Trunk - Week 4 Flashcards
Vertebrae, sacrum, ribs, and sternum
what plane does the axial skeleton occupy?
- median sagittal plane
- includes: skull, vertebral column, ribs, and sternum
- unique to vertebrates
what are the types of vertebrae and how many are there in each type?
- cervical (C) - 7
- thoracic (T) - 12
- lumbar (L) - 5
- sacral (S) - 5 (fused in adulthood)
- coccygeal (Co) - 3 - 5 (variably fused)
primary curve in the thoracic vertebrae
kyphosis
- original curving in utero
- around 1 y/o (walking age) kyphosis develops into a secondary curve of lordosis
secondary curve in the lumbar vertebrae
lordosis
what are the soft tissue structures in the vertebral column?
- intervertebral discs
- anterior longitudinal ligament
- posterior longitudinal ligament
- ligamentum flavum
what are the three primary centers of ossification?
- centrum
- right half of the neural arch
- left half of the neural arch
what are the five secondary centers of ossification?
- ring-like apophyses on superior and inferior margins of the centrum
- tip of each of the transverse and spinous processes
atlas
- C1
- bears the whole skull and articulates with the occipital at the occipital condyle - atlanto-occipital joint
- curved like a bowl
- large foramen for vertebral canal
- no vertebral body
axis
- C2
- allows head to turn from side to side
- articular processes are facing sideways
- dens sticks out
- lacks a typical process
- articular process faces sideways
- atlanto-axial joint
joint that articulates with the atlas and occipital bone
atlanto-occipital joint
joint that articulates with the atlas and axis
atlanto-axial joint
cervical vertebrae
- typically 7, 8 is rare
- invariant with other vertebrates having the same amount
- top and bottom of the body is curved like a bowl
- articular processes are smooth
- slopes inferiorly
- spinous processes is bifid
- dead giveaway: transverse formamen
thoracic vertebrae
- typically 12 and occasionally 13
- defined by how many ribs you have, which is why you could have 13
sacrum
- 5 fused
- fuses in adulthood
- articulates with pelvic girdle in the appendicular skeleton
- responsible for transmitting weight to the lower limbs
intervertebral discs
- found between vertebrae
- has a gel-like cap in the middle called the nucleus pulposus, which is shock bearing. this is what causes a slipped disc when this gets squished and herniated
vertebral arch
neural arch
transverse foramen
- found in the cervical vertebrae
- transmits the vertebral artery to bring blood to the brain
C7
- vertebra prominens
- no bifid appearance
- flat inferior surface
costal elements
- anterior
- analogous with the ribs
T1
- articulates with C7
- costal faucet is a complete circle
- demi-faucet on the bottom is a half-circle
T2 - T9
- relative size of vertebral body
- spinal processes start to angle downwards more and more
- lamina get larger
- two demi-faucets
T10
- body is large, vertebral canal is small
- very different spinal process
- complete or nearly complete faucet with no demi-faucet underneath
- transverse facet not present on any other thoracic vertebrae
T11
- end of the ribcage - floating ribs articulate
- complete faucet
- no faucet on transverse process
- large vertebral body and small canal
- much smaller transverse process
T12
- single faucet on body
- no transverse process
- large spinous process
L1 - L5
- cannot distinguish from one another
- large bodies
- transverse processes
- superior articular faucet
- no costal facet
label
- sacral plateau
- ala
- transverse lines
- articulation w/ coccyx
- sacral foramina
label
- superior articular facets
- median crest
- dorsal wall
what is the function of the ribs?
- protect thoracic viscera
- mechanical framework for respiration
true ribs
- sternal ribs
- ribs 1 - 7
false ribs
- common cartilage
- ribs 8 - 10
floating ribs
- no distal articulation
- ribs 11 - 12
label the parts of a “typical” rib
- tubercle with facet
- head with 2 demi-facets
- neck
- costal groove
- sternal end
- shaft
- angle
characteristics of rib 1
- short, flat, and curved
- scaline tubercle
- subclavian groove
- has two shallow grooves that contain the subclavian artery and subclavian vein
characteristics of rib 2
- tuberosity for serratus anterior
- weak costal groove
- long neck
- curved and short
characteristics of rib 2
- tuberosity for serratus anterior
- weak costal groove
- long neck
- curved and short
characteristics of ribs 3 - 9
- two demi-facets with a crest between them
- neck is not extended
- oval-shaped sternal end
- strong expression of costal groove
characteristics of rib 10
- attaches to T10
- sternal end is round
- short neck
characteristics of rib 11
- no tuberacle
- single facet
- taper at sternal end
- pointed and not pitted
characteristics of rib 12
- no tuberacle
- single facet
- taper at sternal end
- pointed and not pitted
- maybe shorter than rib 1
how do the ribs function respiration?
- diaphragm forms a dome and the dome descends up and down
- volume of thoracic cavity changes when air comes in and out, which changes atmospheric pressure
- scalene muscles contract to raise ribs up to bring air in
- sternum is also raised up to let air in
- costal vertebral joints are mobile and allow rib movement
label the parts
- jugular notch
- first costal notch
- costal notches
- sternal angle (second costal notch)
- clavicular notch
manubrium
- top part of the sternum
- largest and thickest of the sternal elements
- widest part of the bone
xiphoid process
inferior tip of the sternum
- seventh costal notch
- highly variable element
gladiolus
body of the sternum
what is the composition of bone?
- 10% water
- 25% organic
- 65% mineral
what is the mineral composition in bone?
- hydroxyapatite, which includes calcium and phosphorous
noncollagenous proteins (NCPs)
- enzymes
- messengers
- structural proteins
- transport proteins
enzymes
produce chemical reactions and build things by reading DNA
messengers
coordinate processes through signaling
structural proteins
provide mechanical support
transport proteins
bind to things in order to move them around
what are the cortical bone types?
primary and secondary
primary cortical bone
- deposited on existing bone surface
- circumferential lamellae
- primary osteons
- plexiform (in other vertebrates, not humans)
secondary cortical bone
- replaces bone on resorbed surfaces
- haversian systems
woven bone
- embyologic
- transient
- poor structural organization
lamellar bone
- 3 - 7 micrometer unit layers
- collagen orientation is nonrandom
- forms slowly
skeletal mass fraction of cortical and cancellous bone
80% cortical
20% cancellous
skeletal surface of cortical and cancellous bone
33% cortical
67% cancellous
soft tissue of cortical and cancellous bone
10% cortical
75% cancellous
porosity of cortical and cancellous bone
low porosity in cortical
high porosity in cancellous
bone envelopes
- only appositional growth
- all metabolic activity at surfaces
what percentage on adult bone surfaces does periosteal, endosteal, osteonal, trabecular make up?
4.4% periostal
4.4% endosteal
30.4 osteonal
60.8 trabecular
label
- concentric lamellae
- interstitial lamellae
- circumferential lamellae
cortical bone
the solid, dense bone found in the walls of bone shafts and on external bone surfaces
cancellous bone
- also called trabecular
- spongy, porous, and lightweight
