bones

Question 1

divisions of the skeleton

Answer 1

axial and appendicular

Question 2

axial skeleton includes

Answer 2

skull
vertebral column
ribs
sternum

Question 3

skull

Answer 3

makes the skeleton of the head and consists of cranium and mandible

Question 4

vertebral column

Answer 4

consists of vertebrae and intervertebral discs. The vertebral discs include: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral (5 fused to make sacrum), and 4 coccygeal (fused to make coccyx)

Question 5

ribs

Answer 5

12 pairs with their costal cartilages

Question 6

the sternum

Answer 6

together with the thoracic vertebrate and the ribs with their costal cartilage make up the thoracic cage.

Question 7

curves of the vertebral column

Answer 7

• primary — the vertebral curve is concave anteriorly at birth
• secondary — ventral convex cervical curve develops at 3 to 4 months when a baby starts to extend his head
• secondary — ventral convex lumbar curve develops at 12 to 18 months when a baby begins to walk

Question 8

pectoral girdles (shoulder)

Answer 8

is formed of the scapula and clavicle as they connect the upper limb to the axial skeleton at sterno-clavicular joint

Question 9

pelvic girdle

Answer 9

formed at the hip bone as it connects the lower limb to the axial skeleton at the sacro-iliac joint

Question 10

appendicular skeleton

Answer 10

consists of bones in the lower and upper limbs and their girdle (pectoral and pelvic)

Question 11

proximal bone of the upper limb

Answer 11

humerus (in the arm)

Question 12

proximal bone of the lower limb

Answer 12

femur (bone of the thigh)

Question 13

intermediate bone of the upper limb

Answer 13

radius and ulnar

Question 14

intermediate bone of the lower limb

Answer 14

tibial and fibular

Question 15

distal bone of the upper limb

Answer 15

carpus (8) — metacarpals (5 long bones numbered 1 starting from the thumb) — phalanges (3 in each finger except thumb has 2)

Question 16

distal bone of the lower limb

Answer 16

tarsus (7) — metatarsals (5 long bones number from medial to lateral) — phalanges (3 in each toe and the big toe has 2)

Question 17

functions of skeleton framework

Answer 17

• gives the body its structural framework and supports it
• acts as levers upon which muscle acts
• protects vital structures (skull protects brain and thoracic cage protects lungs and heart)
• transmits body weight
• red bone marrow inside the bones (long bones, sternum, ribs, and vertebrate) is the site of blood cells productions
• mineral reservoir

Question 18

bone definition

Answer 18

calcified hard connective tissue composed of living cells and intercellular matrix made up of collagens, minerals, and inorganic salts.

Question 19

compact (cortical) bone [structural classification)

Answer 19

hard, dense like ivory, and usually present on the surface of the bones

Question 20

cancellous (spongy) bones (structural classification)

Answer 20

• irregular trabeculae with spaces that form spongy like network

Question 21

Long bones

Answer 21

elongated in shape formed of a shaft (diaphysis) and two ends (epiphysis). The part of diaphysis nearest to the epiphysis is called the metaphysis

Question 22

the shaft

Answer 22

tubular in shape, composed of a compact bone and an inner medullary cavity, which contains red or yellow bone marrow according to the person’s age. The shaft is surrounded by periosteum.

Question 23

epiphysis

Answer 23

two ends of the long bone, thin outer layer of compact bone and the inner is spongy

Question 24

an epiphyseal plate of cartilage

Answer 24

lies between the diaphysis and epiphysis and is responsible for growth in length

Question 25

short bones

Answer 25

cuboidal, the outer layer is compact and the central is spongy e.g. carpal and tarsal

Question 26

irregular bones

Answer 26

various shapes e.g. hip bone and vertebrae

Question 27

flat bones

Answer 27

consists of two plates of compact bones with spongy bone and bone marrow in between e.g. scapula, skull, and sternum.

Question 28

pneumatic bones

Answer 28

air-filled spaces are lined by mucous membranes like skull bones. this makes the skull lighter and help in resonance of voice. e.g. maxilla

Question 29

sesamoid bones

Answer 29

rounded or oval in shape like the patella to them from wearing out

Question 30

membranous bones

Answer 30

bone develop directly from membrane of connective tissue called mesenchymal ossification e.g. skull, shaft of clavicle, and fascial bones

clavicle is the first bone to be ossified, no medullary cavity

Question 31

cartilaginous bones

Answer 31

• bones first develop from a cartilage model
• at the 8th week of intra-uterine life, a center of bone appears called the primary center of ossification
• the part of the bone ossified is the diaphysis
• After birth, the secondary centers of ossifications appear at the end of the long bones. this part is called the epiphysis leaving a plate of cartilage for elongation
• the fusion between the epiphysis and diaphysis takes 15-22 years (1-2 years earlier in females)

Question 32

periosteum

Answer 32

consists of an outer fibrous layer and an inner cellular layer. absent articulate surface and sesamoid bones

Question 33

periosteum functions

Answer 33

gives attachment to muscles and help growth of bone in width, healing fractures, and source of blood supply

Question 34

nutrient artery

Answer 34

passes through the nutrient foramen in the diaphysis to reach the medullary cavity

Question 35

metaphysical and epiphyseal arteries

Answer 35

anastomose with the nutrient branch

Question 36

periosteal arteries

Answer 36

beneath the muscular and ligaments attachments to bones