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Joint ( Articulations )

Any point where two bones meet, whether or not the bones are movable at that interface


The study of joints


the study of musculoskeletal movement


the study of how the body uses levers and forces to allow for movements in the body

bony joints

1 of the 4 types of joints
is a immovable joint formed with the gap between two bones ossifies and the become in fact a single bone.
example right and left mandibular bones and frontal bones

Fibrous Joints

1 of the 4 types of joints
a pont at which adjacent bones are bound by collagen fivers and emerge from one bone cross the space between them and penetrate into the other.
Three types of these
1. Suture
2. Gomphoses
3. Syndesmosis


Synarthrosis Fibrous Joint
are immovable or only slightly movable fiberous joints that closely bind the bones of the skull to eachother
3 types of suture

Serrate suture

Synarthrosis , Fibrous Joint , Suture
"interlocking wavy lines"
appear as wavy lines along which the adjoining bones firmly inter lock with each other by there serrated margins. Jigsaw puzzle
Resemble a dovetail Joint
ex, Coronal suture
sagittal suture
Lamdoid suture

Lap (Squamous) suture

Synarthrosis , Fibrous Joint , Suture
"Over lapping beveled edges"
resemble a miter joint in wood working
ex. squamous suture
between temporal and parietal bones

Plane (but) Suture

Synarthrosis , Fibrous Joint , Suture
"ends but as a Butt Joint"
Strait non overlapping edges
ex. the palantine processes of the maxillae
inter-maxillary suture


Synarthrosis , Fibrous Joint
Gompho = nail or bolt
In Teeth tooth held in place by fiberous peridontal legament
collagen fivers that extend form tooth to jawbone
allow the tooth to move a little under the stress of chewing


2 bones bound togather by longer collagenous fivers than in a suture or gomphosis
Most movable of fiberous joints
ex radius to ulna
tibia to fibia

Cartilaginous Joints

1 of the 4 types of joints
Amphiarthrosis type of movement
two bones are linked by cartilage
TWO types of these joints
1. Synchondrosis
2. Symphysis


Cartilaginous Joint , Amphiarthrosis
Hayline Cartilage binds joints
Ex. Temporary joint found in epiphyseal plate in children
binding epiphysis and diaphysis
First rib attachment to sternum all other rib attachemnts to sternum are considered synovial joints


Cartilaginous Joint , Amphiarthrosis
"Growing Together"
Fibrocartilage bindes these types of joints "much stronger"
Ex. pubic symphysis
right and left pubic bones joined by INTERPUBIC DISKS
Bodies of vertibrea
intervertebral disks "only a slight amount of space between adjacent vertebrea
collectivley all 23 disks give spine considerable flexibilty

Synovial Joints

1 of the 4 types of joints
Diarthrosis or diarthrodial joint
"Most Complex, most familar type of joint"
bones are separated by a space called a JOINT CAVITY
mobility make them important to quality of life
most important for physical and occupational theripist nurses and physical trainers
freely movable

Articular Cartilage

In synovial joints
(hayaline cartilage that covers the surface of bones)

Joint (articular) cavity

In synovial joints
- seperates articualr surface


In synovial joints
slipperly lubercant made of albumin and hyaluronic acid Simmilar to egg whites, this fluid nourishes articular cartilage and removes waste, makes movement almost friction free

JOINT (articular) CAPSULE

In synovial joints
- connective tissue that encloses the cavity and retains synovial fluid


In synovial joints
- continous with pariosteum of adjoing bones


In synovial joints
composed of mainly fibroblast like cells that secrete synovial fluid
and macrophages that remove debris

Fibrocartilages in joints

In SOME synovial joints
grows inward from the joint capsule
ex articular disks
Meniscus in the knee
absorb shock
guide bones across each other
improve fit between bones
stabilizes the joints reducing the chance for dislocation

Accessory Structures

"accessory stuctures" assoicated with synovial joints
Tendon sheaths


Muscle to bone attachment
strip or sheet of tough dense regular collagenous connective tissue


bone to bone attachement


a fibrous sac filled with synovial fluid between adjacent muscles where tendon passes over bone or between bone and skin
Cushion muscles, modifys direciton of tendon pull

tendon sheaths

elongated cylindrical bursea wraped around a tendon
ex in hands and feet

Exercise and articular Cartilage

Exercise _Warmes synovial fluid

Fluid becomes less viscous & more easily absorbed by articular cartilage

Cartilage swells & provides a more effective cushion against compression

Warm-up period before vigorous exercise helps protect cartilage from undue wear and tear!

