Human Anatomy and Physiology - Joints

Flashcards for vocabulary review on joints, their classification, structure, and common injuries.

Joints/Articulations

Sites where two or more bones meet.

Functions of joints

Gives skeleton mobility and hold skeleton together.

Structural joint classifications

Three types based on what material binds the joints and whether a cavity is present: Fibrous, Cartilaginous, and Synovial.

Functional joint classifications

Three types based on movement joint allows: Synarthroses, Amphiarthroses, and Diarthroses.

Synarthroses

Immovable joints.

Amphiarthroses

Slightly movable joints.

Diarthroses

Freely movable joints.

Fibrous Joints

Bones joined by dense fibrous connective tissue with no joint cavity; most are immovable.

Sutures

Rigid, interlocking joints of skull that allow for growth during youth and ossify and fuse in middle age.

Syndesmoses

Bones connected by ligaments, bands of fibrous tissue; fiber length varies, so movement varies.

Gomphoses

Peg-in-socket joints; only examples are the teeth in alveolar sockets, held by the periodontal ligament.

Cartilaginous Joints

Bones united by cartilage; like fibrous joints, have no joint cavity, not highly movable.

Synchondroses

Bar or plate of hyaline cartilage unites bones; almost all are synarthrotic (immovable).

Symphyses

Fibrocartilage unites bone; strong, amphiarthrotic (slightly movable) joints.

Synovial Joints

Bones separated by fluid-filled joint cavity; all are diarthrotic (freely movable); include almost all limb joints.

Articular cartilage

Hyaline cartilage covering ends of bones that prevents crushing of bone ends.

Joint (synovial) cavity

Small, fluid-filled potential space that is unique to synovial joints.

Articular (joint) capsule

Two layers thick: external fibrous layer (dense irregular connective tissue) and inner synovial membrane (loose connective tissue that makes synovial fluid).

Synovial fluid

Viscous, slippery filtrate of plasma and hyaluronic acid that lubricates and nourishes articular cartilage; contains phagocytic cells to remove microbes and debris.

Capsular ligaments

Thickened part of fibrous layer.

Extracapsular ligaments

Outside the capsule.

Intracapsular ligaments

Deep to capsule; covered by synovial membrane.

Bursae

Bags of synovial fluid that act as lubricating “ball bearings”; reduce friction where ligaments, muscles, skin, tendons, or bones rub together.

Tendon sheaths

Elongated bursae wrapped completely around tendons subjected to friction.

Origin (muscle attachment)

Attachment to immovable bone.

Insertion (muscle attachment)

Attachment to movable bone.

Nonaxial movement

Slipping movements only.

Uniaxial movement

Movement in one plane.

Biaxial movement

Movement in two planes.

Multiaxial movement

Movement in or around all three planes

Gliding movements

One flat bone surface glides or slips over another similar surface.

Angular movements

Increase or decrease angle between two bones.

Flexion

Decreases the angle of the joint.

Extension

Increases the angle of the joint.

Hyperextension

Movement beyond the anatomical position.

Abduction

Movement along frontal plane, away from the midline.

Adduction

Movement along frontal plane, toward the midline.

Circumduction

Involves flexion, abduction, extension, and adduction of limb; limb describes cone in space.

Rotation

Turning of bone around its own long axis, toward midline or away from it.

Medial rotation

Rotation toward midline.

Lateral rotation

Rotation away from midline.

Supination

Rotation of radius and ulna; palms face anteriorly, radius and ulna are parallel.

Pronation

Rotation of radius and ulna; palms face posteriorly, radius rotates over ulna.

Dorsiflexion

Bending foot toward shin.

Plantar flexion

Pointing toes.

Inversion

Sole of foot faces medially.

Eversion

Sole of foot faces laterally.

Protraction

Movement in lateral plane; mandible juts out.

Retraction

Movement in lateral plane; mandible is pulled toward neck.

Elevation

Lifting body part superiorly.

Depression

Lowering body part.

Opposition

Movement of thumb that allows touching thumb to tips of other fingers on same hand or any grasping movement.

Six Types of Synovial Joints

Plane, Hinge, Pivot, Condylar, Saddle, and Ball-and-socket.

Temporomandibular Joint (TMJ)

Jaw joint is a modified hinge joint; most easily dislocated joint in the body.

Shoulder (Glenohumeral) Joint

Most freely moving joint in body; stability is sacrificed for freedom of movement; four rotator cuff tendons encircle the shoulder joint.

Elbow Joint

Humerus articulates with radius and ulna; hinge joint that allows for flexion and extension only.

Hip (Coxal) Joint

Ball-and-socket joint with large, spherical head of the femur articulates with deep cup-shaped acetabulum; good range of motion, but limited by the deep socket; hip dislocations are rare.

Knee Joint

Largest, most complex joint of body; consists of three joints surrounded by single cavity.

Intracapsular ligaments

Help to prevent anterior-posterior displacement of the knee joint.

Anterior cruciate ligament (ACL)

Attaches to anterior tibia; prevents forward sliding of tibia and stops hyperextension of knee.

Posterior cruciate ligament

Attaches to posterior tibia; prevents backward sliding of tibia and forward sliding of femur.

Common knee injuries (the 3 C’s)

Lateral blows to extended knee can result in tears in tibial collateral ligament, medial meniscus, and anterior cruciate ligament.

Sprains

Reinforcing ligaments are stretched or torn; common sites are ankle, knee, and lumbar region of back.

Dislocations (luxations)

Bones forced out of alignment; accompanied by sprains, inflammation, and difficulty moving joint.

Subluxation

Partial dislocation of a joint

Bursitis

Inflammation of bursa, usually caused by blow or friction.

Tendonitis

Inflammation of tendon sheaths, typically caused by overuse.

Arthritis

More than 100 different types of inflammatory or degenerative diseases that damage joints.

Osteoarthritis (OA)

Most common type of arthritis; irreversible, degenerative (“wear-and-tear”) arthritis.

Rheumatoid arthritis (RA)

Chronic, inflammatory, autoimmune disease of unknown cause; immune system attacks own cells.

Gouty arthritis

Deposition of uric acid crystals in joints and soft tissues, followed by inflammation.

Lyme disease

Caused by bacteria transmitted by tick bites; may lead to joint pain and arthritis.