Anatomy of the Skeletal System

Question 1

What is the skeletal system comprised of?

Answer 1

Bone and cartilage

Question 2

What are some of the key features of the skeletal system?

Answer 2

Serves both structural and physiological purposes
Made up of many different types of bones

Question 3

What are the two major anatomical subdivisions of the skeletal system and what is included in each division?

Answer 3

Axial Skeleton:
Skull
Vertebrae
Ribs
Sternum

Appendicular Skeleton:
Bones of upper and lower limbs

Question 4

What are some key features of cartilage?

Answer 4

Multiple different types
Semi rigid but flexible
Composed of chondrocytes that produce extracellular matrix
Generally avascular and has no nerve supply

Question 5

What are some of the functions of cartilage?

Answer 5

Provides a smooth surface for bones to articulate at joints
Acts as a shock absorber
Enables the growth and development of long bones

Question 6

What is the term used to describe the growth and development of long bones?

Answer 6

Endochondral ossification

Question 7

What do bones consist of?

Answer 7

Calcified extracellular matrix

Question 8

What doe bone cells include?

Answer 8

Osteocytes (surrounded by bone matrix)
Osteoblasts (bone forming cells)
Osteoclasts (bone resorbing cells)

Question 9

What are the two types of bone and how can they be differentiated?

Answer 9

Compact bone:
Dense bone
Outer shell of all bones
Surrounds spongy bone

Trabecular (or spongy or cancellous) bone:
Found inside bones

Question 10

Which bones have a periosteum and what is this term?

Answer 10

All bones
An outer fibrous covering

Question 11

What is inside the trabecular bone?

Answer 11

Medullary cavity

Question 12

What can the trabecular bone allow?

Answer 12

Allows bones to compress and allows the blood vessels to run through the bone

Question 13

What are the names of the different classifications of bones and what are examples of these?

Answer 13

Long bone: femur
Short bone: carpal
Flat bone: frontal
Irregular bone: vertebrae
Sesamoid bone: patella

Question 14

What is the main physical feature of long bones?

Answer 14

Greater in width than in length

Question 15

What are some other key physical features of long bones?

Answer 15

Long shaft
Cylindrical cross-section
Usually expanded at either end (epiphyses)
Mainly compact bone with spongy bone at the ends

Question 16

What are some examples of long bones?

Answer 16

Humerus
Phalanges (finger/toe bones)

Question 17

What is the main physical feature of short bones?

Answer 17

Equal in width and in length

Question 18

What are some other key features of short bones?

Answer 18

Composed of mainly spongy bone surrounded by thin layer of compact bone
Allow small movements when articulated together
Spherical

Question 19

What are some examples of short bones?

Answer 19

Wrist (carpal) bones
Ankle (tarsal) bones

Question 20

How are long and short bones defined?

Answer 20

Relative to their width and length
Long/short defines their shape not their size as some long bones can be smaller than short bones

Question 21

Where can flat bones mostly be found?

Answer 21

Mostly around organs like the brain

Question 22

What are the key physical features of flat bones?

Answer 22

Smooth and thin
Don’t have to be laid out flat

Question 23

What is the structure of flat bones?

Answer 23

Layer of trabecular bone between two layers of compact bone

Question 24

What are the main functions of flat bones?

Answer 24

Protect soft internal structures
Provide attachment for muscles

Question 25

What are some examples of flat bones?

Answer 25

Bones of the skull and the sternum

Question 26

What are the key features of irregular bones?

Answer 26

Elaborate in shape Cannot be classified into any of the other categories

Question 27

What are some examples of irregular bones?

Answer 27

Vertebrae Many found in the face

Question 28

Are there many sesamoid bones in the body?

Answer 28

No

Question 29

Where are sesamoid bones located?

Answer 29

Form within tendons of some muscles as the tendons pass over joints Size and distribution vary

Question 30

Why is there variation in the size and distribution of sesamoid bones?

Answer 30

Some sesamoid bones are present in most people, other smaller ones are variable and can develop throughout life

Question 31

What are some examples of sesamoid bones?

Answer 31

Patella (knee cap) Pisiform (carpal bones)

Question 32

What are vertebrae?

Answer 32

Irregular bones that can be divided into 5 groups

Question 33

What are the groups that the vertebrae can be divided into and how many vertebrae are in each group?

Answer 33

Cervical: 7 Thoracic: 12 Lumbar: 5 Sacral (sacrum): 5 Coccygeal: 3-5 w/ coccyx

Question 34

How can the vertebrae be differentiated?

Answer 34

Cervical have transverse foramina (passageways for vertebral artery, vein and sympathetic nerves can pass through) Thoracic have extra articulations for ribs ("branches"/ indent points) Lumbar have neither special feature but have a large body (kidney shaped body which is a little thicker in the front than the back)

Question 35

What are the sacrum and coccyx?

Answer 35

Two sets of vertebrae

Question 36

What is the sacrum?

Answer 36

Five vertebrae fused together

Question 37

What is the coccyx?

Answer 37

Vestigial tail, often fused, made of 3-5 increasingly rudimentary vertebrae

Question 38

What is a joint?

Answer 38

Where one bone articulates with another

Question 39

What are the two basic classifications of joints?

Answer 39

Functional Structural

Question 40

What is the functional classification based on?

Answer 40

A range of motion

Question 41

What are the different types of functional joints and what are some examples of their location?

Answer 41

Synarthrosis: fixed, does not provide any movement (skull) Amphiarthrosis: slightly moveable (ribs and sternum) Diarthrosis: freely moveable (hips, shoulders, knees, etc.)

Question 42

What is the structural classification of joints based on?

Answer 42

The intervening type of tissue

Question 43

What are the different types of structural joints?

Answer 43

Fibrous: connected by dense connective tissue, no joint cavity (Growth plates of long bones --> fuse in late teens/early adulthood) Cartilaginous: connected by hyaline cartilage, no joint cavity Synovial: have a synovial, fluid filled cavity that surrounds the articulating bones

Question 44

What are some examples of where fibrous joints can be located within the body?

Answer 44

Structures of the skull Membranous connections between bones Gomphosis (tooth in bony sockets)

Question 45

What are some examples of cartilaginous joints in the body?

Answer 45

Ribs to sternum Intervertebral discs Growth plates of long bones

Question 46

What is the mobility of synovial joints and what are examples of them?

Answer 46

Freely moveable, wide range of movement (diarthrosis) Most joints of the limbs

Question 47

What are the features that all synovial joints have?

Answer 47

Articular cartilage Synovial/joint cavity Joint capsule Ligaments