exam 2 - joints & lever systems

fibrous

structural classification

connected by dense connective tissue and have no joint cavity

cartilaginous

structural classification

connected by hyaline cartilage and have no joint cavity

synovial

structural classification

have a synovial, fluid-filled cavity that surrounds the articulating bone

joints

permit effective movement and protect soft organs

articulation

where 2 bones meet (bone and cartilage)

synarthrosis

functional classification

DO NOT move

amphiarthrosis

functional classification

small degree of movement

diathrosis

functional classification

allow free movement

Suture

synarthrotic and fibrous

ex: sagittal suture

gomphosis

synarthotic and fibrous

extooth in socket

syndesmoses

amphiarthoracic and fibrous

ex: distal ends of radius/ulna and tibia/fibula

synchrondroses

synarthotic and cartilaginous

connected by hyaline cartilage

ex: sternum ribs 1-12

symphesis

amphiatoracic and cartilaginous

bones connected by fibrocartilage

ex: pubic symphysis and intervertebral discs

fully moveable articulations

plane, hinge, pivot, condyloid, saddle, ball and sockett

ALL: diathoracic and synovial

plane

classification: D & S

flat surfaces come together
ex: tarsals, carpals

hinge

classification: D & S

convex into concave

ex: humerus/ulna, humerus/radius, femur/tibia

pivot

classification: D & S

round surface firs into rings of ligaments

ex: axis and atlas

condyloid

classification: D & S

convex oval fits into epillitical cavity

ex: radius/scaphoid

saddle

classification: D & S

ball and socket

classification: D & S

spherical head fits into concave socket

ex: femur and pelvic / humerus and scapula

bony joint

synostosis - immovable joint

tendon

dense regular connective tissue

attaches muscle to bone

stablizes joints

ligament

connective tissue attaches one bone to another

bursa

fibrous sac filled with synovial fluid located between the adjacent muscles

tendon sheath

elongated bursae wrapped around a tendon

meniscus

cartilage absorbs shock and pressure

lever

any elongated object that rotates around a fixed point called a fulcrum

rotation occurs when an effort overcomes resistance (load) at some other point

first class lever

fulcrum in the middle between effort and resistance

ex: head nodding motion (atlanto-occipital joint)

• fulcrum: atlas

• effort: posterior neck muscles

• load: weight of head

• function: helps balance and extend the head

second class lever

resistance between fulcrum and effort, load is between the fulcrum and effort

ex: flexion at the ankle (standing on tiptoes)

fulcrum: ball of the foot

effort: calf muscles (being used to push up)

load: body weight

function: allows powerful movement with less effort

third class lever

effort is between the fulcrum and the load

ex: elbow flexion (bicep curl)

fulcrum: elbow joint

effort: biceps brachii pulling on radius

load: weight of forearm

function: most common type, allows speed and range of motion but requires more force

uniaxial

bone moves in just one plane or axis

ex: plane joint, hinge, pivot

biaxial

bone moves in two places or axes

ex: saddle (between thumb), condylar (knuckles)

syndesmoses

bones that join together and are held in place with sheets of collagen

dense regular connective tissue

radius and ulna

synchondroses

bones joined together with hayline cartilage between ends of the bone

synovial

most complex joint with varying amounts of mobility

cartilaginous joints

intervertebral discs

and pubic symphysis

multiaxial

bone moves in multiple planes

ex: ball and socket (hip and shoulder)

Symphyses are slightly mobile joints where the articulating bones contain a pad of _________ blank between them.

fibrocartilage