*Area of skin that is innovated by a single spinal nerve.
***use diagram in notes**--nerves do overlap so ether side dermatomes of adjacent nerves
if lesion in spinal nerve, only a small area that is complete loss of sensation.
2 components: dermatome supplied by both the dorsal and the ventral ramus of its spinal nerve. If entire dermatome is numb than the spinal nerve has lesion. If one little part is numb, only one part of the rami is affected.
What factors determine which areas appear black vs white?
1. Density of the tissues
3. Tissue thickness
Normal PA Chest X-Ray—No pathology
-Posterior/Anterior: x-ray is going through posterior (patient has back to the x-ray).
-X-ray is always posted as if you were looking at the patient
-2D image of a 3D image—all compressed both into a single image.
However, anterior structures are seen more clearly.
Which side of the films and right sdies of paitent—always viewed as if facing patient
What is meant by the term “radiolucent”?
What is meant by the term “radiodense” or “radiopaque”?
Very white—absorbed by the tissue
What are the five major categories of radiodense materials normal see in the plain film x-rays?
1. Air or gas
3. Soft tissue (muscle, internal organs)
Normal—PA, can see the anterior images better
AP view—can see the posterior parts of the better
How can hollow soft tissue structures or organs be visualized with conventional radiography? Contrst meterials—can be radiolucent or radiodense
Barrium (radiodense)—positive contrast material is radiodense
Positive and Negative—ex: barium introduced first so as barium past out, air was introduced so can see the residue barium outline walls/ Fluid line= patient was laying on side
Advantages of CT conventional radiography?
-Eliminates the superimposition
-see the tissues that have margerate densities in more detail
Bony elements and regions(subdivions) of the Upper Limb (overview)