branch 8. Thoracic N
9. intercostal N 10. Lateral cutaneous Branch
11. Anterior cutaneous branch
Cervical Plexis
1. consists of (2)
1. Cutaneous branches
2. Muscular Branches
Cervical Plexis
1. Cutaneous Branch innervates(3)
2. Musclular Branch Innervates (10)
1. A. head B. Neck C. Chest
2. A. Omohyoid B. Sternohyoid C. Geniohyoid
D. Thyrohyoid E. Sternothyroid F. Scalenes
G. Sternocleidomastoid H. Levator Scapulae
I. Trapezius J. Diaphragm

Cervical Plexus
1. Phrenic Nerve
Brachial Plexus
1. Immediate nerves emerging from C5-T1: (3)
2. these trunks merge to form...
1. A. Superior Trunk
B. Middle Trunk
C. Inferior Trunk
2. Lateral cord

Brachial Plexus
1. superior trunk 2. Middle trunk
3. Inferior Trunk 4. Musculocutaneous N
5. Median N 6. Ulnar N
7. Radial N 8. Deep radial N
9. Superficial Radial N 10. Palmar Digital N
Brachial Plexus: cords of Brachial plexus
1. lateral cord
2. medial cord
3. posterior cord
1. merging of the trunks
2. an extension of the inferior trunk
3. an extention of the middle trunk

Brachial Plexus
1. roots (ventral rami) 2. Trunks
3. Divisions 4. Cords
5. Peripheral Nerves 6. Superior trunk
7. Middle trunk 8. Inferior Trunk
9. lateral cord 10. posterior cord
11. medial cord 12. axillary N
13. Musculocutaneous N 14. median nerve
Brachial Plexus: cords of Brachial plexus
1. lateral cord
2. medial cord
3. posterior cord
4. lateral and medial cord
1. Extends to musclulocutaneous N
2. extends to form the ulnar N
3. branches from Radial N and Axillary N
4. Extends to form the median N
Brachial Plexus
Spinal Segments Nerve(s)
C5,C6
C5-T1
C5-C7
C6-T1
C8,T1
Brachial Plexus
Spinal Segments Nerve(s)
C5,C6 Axillary Nerve
C5-T1 Radial Nerve
C5-C7 Musculocutaneous Nerve
C6-T1 Median Nerve
C8,T1 Ulnar Nerve

Lumbar Plexus
1. Iliohypogastric N 2. Ilioinguinal N
3. Genitofemoral N 4. Lateral Femoral cutaneous N
5. Femoral N 6. Obturator N

1. Superior Gluteal N 2. Inferior Gluteal N
3. sciatic N 4. posterior femoral cutaneous N
5. Pudineal N

1. Superior Gluteal N 2. Inferior Gluteal N
3. sciatic N 4. posterior femoral cutaneous N
5. Pudineal N 6. . Iliohypogastric N
7. Ilioinguinal N 8. Genitofemoral N
9. Lateral Femoral cutaneous N 10. Femoral N 11. Obturator N 12. saphenous M
1. Reflex
2. A. Reflex arc
B. Begins at a _I_ and ends at a _II_
1. An immediate involuntary response
2. A. The neural “wiring” of a single reflex
B. I. Sensory receptor, II. Peripheral receptor
Reflexes Classifications (4)
1. their development
2. The site where info is processed
3. the nature of resulting motor response
4. complexity of neural circuit
Reflexes Classifications
1. their development (2)
2. The site where info is processed (2)
3. the nature of resulting motor response (3)
4. complexity of neural circuit (2)
1. A. Innate B. Acquired
2. A. Spinal B. Cranial (cerebral)
3. A. Somatic B. Visceral C. Autonomic
4. A. Monosynaptic B. Polysynaptic
Pathway of a reflex arc
(5)
1. Activation of a sensory receptor
2. Relay of information to the CNS
3. Information processing
4. Activation of a motor neuron
5. Response by the effector
Reflex classification
1. Development
A. Innate reflexes
B. Acquired reflexes
A. genetically determined
B. learned
Reflex Classification
2. Response
A. Somatic reflexes (2)
B. Visceral (autonomic) reflexes
A. I. Control Skeletal contractions
II. includes superficial and stretch reflexes
B. Control actions of smooth and cardiac muscles, glands
Reflex Classification
3. Complexity of circuit
A. Monosynaptic
B. Polysynaptic
1. Involves a single segment of the spinal cord
2. Integrates motor output from several spinal segments
Stretch reflex pathway (5)
1. Stimulus stretches a muscle
2. Activates a sensory neuron
3. Information is processed in the spinal cord
4. Motor neurons are activated
5. Muscle (effector) contracts