Classification of bones, joints and ossification

Question 1

What are the two types of internal structures that bone can have?

Answer 1

Compact and spongy

Question 2

Another name for compact bone

Answer 2

Cortical

Question 3

Another name for spongy bone

Answer 3

Trabeular

Question 4

6 types of bones that have been classified by shape

Answer 4

Long
Flat
Irregular
Short
Sutural
Sesamoid

Question 5

Example of long bones

Answer 5

Humerus/metatarsal

Question 6

Example of flat bones

Answer 6

Sternum/roof of skull

Question 7

Example of irregular bones

Answer 7

Vertebrae/pelvic bones

Question 8

Example of short bones

Answer 8

Carpal/tarsal

Question 9

Example of sutural bones

Answer 9

Skull

Question 10

Example of sesamoid bones

Answer 10

Patella

Question 11

Features of long bones

Answer 11

Longer than it is wide

Question 12

Function of long bones

Answer 12

Leverage

Question 13

Features of short bones

Answer 13

Cube-like shape, equal length/width/thickness

Question 14

Functions of short bones

Answer 14

Stability and some motion

Question 15

Features of flat bones

Answer 15

Thin and curved

Question 16

Function of flat bones

Answer 16

Point of attachment for muscles, protects internal organs

Question 17

Features of irregular bones

Answer 17

Complex shape

Question 18

Features of sesamoid bones

Answer 18

Small and round, embedded in tendons

Question 19

Function of irregular bones

Answer 19

Protect internal organs

Question 20

Function of sesamoid bones

Answer 20

Protect tendons from compressive forces

Question 21

What is intramembranous ossification?

Answer 21

Bone forms on or within fibrous connective tissue (e.g. flat skull bones)

Question 22

What is endochondral ossification?

Answer 22

Bone forms from cartilage template, e.g. long bones

Question 23

Process of intramembranous ossification

Answer 23

• Appears as jelly of mesenchyme tissue, within the connective tissue is developing osteoblasts
• Mesenchymal cells differentiate into osteoblasts at the ossification centre
• Osteoblasts are young bone cells that start laying down bone matrix (e.g. calcium/collagen) within mesenchyme tissue
• Gradually matures into osteocyte which continues to lay down bone matrix
• Minerals begin to harden tissue - forms harder bone tissue
• Calcification = hardening of bone = process of ossification and bone formation
• Osteocyte gets trapped within the matrix they are laying down
• Lacunae (space containing osteocyte/chondrocyte) form
• Bone forms

Question 24

When does trabecular bone form?

Answer 24

Growth occurs, trabecular become inter-connected

Question 25

Process of endochondral ossification

Answer 25

- An intermediary forms, which is made of cartilage (the cartilage template) - Cartilage assumes the shape of the bone to be formed - Perichondrium covers outer surface of cartilage - In calcified bone, the equivalent of the perichondrium is the periosteum - Perichondrium is converted to periosteum as the cartilage template hardens due to the action of chondrocytes

Question 26

Where are secondary ossification centres located?

Answer 26

At the ends of the cartilage model of small, long bones

Question 27

In what direction do secondary ossification centres work?

Answer 27

From inwards to outwards

Question 28

In what direction do primary ossification centres work?

Answer 28

From outwards to inwards

Question 29

Which cells assist primary ossification centres?

Answer 29

Perichondria osteoprogenitor

Question 30

What is the structural framework of a joint?

Answer 30

The type of connective tissue that joins bones together

Question 31

What is the functional framework of a joint?

Answer 31

The degree of movement occurring in the joints

Question 32

Characteristics of fibrous joints

Answer 32

- Bones are united by fibrous tissue | - Permit no or very limited range of movement

Question 33

Another word for fibrous joints

Answer 33

Synarthroses

Question 34

What is a syndesmoses joint?

Answer 34

Bones joined by sheet of fibrous tissue band (e.g. interosseous membrane)

Question 35

What is a suture joint?

Answer 35

Interlocking projectons of adjacent bone plates, joined together by a thin layer of fibrous tissue (e.g. joints between cranial bones)

Question 36

What is a gomphoses joint?

Answer 36

Joint connected by fibrous tissue called periodontal membrane (e.g. joint between root of the tooth and alveolar process of mandible or maxilla)

Question 37

Another word for cartilaginous joints

Answer 37

Amphiarthroses

Question 38

Characteristics of cartilaginous joints

Answer 38

- Bones united by hyaline cartilage or fibrocartilage | - Cartilaginous joints allow for little movement

Question 39

What is a synchondroses joint?

Answer 39

Bones usually joined by hyaline cartilage, usually temporarily occur during development, e.g. articulation between epiphysis and diaphysis of long bones

Question 40

What is a primary cartilaginous joint?

Answer 40

Synchondroses

Question 41

What is a secondary cartilaginous joint?

Answer 41

Symphyses

Question 42

What is a symphyses joint?

Answer 42

Bones joined by fibrocartilage, e.g. articulation between vertebrae/hip bones

Question 43

What is Hilton's law?

Answer 43

Any muscle that crosses a joint acts on that joint. Any nerve supplying a muscle also supplies a joint

Question 44

How to describe the structure of a joint

Answer 44

- Identify type of joint - Identify bones involved and articulating parts - Describe attachment of joint capsule if present - Describe attachment of joint ligaments - Describe range of movements occurring at joint and muscles involved - Describe the bursa (if present) - Describe neurovascular supply of joint - Describe clinical anatomy of joint

Question 45

Which structures are found in synovial joints?

Answer 45

- Joint capsule - fibrous membrane wrapping around joint - Synovial membrane - thin, inner membrane - Articular cartilage - normally hyaline cartilage - Joint cavity with synovial fluid - enclosed by synovial membrane - Articular disks (menisci) - Articular ligaments - connects and enforces stability of joints together with capsule and synovial membrane - Articular bursa - cushion-like padding shock absorber

Question 46

3 types of synovial joint

Answer 46

Uniaxial/biaxial/multiaxial

Question 47

Characteristics of uniaxial joints and examples

Answer 47

- Permit movement about one axis and in one plane | - Hinge joints and pivot joints

Question 48

Characteristics of biaxial joints and examples

Answer 48

- Permits movement about two perpendicular axes in two perpendicular planes - Saddle joints, e.g. carpometacarpal joints - Condyloid (ellipsoidal) joints, e.g. metacarphophalangeal joints

Question 49

Characteristics of multiaxial joints and examples

Answer 49

- Permit movement around three or more axes in three or more planes - Ball and socket (spheroid) joints - Gliding (plane) joints