Appendicular System -- bones, joints, fractures

appendicular skeleton

126 bones

• limbs

• shoulder and pelvic girdles

bone functions

• attachment for muscles

• mechanical basis for movement

• protection of internal organs

• support frame for body

• storage for calcium, phosphorus, and other salts

• production of red and white blood cells

classification of bones

long, irregular, short, and flat bones

long bones

• limbs

• compact bones

• spongy bones

• periosteum

• only bones found in appendicular system/limbs

  • consist of body and two enlarged articular ends

irregular bones

• limbs

• peculiar shape (vertebrae, facial bones, and pelvic bones)

short bones

carpal and tarsal bones

• consist mainly of cancellous bone with a thin outer layer of compact bone

flat bones

calvarium, sternum, ribs, and scapulae

• consist of two plates of compact bone

  • middle layer of cancellous bone called diploe

sesamoid bones

• very small and oval

• develop inside and beside tendons

• protect the tendon from excessive wear

• largest is patella

general bone features

• bone marrow produces red and white blood cells and is also really sensitive to radiation

• yellow marrow stores fat cells

• medullary cavity

• periosteum

• endosteum

medullary cavity

• central cavity of long bones

• contains trabeculae filled with yellow marrow (important to see during an x-ray, meaning it was properly exposed)

• red marrow found in the ends of long bones

periosteum

tough, fibrous connective tissues that covers bone, except at articular ends

endosteum

lines marrow cavity and helps with growth and repair of bone

ossification

• term that applies to the development and formation of bones

• begins in the second month of embryonic life

• two processes:

  • intramembranous

  • endochondral

intramembranous ossification

flat bones are formed from this type of ossification

endochondral ossification

• short, irregular, and long bones are created by this type of ossification

• occurs form two distinct centers of development:

  • primary

  • secondary

primary ossification

begins before birth and forms long central shaft in long bones (diphysis)

secondar ossification

occurs after birth when separate bones begin to develop at both ends of long bones

• metaphysis

• epiphyseal plate/growth plate

• ends are called epiphyses

processes or projections

extend beyond or project out from the main body of a bone

depression

hollow or depressed areas

• fissure, foremen, fossa, groove, meatus, notch, sinus, sulcus

fractures

a break in bone

condyle

rounded process at an articular end

coracoid

beaklike process

coronoid

crownlike process

crest

ridgelike process

epicondyle

projection above a condyle

facet

small, smooth-surfaces articular process

hamulus

hook-shaped process

head

expanded end of a long bone

horn

hornlike process

line

linear elevation; not as prominent as a crest

malleolus

club-shaped process

protuberance

projecting prominence

spine

sharp process

styloid

long, pointed process (radius and ulna)

trochanter

either of the two large, rounded, and elevated processes of the proximal femur

tubercle

small, rounded, and elevated process

tuberosity

large, rounded, and elevated process

fissure

cleft or deep groove

foramen

hole in a bone or transmission of vessels and nerves

fossa

pit, fovea, or hollow space

groove

shallow linear channel

meatus

tubelike passageway

notch

indentation in the border of a bone

sinus

recess, groove, cavity, or hollow space

sulcus

furrow or trench

classification of joints

structural: classified by tissue type

• fibrous, cartilaginous, synovial

function: classified by function

• synarthrodial, amphiarthrodial, diarthrodial

fibrous

held together by fibrous tissue

• not all joints are immovable, some are slightly moveable and some are limited movement

• mostly classified are immoveable

syndesmosis and suture

cartilaginous

held together by cartilage

• not all joints are slightly moveable, some are immovable

symphyses and synchondroses

synovial

synovial fluid in joint capsule

• are freely moveable, if movement is restricted it is because of tendons and ligaments preventing the movement

• 7 movement types 

• diarthordial

plane 

gliding movement

• ex: intermetacarpal, intercarpal, carpometacarpal

ginglymus

hinge that allows for flexion and extension

• ex: interphalangeal/elbow joint

trochoid

pivot that allows for rotation or rolling on an axis

ellipsoid

condyloid — allows for adduction and abduction as well as flexion and extension

sellar

saddle

spheroidal

ball and sock — have the greatest range of movement but prone to dislocation

bicondylar

2 condyles on top of each other

subluxation

partial dislocation of joint

dislocation or luxation

displacement of bone from joint

contusion

a “bruise” type injury without a fracture or break in the skin

sprain

forced wrenching or twisting of a joint, resulting in partial rupture or tearing of supporting ligaments, presents with a lot of swelling

fracture types

incomplete fracture, simple fracture, compound fracture, complete fractures, comminuted fractures

incomplete fracture

fracture does not transverse through entire bone

• ex: torus or buckle, greenstick, plastic fracture

simple fracture

bone does not break through skin, closed fracture, usually a transverse fracture

compound fracture

bone protrudes through skin, an open fracture

complete fracture

breaks into two pieces

• ex:

  • transverse —- broken straight across

  • oblique — broken @ an angle

  • spiral fracture — breaks and turns when broken

comminuted fracture

breaks into two or more fragments

• ex:

  • segmental — fractures in multiple places

  • butterfly

  • splintered fracture — splinters into multiple pieces when broken

impacted fracture

one fragment driven into another end of a bone

colles’ fracture

• most common type of fracture

• posterior displacement of distal radius

• lateral projection will confirm

• reverse colles’ fracture is an anterior displacement

monteggia’s fracture

proximal ulna fracture along with dislocation of radial head

pott’s fracture

ankle fracture of distal fibula with frequent fracture of medial malleolus

compression fracture

vertebral body collapses or is crushed

stellate fracture

fracture lines radiate from a center point of injury

tuft fracture

comminuted fracture of distal phalanx

osteogenesis imperfecta

• nicknamed “brittle bone disease”

• an inherited generalized disorder of connective tissue by multiple fractures and an unusual blue color of the normally white sclera of the eye

battered-child syndrome

• multiple, repeated, physically induced injuries in young children caused by parent or guardians

• also known as suspected nonaccidental trauma (SNAT)

• imaging professionals have a legal responsibility to report suspicious cases to their supervisors

  • facility is legally obligated to notify authorities

osteoarthritis

• degenerative joint disease

• non-inflammatory

• most common type of arthritis

rheumatoid arthritis

• chronic systemic idiopathic disease

• appears primarily as a noninfectious inflammatory arthritis of the small joints of the hands and feet

bursitis

• inflammation of the small fluid-filled sac located near the joints that reduce the friction caused by movement

• causes:

  • repeated physical activity (most common) — tennis elbow

  • trauma

  • rheumatoid arthritis

  • gout

  • infections

osteomyelitis

• bacterial

• an inflammation of the bones and marrow caused by a variety of infectious organisms

• infectious organisms reach bone by hematogenous spread, extension from an adjacent site of infection, or direct introduction of organisms (after trauma or surgery)

osteoporosis

• generalized or localized deficiency the mass of bone

• its causes include aging and postmenopausal hormonal changes (most common in women)

• a decrease in kVp is required to obtain quality image

simple bone cyst

• true fluid-filled cyst with a wall of fibrous tissue, which most often occurs in the proximal humerus or femur at the metaphysis

• it is asymptomatic

• often discovered either incidentally or after pathologic fracture 

neoplasm

• cancerous or non-cancerous (benign)

  • bone metastisis (cancerous)

• many types

• can be osteolytic (bone destructive) or osteoblastic (bone constructive)