A white teaching skeleton against a black background, seen from the skull down to the ribs

ANATOMY AND PHYSIOLOGY · CHAPTER 7

The Human Skeleton

Follow along with your worksheet, one question at a time.

mrsajdak.com/skeleton

Photo: FotoEmotions, CC0

BEFORE YOU START

206 bones, one system

A chest X-ray: the ribs, collarbones and spine show up pale against the dark lungs

Skeletal system

Your bones, plus the cartilage and ligaments that join them.

A technologist at a control desk, looking through a window at a person lying in a ring-shaped scanner

Real scans

The model shows all 206 bones of one adult. It was built from real scans.

In this lab you will

1. Sort the bones two ways.

2. Count them.

3. Find bones from clues.

4. Take a hand and a foot apart.

5. Test yourself.

Your bones come in many shapes. Why are they not all the same?

Photos: Mikael Häggström, CC0 · U.S. Air Force

BEFORE YOU START

Get set up

1

Open mrsajdak.com/skeleton on your device.

2

Write your name, the date and your period on the worksheet.

3

Wait for the skeleton to show up. It can take a few seconds.

4

Find the two tabs. Stay on Explore for Parts 1 to 5.

The top of the lab page, showing the title The Human Skeleton and two tabs: Explore and Find the bone
Where in the labWorksheetQuestions
Explore: Axial / appendicularPart 11 to 3
Explore: ShapePart 24 to 7
Explore: RegionPart 38 to 10
Explore: SearchPart 411
Explore: Take it apartPart 512
Find the bonePart 613

Screenshot: mrsajdak.com/skeleton

BEFORE YOU START

Move the model

1

Drag to turn the skeleton.

2

Scroll or pinch to zoom in and out.

3

Click a bone. Its card shows up next to the model.

4

Read the three tags on the card. Then read the fact under them.

5

Lost? Press Whole body.

The 3D skeleton in the lab with the left upper arm bone picked, and six view buttons along the bottom: Front, Back, Their left, Their right, Top, Whole body
The bone card for the left humerus: three tags that say Appendicular, Long bone and Arm, one fact, and the buttons Zoom to it, See it alone and Hide it

The tags say axial or appendicular, the shape, and the part of the body.

Their left means the skeleton’s left, not yours.

Screenshots: mrsajdak.com/skeleton, Explore tab

An old engraving of a human skeleton standing with one arm held out, seen from the front

EXPLORE TAB · QUESTIONS 1 TO 3

Part 1. Two skeletons

The axial skeleton is the center line of your body.

The appendicular skeleton is everything that hangs from it.

You will color the model to see both.

Engraving after B. S. Albinus, about 1820, public domain

PART 1 · QUESTION 1

Color it two ways

1

Find Color the bones by. Press Axial / appendicular.

2

Turn the model. Look at both colors from the front and the back.

3

Read the key under the buttons. It gives the number of bones in each skeleton.

4

Write both numbers. Add them to get the total.

A close view of the lower legs and feet in the lab after the bones are colored. Every bone in view is blue, and one shin bone is picked
The Color the bones by box in the lab, with four buttons: Natural, Axial / appendicular, Shape and Region

The key shows up under these four buttons.

Press Front and Back to turn the model fast.

Click a row in the key to light up just that skeleton. Click it again to bring the rest back.

Screenshots: mrsajdak.com/skeleton, Explore tab

PART 1 · QUESTIONS 2 AND 3

Click, then tick

1

Click a bone from your table. Or type its name in Search.

2

Read the first tag on its card. It says Axial or Appendicular.

3

Tick one box in that row.

4

Do all eight bones.

The bone card for the left tibia. Its first tag says Appendicular

This card is for the tibia. It is not in your table.

The sternum comes in three pieces. Any piece works.

QUESTION 3

In the trunk, but appendicular?

The clavicle, scapula and hip bone sit in your trunk. They are not in your arms or legs.

Look at what each one joins. Then read the line under Appendicular skeleton in the key.

Screenshot: mrsajdak.com/skeleton, Explore tab

A museum case holding every bone of a human skeleton, taken apart and laid out flat in the shape of a body

EXPLORE TAB · QUESTIONS 4 TO 7

Part 2. Sort by shape

Bones come in five shapes: long, short, flat, irregular and sesamoid.

You will count each kind. Then you will ask what each shape is good for.

Photo: Daderot, public domain

PART 2 · QUESTIONS 4 AND 5

Five shapes in the key

1

Press Shape.

2

Read the five kinds in the key. Each kind has a color and a number.

3

Copy the five numbers into the table for Question 4.

4

Click a row in the key. Only that kind stays lit. Click it again to bring the rest back.

5

For Question 5, click each bone. Read the shape tag on its card.

The whole skeleton in the lab with only the short bones lit in yellow at the wrists and ankles. Every other bone is faded to pale grey
The key in the lab for Shape: Long bones, Short bones, Flat bones, Irregular bones and Sesamoid bones, each with a color and one line that describes it. The Short bones row is picked

Here the Short bones row is lit. Your numbers are at the right end of each row.

Screenshots: mrsajdak.com/skeleton, Explore tab

PART 2 · QUESTIONS 5 TO 7

Shape is not size

QUESTION 5

9

Nine bones to sort

Click each bone. Its card has a shape tag.

Some are tiny. Type the name in Search. Then press Zoom to it.

QUESTION 6

Small

Small, but a long bone?

Click a fingertip bone. Read the fact on its card.

Then read the note under the key. What are bones sorted by?

QUESTION 7

Job

Around the brain and the heart

Light up one shape at a time. Which shape wraps the brain and the heart?

Read the line under that shape in the key. How does the shape fit the job?

