Ch 8 Flashcards
Articulations
joints hold bones together but may permit movement
point of contact: b/w 2 bones, b/w cartilage and bone, and b/w teeth and bones
Classification
based on movement and anatomy
Based on movement
synarthrosis, amphiarthrosis, and diarthrosis
Synarthrosis
immovable
Amphiarthrosis
slightly movable
Diathrosis
moves freely
Based on anatomy
fibrous (collagen), cartilaginous (cartilage), or synovial (joint capsule and accessory ligaments)
Fibrous joints
lack synovial cavity
bones held closely together by fibrous connective tissue
little or no movement (synarthrosis or amphiarthrosis)
3 structure types: sutures, syndesmoses, gomphoses
Suture
thin layer of dense fibrous connective tissue unites bones of the skull
immovable(synarthritic)
Syndesmosis
fibrous joint
bones united by ligament
slightly movable
anterior tibiofibular joint and interosseous membrane
Gomphosis
ligament holds cone shaped peg in bony socket
immovable
teeth in alveolar processes of maxillae or mandible
Cartilage joints
lacks a synovial cavity
allows little or no movement
bones tightly connected by fibrocartilage or hyaline cartilage
2 types: sychondroses or symphyses
Synchondrosis
connecting material is hyaline cartilage
immovable
epiphyseal plate or joints b/w ribs and sternum
when fusion occurs it becomes a synostosis
Symphysis
fibrocartilage is connecting material
slightly movable
intervertebral discs and pubic symphysis
Synovial joint features
- 2 bones separated by fluid filled cavity
- joint capsule has 2 layers- synovial membrane and articular cartilage
- Synovial fluid components- blood filtrate, hyaluronic acid, and glycoproteins
- Synovial fluid functions- lubricate joint surface, nourish chondrocytes, and shock absorber
Synovial joint accessory structures
ligaments, articular discs, fat pads, and bursae
Ligaments
reinforce and strengthen joint capsule
connect bone to bone with dense regular CT
Ligament types
extrascapular ligaments (outside joint capsule) intracapsular ligaments (w/in capsule)
Articular Discs
pads of fibrous cartilage that subdivide a cavity
also known as meniscis
ulnolunate joint, knee joint
Articular disc functions
channel flow of synovial fluid modify articular surfaces restrict movements at joint cushion articulation surfaces help distribute body weight
Fat pads
adipose tissue surrounding the synovial capsule
tibiofemoral joint
Functions of fat pads
protect articular cartilage
packing material
fills spaces when joint changes shape
Bursae
small, fluid filled pockets of connective tissue
found in hypodermis, b/w tendons/ligaments and bones
they cushion and support, aid in movement of tendons
Types of movement
gliding, angular movement, circumduction, rotation
Gliding
two opposing surfaces slide past one another
Angular movement
change in angle b/w the shaft and the articular surface
Circumduction
a type of angular motion
rotation of the shaft while changing the angle
Rotation
spinning of the shaft w/out changing the angle
Types of angular movement
Abduction, adduction, flexion, extension, hyperextension
Abduction
towards midline
Adduction
away from midline
Flexion
decrease angle relative to anitomical
Extension
increase angle
Hyperextension
beyond anitomical
Types of rotation
pronation and supination
Pronation
hand down
Supination
hand up
Special movements
Eversion/ inversion dorsiflexion/ plantar flexion lateral flexion protraction/ retraction oppostion depression/elevation
Eversion
point away from midline
Inversionn
point in toward midline
Dorsiflexion
superior, decrease angle, point up
Plantar flexion
inferior, decrease angle down
Lateral flexion
decreasing angle to side
Protraction
bringing anterior
Retraction
bringing posterior
Opposition
touching two digits together
Depression
brought inferior
Elevation
brought superior
Synovial joints
trade off b/w flexibility and stability
due to: shape of articulating surfaces, tightness of ligaments, presence of accessory ligaments
Types: plane, hinge, pivot, condylar, saddle, and ball and socket
Plane joints
bone surfaces are flat or slightly curved
side to side movement only
rotation prevented by ligaments
intercarpal or intertarsal joints, sternoclavicular joint, vertebracostal joints
Hinge joint
convex surface of one bones fits into concave surface of 2nd bone
uniaxial like a door hinge
knee, elbow, ankle, interphalangeal joints
movements produced: flexion, extension, hyperextension
Pivot joint
rounded surface of bone articulates with ring formed by 2nd bone and ligament
uniaxial since it allows only rotation around longitudinal axis
proximal radioulnar joint: supination and pronation
atlanto-axial joint: turning head side to side “no”
Condylar joint
oval shaped projection fits into oval depression
biaxial
flexion/ extension or abduction/ adduction ispossible
wrist and metacarphalangeal joints for digits 2 to 5
Saddle joint
one bone saddle-shaped, other bone fits as a person would sitting in that saddle
biaxial
circumduction allows tip of thumb travel in circle
opposition allows tip of thumb to touch tip of other fingers
trapezium of carpus and metacarpal of the thumb
Ball and socket joint
ball fitting into caplike depression
multiaxial
flexion extension, abduction adduction, rotation
shoulder joint, hip joint
TMJ
hinge joint
b/w condylar process of madible and mandibular fossa
condyles slide back and forth along joint socket
2 synovial joints
modified hinge jaw
Intervertebral articulations- Zygapophysial
zygapophysial
vertebrae articulate and superior and inferior articular processes
plane joint
restricts lateral movement
Discs
allows flexion, extension, lateral flexion and rotation
anulus fibrosus, fibrocartilage
nucleus pulposus
Herniated disc
slipped disc nucleus pulposus breaks through anulus fibrosus
movements of vertebral column compresses nucleus
Shoudler
glenohumeral joint
head of humerus meets glenoid cavity
glenoid cavity covered by glenoid labrum
Elbow
two joints:
humerous and ulna- hinge and flexion/extension
radius and ulna- pivot and pronation/supination
Wrist and hand
radiocarpal joint- flexion/extension, abduction/ adduction intercarpal joints- plane carpometacarpal joints thumb- saddle other digits- plane