Repetitive compression of nonvascular cartilage during exercise squeezes fluid and metabolic waste out of the cartilage

When weight removed, cartilage absorbs synovial fluid like a sponge taking in oxygen and nutrients to the chondrocytes

Without exercise, cartilage deteriorates more rapidly from inadequate nutrition and waste removal
Excessive stress on joints however can lead to osteoarthritis
Swimming is a low-impact exercise that does not place undue stress on joints

Axes of Rotation

a moving one has a relatively stationary axis of rataion that passes through the bone in a direction PERPENDICULAR to the plane of movement
3 types
1. Monoaxial
2. Biaxial
3. Multiaxional

Monoaxial joint

joint has one degree of freedom or axis of rotation
ex. Interphalangeal joint, elbow joint
* only used in synovial joints


joint has two degrees of freedom or axes of rotation
ex. Metacarpophalangeal joint
* only used in synovial joints


joint has three degrees of freedom or axes of rotation
only found in two place hip and shoulder joint
ex. Glenohumeral (humeroscapular) joint
hip joint
*ball and socket joints are the only ones that have multiaxional
* only used in synovial joints

1. Ball and socket joints

synovial joint
smooth hemispehrical head fits with in a cuplike socket
only two types
1. shoulder joint - glenoid cavity of scapula
2. hip joint - head of femur into acetabulum of hip bone
*only ones that have multiaxional

Degrees of freedom

number of anatomical planes that a joint can move

Classes of Synovial Joints

6 classes
1. Ball and socket Joints
2. Condylar (ellipsoid) joints
3. Saddle joints
4. Plane (gliding) Joints
5. Hinge Joints
6. Pivot joints

2. Condyloid (ellipsoid) joints

Oval convex surface on one bone fits into a complementary shaped depression on the other

radiocarpal joint of the wrist
Metacapophalangeal joints at the bases of the fingers

3. Saddle joints

Biaxial joint
Both bones have an articular surface that is shaped like a saddle, concave in one direction and convex in the other
eg. trapeziometacarpal joint - base of thumb
sternoclavicular joint - clavicle articulates with sternum
**more movable than a condyloid or hinge joint forming the primate APPOSABLE THUMB

4. Plane (gliding) Joints

Usually biaxial joint
Flat articular surfaces in which bones slide over each other with relatively limited movement
ex. carpal bones of wrist (intercarpal)
tarsal bones of ankle (intertarsal )
articular processes of vertebrae
Any one joint moves only slightly, but the combined action of the many joints in wrist, ankle, and vertebral column allows for considerable movement

5. Hinge Joints

One bone with convex surface fits into a concave depression on other bone
elbow joint - ulna and humerus (humeroulnar)
Knee joint - femur and tibia (tibiofemoral)
finger and toe joints (interphalangeal)

6. Pivot joints

One bone has a projection that is held in place by a ring-like ligament on another bone
Bone spins on its longitudinal axis
atlantoxial joint (dens of axis and atlas)
proximal _radioulnar_ joint allows the radius to rotate during pronation and supination

ROM Range of Motion

The degrees through which a joint can move
an aspect of joint performance
physical assessment of a patient's joint flexibility
measured by a __gonimeter
Range of motion determined 3 ways
1. structure of the articular surfaces
elbow - olecranon of ulna fits into olecranon fossa of humerus
2. strength and tautness of __ligaments__ and joint capsules
stretching of ligaments increases range of motion
"double-jointed" people have long or slack ligaments
3. action of the __muscle__ and __tendons___
nervous system monitors joint position and muscle tone
muscle tone - state of tension maintained in resting muscles

Zero Position

the position of a joint when a person is in the standard anatomical position

-joint movements are described as deviating from the zero position or returning to it


movement that decreases the joint angle


movement that straightens a joint and generally returns a body part to zero position


further extension of a joint beyond the zero position
ex. the wrist in the back position


movement of a body part in the frontal plane away form th mid line of the body
ex. arms move out from side of body


raises the arm over the back or front of head


movement in the frontal plane back towards the mid line
ex. moving arms from out to sides of body back to zero postion
*adding back to the body


rasing the shoulders up
a movment that raisis a body part in the vertically in the frontal plane


