The image above illustrates an NADH-TR stain showing dark type 1 and pale type 2 fibers. The latter would appear dark in ATPase stain. At least two subtypes are now identified among type 2 fibers using different methods of staining. All of the muscle fibers in a given motor unit are of the same histochemical types, either type 1 or type 2, suggesting that the neuron determines the type of muscle fibers. The fibers of adjacent motor units overlap and intermingle resulting in a characteristic mosaic or checkerboard pattern.

This H&E image shows a large group of atrophic fibers [center] next to a group of normal fibers (left), a typical example of group atrophy.

The denervated muscle fibers are in the vicinity of intact axons and may become reinnervated by collateral sprouting. Since the motor neuron determines the muscle fiber type, all of the re-innervated fibers are converted to a single histochemical fiber type with loss of the normal checkerboard pattern. This phenomenon is called "type grouping." The image above illustrates typical type grouping in an ATPase stain. Note the area of dark type 2 fibers next to a large area of pale type 1 fibers. Normal checkerboard pattern is lost.   

The frontal chest radiograph showed a large antrerior mediastinal soft tissue mass on the right side adjacent to the heart. A plain and contrast enhanced CT Chest showed a large, well defined, lobulated, anterior and superior mediastinal mass with cystic components. In view of the clinical presentation this lesion was thought to be thymoma.

Amytrophic lateral sclerosis:

weakness, atrophy, fasciculationshyperreflexia

Note atrophy in ALS

Lou Gehrig—famous N.Y. Yankee first baseman who had ALS and thus it is commonly called “Lou Gehrig disease.”

note thin ventral roots in ALS patient-why?

Lumbosacral radiculopathy. Sagittal MRI showing loss of intervertebral disc height at L5/S1. Herniations of the nucleus pulposus are noted at L4/5 and L5/S1

Think about patient’s problems, physical exam and tests you would request to verify yourdiagnosis!

Chief complaintRight leg pain

History of present illness42 year old female with an eight week history of mostly right leg pain. The pain radiates to the sole and outside of her foot and is accompanied by numbness and tingling. This episode of pain started as back pain but within a week had moved to being mostly in her leg.

Physical exam42 year old healthy female who stands through most of the history. She has an absent ankle jerk on the right leg. There are no focal motor deficits, and the neurological exam is otherwise negative. She has a markedly positive straight leg test and crossed straight leg test (raising the affected and unaffected leg recreates her leg pain).

Imaging studiesMRI scan shows a large disc herniation at L5-S1. There is also disc degeneration present at the L5-S1 disc. The axial scan (not shown) shows that the disc impinges on the right S1 nerve root.

This is an image of an MRI of the normal lumbar spine [low back]. The vertebrae are marked with numbers; one can see lumbar vertebrae 2 through 5 and finally the S1 vertebra [which is the Sacral #1 vertebrae]. The discs are in-between the vertebrae and are number accordingly. For example, the L3/4 disc has a black arrow pointing to it. The discs always have 2 numbers for identification. The Red arrow points to the fluid in spinal canal; this fluid appears as a whitish color on the MRI. The Blue arrow points to a nerve roots in the canal.

MRI delineates a mass of the distal 6 centimeters of the spinal cord involving the conus medullaris, (which ends at the upper aspect of L2).

Think about this patient’s neurologicaldeficits/problems!

A 34-year-old man suffered from severe neck and shoulder radicular pain of 1 year duration. His pain soon became electric-like, shooting in nature and involving the left upper limb and ulnar side of the left hand. Neurologically, he had minimal sensory impairment over the left C7 dermatome.

An MRI of the cervical spine demonstrated a C6-C7 herniated nucleus pulposus ((at right) A needle electromyogram examination confirmed the presence of a C6-C7 radiculopathy.

bony metastasis affecting cauda equina

see the conus just dorsal to it?

possible deficits in comparison to conus lesions?

Representative of Case History #1

DUCHENNES MUSCULAR DYSTROPHY

Gower’s Sign

•marked enlargement of calves•hyperlordosois•decreased tendon reflexes•normal sensation

•in A, patient is attempting to raise eyelids as high as possible

•In B, same patient has had an iv injection of Tensilon, an acetylcholinsterase inhibitor. Eyelids go higher for a while

A B

Representative of Case History #2

MYASTHENIA GRAVIS

Cervical or lumbar? Arrow points to ?????

Vitamin B-12–associated neurological diseases. Pernicious anemia. Characteristic lemon-yellow pallor with raw beef tongue lacking filiform papillae

Think of the neurological deficits/pathways/tests associated with SCD!

Write a practice question For me! Please make E the answer so I can answer it correctly![

What do these MRIs show?

What is the arrow pointing to?

Dorsal view of spinal cord, dorsal roots and ganglia of C7

Think about the the results of a lesion here. Write a few practice questions!

What pathway is in blue? Right or left?

Bulge/nucleus indicated by the arrow=Clark’s nucleusThink of a question I could ask!

Any thoughts on the Babinski?

WHERE IS THE EXACT LOCATION OF THE LESION?

JUST WHAT IS CAUSING THE DEFICIT?

The thin bridge of bone that connects the superior and inferior facets is the pars interarticularis; if broken=spondylolysis. Spondylolisthesis=slipping forward of the vertebral body ("listhesis" means "to slip forward").Most common at L4 and L5 where spine curves into its most pronounced "S" shape and where the stress is heaviest.

LEFT: The picture above shows Spondylolysis. Notice the “scottie dog” shape of the pars interarticularis and the fracture line where the dog's collar would be.RIGHT:    This picture shows a more severe state, Spondylolisthesis.  This condition occurs when the fracture on the right becomes unstable and allows the vertebrae aboveto slip anteriorly (to the front) on the vertebrae below. 

“SCOTTIE”

Where is the lesion that results in this mannerism? Perhaps hehas a C6 (six shooter) radiculopathy with funny feelings (paresthesias)!

A

B

C

D

E

F

Know These!!!!

LMN?? or Corticobulbar?

A

B

C

D

EF

Know These!!!!

F

G

E

DC

A

B

Know These!!!!

A B C D

EKNOW

PYROLIVE

PYR DEC

KNOW

PYR

KNOW PYRAMID

1012OLIVEPYRAMID

98v

8a7i

7m5s5m

6

11

PONS