Bones

Question 1

Functions of Bone

Answer 1

• Structure
• Assist Movement
• Protection
• Blood cell production
• Mineral Storage
• Energy Storage

Question 2

Classification of Bones

Answer 2

• Long
• Short
• Flat
• Irregular
• Sesamoid

Question 3

Long Bone

Answer 3

• Hard, dense bones that provide strength, structure, and mobility
• Longer than wide
• Most bones of the appendicular skeleton

Question 4

Short Bone

Answer 4

• As wide as they are long
• Primary function is to provide support and stability with little to no movement
• Carpals and tarsals (that all?)

Question 5

Flat Bone

Answer 5

• Principal function is either extensive protection or the provision of broad surfaces for muscular attachment
• Parietal, frontal, occipital, ribs, sternum (that all?)

Question 6

Irregular Bone

Answer 6

• Bones that don’t fit into the other categories

- Ethmoid, sphenoid, vertebrae, pelvic bones (that all?)

Question 7

Sesamoid Bone

Answer 7

• Bone embedded in a tendon

- Patella, pisiform, big toe, thumb (that all?)

Question 8

Diaphysis

Answer 8

• Shaft of long bone
• Outer surface is lined by periosteum
• Lined by the endosteum on the inside

Question 9

Epiphysis

Answer 9

• Articulating ends of long bone
• Outer surface is cortical (compact or lamellar) bone
• Inner surface is spongy (cancellous or trabecular) bone

Question 10

Metaphysis

Answer 10

• Portion between the shaft and the wide parts of the ends

- Corresponds to the area of the epiphyseal line in ossified bone

Question 11

Epiphyseal Plate

Answer 11

• Responsible for longitudinal growth
• A hyaline cartilage plate in the metaphysis at each end of a long bone
• Plate is found in children and adolescents
• The plate is replaced by an epiphyseal line in adults
• Usually closes by 25th year

Question 12

Periosteum

Answer 12

• Lines the outer surface of the diaphysis, except the articular surface, points of ligament/tendon insertion, and surface of sesamoid bones
• Made up of 2 layers:
  - Inner reproductive layer (stratum osteogeneticum)
  - Outer fibrous layer (stratum fibrosum)

Question 13

Functions of the Periosteum

Answer 13

• Nutrition: ?
• Protection: ?
• Growth: responsible for diametric growth and critical for callus formation after a fracture

Question 14

Osteon

Answer 14

The basic unit of structure in compact bone

Question 15

Structure of an Osteon

Answer 15

• Lamellae
• Central (Haversian) canal
• Perforating canals
• Lacuna
• Canaliculi

Question 16

Lamella

Answer 16

• Concentric rings that runs parallel to the long axis of the bone

Question 17

Central (Haversian) Canal

Answer 17

• Runs through the core of osteon, parallel to long axis of the bone
• Contains nerves, arterioles, and venules

Question 18

Perforating Canal

Answer 18

• Connects the central canals

- Contains nerves, arterioles, and venules?

Question 19

Lacuna

Answer 19

?

- The space withing lamella that contains osteocytes (mature bone cells)

Question 20

Canaliculi

Answer 20

• Tiny canals which interconnect lacunae

- They provide a pathway for nutrients to diffuse from the central canal to osteocytes within their own osteon

Question 21

Osteoblast

Answer 21

Young bone-forming cells that cause the hard extracellular matrix of bone to develop

Question 22

Osteocyte

Answer 22

Mature bone cells that maintain the structure of bone

Question 23

Osteoclasts

Answer 23

Bone-dissolving cells

Question 24

Compact Bone

Answer 24

• AKA cortical or lamellar bone
• Hard, dense bone
• Made up of the Haversian system, in concentric layers
• Forms the surface of all bones
• Forms the shaft of long bones

Question 25

Spongy Bone

Answer 25

- AKA cancellous or trabecular bone - Lamellae are not arranged in concentric layers Lamellae are arrange in lines that correspond with the lines of maximal stress - Contains red bone marrow, responsible for red blood cell production

Question 26

Fontanels

Answer 26

- 6 fibrous membranes that form the "soft spots" on a babies skull - Allows the skull to deform during birth

Question 27

Anterior (Frontal) Fontanel

Answer 27

- Between the 2 parietal bones | - Largest and last to close (18-24 months)

Question 28

Posterior (Occipital) Fontanel

Answer 28

- Between the 2 parietal and occipital bone | - Closes in about 2 months

Question 29

Anterolateral (Sphenoidal) Fontanel

Answer 29

Usually closes by about 3 months

Question 30

Posterolateral (Mastoid) Fontanel

Answer 30

Usually closes by about 12 months

Question 31

Bones of the Orbit

Answer 31

7 bones: - Sphenoid - Lacrimal - Zygomatic - Frontal - Maxilla - Palatine - Ethmoid

Question 32

Angle of Inclination

Answer 32

- The angle formed between the femoral neck and femoral shaft in the frontal plane - Normal: ~ 125 degrees in an adult, ~ 120 in elderly

Question 33

Coxa Varum

Answer 33

Angle of Inclination of < 120 degrees

Question 34

Coxa Valgum

Answer 34

Angle of Inclination of > 135 degrees

Question 35

Angle of Torsion

Answer 35

- The angle formed between the femoral neck and femoral shaft in the transverse plane - Normal: ~ 15 degrees in adults - Head and neck of femur rotate outward from shaft of femur

Question 36

Femoral Anteversion

Answer 36

- Torsion angle > 15 degrees - Possible cause of pigeon toe - Also causes winking patella

Question 37

Femoral Retroversion

Answer 37

- Torsion angle < 15 degrees | - Possible cause of duck walk