Milestone 3 -- Thalamus & Motor System 1: Spinal Cord

1

Muscle spindles

2

spinal nerve

3

dorsal root ganglion

4

afferent fibers

5

alpha-motor neuron

6

efferent fibers

7

neuromuscular junction

8

muscle

9

spinal

1

medullary pyramid

2

lateral corticospinal tract (crossed, 90%)

3

anterior corticospinal tract (uncrossed— 10%)

1

upper motor neuron

2

UMN travels thru white matter (interior) of cortex

3

corticospinal tract

4

pyramidal decussation (at spinomedullary junction)

5

ventral

6

lower motor neuron

7

upper motor neuron & lower motor neuron

8

grey matter

1

C1-C3

2

C4 (C3-C5)

3

C5

4

C6

5

C7

6

C7-C8

7

T1

8

T1-T12

9

T7-L1

10

L2

11

L3

12

L4-L5

13

L4-S1

14

Cervical

15

Thoracic

16

Lumbar

17

Sacral

1

Neck Muscles

2

Diaphragm

3

Shoulder (deltoid)

4

Wrist

5

Triceps

6

Fingers

7

Hand

8

Intercostals (trunk)

9

Abdominals

10

Hips

11

Quadriceps

12

Hamstrings - Knee

13

Foot

1

Stretch (patellar tendon)

2

Patella

3

golgi tendon organ

4

muscle spindle

5

dorsal root ganglion

6

Type 1a sensory fiber

7

Motor fiber excitatory

8

Motor end plates

1

Biceps

2

Triceps

3

Finger flexors

4

Patellar-jerk reflex; Quadriceps

5

Ankle reflex; Achilles tendon

1

C5-C6

2

C7-C8

3

C8-T1

4

L2-L4

5

S1-S2

1

Withdrawal

2

sensory nerve

3

dorsal root ganglion

4

afferent fibers

5

internucial cell

6a

alpha-motor neuron

6b

inhibitory interneuron

7a (applies to both excitatory bicep & inhibitory tricep pathways)

efferent fibers

7b

Triceps motor cell

8

motor nerve

9a

biceps contraction

9b

triceps inhibition —> relaxation

1a

Diaphragm

1b

Diaphragm; Contracts to increase the thoracic diameter for inspiration

2a

External intercostals

2b

External intercostals; Contract to raise the ribs for inspiration

3a

Internal intercostals

3b

Internal intercostals; Assist in rib depression for forced expiration

4a

Abdominal muscles

4b

Abdominal muscles; Increase intrathoracic pressure for forced expiration

5

rectus abdominus, internal oblique, external oblique, transversus abdominus

1

C3-C5

2

T1-T12

3

T1-T12

4

T6-T12

1

Midline nucleus

2

Internal medullary lamina

3

Anterior nucleus

4

Ventral anterior nucleus

5

Reticular nucleus

6

Ventrolateral nucleus

7

Lateral dorsal nucleus