Arthrology

Sentenced to Life in the Joint

Arthrology – the study of joint structure, function and dysfunction

• Kinesiology – study of musculo-skeletal movement

• Articulations – any point where two bones meet (joint)

• Joints are named for the bones involved

Classification of Joints 1. Bony (Synostosis) – immovable joint

Classification of Joints

2. Fibrous (Synarthrosis) – adjacent bones bound by

collagen fibers

A. Sutures – Serrate, Lap, Plane

B. Gomphoses – Attachment of a tooth to its socket

C. Syndesmoses – 2 bones bound by longer

collagenous fibers

Classification of Joints 3. Cartilaginous Joints (Amphiarthrosis)

– Synchondroses – bones bound by hyaline cartilage

– Symphyses – bones joined by fibrocartilage

4. Synovial Joints (diarthrosis) - freely movable Classification of Joints

Range of Motion • Range of Motion Determination

– Structure of the articular surfaces

– Strength and tautness of ligaments

– Action of muscles and tendons

Classes of Synovial Joints • Determined by their articular surface

shape and the number of degrees of freedom

• Ball and Socket Joint – Smooth hemispherical head that fits into a

cup-like socket

• Condylar (ellipsoid) Joint – Oval convex surface on one bone that fits

into a similar shaped depression on the 2nd bone

• Saddle Joints – Both bones have a saddle-shaped surface

– 1 bone concave, the other convex

Classes of Synovial Joints • Plane (gliding) Joints

– Bone surfaces are flat or very slightly concave or convex – bones slide over one another

• Hinge Joints

– One bone has a convex surface that fits into a concave depression on the other bone

• Pivot Joints

– a bone spins on its longitudinal axis

*NOTE: Some joints are not neatly classified

Terms of Joint Movements NOTE: All terms are based off of anatomical position, this is called zero position for each joint • Flexion – decrease a joint angle • Extension – straightens a joint; returns to zero position • Hyperextension – extension beyond zero position

Terms of Joint Movements • Abduction – moving a body part away from the

body midline in the frontal plane

• Adduction – movement in towards the midline in the frontal plane

• Hyperadduction – crossing arms or legs

• Hyperabduction – raise the arms high enough to cross over the front or back of the head

Terms of Joint Movements

• Elevation – raises a body part vertically in the frontal plane

• Depression – lowers a body part

Terms of Joint Movements

• Protraction –anterior movement of a body part in a horizontal plane

• Retraction – posterior movement

Terms of Joint Movements • Circumduction – one end of an appendage

remains still while the other makes a circular motion

Terms of Joint Movements

• Rotation – a bone spins on its long axis

– Medial (internal) – towards the midline

– Lateral (external) – away from the midline

Terms of Joint Movements

• Supination – the forearm moves to turn the palm to face anteriorly

• Pronation – Causes the palm to face posteriorly or downward

Thumb Movements

• Opposition – moves the thumb to touch the tips of the other fingers

• Reposition – return of the thumb to zero position

Foot Movements • Dorsiflexion – movement

where the toes were elevated

• Plantar Flexion – Movement of the foot so the toes point downward

• Inversion – turning the soles medially

• Eversion – turning the soles laterally

Injuries

• Strain – painful overstretching of a tendon or muscle

• Sprains – torn ligament or tendon with damage to a meniscus or other cartilage

• Tendinitis – a tendon sheath is inflamed

• Bursitis –

inflammation

of a bursa

Injuries – Bone Fractures • Closed – skin is not broken

• Open – skin is broken and bone is visible

• Complete – broken in 2 or more pieces

• Incomplete – partial fracture, bone remains joined

• Nondisplaced – bone is still in anatomical position

• Displaced – broken portions are out of anatomical position

Fracture Healing

1. Blood clot forms

2. Blood capillaries grow into the clot

3. Osteoclasts, osteogenic cells, macrophages, and

fibroblasts convert the blood clot to granulation

tissue

4. Fibroblasts in granulation tissue deposit collagen

and chondroblasts produce fibrocartilage, the soft

callus

5. Osteoblasts produce a bony collar, the hard callus

6. Remodeling takes 3-4 months

Fracture Healing