THE SKELETAL JOINTS

JOINTSJOINTS• Joints are where two or more bones articulate

(move).• Joints are classified according to how much

movement they allow.

1. Suture – these are fixed or immovable joints such as the cranium, sacrum and the coccyx.

2. Cartilaginous – these are slightly movable joints such as the vertebrae.

3. Synovial – these are freely movable joints such as the shoulder and hip.

Fibrous JointsFibrous Joints

• Bones are united by dense connective tissue consisting of collagen fibers which run between bones.

• There is no joint cavity.

• ONLY found in the skull.

Cartilaginous JointsCartilaginous Joints

• Joints where the articular surfaces of the bones forming the joints are attached to each other by cartilage and ligaments.

• Allows only a limited degree of movement.

• Examples:– cartilage between vertebrae, – between the pubic bones

Synovial jointsSynovial jointsThere are 6 types of synovial joint.

1. Ball & socket – hip and shoulder.

2. Hinge – knee, elbow and ankle.

3. Pivot – radius/ulna, atlas/axis (neck).

4. Saddle – thumb.

5. Condyloid – wrist.

6. Gliding – between vertebrae in spine.

Ball & Socket jointsBall & Socket joints

• The hip joint• The head of the femur fits into a

deep fossa called the acetabulum on the pelvic bone.

• This deep cavity gives the hip joint stability.

• The presence of strong ligaments add to the stability making it difficult to dislocate the hip.

• The shoulder joint• The head of the humerus

fits into a shallow cavity on the scapula called the glenoid fossa.

• The shoulder is the most mobile joint in the body but is also fairly unstable because of the shallow cavity.

• Stability is improved by ligaments and muscles.

Ball & Socket joints continued…Ball & Socket joints continued…

Hinge JointsHinge Joints

• The knee joint• In the knee joint the femur

articulates with the tibia.• The patella (knee cap)

helps to give a better angle of pull.

• The fibula is not part of the knee joint and so the tibia is the weight bearing bone.

• The ankle joint• In the ankle, the talus

articulates with the tibia and fibula.

• Ligaments provide stability to the joint.

• The elbow joint• In the elbow the

humerus articulates with the radius and the ulna.

• Movement can only occur in one plane.

Hinge Joints Continued…Hinge Joints Continued…

The Pivot JointThe Pivot Joint• The radius/ulna • In this joint the radius and

ulna articulate within the elbow joint.

• This joint allows the elbow some twisting movement.

• Atlas/axis• In this joint the atlas and

axis bones articulate to allow a rotation movement as in shaking your head.

CondyloidCondyloid• The wrist• Bones are oval in shape

with one concave and the other convex.

• Move from side to side and back and forth, but NO rotation.

• In this joint the radius and ulna bones articulate with 3 of the carpal bones.

Plane Joint (Gliding joint)Plane Joint (Gliding joint)

• Spine, carpals and tarsals

• Bone surfaces are flat and only short, gliding movements are allowed.

Saddle JointSaddle Joint• This type of joint occurs

when the touching surfaces of two bones have both concave and convex regions with the shapes of the two bones complementing one other and allowing a wide range of movement.

• The only saddle joint in the body is the thumb.

Synovial Joint AnatomySynovial Joint Anatomy

• Ligaments – connect bone to bone

• Tendons – connect muscle to bone

• Cartilage – cushion between bones

• Synovial Fluid – lubrication/oil to reduce friction between bones

• Joint Cavity – space full of synovial fluid

Knee JointKnee Joint

Tendon

Articular/HyalineCartilage