7-1. The Skeleton - overview and the skull

Question 1

The skeleton is composed mostly of ___, with __ in a few areas.

Answer 1

bone, cartliage

Question 2

The skeleton accounts for ___ of body weight.

Answer 2

about 20%

Question 3

The skeleton has ___ bones, grouped ____.

Answer 3

206; into two divisions: axial and appendicular

Question 4

axial skeleton

Answer 4

the 80 bones that form the central axis of the body, including the bones of the skull, vertebral column, and thorax.

Question 5

skull

Answer 5

made of 22 bones - 8 cranial bones and 14 facial bones

Question 6

sutural bones

Answer 6

seams that join the skull bones to each other - they are immovable joints

Question 7

What are the 4 major sutural bones?

Answer 7

sagittal
coronal
lambdoid
squamos

Question 8

sagittal suture

Answer 8

between the two parietal bones at midline

Question 9

coronal suture

Answer 9

between the frontal bone and parietals (“crown”)

Question 10

lambdoid suture

Answer 10

between the parietals and occipital (at back)

Question 11

squamos suture

Answer 11

2 of them (one on each side) - between parietals and temporal bones (S shaped)

Question 12

fontanelles

Answer 12

“soft spots” - fibrous membranes found between cranial bones at birth

Question 13

Fontanelles are replaced with ___ by ____ ossification by age 2.

Answer 13

bone; intramembranous

Question 14

What are the functions of fontanelles?

Answer 14

passage through birth canal

allows rapid growth of brain during the first two years of life

Question 15

cranial bones

Answer 15

8 bones that enclose and protect the brain in the cranial cavity

Question 16

frontal bone

Answer 16

1 shell shaped bone forming the forehead

holes called the supraorbital foramina allow arteries and nerves to pass into forehead

Question 17

parietal bones

Answer 17

2 large curved bones that form most of the cranium

Question 18

temporal bones

Answer 18

2 bones at the side of the skull; contain the external acoustic meatus (opening to the ear). The lower jaw fits into the mandibular fossa (depressions on inferior surface)

Question 19

occipital bone

Answer 19

1 bone that forms most of the back and base of the skull. A large opening at the base called the foramen magnum is where the brain connects to the spinal cord

Question 20

sphenoid bone

Answer 20

1 butterfly shaped bone at the center of the cranium; articulates with all other cranial bone. Superior surface contains the sella turcica, a saddle shaped depression where the pituitary gland is cradled

Question 21

ethmoid bone

Answer 21

1 small bone between the orbits and behind the nasal bones. Superior surface is perforated by many small holes (cribriform plate) through which the olfactory nerves transmit signals from nasal mucosa to brain.

Question 22

Which cranial bones are paired?

Answer 22

parietal bones and temporal bones

Question 23

Which cranial bone articulates with all other cranial bones?

Answer 23

sphenoid bone

Question 24

List the cranial bones

Answer 24

frontal bone (1)
parietal bones (2)
temporal bones (2)
occipital bone (1)
sphenoid bone (1)
ethmoid bone (1)

Question 25

facial bones

Answer 25

14 bones forming the framework for the face, provide cavities for the organs of sight, taste, and smell, and anchor the muscles of facial expression

Question 26

List the facial bones

Answer 26

nasal bones - 2
maxilla - 2
zygomatic bone - 2
mandible - 1
lacrimal bone - 2
palatine bone - 2
vomer bone - 1
inferior nasal concha - 2

Question 27

nasal bones

Answer 27

2 thin rectangular bones that form the bridge of the nose

Question 28

maxilla

Answer 28

2 bones forming the upper jaw; two palatine processes form most of the roof of the mouth

Question 29

cleft palate

Answer 29

result of the two palatine processes of the maxilla not fusing properly during development

Question 30

zygomatic bone

Answer 30

2 bones forming the cheek and part of the orbit

Question 31

mandible

Answer 31

1 bone forming the lower jaw - only moveable skull bone. It is the largest, strongest bone of the face.

Question 32

temporo mandibular joint

Answer 32

posterior mandibular condyle of the mandible articulates with the temporal bone

Question 33

lacrimal bone

Answer 33

2 smallest facial bones, behind the nasal bones on the medial orbit wall; a deep groove, the lacrimal fossa, helps drain tears

Question 34

palatine bone

Answer 34

2 bones forming the back of the hard palate

Question 35

vomer bone

Answer 35

1 small plow shaped bone found within nasal cavity; forms the lower part of the nasal septum; top of septum is formed by the perpendicular plate of the ethmoid bone

Question 36

inferior nasal concha

Answer 36

2 curved bones forming lateral walls of nasal cavity

Question 37

Which facial bone is the largest and strongest?

Answer 37

mandible

Question 38

Which facial bone is the smallest?

Answer 38

lacrimal

Question 39

Which facial bone is moveable?

Answer 39

mandible

Question 40

Which facial bones are not paired?

Answer 40

mandible

vomer

Question 41

sutural bones

Answer 41

tiny irregularly shaped bones that may appear between the sutures of the cranium. Their number varies and is not included in the average number.

Question 42

hyoid

Answer 42

U shaped bone that lies just below the mandible in the neck, at the top of the larynx. The only bone in the body that does not articulate directly with any other bones. Suspended from the styloid process of the temporal bone by ligaments. broken - sign of strangulation

Question 43

What is the only bone in the body that does not articulate directly with any other bone?

Answer 43

hyoid bone

Question 44

paranasal sinuses

Answer 44

5 skull bones contain these mucosa lined, air filled sinuses; small openings connect them to the nasal cavity. Lighten the skull and moisten air