Skeleton Anatomy/Bones Flashcards
Explain the general structure of bone
made of osteons (haversian system)
30% organic (type 1 collagen)
70% inorganic (calcium/phosphate salts)
what cells are involved in bone remodelling?
osteoblasts - build up new bone
osteoclasts - break down old bone
explain how rickets is caused by abnormal bone structure
vitamin D deficiency (required for calcium absorption)
bones become overly flexible lacking mineral content
explain how osteogenesis imperfecta is linked to abnormal bone structure
genetic condition where collagen production is affected
bones are brittle and fracture easily
name the the general structure of a typical bone
long tube-like diapysis, strong and flexible, mostly compact bone
2 epiphyses, articular surfaces for joints, spongy bone compact on surface
epiphyseal growth plate, separates diaphysis and epiphyses, growth site, once growth complete the plate ossifies (epiphyseal line)
explain the outer/inner structure layers of bones
periosteum - covers outer surface of bone, tendon site of attachment
endosteum - lines internal surfaces of cavities within bones
what are the 5 classifications of bone shape? and name an example for each
- long (long diapysis = shaft), e.g femur
- short (similar width/length) e.g wrist/ankle bones
- flat bones (thin, flat, usually curved) e.g skull, ribs
- irregular (dont fit in any category) e.g vertebrae, facial bones
- sesamoid (small, round bones embedded in tendons, protects tendon and increases movement) e.g patella
name the 3 main joints bones are connected by
fibrous (sutures)
cartilaginous (IVDs)
synovial ‘true’ joints (humerus)
describe the axial skeleton bones
skull (22 bones)
vertebral column (~33 bones)
ribs (12 pairs)
sternum
name the bones of the appendicular skeleton
pectoral/pelvic girdle
arm/hand bones
leg/foot bones
describe the 2 skull regions of bones
vicerocranium (facial skeleton) = 14 bones
neurocranium (surrounding brain) = 8 bones
explain the groups of bones in the vertebral column
cervical (7) - small, relatively mobile, susceptible to dislocation
thoracic (12) - articulate with ribs, long processes for muscle attachment
lumbar (5) - largest body, susceptible to herniated IVDs
sacrum (5 fused) - vertebrae fused, articulates with hip bones
coccyx (~4 fused) - tailbone, susceptible to fracture
explain the girdles of the appendicular bones
girdles - attach limbs to body
pectoral girdle - clavicle and scapula, clavicle only bone connecting upper limb to axial skeleton, facilitates movement
pelvic girdle - innominates (unarmed), made of the ilium, ischium and pubis, provides stability (transfers weight to limbs), protects pelvic organs, different shape in males and females
explain the bones in the upper limb
arm - humerus
forearm - radius and ulna
wrist - carpals (8)
hand - metacarpals (5) and phalanges (14)
explain the bones in the lower limbs
thigh - femur
knee - patella
leg - tibia and fibula
ankle - tarsals (7)
foot - metatarsals (5) and plalanges (14)
what are bone markings? name and explain them
roughened ridges/grooves relating to structures associated with bones
condyles/epicondyles (form joint surfaces/attach muscles)
crest/line (ridges where muscles attach)
facet (forms joint surfaces)
foramen/notch (hole or notch where vessels pass through)
fossa (dip/curve where muscles sit)
process/protuberance/spine (bumps in bone)
explain the anatomy and function of the sternum and ribs
surround and protect thoracic organs (thoracic cage) and important role in respiration
flexibility provided by costal cartilages anteriorly
explain the surface landmark on the sternun
sternal angle - where sternum projects anteriorly most
at level of 4th/5th thoratic vertebrae
2nd ribs articulate/join at the sternal angle
explain importance of sternal angle
horizontal plane at sternal angle passes through several important surfaces
allows us to palpate/locate 2nd ribs
can count ribs (cant feel rib 1 from surface)
name the importance of locating rib 2
listening to heart valves and sections in specific locations (certain valves inbetween each specific ribs)
what are the 2 types of ossification?
endochrondal ossification - cartilage model made first then replaced
intramembranous ossification - bone formed directly in mesenchyme
what are the primary and secondary ossification centres?
primary - first part to form, can have more than 1 (diaphysis in long bone)
secondary - epiphysis
explain how osteoporosis can occur, and is it more common in M or F?
bone removed faster than laid down, bone density reduced, more susceptible to fracture
more common in females as oestrogen promotes osteoblast activity
can result in excessive kyphosis (exaggerated external curve in vertebrae) where vertebral bodies collapse
what is periostisis? how is it caused?
inflammation of the periosteum and can lead to extra bone being laid down
caused by infection such as staphylococcus or congenital syphilis (acute) or trauma/bone stress (chronic)
what are osteocytes?
dormant bone cells sensetive to stimuli
name the 6 stages of the bone metabolic unit (BMU) in bone remodelling
activation (osteoclasts)
reabsorption (bone matrix)
osteoblast recruitment
osteoid formation
mineralisation
quiescence
what is the key mediator for osteoclast formation, function and survival?
RANK ligand
what is the inhibitor of the RANK ligand?
OPG
what is the role of OPG?
regulates bone mineral density (BMD)
name the determinants in bone mass/density
calcium/phosphates
parathyroid hormone (PTH)
cholecalciferol and calcitrol
estrogen (sex hormones)
name the bone disorders associated with mineralisation loss
osteomalacia and rickets
name the bone disorders associated with low bone mass
osteoporosis, OI
name the bone disorder associated with high bone mass
osteopetrosis
name the bone disorders associated with high bone turnover
pagets, hyperparathyroidism, thyrotoxicosis
name the bone disorders associated with low bone turnover
adynamic disease, hypophosphatasia
explain the characteristics of osteoporosis (OP)
reduced total bone mass, adequate mineralisation of present osteoid, oestrogen deficiency, increased bone reabsorption
explain the characteristics of corticosteroid-induced osteoporosis
increased osteoclast activity, decreased osteoblast activity, impaired collagen function, increased bone turnover, poor bone formation/healing
explain the characteristics of hyperparathyroidism
unregulated PTH secretion, hypercalcaemia (low phosphate)
increased bone turnover
often OP (increased with age)
what would be found on an x-ray showing hyperparathyroidism?
subperiosteal bone reabsorption
generalised decrease in bone density
brown tumors
chondrocalcinosis (knee, wrist, shoulder)
explain the characteristics of pagets disease
rapid bone turnover
bone resorption/formation increased
disorganised structure
reduced bone strength
linked to osteosarcoma TSG
what 2 failures cause osteopetrosis?
osteoclastic/chondroclastic resorption
remodelling failure
describe the characteristics of OI
collagen 1 deficiency
low muscle tone
bluish sclerae
recurrent childhood fractures
deformities
Name the 14 bones of the face
mandible (jaw)
vomer (posterior septum)
maxilla (2)
palatine (2)
zygomatic (2)
lacrimal (2)
nasal (2)
inferior nasal conchae (2)
name the 8 bones of the head/skull
frontal
sphenoid
temporal (2)
ethmoid
occipital
parietal (2)
