joints + shoulder bone & joints Flashcards
what is a joint
- also known as articulation
-the site where 2 or more bones connect
why are joints important
- link the skeletal system
-joints facilitate movement of the skeleton
stability vs. mobility
most stable- less mobility
less stable- more mobility
classification of joints
- function: based on range of motion permitted
- structure: what tissues join the articulating bones
function + structure of joints
synarthrosis: NO movement- fibrous, cartilaginous, bony fusion
amphiarthrosis: little movement- fibrous, cartilaginous
diarthrosis: wide range of motion- synovial
synarthroses joints
- immobile or nearly immobile
-strong union between articulating bones
-fibrous, cartilaginous, or bony fusion
example: pelvis
amphiarthroses joints
-slightly moveable
- cartilaginous amphiarthrosis
- bones joined by wedge of cartilage
diarthrosis: synovial joints
-specialized for movement (wide range of motion)
all synovial joints have:
1. joint capsule
2. articular cartilage
3. joint cavity filled synovial fluid
4. synovial membrane
5. accessory structures
anatomy of synovial joint
- joint capsule
- articular cartilage
- joint cavity filled synovial fluid
- synovial membrane
- accessory structures
joint capsule (synovial joint)
-surrounds synovial joint, encloses joint cavity
made of:
1. outer dense connective tissue layer
2. inner synovial membrane
synovial membrane (synovial joint)
lines inner surfaces of the joint (doesn’t cover the articulating bone surfaces)
- produces synovial fluid
synovial fluid (synovial joint)
-fills the joint cavity
-lubricates
-absorbs shock
-distributes nutrients to cells of the articular cartilage
articular cartilage (synovial joint)
- covers surfaces of articulating bones
-smooth surface helps reduce friction during movement
accessory structures of synovial joints
- menisci
- ligaments
- bursae
- fat pads
- provides support and additional stability
(not always present only certain joints)
menisci (meniscus) (synovial joints)
- fibrocartilage pads between bone
-reduce friction, disperse weight, protect & cushion joint surface
ligaments (synovial joints)
- fibrous connective tissue connecting BONE to BONE
- support & strengthen synovial joints
relative to joint capsule can be located: - outside (extracapsular)
-inside (intracapsular)
example of extracapsular ligament
patellar tendon PCL
example of intracapsular ligament
ACL
bursa
- small fluid-filled pockets in connective tissue, occur around tendons and bones
- filled with synovial fluid, lined by a synovial membrane
- reduce friction
- act as shock absorbers
fat pads
- usually found around the periphery of the joint
- protect articular cartilages
-cushion joint as a whole
types of movement at synovial joints
-gliding
-angular
-rotational
-special movements
gliding joint
planar/linear movement
- two opposing (flat) surfaces slide past each other
ex. intertarsal joints of foot
what is angular movement
-movement that changes the angle between articulating bones
adduction
movement toward the midline
abduction
movement away from the midline
circumduction
-extension
-flexion
-adduction
-abduction
medial (internal) rotation
rotation towards the midline
lateral (external) rotation
rotation away from the midline
supination
rotation of the forearm that makes the palm face up
pronation
rotation of the forearm that makes the palm face posteriorly (radius rolls across anterior surface of ulna)
inversion
sole of foot twists inward
eversion
sole of foot twists
dorsiflexion
elevate sole of foot
plantar flexion
point toes down
opposition
thumb moves across palm to touch the tips of the fingers
reposition
thumb and fingers move from opposition to anatomical position
protraction
moving part of body anteriorly in the horizontal (transverse plane)
retraction
part of the body moves posteriorly in the horizontal plane
elevation
structure moves in a superior direction
depression
structure moves in an inferior direction
special movements: vertebral column
lateral flexion- vertebral column bends to the side (side-side)
flexion/extension
rotation (twisting)
hinge joint
-monoaxial (flexion & extension)
-convex surface of a bone fits into a con cave surface of a bone
examples of hinge joints
-ankle
-knee
-interphalangeal
-elbow
pivot joint
-monoaxial permits rotation
- pointed surface of bone articulates with a ring (bone and ligament)
examples of pivot joint
- C1 & C2 (atlanto-axial joint)
- proximal radioulnar joint
ellipsoidal (condylar joint)
biaxial- permits motion across 2 axes
- oval articular face (condyle) sits within a depression on the opposing surface
-flexion, extension, abduction, adduction
examples of ellipsoidal (condylar joint)
metacarpophalangeal joints 1-5 of the hand
saddle joint
biaxial- angular movement across 2 axes, opposition
- articular surface of a bone fits into a saddle-shaped bone
examples of saddle joint
first carpometacarpal joint (base of the thumb)
ball-and-socket joint
triaxial- angular and rotational movement across three axes
- round head of bone fits into a cup-shaped depression of a bone
-angular motion, circumduction, rotation
examples of ball-and-socket joint
-shoulder joint
-hip joint
types of synovial joints
-hinge
-pivot
-ellipsoidal (condylar)
-saddle
-ball and socket
component of the pectoral girdle
- clavicle
- scapula
parts of clavicle- superior view
acromial/lateral end (1/3, concave)
- articulates with the acromion of scapula
sternal/medial end (2/3, convex)
- articulates with the sternum
parts of clavicle- inferior
rough inferior surface
- attachment sites for muscles and ligaments
conoid tubercle- a small rounded projection
sternoclavicular joint
the joint where the clavicle and sternum articulate
- clavicular notch
- manubrium of the sternum
borders of the scapula
medial border- come together in middle of back
lateral border
what are the fossae of the scapula
- supraspinous fossa
- infraspinous fossa
- subscapular fossa
parts of the anterior scapula
acromion
- articulates with the lateral end of clavicle
- larger process
coracoid process
- smaller process
- anterior
parts of posterior scapula
spine of scapula
- divides posterior surface into supraspinous fossa and infraspinous fossa
acromion
- at the end of the spine
lateral parts of the scapula
- acromion
- glenoid fossa (glenoid cavity, forms shoulder joint)
- coracoid process
glenohumeral joint
- ball and socket joint
- protected by bursae
Acromioclavicular joint
clavicle (lateral end) + acromion
has the acromioclavicular ligament
coracoacromial joint
Acromion + coracoid process
has the coracoacromial ligament
proximal humerus
- head
- greater tubercle (lateral)
- lesser tubercle (medial)
- intertubercular groove
- surgical neck (where most fracturs occur)
shaft of humerus
deltoid tuberosity
what is a tuberosity
- a rough evaluated surface, usually named for muscle attachments
distal humerus features
anterior
- capitulum
- trochlea
- radial fossa
- coronoid fossa
forms the condyle
posterior
- trochlea
- olecranon
what is a condyle
a rounded knob that articulates with other bones
what are the 3 fossa’s of the distal humerus
-radial fossa (anterior)
- coronoid fossa (anterior)
- olecranon (largest, posterior)
bony prominences of humerus
- lateral epicondyle (small)
- medial epicondyle (large)
bones of forearm
radius
ulna
radius
- “thumb side”
- lateral in anatomical position
- radial artery pulse
ulna
- “pinky side”
- medial in anatomical position
- elbow joint range of motion
parts of the radius- proximal
- head
- neck
- radial tuberosity (attachment side for biceps brachii)
parts of the ulna- proximal
trochlear notch
- articulates with trochlea of humerus
radial notch
- articulates with head of radius
- forms proximal radio-ulnar joint
olecranon
- at limit of extension
- projects into olecranon fossa on posterior humerus
coronoid process
- at limit of extension
- projects into coronoid fossa on anterior humerus
