In the present study the diameter of shaft, diameter of medulla and the medullary index of the human and different animal hair were measured. It was found that, medullary index, which was less than 0.25in human hair and more than 0.44in animal hair is useful parameter to distinguish between human and animal hair. 10
What is the medullary index?
The medullary index is defined as the ratio between the diameter of medulla and the diameter of the entire hair, (this is a dimensionless unit). It is known that a human's medulla is considerably thinner than an other animal's one.
What is the medullary index of an animal hair?
The medullary index is defined as the ratio between the diameter of medulla and the diameter of the entire hair, (this is a dimensionless unit). It is known that a human's medulla is considerably thinner than an other animal's one. For animals, it is 1/2 or more, for humans, 1/3 or less. At the given case, the index is So this is an animal hair.
What is Medullary carcinoma?
Medullary carcinoma is a rare and distinct subgroup of breast carcinomas accounting for less than 5% of all invasive breast cancers.[1] Medullary carcinoma is a rare and distinct subgroup of breast carcinomas accounting for less than 5% of all invasive breast cancers.[1] NCBI Skip to main content
What does medullary index measure?
Medullary Index Determined by measuring the diameter of the medulla and dividing it by the diameter of the hair. Medullary index for human hair is generally less than 1/3. For animal hair, it is usually greater than 1/2.
What is the medullary index and why is it important quizlet?
The medullary index measures the diameter of the medulla relative to the diameter of the hair shaft. For humans, the medulla generally occupies less than one-third the diameter of the shaft, while for animals it is generally one-half or greater. The medulla may be continuous, interrupted, fragmented, or absent.
What is the medullary index in humans?
Humans have a medullary index of less than 1/3 while the medullary index of animals is greater than 1/3.
Why is the medulla useful in species identification?
To identify different species of hair, it is necessary to look at the medulla pattern to determine the origin of the hair. The medulla pattern in human hair is fragmented or absent (except for the Mongoloid race), while in animals their medulla is continuous or interrupted (in a pattern).
What is the medullary index quizlet?
the medullary index measures the diameter of the medulla relative to the diameter of the shaft and is normally expressed as a fraction.
Which methods are used for comparing the color of 2 fibers?
Microspectrophotometry is a quick, accurate, and reproducible method to compare colored fibers for forensic purposes.
How do we determine the human hair from animal hair?
Human hairs are generally consistent in color and pigmentation throughout the length of the hair shaft, whereas animal hairs may exhibit radical color changes in a short distance, called banding. The distribution and density of pigment in animal hairs can also be identifiable features.
Can you determine species from hair?
The cuticle of the hair shaft is made of keratin scales or plates that overlap in characteristic pattern. Making a casts of hair is a forensic method that is used to determine cuticle patterns of different species.
Does all human hair contain a medulla?
The medulla, also referred to as the pith or marrow of the hair, is the innermost layer. Composed of round cells, this layer is normally found in thick and/or coarse hair. Naturally blonde and fine hair generally does not have a medulla.
Which feature is the most important in making a species identification in animal hair?
The distinctive scale pattern formed by animal hair makes it an important feature for species identification.
Where is the medulla found and what might it look like?
The medulla is found on the interior of the hair; it may be continuous, fragmented, or absent. The cuticle is found on the outside of the hair shaft; it has a scale pattern. In the cortex.
What information can be obtained through hair analysis?
Hair analysis is done by evaluating hair structure and DNA from cells attached to the root of the hair. It can be used to find out if people are related. Forensic hair analysis can be done to help identify a person who may have been present at a crime scene.
Where do the medullary cavities of bone exist quizlet?
The medullary cavity of a bone exists in the: diaphysis.
What are the 4 medulla patterns?
In the Present Study medulla has been classified into Absent, Fragmented, Discontinuous and Continuous types (Photo attached).
Can the racial origin of hair be determined why or why not if so how?
Sometimes a cross-sectional examination of hair may also aid in the identification of race. Cross sections of hair from Caucasians are oval to round in shape, whereas cross sections of Negroid hair are flat or oval in shape. Through DNA, specific information may be determined about the donor's racial origin.
What is the difference between the medulla of human and animal hairs?
The medulla, when present in human hairs, is amorphous in appearance, and the width is generally less than one-third the overall diameter of the hair shaft. The medulla in animal hairs is normally continuous and structured and generally occupies an area of greater than one-third the overall diameter of the hair shaft.