Structural Classification: Fibrous Joints

Neighboring bones are joined together with a solid mass of dense irregular connective tissue

Structural Classification: Cartilaginous Joints

Bones are connected by cartilage; little to no movement

Structural Classification: Synovial Joints

Joins adjacent bones by a joint capsule that is continuous with
the periosteum of the connecting bones; allows for wide ranges of movement
(diarthroses)

Articular/Synovial capsule, two layers:

1. Outer fibrous layer made of dense regular connective tissue;
strengthens joint
2. Inner synovial membrane; secretes synovial fluid

Articular cartilage:

• Articular surfaces in synovial joints are covered by hyaline cartilage
• Reduces friction and acts as shock absorber

Types of Synovial Joints

1. Plane joints:
2. Hinge joints:
3. Pivot joints:
4. Condylar joints:
5. Saddle joints:
6. Ball-and-socket joints:

1. Plane joints:

uniaxial; side to side movemen

2. Hinge joints:

uniaxial; like hinge of a door

3. Pivot joints:

uniaxial; one bone rotates on its longitudinal
axis

4. Condylar joints:

biaxial; oval, concave surface of one
bone; convex of the othe

5. Saddle joints:

biaxial; joint surfaces resemble saddle
shape

6. Ball-and-socket joints:

multiaxial; spherical head into
cuplike socke

gliding motion

• Simple movement with a limited range
• Flat bones move from side to side and back and forth with one another
• Ex: Intercarpal or Intertarsal joints

angular motion

Increases or decreases the angle between bones
• Flexion
• Extension
• Hyperextension
• Lateral flexion
• Abduction
• Adduction
• Circumduction

rotation motion

In rotation, a bone turns on its
longitudinal axis

• Lateral rotation
• Medial rotation
• Pronation
• Supination

special movement

Movements that only occur at specific
joints
• Depression vs. elevation
• Dorsiflexion vs. plantar flexion
• Inversion vs. eversion
• Protraction vs. retraction
• Opposition

Double-Jointed(ness)

What we think of as being double-jointed is actually
hyper-mobility, the ability to move a joint beyond
the ‘normal’ range of movement

potential cause of Double Jointed(ness)

◦ Abnormal shapes at the ends of bones
◦ Flexibility of ligaments and tendons (hormone/protein-based)
• (differences in sex/race based on collagen)
◦ Muscle tone (or lack of)
◦ Impaired proprioception

osteoarthritis

• Chronic and degenerative, can affect any joint
• Damage to articular (hyaline) cartilage covering bony
surfaces at articulations
• Injury, overuse, genetics
• Most common chronic joint problem

rheumatoid arthritis

• Systemic, autoimmune disease
• Immune system attacks joints leading to inflammation of the
synovium
• Starts in small joints and moves to larger joint

The Temporomandibular Joint (TMJ)

The TMJ is a diarthrotic, synovial (primarily) hinge joint between the condylar process of the mandible and the mandibular fossa of the temporal bone
• The only freely movable joint between skull bones
• Functions:
◦ Depress/Elevate
◦ Protract/Retract
◦ Lateral displacement
◦ Rotation

Atlanto-axial Joint

• Between the first (atlas) and second (axis) cervical vertebrae
• The atlas rotates around the peg-like dens of the axis
• Pivot joint

The Shoulder Joint (Glenohumeral joint)

Ball and socket joint
• Glenoid cavity of the scapula and head of the humerus
• Rotator cuff muscles anchor the humerus to the scapula and provide the
most strength to this joint
• Labrum – ring-shaped hyaline cartilage
that deepens the socket
Movements
• More freedom than ANY other joint
• Flexion/Extension/Hyperextension
• Abduction/adduction
• Medial/Lateral rotation
• Circumduction

What is a Shoulder Dislocation?

Dislocation of the Glenohumeral Joint
• Anterior shoulder dislocation accounts for
approximately 95% of dislocations of the shoulder
• Posterior dislocations are often missed as the pt will keep the
arm internally rotated and ADDucted
• 95% of dislocations are from trauma
• Up to 40% of persons will also have injury to the
axillary nerve

Shoulder Separation

• Dislocation of the Acromioclavicular (AC) Joint (synovial)
• If the strong coracoclavicular ligament is also torn, the upper limb droops
because it is suspended from the clavicle by this ligament.

elbow Radial collateral ligamen

from lateral epicondyle of humerus – blends with

elbow Annular ligament of the radius

encircles and holds the head of the radius in the radial notch

elbow Ulnar collateral ligament:

extends from medial epicondyle to the coronoid process and olecranon of ulna and consists of three bands

the hip

• Intrinsic to the fibrous capsule of the
hip joint
• Iliofemoral (Y ligament of Bigalow)
• Pubofemoral
• Ischiofemoral

The Knee Joint

• Modified hinge joint
• Largest and most complex joint in the body
• Associated ligaments/structures
• Meniscus: fibrocartilage disc (2) between tibia and
femur
• Medial (tibial) and lateral (fibular) collateral
ligaments
• Patellar ligament (not shown here)
• Anterior cruciate ligament (ACL)
• Posterior cruciate ligament (PCL)

Anterior cruciate ligament (ACL)

• Limits anterior translocation
• Anterior, intercondylar tibial plateau → posterior part of lateral
femoral condyle

Posterior cruciate ligament (PCL)

• Limits posterior translocation
• Posterior, intercondylar tibial plateau→ anterior part of medial
femoral condyl

Meniscus

fibrocartilage disc (2) between tibia and
femur
• Medial: C shaped
• Attached to the medial (tibial) ligament
• Lateral: O shape

Anterior Drawer Test

• Pull tibia anteriorly with a flexed knee
• Tests the integrity of AC

posterior Drawer Test

• Push tibia posteriorly with a flexed knee
• Test the integrity of the PC