Unit 3: Ch 8 (Skeletal System)

Question 1

of bones

Answer 1

• Bones at birth: 270
• Bones at adulthood: ~ 206
  
  • Varies with the development of sesamoid bones
  • Varies with the presence of sutural bones in skull

Question 2

Describe the vertebral curvatures

Answer 2

• Primary
  
  • Present at birth
  • 1 continuous curve
• Secondary
  
  • Takes time to develop
  • By adulthood, there are 4 curvatures
    
    • Cervical lordosis: C1 - C7
    • Thoracic kyphosis: T1 - T12
    • Lumbar lordosis: L1 - L5
    • Pelvic kyphosis: S1

Question 3

Male/female pelvis differences

• General appearance
• Tilt
• Brim/Inlet
• Outlet
• Subpubic angle

Answer 3

• General appearance
  
  • Male: More massive, rougher, heavier processes
  • Female: Less massive, smoother more delicate processes
• Tilt
  
  • Male: Upper end of pelvis relatively vertical
  • Female: Upper end of pelvis tilted forward
• Brim/Inlet
  
  • Male: Heart-shaped
  • Female: Round or oval
• Outlet
  
  • Male: Smaller
  • Female: Larger
• Subpubic angle
  
  • Male: Narrower, usually 90° or less
  • Female: Wider, usually 100° or more

Question 4

Answer 4

Question 5

Cervical Vertebrae

• Function
• Location

Answer 5

• Function: Supports the head and allows for its movement
• Location: C1 - C7
• Notes
  
  • C1 (Atlas)
    
    • Supports the head
    • Little more than a delicate ring surrounding a large vertebral foramen; no body
  • C2 (Axis)
    
    • Allows rotation of the head, as in gesturing “no”
    • Most distinctive feature is a the dens (aka odontoid process). No other vertebra has a dens
    • 1st vertebra to exhibit a spinous process, which has a bifid tip

Question 6

Coccyx Vertebrae

• Function
• Location

Answer 6

• Function
  
  • Provides attachment for the muscles of the pelvic floor
  • Co1 has a pair of horns (cornua) that serve as attachment points for ligaments that bind the coccyx to the sacrum
• Location
  
  • Co1 to Co4 (or sometimes Co5)
  • Fuse between 20-30 YOA

Question 7

Condyle

Answer 7

Smooth, rounded articular process; “knuckle” of any bone

Question 8

Cranial Bones

Answer 8

• 8 total
  
  • Frontal (1)
  • Parietal (2)
  • Occipital (1)
  • Temporal (2)
  • Sphenoid (1)
  • Ethmoid (1)

Question 9

Major parts of the cranium

Answer 9

• Calvaria
  
  • Composed of multiple bones that form the roof and walls of the skull
• Base
  
  • Cranial cavity floor
  • Composed of 3 paired depressions called cranial fossae
    
    • Anterior cranial fossa
    • Middle cranial fossa
    • Posterior cranial fossa (deepest)

Question 10

Extensions & Projections

Answer 10

• Crest: A narrow ridge
• Epicondyle: An expanded region superior to a condyle
• Line: A slightly raised, elongated ridge
• Process: Any bony prominence
• Protuberance: A bony outgrowth or protruding part
• Spine: A sharp, slender, or narrow process
• Trochanter: Two massive processes unique to the femur
• Tubercle: A small, rounded process
• Tuberosity: A rough elevated surface

Question 11

Facial Bones

Answer 11

• 14 total
  
  • Maxillae (2)
  • Palatine (2)
  • Zygomatic (2)
  • Lacrimal (2)
  • Nasal (2)
  • Vomer (1)
  • Inferior nasal conchae (2)
  • Mandible (1)

Question 12

Foramen

Answer 12

opening or hole (pl. foramina)

Question 13

Fossa

Answer 13

shallow depression

Question 14

Head

Answer 14

a spherical process at end of a long bone

Question 15

List bones in the upper appendicular system

Answer 15

Question 16

List bones in the axial skeleton

Answer 16

Question 17

Lower limbs

Answer 17

• 60 total
  
  • Femurs (2)
  • Patellae (2)
  • Tibiae (2)
  • Fibulae (2)
  • Tarsal bones (14)
  • Metatarsal bones (10)
  • Phalanges (28)

