Anatomy - Joints

Articulations (joints)

A place where bones meet. There are 3 types of joints:

Synovial

Fibrous

Cartilaginous

Synovial joint

Moving joints. Separated by the synovial cavity. Freely moveable. All joints are in the limbs.

Fibrous joint

Bones held together by fibrous connective tissue. No movement occurs. E.g sutures in the skull

Cartilaginous joint

Bones are connected by cartilage. Slight movement. E.g. Public symphysis, joints between the vertebrae, joint between first rib and sternum

Synovial fluid

The synovial cavity contains synovial fluid which is secreted by the synovial membrane - a connective tissue membrane.

Movements at synovial joints

Flexion

Extension

Circumduction

Adduction

Abduction

Rotation

Supination

Pronation

Inversion

Eversion

Dorsiflexion

Plantar flexion

Flexion

Decrease the angle between bones

Extension

Increase the angle between the bones

Circumduction

Circular movement at a joint

Adduction

Movement.towards the midline

Abduction

Movement away from the midline

Rotation

Turning a bone on its axis

Supination

Turning the hand up or forward

Pronation

Turning the.hand backwards or down

Inversion

Turning the sole of the foot inwards

Eversion

Turning the sole of the foot outwards

Dorsiflexion

Bending the foot towards the leg e.g. painting the toenails

Plantar flexion

Pointing the tow downwards e.g. tip toes

Types of synovial joints

Plane joint

Hinge joint

Pivot joint

Condyloid joint

Saddle joint

Ball and socket joint

Plane joint

Flat articular surfaces. Short slipping or gliding movements. Intercarpal and Intertarsal joints e.g. wrist

Hinge joint

Cylinder fits into a trough. Movement in one plane only (like a hinge). E.g. Elbow and interphalangeal joints

Pivot joint

Rounded end of one bone sits in a sleeve made from ligaments. Rotation around axis. Axis amd atlas, proximal radioulnar joint

Condyloid joint

Overall surface of one bone sits in a shallow bowl. Movement around 2 axis. E.g. Knuckle joints amd wrist (radiocarpal)

Saddle joint

Surface is saddle shaped. Greater freedom of movement than a condyloid joiny. E.g. Carpometacarpal thumb joint

Ball and socket joint

Ball of one bone fits into the cup of another bone. Universal movement. E.g. Hip amd shoulder

The knee joint

Interior cruciate ligament

Fibular collateral ligament

Tibial collateral ligament

Menisci

Quadriceps tendon

Patella

Articulates with the femur and tibia. The fibular is only connected to the knee joint by the ffibular collateral ligament.

Bursae

A small sac filled with synovial fluid. Found in areas subject to stress. Helps ease movement.

Meniscus

An additional disc or wedge shaped piece of cartilage found between bones. Improves fit between the bones making the joint more stable