axial skeleton

Question 1

name the 2 divisions of the skeletal system

Answer 1

axial
appendicular

Question 2

how many bones is the axial skeleton composed of? and where?

Answer 2

80 bones around body axis

e.g. head, hyoid (found in neck), ribs, sternum, & vertebrae

Question 3

appendicular skeleton is composed of how many bones? and where?

Answer 3

126 bones of upper & lower limbs plus girdles that connect them

pectoral and pelvic

Question 4

name the areas of the axial skeleton (from superior to inferior)

Answer 4

Skull
- Cranial
- Facial

Hyoid

Thorax
- Sternum
- Ribs

Vertebral Column

Question 5

the skull and hyoid bone include what areas of bones

Answer 5

cranial and facial

Question 6

how many cranial bones are there and name them and their location

Answer 6

8 in total

Frontal, (a single bone at front of cranium)

2 parietal (to side or head),

2 temporal (just below the parietal bone), occipital (single bone at back of head), sphenoid, and ethmoid (nearer front of face)

Question 7

what are cranial bones important for

Answer 7

protecting brain

Question 8

how many facial bones are there and name them

Answer 8

14

2 nasal,
2 maxillae,
2 zygomatic,
mandible (jawbone, largest of facial bones),
2 lacrimal,
2 palatine,
2 inferior nasal conchae, &
the vomer (found in middle of nasal cavity)

Often 2 of each bone as one on either side of face

Question 9

explain the growth of facial bones

Answer 9

Growth ceases at age 16

These bones grow lots after birth until age 16, where size and shape of cranium is achieved

Question 10

what are sutures

Answer 10

immoveable joints between skull bones

Question 11

name the 4 sutures, and there locations, including what bones they separate

Answer 11

Coronal, sagittal, lambdoidal, squamous

Sagittal suture
runs from front to back separating the (2 hemispheres of the head bone), so separates the parietal bones on one side of head from other

Coronal suture
separates the parietal and frontal bone

The parietal and temporal bones are separated by squamous suture

The lambdoid suture
is positioned at the back of the head and separates the occipital and parietal bones

Question 12

explain Paranasal sinuses-cavities

Answer 12

Located in bones near nasal cavity

Mucous membranes – to assist mucus production

Resonating chambers – to help produce sounds when we speak. Explaining why when we get colds we sound different due to the excess mucus in these areas

Question 13

name and locate the Paranasal sinuses-cavities

Answer 13

The frontal sinus – just above the eye

Ethmoidal cells – found deeper within the nasal cavity, behind the eyes

Sphenoidal sinus – further back in face, behind the ethmoidal cells

Maxillary sinus – largest cavity, and is closer to the maxilla

Question 14

explain the fontanelle part of the foetal skull

Answer 14

Soft spot in foetal skull

Allow deformation at birth, as no sutures, only gaps the gaps will eventually Calcify to form sutures via – intramembranous ossification, so fontanelle can close up as child ages

cranium needs flexibly in babies, so cranium can be slightly squeezed during birthing process at the ‘soft spot’ so no damage to cranial bones. This also allows expansion as brain grows fast during this time.

Question 15

what is most rapidly growing organ within the developing human

Answer 15

brain

Question 16

explain the vertebral column

Answer 16

Encloses spinal cord

Supports head

Point of attachment for muscles of back, ribs and pelvic girdle

Question 17

what are each of the bones in the vertebral column called
and how many are in adults and embryo

Answer 17

7 cervical vertebrae
12 thoracic
5 lumbar
1 sacral – which is 5 bones fused together
1 coccyx – which is 3 or 4 bones fused together

In adult – 26

In embryo – 33 vertebral bones
As these individual bones fuse together as we age into adulthood

Question 18

explain the 4 normal curves in vertebral column (name and locate them and explain why we need them)

Answer 18

Relative to front: cervical & lumbar curves are convex (protrude to the anterior position)

Thoracic & sacral curves are concave (protrude towards posterior part of body)

Theyre important as increase strength, help in balance and absorb shocks

Question 19

describe fetal compared to adult curves in the vertebral column

Answer 19

Curve shape differs from adult to growing foetus

Question 20

each vertebra is separated into what 2 anatomical structures

Answer 20

Body- disc-shaped front part

Vertebral arch- extends back from body
- creates with the body a hole called vertebral foramen, through which the spine passes

Question 21

Branching sections of the vertebral arch makes up what 7 processes and describe them

Answer 21

Transverse process extending laterally on each side =2

Spinous process extending dorsally =1

Two each of Superior and inferior articular processes - attach to neighbouring vertebrae =4

Question 22

what does the thorax/chest comprise of

Answer 22

thoracic cage
sternum
ribs

Question 23

explain the thoracic cage in the chest/thorax

Answer 23

Sternum, costal/rib cartilages & ribs and bodies of T1-T12 vertebrae

Question 24

explain the sternum in the chest/thorax

Answer 24

formed from 3 bones that fuse by age
~at about 25yrs

= manubrium, body, xiphoid process

Question 25

explain the ribs in the chest/thorax

Answer 25

12 pairs (numbered from top to bottom)

Ribs 1-7 articulate with sternum directly by costal cartilage = these are considered as true ribs

Ribs 8-12 – false ribs:

ribs 11-12 –floating ribs