Lowering the body in the vertical position
Lowereing the shoulders


anterior movements of a body part in the tranverse (horzontal) plane
*with arm out front moving shoulder forward


Posterior movements of a body part in the tranverse (horzontal) plane
*with arm out front moving shoulder backwards


One end of an appendage remains __stationary_ while the other end makes a __circulat___ motion
Finger, hand, thigh, foot, trunk, head
Sequence of flexion, abduction, extension and adduction movements
baseball player winding up for a pitch


- movement in which a bone spins on its longitudinal axis
rotation of trunk, thigh, head or arm
two types

1. _Medial __ (internal) rotation turns the bone inwards

2. _Lateral__(external) rotation turns the bone outwards


- forearm movement that turns the palm to face anteriorly or upward
forearm supinated in anatomical position
radius is parallel to the ulna
*Holding a bowl of soup


- forearm movement that turns the palm to face posteriorly or downward
radius spins on the capitulum of the humerus
disc spins in the radial notch of ulna
radius crosses stationary ulna like an X

Movements of Head and Trunk

3 types

1. Flexion, of vertebral column bending forwards
2. hyperextension, of vertebral column bend bacwards
3. lateral flexion of vertebral column bend to side

Rotation of Trunk and Head

Right and left rotation of trunk
Right and left rotation of head

Special Movements of Mandible

Protraction - retraction - protract when you prepare to take a bite
Elevation - depression - depress the mandible to take a bite
Lateral _Excursion__ - right or left movement from the zero position
Medial excursion - movement back to the median, zero position
side-to-side grinding during _Chewing___

Special Movement of Hand and Digits

Rember all relative to anatomical position

ulnar flexion - tilts the hand toward the little finger
radial flexion - tilts the hand toward the thumb
flexion of fingers - curling them
extension of fingers - straightening them
abduction of the fingers - spread them apart
adduction of the fingers - bring them together again
flexion of thumb - tip of thumb directed toward palm
extension of thumb - straightening the thumb
radial abduction - move thumb away from index finger 90°
palmar abduction - moves thumb away from hand and points it anteriorly
adduction of thumb - moves it to the zero position
_opposition__ - move the thumb to touch the tips of any of the fingers
__reposition___ - return the thumb to the zero position

Common Joint Injuries

1. Sprains__

2. Cartilage _____ Injuries

3. Dislocations (Luxation)


Ligaments are stretched or torn
Heal slowly - poorly vascularized
Completely torn - surgery or replacement

Cartilage Injuries

Remain torn due to avascularization
Arthroscopic surgery to remove damaged tissue
Joint is less stable after removal

Dislocations (Luxation)

Bones are forced out of alignment
Must be reduced
Bones returned to normal position

Knee Injuries

Highly vulnerable to rotational and horizontal stress

Most common injuries are to the meniscus and anterior cruciate ligament __ACL__

heal slowly due to scanty blood flow

___Arthroscopoy___ - procedure in which the interior of the joint is viewed with a pencil-thin arthroscope inserted through a small incision
less tissue damage than conventional surgery
recovery more quickly
graft from patellar ligament or hamstring tendon is often used

Inflammatory & Degenerative Conditions

1. _Bursitis__
2. Tendonitis-
3. Arthritis -
Rheumatologists - physicians who treat arthritis and other joint disorders

Three types of Arthritis
1. Osteoarthritis Most common
2. Rheumatoid Arthritis (RA)
3. Gouty Arthritis (Gout)


- inflammation of a bursa
Usually caused by a blow or friction


inflammation of tendon sheaths

Arthritis 3 types

a broad term for pain & inflammation
most common crippling disease in the United States
Three types of Arthritis
1. Osteoarthritis Most common
2. Rheumatoid Arthritis (RA)
3. Gouty Arthritis (Gout)

1. Osteoarthritis Most common

- most common form of arthritis
'wear-and-tear arthritis'
results from years of joint wear
articular cartilage softens and degenerates
accompanied by crackling sounds called _CREPITUS
bone spurs develop on exposed bone tissue causing pain
rarely occurs before age 40
affects 85% of people over 70 years old
Obesity_ is a risk factor
joints of fingers, intervertebral, hips and knees are most likely areas of OA

