PTA 220 chp 4 Articular System: Types, Structures, and Pathologies in Joints

Anatomical Joint

Connection between two bones.

Osteo

Bone.

Arthro

Joint.

Synarthrosis

Type of joint that provides stability.

Diarthrosis

Type of joint that provides mobility.

Synarthrodial Joint

Fibrous joint with essentially no motion, provides shape and strength.

Suture

Layer of fibrous periosteum between two bones, i.e. sutures of the skull.

Syndesmosis

Ligamentous joint held together by fibrous tissue, ligaments, and interosseous membranes.

Gomphosis

Joint where a tooth is anchored in its dental socket.

Cartilaginous Joint

Also called an amphiarthroidial joint, allows a small amount of motion and provides stability.

Diarthrodial or Synovial Joint

Joint with no direct union between bone ends, filled with synovial fluid.

Gliding Joint

Nonaxial joint with irregular shape, allowing joint surfaces to glide over one another.

Hinge Joint

Uniaxial joint allowing movement in one plane, such as flexion and extension.

Pivot Joint

Uniaxial joint allowing rotation around a bone.

Condyloid Joint

Biaxial joint allowing movement in two directions.

Seller (Saddle) Joint

Biaxial joint with surfaces that are both convex in one plane and concave in the other.

Ball and Socket Joint

Triaxial joint allowing for motion in all three axes.

Joint Motion

The specific movement allowed by a type of joint.

Flexion

Bending movement that decreases the angle between body parts.

Extension

Straightening movement that increases the angle between body parts.

Abduction

Movement away from the midline of the body.

Adduction

Movement toward the midline of the body.

Bone

Usually two bones make up a joint. Direction and amount of movement dictated by the articular surface of the bones at each end.

Ligament

Supports and holds two bones together. Bands of fibrous connective tissue. Flexible but not elastic - allows motion but keeps bones close together. Prevent excessive joint movement.

Capsule

Found in every synovial joint. Surrounds and encases the joint and protects the articular surfaces of the bones. Outer layer - fibrous tissue. Provides support and protection to the joint. Usually reinforced by ligaments.

Capsule (Inner layer)

Lined with a synovial membrane. Secretes synovial fluid. Reduces friction. Helps joint move freely. Provides some shock absorption. Source of nutrition for articular cartilage.

Cartilage

Dense fibrous connective tissue capable of withstanding a great amount of pressure and tension. 3 types of cartilage: Articular (Hyaline), Fibrocartilage, Elastic.

Articular (Hyaline) Cartilage

Covers the ends of opposing bones. Provides a smooth articulating surface in all synovial joints. Has no blood or nerve supply - receives nutrition from synovial fluid. If damaged, unable to repair itself.

Fibrocartilage

Acts as a shock absorber. Important for weight-bearing joints, i.e. meniscus at the knee, disks between the vertebrae and between the sternum and clavicle. Labrum is composed of fibrocartilage. Deepens the glenoid fossa in the shoulder joint.

Elastic Cartilage

Designed to help maintain the shape of a structure, found in the external ear and larynx.

Tendon

Connects muscle to bone. May be encased in tendon sheath to protect the tendon from pressure and friction, i.e. tendons passing over the wrist.

Aponeurosis

Broad, flat, tendonious sheet. Provides a base for muscle to attach when bone is not present, i.e. abdominal muscles at midline attach to linea alba.

Bursa

Small padlike sac that reduces friction between moving parts. Located under tendons and over bony prominences, i.e. olecranon bursa over the olecranon process. Lined with synovial membrane and filled with clear fluid.

End Feel

Quality of the feel when slight pressure is applied at the end of the joint's passive range of motion.

Bony end feel (Hard)

Hard abrupt limit to joint motion where bone contacts bone at the end of the ROM, i.e. terminal elbow extension.

Capsular (Firm) End Feel

Hard with slight give, i.e. wrist flexion/extension.

Soft tissue approximation (Soft)

Soft tissue of body segments prevent further motion, i.e. hip flexion in sitting, elbow flexion.

Boggy End Feel

Wet sponge feel, associated with edema.

Empty End Feel

Lack of mechanical limitation of joint range of motion; pain may limit the movement.

Springy block End Feel

Rebound movement that occurs with internal derangement of a joint.

Muscle guarding

Reflex muscle spasm during movement as a protective response.

Ovoid joint

Two bones forming convex-concave relationship; most synovial joints are ovoid.

Sellar (saddle-shaped) joint

Each joint concave in one direction and convex in another, i.e. carpometacarpal joint of the thumb.

Congruent Joint Position

Maximum contact, tightly compressed, difficult to distract; also known as 'closed-packed' position.

Incongruent Joint Position

All other positions; referred to as 'open-packed' position (resting position).

Types of Arthrokinematic Motion

Roll - Rolling of one joint surface on another. Glide (slide) - Linear movement of a joint surface parallel to the plane of the adjoining joint surface. Spin - Rotation of the movable joint surface on the fixed adjacent surface.

Convex-Concave Rule

When concave surface is moving on a convex surface, they roll and glide in the same direction as distal end of bone. When convex surface moves on concave surface, they roll and glide in the opposite direction distal end of bone.

Dislocation

Complete separation of two articular surfaces of a joint.

Subluxation

Partial dislocation of a joint.

Sprain

Partial or complete tearing of fibers of a ligament.

Strain

Overstretching of muscle fibers.

Tendonitis

Inflammation of a tendon.

Tenosynovitis

Inflammation of the tendon sheath.

Synovitis

Inflammation of the synovial membrane.

Capsulitis

Inflammation of the joint capsule.