anatomy exam 3

articulation

site where two or more bones meet

functions of joints

give skeleton mobility, hold skeleton together

two classifications of joints

functional and structural

functional classification of joints

based on the amount of movement joint allows

three functional classifications of joints

synarthroses, amphiarthroses, diarthroses

synarthroses

immovable joints

amphiarthroses

slightly movable joints

diarthroses

freely movable joints

fibrous joints

bones connected by FCT, no joint cavity, most synarthrotic

cartilaginous joints

joined by hyaline or fibrocartilage, no joint cavity, not highly movable.

synovial joints

joined in a joint cavity with lubricating fluid, allows for free movement. all of diarthrotic and most common joints in the body

fibrous joint types

sutures, syndesmoses, gomphoses

fibrous joints: sutures

rigid, interlocking joints. immovable joints for protection of brain, contain short connective tissue fibers

fontanelles

soft spots between skull bones, wider areas of connective tissue that allow for growth during youth

fibrous joints: syndesmoses

2 parallel bones connected by ligaments (bands of fibrous tissue.) fiber length varies so movement varies

fibrous joints: gomphoses

specialized fibrous joint that anchors the root of a tooth into its bony socket. peg-in-socket joints of teeth in alveolar sockets. fibrous connection is the periodontal ligament

two types of cartilaginous joints

synchondroses and symphyses

cartilaginous joints: synchondroses

hyaline cartilage unites bones, all are synarthrotic

cartilaginous joints: symphyses

fibrocartilage units bone, strong, flexible, and amphiarthroses

six distinguishing features of synovial joints

articular cartilage (hyaline cartilage), joint cavity, articular capsule, synovial fluid, different types of reinforcing ligaments, nerves and blood vessels

purpose of hyaline cartilage in synovial joints

prevents crushing of bone ends

joint cavity

small fluid filled potential space

articular capsule layers

external fibrous layer and inner synovial membrane

external fibrous layer

dense irregular CT

inner synovial membrane

loose CT, makes synovial fluid

synovial fluid

viscous, slippery filtrate of plasma and hyaluronic acid. lubricates and nourishes articular cartilage. contains phagocytic cells to remove microbes and debris

capsular ligaments

thickened parts of the fibrous layer, may be intracapsular or extracapsular

extracapsular ligament

outside the capsule

intracapsular ligament

deep to extracapsular ligaments, thickened part of fibrous layer

fatty pads

feature in some synovial joints, for cushioning between fibrous layer and synovial membrane

articular discs

feature in some synovial joints, fibrocartilage separates articular surfaces to improve "fit" of the bone ends, stabilize joint, and reduce wear and tear. ex: menisci

bursae

associated with synovial joints, sacs that are lines with synovial membrane, reduces friction where ligaments muscles skin tendons or bones rub together

tendon sheaths

associated with synovial joints, elongated bursae wrapped completely around tendon subjected to friction

types of synovial joints

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

pivot joint

rounded portion of a bone is enclosed within a ring formed partially by the articulation with another bone and partially by a ligament (c1-c2)

hinge joint

the convex end of one both articulates with the concave end of the adjoining bone (elbow, knee). allows only for bending and straightening motions along a single axis

condyloid joint

the shallow depression at the end of one bone articulates with a rounded structure from an adjacent bone or bones (wrist, knuckles)

ball and socket joint

the joint with the greatest range of motion, the rounded head of one bone (ball) fits into the concave articulation (socket) of the adjacent bone (hip and shoulder only)

plane joint

the articulating surfaces of the bones are flat or slightly curved and of approximately the same size which allows the bones to slide against each other (feet, vertebrae)

saddle joint

both of the articulating surfaces for the bones have a saddle shape which is concave in one direction and convex in the other (hand)

origin

attachment to immovable bone

insertion

attachment to movable bone

muscle contraction causes insertion to

move toward origin

nonaxial

gliding movements only

uniaxial

movement in one plane

biaxial

movement in two planes

multiaxial

movement in or around all three planes

three general types of movements at synovial joints

gliding, angular movements, rotation

angular movements

increase or decrease angle between two bones, movement along saggital plane. flexion, extension, hyperextension, abduction, adduction, circumduction

rotation

turning of bone around its own long axis, toward midline or away from it. medial and lateral rotation ex: between c1 and c2

