Forbush High

School

Anatomy and

Physiology

presents:

Joints and

Movements

.

Joints

• Joints and their classification

– bony joints

– fibrous joints

– cartilaginous joints

• Synovial joints

• Anatomy of selected diarthroses

– humeroscapular joint

– elbow joint

– coxal joint

– knee joint

Joints and Their Classification

• Arthrology = study of the joints

• Kinesiology = study of musculoskeletal

movement

• Classified by freedom of movement

– diarthrosis (freely movable)

– amphiarthrosis (slightly movable)

– synarthrosis (little or no movement)

• Classified how adjacent bones are joined

– fibrous, cartilaginous, bony or synovial

Bony Joint (Synostosis)

• Gap between two bones ossifies

– frontal and mandibular bones in infants

– cranial sutures in elderly

– attachment of first rib and sternum

• Can occur in either fibrous or

cartilaginous joint

Fibrous Joints (Synarthrosis)

• Collagen fibers span the space

between bones

– sutures, gomphoses and syndesmoses

• Immovable fibrous joints – bind skull bones together

• Serrate - interlocking lines – coronal, sagittal and lambdoid

sutures

• Lap - overlapping beveled edges – temporal and parietal bones

• Plane - straight, nonoverlapping edges – palatine processes of the

maxillae

Fibrous Joint --

Sutures

Types of Sutures

Fibrous Joint -- Gomphoses

• Attachment of a tooth to

its socket

• Held in place by fibrous

periodontal ligament

– collagen fibers attach

tooth to jawbone

• Some movement while

chewing

• Two bones bound

by ligament only

– Interosseus membrane

• Most movable of fibrous joints

• Interosseus membranes unite

radius to ulna and tibia to fibula

Fibrous Joint -- Syndesmosis

Cartilaginous Joint -- Synchondrosis

• Bones are joined

by hyaline

cartilage

– rib attachment to

sternum

– epiphyseal plate in

children binds

epiphysis and

diaphysis

Cartilaginous Joint -- Symphysis

• 2 bones joined by fibrocartilage

– pubic symphysis and intervertebral discs

• Only slight amount of movement is possible

Synovial Joint

• Joint in which two

bones are

separated by a

space called a joint

cavity

• Most are freely

movable

General Anatomy • Articular capsule encloses joint cavity

– continuous with periosteum

– lined by synovial membrane

• Synovial fluid = slippery fluid; feeds cartilages

• Articular cartilage = hyaline cartilage covering

the joint surfaces

• Articular discs and menisci

– jaw, wrist, sternoclavicular and knee joints

– absorbs shock, guides bone movements and

distributes forces

• Tendon attaches muscle to bone

• Ligament attaches bone to bone

Tendon Sheaths and Bursae

• Bursa = saclike

extension of joint

capsule

– between nearby

structures so slide

more easily past each

other

• Tendon sheaths =

cylinders of

connective tissue

lined with synovial

membrane and

wrapped around a

tendon

Components of a Lever

• A lever is a rigid object that rotates around

a fixed point called a fulcrum

• Rotation occurs when effort overcomes

resistance

– resistance arm and effort arm are described

relative to fulcrum

Mechanical Advantage of a Lever

• Two kinds of levers

– lever that helps increase output of force

• human moving a heavy object with help of

crowbar

– lever move object further and faster

• movement of row boat with paddle

• Types of levers produce either increase

in speed or force

Mechanical Advantage

• Mechanical advantage is calculated from the

length of the effort arm divided by the length of

the resistance arm

• Contraction of the biceps muscle causes the

hand to move fast and further (MA <1.0)

