The Skeleton Flashcards

1
Q

Skeletal Subdivisions

A

Axial -Postcranial -Vertebrae

                          - Thorax
     - Cranial (Skull) - Canium
                              - Facial

Appendicular - Pelvic girdle

                    - Pelvic Limb
                    - Pectoral girdle
                    - Pectoral limb
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2
Q

What is a skeleton?

-5 functions of the skeleton

A

-Skeleton comprises of bone that is articulated at joints and are united by ligaments. Also includes cartilage

FUNCTIONS:

  • provides body form
  • Forms non-collapsible cavities
  • Levers for muscle action
  • Houses bone marrow
  • Calcium/Phosphate store
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3
Q

Number of bones in the different components of skull

A

Skull = 22 bones

  • Cranial bones = 8 (direct contact w/ brain)
  • Facial Bones = 13 (no brain contact)
  • Mandible = 1 (lower jaw)
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4
Q

Sutures: what they are & 3 types

A
  • Suture: generally convoluted thick fibrous joints between plates (in skull)
    • some fuse, though some maintain through life

3 types w/in skull:

  • Coronal suture: separates frontal bone from parietal bones
  • Sagittal suture: between left and right parietal bones
  • Lambdoid suture: between parietal bones and occipital bones
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5
Q

What is the:

Hyoid

Hard palate

A

-Hyoid chain of single bones that have fused in humans - supports and protects larynx

  • Hard palate: mammalian features allowing infants to suckle
    • separates nasal and oral cavities
    • formed by shelf-like horizontal extensions of maxilla and palatine bones
      • failure of process = cleft plate
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6
Q

The Human Spine

A

-has a triple curvature to balance body weight vertically

FORMULA: C7-T12-L5-S5-Co4

  • Cervical vertebrae (7 bones)
  • Thoracic vertebrae (12 bones)
  • Lumbar vertebrae (5 bones)
  • Sacrum (5 fused bones)
  • Coccyx (4 fused bones)

Kyphosis: curves backwards (spine curves more towards posterior)
Lordosis: curves forwards (spine curves more towards anterior)
Scoliosis: curves to side

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7
Q

The Atlas & the Axis (C1 & C2 of cervical vertebrae)

A

Atlas:

  • articulates w/ condyles of occipital bone (in skull)
  • has deep superior artiular facets
  • lacks a body
  • allows us to nod our head*

Axis:

  • has odonoid process or dens
  • acts as axis of rotation between atlas and skull
  • dens is what fits inside atlas
  • atlanto-axis = no movement

X for no

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8
Q

Thorax

A
  • 7 pairs of true ribs (1-7) [directly connect to sternum]
  • 5 pairs of false ribs (8-12) [not directly connected to sternum]
    • 2 of which are floating ribs (11-12) - not connected to sternum at all
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9
Q

Pectoral Girdle

A
  • consist of 3 main elements: scapula, clavicle and coracoid (fused to scapula)
  • clavicle derived from dermal bone of skull and forms by intramembranous ossification
  • more highly evolved than pelvic girlde
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10
Q

Pelvic Girdle

A

-Retains its 3 ancestral elements: ilium, ishium and pubis (all unite at acetabulum

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11
Q

Limb Homology

A
  • Both limbs consist of similar sequence of bones and joints
  • *modern tetrapods are all ancestrally pentadactyl
  • carpus and tarsus (wrist and ankle) consist of jumble of short bones
  • carpals = hands
  • tarsals = feet
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