gliding movements of synovial joints

one flat bone surface glides or slips over another similar surface ex: intercarpal joints

flexion

decreases the angle of the joint

extension

increases the angle of a joint

hyperextension

excessive extension beyond normal range of motion

supination and pronation occurs

radius and ulna

dorsiflexion and plantarflexion occurs

foot

inversion and eversion occurs

foot

protraction and retraction occurs

mandible

elevation and depression occurs

mandible

opposition occurs

thumb

five main synovial joints

jaw, shoulder, elbow, hip, knee

temporomandibular joint (TMJ)

modified hinge joint that articulates with temporal bone. articular capsule thickens into strong lateral ligament

two types of movement TMJ

hinge and gliding. most easily dislocated joint in the body

shoulder (glenohumeral) joint

most freely moving joint in body, largest range of motion. ball and socket joint

glenoid labrum

fibrocartilaginous rim around glenoid cavity, helps add depth to shallow cavity

reinforcing ligament of glenohumeral joint

coracohumeral ligament, helps support weight of the upper limb

primary support

comes from reinforcing muscle tendons contribute most to joint stability

Four rotator cuff tendons encircle the shoulder joint

supraspinatus, infraspinatus, teres minor, subscapularis (SITS)

elbow joint

humeroulnar joint, hinge joint, angular ligament

humeroulnar joint

humerus articulates with radius and ulna

hinge joint (elbow)

formed primarily from trochlear notch of ulna articulating with trochlea of humerus (allows for flexion and extension)

anular ligament of elbow

surrounds head of radius, two capsular ligaments restrict side to side movement (ulnar collateral ligament and radial collateral ligament

hip joint

ball and socket joint

ball and socket joint (hip)

carrying body weight, so designed for strength and stability less range of motion, more restricted movement

acetabular labrum of hip

rim of fibrocartilage that enhances depth of socket

reinforcing ligaments of hip joint

illiofemoral ligament, pubofemoral ligament, ischiofemoral ligament, ligament of head of femur

ligament of head of femur (ligamentum teres)

slack during most hip movements so not important to stabilizing, contains artery that supplies head of femur

knee joint

largest and most complex joint of body, consists of the femoropatellar joint, medial tibiofemoral joint, lateral tibiofemoral joint

femoropatellar joint

found between the patella and distal femur, allows gliding motion during knee flexion

lateral tibiofemoral joint

located between the medial and lateral condyles of the femur and the medial and lateral condyles of the tibia

how many bursae are in the knee?

at least 12

anteriorly, quadriceps tendon gives rise to three broad ligaments that run from patella to tibia

medial and lateral patellar retinacula that flank the patellar ligament

knee jerk reflex is controled by

tapping the patellar ligament

ligaments that help stabilize the knee

capsular, extracapsular and intracapsular

ligaments that prevent hyperextension

capsular and extracapsular

ligaments that prevent rotation when knee is extended

fibular and tibial collateral ligaments

ligament that stabilizes posterior knee joint

oblique popliteal ligament

ligament that reinforces joint capsule posteriorly

arcuate popliteal ligament

ligament that helps prevent anterior- posterior displacement

intracapsular ligaments (reside in capsule)

anterior cruciate ligament (ACL)

attaches to anterior tibia, prevents forward sliding of tibia and stops hyperextension

posterior cruciate ligament (PCL)

attaches to posterior tibia, prevents backward sliding of tibia and forward sliding of femur

common knee injuries

3 c's: collateral ligaments, cruciate ligaments, cartilages (menisci)

lateral blows to extended knee can result in

tears in tibial collateral ligament, medial meniscus and ACL (the unhappy triad)

in fetuses, when do synovial joints resemble adult joints

embryonic week 8

muscles

organs that use chemical energy to contract. takes up nearly half of body's mass and transforms ATP to directed mechanical energy

3 types of muscles

skeletal, smooth, cardiac

skeletal muscle

organs attached to bones and skin, has muscle fibers, appears striated (non-branching fibers), voluntary, contract rapidly, tire easily, powerful, require nervous system stimulation

cardiac muscle

only in heart, bulk of heart walls, striated (branching fibers), can contract without nervous system stimulation (involuntary)

smooth muscle

in walls of hollow organs (ex: stomach, bladder), non striated, involuntary

structure of skeletal muscle

comprised of skeletal muscle tissue, nervous tissue, blood and other CT