Define joints

sites where 2 or more bones meet

Name the functions of joints

• hold skeleton together
• give skeleton mobility

How are joints classified?

• fibrous joint
• cartilaginous joint
• synovial joint

Fibrous joint

joined by fibrous tissues and ligaments, no cavity present; so slightly movable.

sutures (e.g. cranial bones)

syndesmoses (tibia and fubula, radius and ulna)

gomphoses (peg in socket joints of teeth and alveolar sockets)

Cartiloginous joints

united by cartilages; no cavity, movable; e.g. pubic symphysis

synchordoses (ribs and sternum, costal cartilage)

Synovial joint

there is cavity, bones are separated by fluid= synovial fluid freely movable; i.e. shoulder joint, hip joint)

Synarthroses

immovable

Amphiarthroses

slightly moveable

Diarthroses

freely movable

Features of Synovial Joints

1. all are diarthrotic
2. include all limb joints and most joints of the body
3. posse articular cartilage (hyaline)
4. joint or articular cavity (potential space)
5. articular capsule (synovial membrane)
6. synovial fluid (white viscous fluid from plasma and hyaluronic acid)
7. reinforcing ligaments (capsular, extracapsular and intracapsular ligaments)
8. nerves and blood vessels (sensory nerves, nourishes)

Factors that influence Synovial joint

1. articular surfaces (shapes: shallow socket)
2. ligaments: unite bone prevent excessive and undesirable motion)
3. muscle tone: keeps low levels contractile, kept taut at all time, ready to react to stimulation

Types of mucle attachments of Synovial Joints

1. muscle origin (attatchment to the immovable bone)
2. insertion (attachment to the movable bone)
3. movement (muscles move from the insertion point to toward the ine origin during contraction)

Types of Movements of Synovial joints

1. gliding movements
2. angular movements: increases and decreases the angle btw 2 bones: include- flexion, extension, hyperextension, abduction, adduction, and circumduction
3. rotation movements
4. special movements such as supination and pronation; dorsiflexion and plantar flexion; inversion and eversion; protraction and retraction; elevation and depression; and opposition

Supination and pronation

turning backward and turning forward (i.w. radius around the ulna)

Dorsiflexion and plantar flexion of foot

up and down movement of foot at ankle

inversion and eversion

sole moves medially or laterally

protraction and retraction

anterior and posterior movement at transverse plane

elevation and depression

lifting a body part superiorly or moving inferiorly.

I.E- superior- shrugging shoulder (scapulae) and inferior (mandible movement when chewing gum

Opposition (movement)

touch thumb to the finger tips of the other finger

6 types of synovial joints based on shape of articular srufaces

1. Plane (intercarpal joints)- nonaxial joints, flat articular surfaces & short gliding movements
2. Hinge (elbow joints): uniaxial joints, motion along a single plane & flexion and extension only
3. Pivot (round end fits to a ring; proximal radius joint): rounded end of one bone conforms to a "sleeve" or ring of another bone & uniaxial movement only
4. Condyloid (metacarpal joints): biaxial joints, both articular surfaces are oval and permit all angular movements
5. Saddle (carpal-metacarpal joint of thumb): biaxial, allow greater freedom of movement than condyloid joints. Each articular surface has both concave and convex areas
6. Ball and socket (shoulder point): multiaxial joints, the most freely moving synovial joints

Plane (intercarpal joints)

- nonaxial joints, flat articular surfaces & short gliding movements

Hinge (elbow joints)

uniaxial joints, motion along a single plane & flexion and extension only

Pivot

(round end fits to a ring; proximal radius joint): rounded end of one bone conforms to a "sleeve" or ring of another bone & uniaxial movement only

Condyloid

(metacarpal joints): biaxial joints, both articular surfaces are oval and permit all angular movements

Saddle

(carpal-metacarpal joint of thumb): biaxial, allow greater freedom of movement than condyloid joints. Each articular surface has both concave and convex areas

Ball and socket

(shoulder point): multiaxial joints, the most freely moving synovial joints

Joints that surround the knee joing

single joint cavity: femoro-patella, lateral and medial tibiofemoral and minisci of the tibi

Glenohumeral joint

shoulder joint

ball and socket joint- head of humerus an glenoid fossa of the scapula

stability is sacrificed for greater freedom of movement

Elbow joint

radius and ulna articulate w/the humerus, hinge joint formed mainly by trochlear notch of ulna and trochlea of humerus. Flexion and extension only.

Coxal joint

hip joint. ball and socket joint. Head of the femur articulates w/the acetabulum. Good range of motion, but limited by the deep socket.

Acetabular labrum- enhances depth of socket

Temporomendibular joint

mandibular condyle articulates w/the temporal bone.

2 types of movement- hinge- depression and elevation of mandible

and gliding- side to side (i.e.- grinding teeth)

Common joint injuries

• sprain
• cartilage tears
• dislocations
• subluxation