BIO120 ARTICULATIONS AND BODY MOVEMENTS

articulations

= joint, allow for flexibility for gross body movements and to hold bones together

functionally, articulations/joints are classified as either

synarthrosis, amphiarthrosis, or diarthrosis

synarthroses

non movable joints

amphiarthroses

slightly movable joints

diarthroses

freely movable joints

structurally, articulations/joints are classified as either

fibrous joints, cartilaginous joints, or synovial joints

fibrous joints

bones held together by fibrous tissues, most are synarthrotic. no joint cavity. there are 3 types: sutures, syndesmoses, and gomphoses

sutures

joints with bones with irregular edges interlocked by short connective tissue fibers; ex: skull

syndesmoses

joints with bones connected by short ligaments; ex: fibrous connective tissue that connects the fibula and tibia

gomphoses

joint that holds the teeth in the mandible via the periodontal ligament

cartilaginous joints

joints held together by a pad of cartilage, most are amphiarthrotic (slightyly movable). no joint cavity. 2 types: symphyses and synchondroses

symphyses

joints with bones that are connected by a flat disc of fibrocartilage; ex: pubic symphysis, vertebrae

synchondroses

bones connected by hyaline cartilage; ex: epiphyseal plates of children

synovial joints

separated by cavity or joint, has synovial membrane and synovial fluid, are diarthrotic

joint (articular) cavity

space between the articulating bones, contains small amount of synovial fluid

articular capsule

2 layers, a fibrous layer of dense regular connective tissue + a layer of synovial membrane, secretes synovial fluid

articular cartilage

hyaline cartilage, covers surface of bones forming joints

synovial fluid

viscous fluid that reduces friction between joints

reinforcing ligaments

hold bones of joints together

capsular ligaments

thickenings of the fibrous layer of the articular capsule

extracapsular ligaments

found outside of the articular capsule

intracapsular ligaments

found within the articular capsule

patellar ligament

connects patella to tibia

nerves and blood vessels of synovial joints

detects pain and joint stretching

bursae

synovial fluid filled sacs that cushion joints

meniscus

padding between articulating bone

origin

point of attachment of the muscle that doesn't move

insertion

point of attachment of muscle that moves

contraction of muscle

muscle fibers shorten, the insertion move towards the origin

flexion

decreases the angle between the origin and the insertion

extension

increases the angle between the origin and insertion

hyperextension

extension greater than 180 degress

abduction

movement away from the midline

adduction

movement towards the midline

rotation

rotation of head

circumduction

movement that makes an imaginary cone along the long axis of a bone

pronation

turning of the hand from the anatomical position, radius crosses over ulna. back of hand is anterior

supination

turning of the hand to return to the anatomical position, the radius and ulna are parallel

inversion

turning of the feet medially, inward

eversion

turning of the feet laterally, outward

dorsiflexion

movement of the feet upward

plantar flexion

movement of the feet downward

sprain

excessive stretching or tearing away of the ligaments reinforcing a joint

dislocation

bones being forced out of normal position

spur

extraneous growth of bone tissue where it doesn't usually grow

synovial membrane

connective tissue that encloses and protects knee joints

marrow cavity

stores yellow marrow/adipose

medial and lateral menisci

shock absorbtion

fibrous capsule

prevents excessive movement and dislocation

tibial + fibular collateral ligaments

maintain proper alignment of knees, prevents excessive extension of knee

plane/gliding joint (nonaxial)

ex: intercarpal joints, acromioclavicular (AC) joint

hinge joint (uniaxial)

ex: elbow joint, knee joint

pivot joint (uniaxial)

ex: atlas/axis

condyloid/ellipsoidal joint (biaxial)

ex: metacarpophalangeal joints

saddle joint (biaxial)

ex: carpometacarpal joint, sternoclavicular joint

ball and socket joint (multiaxial)

ex: shoulder and hip joints

lateral rotation

rotating the leg away from midline

medial rotation

rotating the leg towards midline