Human Osteology

WP_20141118_002Hi everyone,

I hope you have enjoyed reading the lesson plans. This concludes the work we did during the fall semester of 2014. See you in the spring!

Week 9: Human Osteology

Activity: Smithsonian’s Skeleton in the Cellar

Topic: Human Osteology

As we learned last week, our bones can tell a story about our lives. In addition to providing key information regarding health, diet, and overall similarity to other species, our bones are provide specific information regarding an individual’s life history. For example, an osteologist can determine whether a particular specimen belongs to a male or female, or adult or child, based on specific features on an individual bone.

Helpful hints for osteological analysis:

  1. Orient your specimen so that you are seeing the same bone as the picture.
  2. ALWAYS ALWAYS ALWAYS use both hands to pick up the castes or keep them on the table.

Activity:

For today’s activity, we will learn how to determine whether a skeleton belongs to a male or female. Osteologists and physical anthropologists generally refer to this as sexing a skeleton. To identify an individual’s biological sex, osteologists compare the size and shape of skeletal features.

-Most useful bones are the skull and the pelvis.

Ask the students’s opinion on which bones should differ between men and women? Why?

-Why these bones? Facial features differ; childbirth.

  1. For the activity, introduce and discuss the differences to the entire class. Point out the features on the pelvis to each group.
  2. Discuss different parts of the pelvis and the features that are used to sex a skeleton.
    1. Sciatic notch
      1. Males are narrow
      2. females are wider.
    2. Auricular surface (connects the pelvis to the sacrum, or the large bone at the base of the spine)
    3. Men: flat
    4. Women: surface is raised
  3. Ask students to compare the Skeleton in the Cellar to the examples that they have and to fill in the sheet.
  4. Discuss the features of the Skull that help osteologists to sex a skeleton, walking students through each example as a class and pointing the features out within the individual groups.
    1. Skull has 2 parts:
      1. Cranium (holds brain, etc.)
      2. Mandible (jaw)
    2. Male and female skulls have a number of different features:
      1. Brow ridges:
        1. Males are larger and more prominent;
        2. Females are smaller, more gracile.
      2. Foreheads:
        1. Males: sloping forehead
        2. Females: vertical forehead
      3. Mastoid process (projection behind the ear):
        1. Males: larger
        2. Females: smaller
      4. Occipital muscle attachments (bone gets thicker when attached to big muscles)
        1. Males: greater definition at the back of the head.
        2. Females: less definition.
      5. Chin:
        1. Males: chin is more square, vertical jaw angle
        2. Females: chin is more pointed; more rounded jaw angle.
      6. Overall:
        1. Females have a smoother bone surface due to smaller muscles
  5. Ask students to use these data to characterize the Skeleton in the Cellar, describing the brow ridge, neck attachment, mastoid process, angle of the jaw, and the chin.
  6. Once complete, ask students to determine whether the skeleton in the cellar is a male or a female (it was most likely male).

Discussion:

Ask the students’s opinion on which bones should differ between men and women? (skull and pelvis are most useful). Why?

-Why these bones? Facial features differ; childbirth.

 

Was it hard to determine the sex of the Skeleton in the Cellar?

-What could make it difficult to determine?

-women with robust frames; men with gracile frames

-not having all of the bones present

Which features were the most useful for determining the sex for the class?

For the pelvis? (probably the sciatic notch)

For the cranium? (see what they say).

Emphasize that this is just one line of information that can be gleaned from osteological analysis, as more information would be revealed with additional training.

However, these types of analyses are important, as they can help us figure out the sex of an unknown specimen.

Who would be interesting in finding out the sex of an unknown individual?

-Forensic anthropologists

-policemen, detectives

-archaeologists

-other people….