Joints and Articulations - · PDF file–Synovial Joints. Functions ... Hinge Joint •Convex surface of one ... •Allows for a variety of movement. •Example: bones

Joints and Articulations

Anatomy & Physiology

Joints and Articulations:

Junctions between bones.

• Types/Categories

– Fibrous Joints

– Cartilaginous Joints

– Synovial Joints

Functions

• Bind parts of the skeleton.• Allow for bone growth.• Permit changes of skeleton

during childbirth.• Allow for movement.• Vary considerably in

structure and function.• Classified based on degree

of movement.AND/OR

• The type of tissue that bonds the bones together.

Quick Fact

There are 230 joints/articulations

in the body!

Fibrous Joints• Connect bones that are

very close to one another.

• A thin layer of connective tissue joins the bones together.

• No measurable movement occurs at this joint.

• Example: sutures between bones of the skull.

Cartilaginous Joints

• Use of hyaline cartilage to connect bone.

• Allows limited movement.

• Absorbs shock.

• Example: intervertebral discs.

Synovial Joints

• Most joints fit into this category.

• Permits free movement.

• Structurally complex.

• Ends of bones are covered with smooth cartilage = allows for gliding and prevents bones from rubbing together.

• Surrounds a joint capsule filled with fluid to lubricate joints.

• Some have flatened shock absorbing pads called meniscus.

• Some have a bursae that allows for tendons to glide smoothly over the joint.

Types of Synovial Joints

• Ball-and-socket

• Condyloid

• Gliding

• Hinge

• Pivot

• saddle

Ball-and-Socket

• Bone with a rounded (ball-shaped) end that articulates with a cup-shaped cavity.

• WIDE range of motion

• Example: Shoulder and Hip

Condyloid Joint

• Oval shaped bone extension fits into a shallow cavity.

• Can move in different directions but NOT rotate.

• Example: between metacarpals (bone of palm) and phalanges (fingers).

Gliding Joint

• Articulations on an almost flat plane.

• Allow for sliding or twisting motion.

• Examples:

– Between carpal (wrist) and tarsal (ankle) bones.

– Sternum and ribs.

– Sacrum and pelvis

Hinge Joint

• Convex surface of one bone fits into concave surface of another bone.

• Resembles the hinge of a door.

• Examples:

– Joints of the phalanges

– Elbow

Pivot Joint

• Cylindrical surface of one bone rotates in the ring formed between another bone and a ligament.

• Permits rotation.

• Example:

– Radius and ulna

– Cervical vertebrae (neck) and skull.

Saddle Joint

• BOTH bone surfaces have both a concave and convex surface.

• Bone fits like a puzzle piece.

• Allows for a variety of movement.

• Example: bones between metacarpal (hand) and thumb.

Special Considerations

• Arthritis:inflammation of one or more joints that results in pain, swelling, stiffness, and limited movement

Special Considerations

• Arthrocentesis: removal of fluid from the joint capsule to alleviate pressure and swelling.

Special Considerations

• Arthrodesis: surgical union of a joint; fusing two or more bones together

Surgical Union of Lumbar

(lower back) Vertebrae.

Meniscus Tears• Meniscus are ligaments

found in the knee joint.

• They assist in stabilizing the knee and limiting motion that could cause injury.

• Most injuries require surgical correction.

• Becoming more common in young athletes.