First-Class Lever

• Has fulcrum in the middle between effort and resistance

• Atlantooccipital joint lies between the muscles on the

back of the neck and the weight of the face

– loss of muscle tone occurs when you nod off in class

Second-Class Lever

• Resistance between fulcrum and effort

• Resistance from the muscle tone of the

temporalis muscle lies between the jaw joint and

the pull of the diagastric muscle on the chin as it

opens the mouth quickly

Third-Class Lever

• Effort between the resistance and the fulcrum

– most joints of the body

• The effort applied by the biceps muscle is applied

to the forearm between the elbow joint and the

weight of the hand and the forearm

Range of Motion

• Degrees through which a joint can move

• Determined by

– structure of the articular surfaces

– strength and tautness of ligaments, tendons

and capsule

• stretching of ligaments increases range of motion

• double-jointed people have long or slack

ligaments

– action of the muscles and tendons

• nervous system monitors joint position and

muscle tone

Axes of Rotation

• Shoulder joint has 3 degrees of freedom = multiaxial joint

• Other joints – monoaxial or biaxial

Types of Synovial Joints

Ball-and-Socket Joints

• Smooth hemispherical head fits within

a cuplike depression

– head of humerus into glenoid cavity of

scapula

– head of femur into acetabulum of hip bone

• Multiaxial joint

Condyloid (ellipsoid) Joints

• Oval convex surface on one bone fits

into a similarly shaped depression on

the next

– radiocarpal joint of the wrist

– metacarpophalangeal joints at the bases

of the fingers

• Biaxial joints

Saddle Joints

• Each articular surface is shaped like a

saddle, concave in one direction and

convex in the other

– trapeziometacarpal joint at the base of the

thumb

• Biaxial joint

– more movable than a condyloid or hinge

joint forming the primate opposable thumb

Gliding Joints

• Flat articular surfaces in which bones

slide over each other

• Limited monoaxial joint

• Considered amphiarthroses

Hinge Joints

• One bone with convex surface that fits

into a concave depression on other

bone

– ulna and humerus at elbow joint

– femur and tibia at knee joint

– finger and toe joints

• Monoaxial joint

Pivot Joints

• One bone has a projection that fits into a

ringlike ligament of another

• First bone rotates on its longitudinal axis

relative to the other

– atlantoaxial joint (dens and atlas)

– proximal radioulnar joint allows the radius

during pronation and supination

Movements of joints

Flexion, Extension and Hyperextension

• Flexion

decreases the

angle of a joint

• Extension

straightens and

returns to the

anatomical

position

• Hyperextension

= extension

beyond 180

degrees

Flexion, Extension and Hyperextension

Abduction and Adduction

• Abduction is movement of a part away from the midline – hyperabduction – raise arm over back or front of head

• Adduction is movement towards the midline – hyperadduction – crossing fingers

Elevation and Depression

• Elevation is a movement that raises a bone

vertically

– mandibles are elevated during biting and clavicles

during a shrug

• Depression is lowering the mandible or the

shoulders

Protraction and Retraction

• Protraction =

movement

anteriorly on

horizontal plane

– thrusting the jaw

forward,

shoulders or

pelvis forward

• Retraction is

movement

posteriorly

Circumduction

• Movement in which

one end of an

appendage remains

stationary while the

other end makes a

circular motion

• Sequence of flexion,

abduction, extension

and adduction

movements

– baseball player

winding up for a pitch

Rotation

• Movement on

longitudinal axis

– rotation of trunk,

thigh, head or

arm

• Medial rotation

turns the bone

inwards

• Lateral rotation

turns the bone

outwards

Supination and Pronation

• In the forearm and foot

• Supination

– rotation of forearm so that

the palm faces forward

– inversion and abduction

of foot (raising the medial

edge of the foot)

• Pronation

– rotation of forearm so the

palm faces to the rear

– eversion and abduction of

foot (raising the lateral

edge of the foot)

Movements of Head and

Trunk

• Flexion, hyperextension and lateral flexion of

vertebral column

Rotation of Trunk and Head

• Right rotation of trunk; rotation of head

Movements of Mandible

• Lateral excursion =

sideways movement

• Medial excursion =

movement back to the

midline

– side-to-side grinding during

chewing

• Protraction – retraction of

mandible

Movement of Hand and Digits

• Radial and ulnar flexion

• Abduction of fingers and thumb

• Opposition is movement of the thumb to approach or touch the fingertips

• Reposition is movement back to the anatomical position

Movements of the Foot

• Dorsiflexion is raising of the toes as when you swing the

foot forward to take a step (heel strike)

• Plantarflexion is extension of the foot so that the toes

point downward as in standing on tiptoe

• Inversion is a movement in which the soles are turned

medially

• Eversion is a turning of the soles to face laterally

The Humeroscapular Joint • Most freely movable joint in the body

– shallowness and looseness

– deepened by glenoid labrum

• Supported by ligaments and tendons

– 3 glenohumeral, coracohumeral, transverse humeral and biceps tendon are important joint stabilizer

• Supported by rotator cuff musculature

– tendons fuse to joint capsule and strengthens it

– supraspinatus, infraspinatus, teres minor and subscapularis,

• 4 Bursae associated with shoulder joint

Stabilizers of the Shoulder Joint

Tendons of Rotator Cuff Muscles

Dissection of Shoulder Joint

The Elbow

Joint • Single joint capsule

enclosing the

humeroulnar and

humeroradial joints

• Humeroulnar joint is

supported by collateral

ligaments.

• Radioulnar joint is head

of radius held in place

by the anular ligament

encircling the head

Elbow Joint

The Coaxal (hip) Joint • Head of femur

articulates with acetabulum

• Socket deepened by acetabular labrum

• Blood supply to head of femur found in ligament of the head of the femur Joint capsule strengthened by ligaments

Hip Joint • Joint capsule strengthened by ligaments – pubofemoral

– ischiofemoral

– iliofemoral

Dissection of Hip Joint

The Knee Joint • Most complex diarthrosis

– patellofemoral = gliding joint

– tibiofemoral = gliding with slight rotation and gliding possible in flexed position

• Joint capsule anteriorly consists of patella and extensions of quadriceps femoris tendon

• Capsule strengthened by extracapsular and intracapsular ligaments

Knee Joint – Sagittal Section

Knee Joint – Anterior and Posterior Views

• Anterior and lateral cruciate ligaments limit anterior

and posterior sliding movements

• Medial and lateral collateral ligaments prevent rotation

of extended knee

Knee Joint – Superior View

• Medial and lateral meniscus absorb shock

and shape joint

Dissection of Knee Joint

Joint Prostheses