The top of a human skull seen from above, with a zigzag line running across it where two bones join

EXPLORE TAB · QUESTIONS 8 TO 10

Part 3. Count them

A skull looks like one bone. The zigzag line shows where two bones meet.

You will count the bones in each region of the body. Then you will find where most of them are.

Photo: MAKY.OREL, CC0

PART 3 · QUESTION 8

Count by region

1

Press Region.

2

Click a row in the key. That part of the body lights up. The rest fades.

3

Find the six parts from your table in the key.

4

Copy the number at the right end of each row.

The key in the lab for Region: Skull, Cranium, Face, Ear bones, Hyoid, Vertebral column, Rib cage, Shoulder girdles, Arms and hands, Arms, Wrists and hands, Hip bones, Legs and feet, Legs, and Ankles and feet. The Arms row is picked
The whole skeleton in the lab with only the six arm bones lit in green. Every other bone is faded to pale grey

Here the Arms row is lit. It is not in your table.

Rows set in a little are parts of the row above them.

Screenshots: mrsajdak.com/skeleton, Explore tab

PART 3 · QUESTIONS 9 AND 10

How big a share?

1

Add your wrists and hands number to your ankles and feet number.

2

Divide the sum by 206.

3

Multiply by 100. That is the percent.

Example

Say one part of the body has 30 bones. Another part has 20.

Together they have 50 bones.

50 ÷ 206 × 100 = 24

That is about 24% of all 206 bones.

These are not your numbers. Use your own.

QUESTION 10

Why so many small bones?

Think about what your hands and feet do all day.

What happens at each place where two bones meet? How does that help a hand or a foot?

A plastic model of a human skull lying on grass, seen from the side, with each bone painted a different color

EXPLORE TAB · QUESTION 11

Part 4. Find the bone from the clue

Every bone in the lab has a card. Each card gives one fact.

You get eight clues. Match each clue to its bone.

Photo: John Campbell, CC BY 2.0

PART 4 · QUESTION 11

Some bones hide inside the skull

1

Search for the bone. Click its name.

2

Press See it alone on its card. Every other bone fades.

3

Scroll out a little. Now you can see where the bone sits in the head.

4

Press Show every bone to bring the skeleton back.

The head and neck of the skeleton faded to pale grey, with one small bone lit in blue between the eyes
The bone card for the ethmoid bone, with the buttons Zoom to it, See it alone and Hide it

This is the ethmoid bone. It is not one of your eight answers.

Two of your eight bones hide like this one.

Screenshots: mrsajdak.com/skeleton, Explore tab

A rock climber seen from behind, dipping one hand into a bag of chalk. The other hand is open and white with chalk

EXPLORE TAB · QUESTION 12

Part 5. Take a hand and a foot apart

Your hands grip, pinch and hold. Your feet balance your whole body.

You will pull the model apart. Then you will count every bone in one hand and one foot.

Photo: NPS / Emily Hassell

PART 5 · QUESTION 12

Pull it apart and count

1

Press Shape.

2

Drag the Take it apart slider all the way to the right.

3

Zoom in on one hand. Count three groups: wrist bones, palm bones and finger bones.

4

Do the same for one foot: ankle bones, middle-of-foot bones and toe bones.

5

Add each row to get the total.

The whole skeleton in the lab pulled apart, so there are gaps between the bones. The bones are colored by shape
The Take it apart box in the lab: a slider dragged all the way to the right, two tick boxes for cartilage and teeth, and a Show every bone button

Short bones are the wrist and ankle bones. They share one color.

Lost count? Click a bone. Its card tells you what it is.

Screenshots: mrsajdak.com/skeleton, Explore tab

PART 5 · QUESTION 12

Check your count

NEW WORDS

Three groups

Carpals are wrist bones. Tarsals are ankle bones.

Metacarpals are palm bones. Metatarsals are in the middle of the foot.

Phalanges are finger bones and toe bones.

THE THUMB

Count its phalanges

Zoom in on the thumb. Count its bones past the palm.

Now count the same bones in one other finger.

Write both numbers under the table.

Example

Say one side of a body part has 20 bones.

Both sides together have 40.

20 × 2 = 40

Now double your own one-hand total. Does it match your wrists and hands number from Question 8?

These are not your numbers. Use your own.

PART 6 · QUESTION 13

Find the bone

1

Press the Find the bone tab.

2

Leave it on Major bones. Press Start a round.

3

The lab names a bone. Click that bone on the model.

4

You score a point only on the first click. After three misses, the lab shows you the bone.

5

Play two rounds. Write both scores. Then write one bone you missed and where it is.

The skeleton in the lab during a round, with a box at the top that reads Find the sternum’s manubrium, 6 of 10
The Find the bone box in the lab with the buttons Major bones, Every bone, Hands and feet, Start a round and Show me, above a Score box that lists each bone found so far

Show me gives up on a bone. It counts as a miss.

Screenshots: mrsajdak.com/skeleton, Find the bone tab

WRAP IT UP · QUESTION 14

Does shape fit the job?

The claim

“A bone’s shape fits the job it does.”

Evidence 1

Pick a bone, or a group of bones, from one part of this lab. Name its shape.

Evidence 2

Pick another from a different part of the lab. A different shape works well.

Reasoning

For each one, say how the shape helps the bone do its job.

One long human bone photographed twice on a dark table, from the front and from the back

One bone, seen from the front and from the back. What job would this shape be good for?

Photo: MAKY.OREL, CC0

A small bronze model of a human skeleton with joints that move, seen from the skull down to the knees

LAST CHECK

Before you hand it in

Name, date and period are on top.

Every table is full.

Questions 2 and 5 have one tick in each row.

Question 14 uses evidence from two parts of the lab.

Photo: Science Museum, London, via Wellcome Collection, CC BY 4.0