Chapter 7: The Axial Skeleton

Question 1

What is the Axial Skeleton?

Answer 1

• forms the vertical, central axis of the body
• 80 bones
• skull has 22 bones
• vertebral column has 24 bones and 2 fused
• thoracic cafe had 12 pairs of ribs and the sternum

Question 2

What are the 4 unique features of the skull?

Answer 2

1) cranial cavities
2) paranasal sinuses
3) sutures
4) fontanelles

Question 3

What Are the seven cranial bones?

Answer 3

1) Parietal bone
2) sutural bone
3) occipital
4) frontal bone
5) sphenoid
6) ethmoid
7) temporal

Question 4

What are the 6 facial bones?

Answer 4

1) lacrimal
2) nasal bone
3) zygomatic
4) maxilla
5) mandible
6) vomer

Question 5

What are the parts of the occipital bone?

Answer 5

• Squamous part: forms the posterior region of the skull
• Basilar part: foramen magnum
• foramen magnum: spinal cord, vertebral, spinal arteries, and accessory nerve
• hypoglossal canal: hypoglossal nerve

Question 6

What are the four functions of the paranasal sinuses?

Answer 6

1) Lighten skull mass
2) increase nasal surface area
3) resonating chamber
4) protection through mucus

Question 7

What are the types of sutures?

Answer 7

1) top of skull-> coronal suture -> unites frontal to parietal bones (saggital connects parietal together)
2) posterior of skull-> lamboid suture-> unites Parietal to occipital
3) squamous -> connects parietal to temporal bones

Question 8

Describe the Hyoid bone

Answer 8

• doesn’t articulate with any other bone
• suspended from the styloid process
• attachment site for the tongue, neck and pharynx muscles
• consists of a horizontal, rectangular body and paired projectors called the lesser and greater horns

Question 9

What is the coccyx?

Answer 9

A triangular bone that forms 3-5 vertebral bones fusing. Fusion takes several years

Question 10

What is the sacrum?

Answer 10

• fusion of the 5 sacral vertebrae
• happens at ~ 16-30 years of age
• transverse ridges mark fusion sites

Question 11

How many vertebrae are there?

Answer 11

24 plus the sacrum and coccyx

Question 12

What are the three regions of the vertebral column?

Answer 12

1) cervical (C1-C7)
2) Thoracic (T1-T12)
3) Lumbar (L1-L5)

Question 13

What are the vertebral curvatures?

Answer 13

• primary curves in fetus = thoracic and sacral
• secondary curves = 3-4 months of age = cervical and lumbar

Question 14

Describe the classification of ribs

Answer 14

12 pairs of ribs with their costal cartilages
- Ribs 1-7 are classified as true ribs
- ribs 8-12 are classified as false ribs with the last two peaked being floating ribs

Question 15

What are the parts of the sternum?

Answer 15

1. Xyphoid process
2. Body
3. Manubrium

Question 16

What is the thorax?

Answer 16

• the rib cage (ribs + sternum)
• protects heart and lungs