2. Rheumatoid Arthritis (RA)

arthritis (RA) - _auto immune__ attack against the joint tissues
misguided antibodies (rheumatoid factor) attack synovial membrane
enzymes in synovial fluid degrade the articular cartilage
joint begins to ossify
__ankylasis__ - solidly fused, immobilized joint
remissions occur
steroids and aspirin control inflammation

3. Gouty Arthritis (Gout)

Hereditary disease
More common in men
Metabolic disorder - excess uric acid build-up
___Uric Acid____- normal waste product excreted in urine
Excessive production or slow excretion
Urate crystals form in soft tissues and joints - pain
Great toe most affected

Artificial Joints (prosthesis)

__Arthroplasty___ - the replacement of diseased joint with artificial device called _prosthesis_

Temporomandibular Joint (TMJ)

articulation of the condyle of the mandible with the mandibular fossa of the temporal bone
combines elements of condylar, hinge, and plane joints
deep yawn or strenuous depression can dislocate the TMJ
condyles pop out of fossa and slip forward
relocated by pressing down on molar teeth while pushing the jaw backward

Which of the following is not a characteristic of a synovial joint?
A. synovial fluid
B. fibrous capsule
C. collagen fibers crossing the articulation (joint)
D. synovial membrane
E. all of the above are characteristic

C. collagen fibers crossing the articulation (joint)

_____ joints are found between carpal bones.
A. ball and socket
B. hinge
C. saddle
D. pivot
E. gliding

collagen fibers crossing the articulation (joint)
E. gliding

This type of fibrous joint connects the parietal bones to the occipital bone
A. pivot
B. syndesmosis
C. gomphosis
D. suture
E. symphysis

D. suture

A joint that cannot move at all, such as a skull suture, is classified as a
A. amphiarthrosis
B. diarthrosis
C. synarthrosis
D. synovial
E. bursae

C. synarthrosis

When you hold your arm straight out, the type of movement is called
A. flexion
B. extension
C. excursion
D. abduction
E. pronation

B. extension

then watching tv and you move your arm to the back of the coutch what it this action


The angle at which a joint can move is called its ____________

range of motion

at the ancle both the tibia and fibula articulate with what tarsal bone?


Shoulder Joint

Glenohumeral (humeroscapular)
the hemishperical head of the humerous articulates with the glenoid cavity of the scapula
*most freelymoving joint in the body

glenoid labrum

fibrocartialage ring that deepens the geloid cavity

Genohumeral humerscapular How supported

biceps barachii tendon
anteriorly rotator cuff tendons

four tendons fuse " SITS" Muscles
Teres Minor

Shoulder dislocaton


doward displacement of humerus
often happens when arm is abducted then recieves a blow from above.
rotator cuff protects in all dirctions except INFERIORLY
Joint Protected by
coracoid process

The Elbow Joint

two articulations
Humeroulnar joint - hinge joint
Humerodial joint - pivot Joint
both joint inclsed in a single joint capsule called OLECRANON BURSA on posterior side of elbow

Hip Joint

Head of femur inserts into acetabelum of hip bone

acetabular labrum

on hip joint
horseshoe shaped ring of fibrocartialge the deepens the ring

Fovea capitis

hip joint
Pit on the head of femur
round ligament or ligamentum teres
also has artery that supplies blood to head of femur

The Knee Joint

Tibiofemoral joint
Largest and most complex of all Diarthrosis joints of the body
mainly a hinge joint
capable of slight rotation and lateral gliding when knee is flexed
Has a joint capsule enclosing only the lateral and posterior aspects of the knee not the anterior
contains two c shaped cartilages
1. lateral meniscus
2. medial meniscus little pads of fivro cartilage
both joined by traverse ligaments

The Knee joint

ACL anterior curciate Ligament
PCL posterior cruciate ligament


the abilty to walk on 2 feet
abiility to lock the knees is important factor in walking
when locked the ligaments are twisted and taut

the Ankle Joint

Talocrural joint
includes two articulations
1. medial joint between the tibia and the talus
2. lateral joint between the fibula and talus
both enclosed by one capsule
MALLELI of tivia and fibula overhand the talus on either side and prevent side to side motion.

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