Question 18

Lumbar Vertebrae

• Function
• Location

Answer 18

• Function
  
  • Thick, stout body and a blunt, squarish spinous process for attachment of lumbar muscles
  • Arrangement resists twisting of the lower spine
• Location: L1 - L5

Question 19

Meatus

Answer 19

canal-like opening

Question 20

Passages & Cavities

Answer 20

• Canal: A tubular passage or tunnel in a bone
• Fissure: A slit through a bone
• Foramen: A hole through a bone, usually round
• Meatus: A canal
• Sinus: An air-filled space in a bone

Question 21

Pectoral girdle

Answer 21

• 4 total
  
  • Scapulae (2)
  • Clavicles (2)

Question 22

Pelvic girdle

Answer 22

• 2 total
  
  • Hip bones (2)

Question 23

Process

Answer 23

projection or elevation on a surface

Question 24

Prominent skull cavities

Answer 24

• Cranial cavity
• Orbits
• Nasal cavity
• Oral (buccal) cavity
• Middle- and inner-ear cavities
• Paranasal sinuses
• Frontal sinus
• Sphenoidal sinus
• Ethmoidal sinus
• Maxillary sinus

Question 25

Ribs

Answer 25

• R1 - R7: True Ribs
  
  • Individual costal cartilage
  • Articulate with a transverse costal facet
  • Rib tubercle present
• R8 - R10: False Ribs
  
  • Costal cartilage shared with R7
  • Articulate with a transverse costal facet
  • Rib tubercle present
• R11 - R12: Floating Ribs
  
  • No costal cartilage
  • Does NOT articulate with a transverse costal facet
  • NO rib tubercle

Question 26

Sacrum Vertebrae

• Function
• Location

Answer 26

• Function
  
  • Bony plate that forms the posterior wall of the pelvic girdle
• Location
  
  • S1 - S5, in children
  • Will eventually become a fused structure (~16 YOA)

Question 27

Sesamoid bones

Answer 27

• Bones that form within some tendons in response to strain
• Example: the patella

Question 28

Sinus

Answer 28

(bay or pocket) cavity in a bone

Question 29

Skeletal Systems & Major Bones

Answer 29

• Axial System
  
  • Forms central supporting axis of the body
  • Skull
  • Vertebrae
  • Sternum
  • Ribs
  • Sacrum
  • Hyoid
• Appendicular System
  
  • Pectoral girdle
  • Upper extremity
  • Pelvic girdle
  • Lower extremity

Question 30

Answer 30

Question 31

Spine

Answer 31

pointed process

Question 32

Surface Markings

Answer 32

• Spine
• Condyle
• Foramen
• Fossa
• Meatus

Question 33

Sutural bones

Answer 33

• Skull bones that fuse together

Question 34

Thoracic Vertebrae

Answer 34

• T1 - T12
• Supports the thoracic cage enclosing the heart and lungs
• Each vertebra corresponds to rib a attachment
• Notes
  
  • No other vertebrae have ribs
  • Lack the transverse foramina and bifid processes that distinguish the cervical vertebrae
  • Distinctive features
  • Spinous processes are relatively pointed and angle sharply downward
  • Body is somewhat hear-shaped
  • Body has small, smooth, and slightly concave spots called costal facets for rib attachment
  • T1-T10 have a shallow, cuplike transverse costal facet at the end of each transverse process
  • Provide a 2nd point of articulation for ribs 1-10
  • There are no transverse costal facets on T11 and T12 because ribs 11 and 12 attach only to the bodies of those two vertebrae

Question 35

Trochanter

Answer 35

rough, large projection

Question 36

Type of bone between the vertebrae

Answer 36

Fibrocartilage

Question 37

Upper limbs

Answer 37

• 60 total
  
  • Humerus (2)
  • Radius (2)
  • Ulna (2)
  • Carpal bones (16)
  • Metacarpal bones (10)
  • Phalanges (28)

Question 38

Vertebral functions

Answer 38

• Support the skull and trunk
• Protect the spinal cord
• Absorb stress of walking, running, and lifting
• Provide attachments for limbs, thoracic cage, and postural muscles

Question 39

Vertebral markers

Answer 39

• Cervical lordosis
  
  • Infant lifting head on its own
• Lumbar lordosis
  
  • When a person is able to start walking on his/her own (~1 YOA)
• C7 (aka vertebra prominens)
  
  • Landmark for counting vertebrae by palpation
  • Forms a prominent bump on the lower back of neck