Human Anatomy – Chapter 9: Joints

Vocabulary flashcards summarizing major structures, joint types, movements, specific joints, and pathological terms from Chapter 9 (Joints) lecture notes.

Arthro-

Greek root meaning "joint."

Synarthrosis

A functional classification of joints that are immovable; common in the axial skeleton.

Amphiarthrosis

A functional classification of joints that are slightly movable; common in the axial skeleton.

Diarthrosis

A functional classification of joints that are freely movable; common in the appendicular skeleton (all synovial joints).

Fibrous Joint

Structural joint in which bones are united by fibrous connective tissue and lack a joint cavity; generally immovable or slightly movable.

Cartilaginous Joint

Structural joint in which bones are united by cartilage and lack a joint cavity.

Synovial Joint

Structural joint in which bones are separated by a fluid-filled cavity; all are diarthroses (freely movable).

Suture

Type of fibrous joint with short fibers; occurs only between skull bones.

Syndesmosis

Fibrous joint where bones are connected exclusively by ligaments; movement depends on fiber length (e.g., tibiofibular joint, interosseous membrane of forearm).

Gomphosis

Peg-in-socket fibrous joint; example is a tooth anchored in its socket by the periodontal ligament.

Synchondrosis

Cartilaginous joint in which bones are united by hyaline cartilage (e.g., epiphyseal plate, first rib–manubrium joint).

Symphysis

Cartilaginous joint in which bones are united by fibrocartilage; slightly movable (e.g., pubic symphysis, intervertebral discs).

Articular Cartilage

Hyaline cartilage covering the ends of bones in synovial joints; absorbs compression.

Joint (Articular) Cavity

Space in a synovial joint that contains a small amount of synovial fluid.

Articular Capsule

Two-layered capsule enclosing a synovial joint; outer fibrous layer strengthens, inner synovial membrane produces synovial fluid.

Synovial Membrane

Loose connective tissue lining the inner capsule of a synovial joint and secreting synovial fluid.

Synovial Fluid

Viscous, blood-filtrate lubricant containing glycoproteins; reduces friction and supports "weeping lubrication."

Weeping Lubrication

Process by which compression squeezes synovial fluid in and out of articular cartilage, nourishing and lubricating it.

Reinforcing Ligament

Ligament that strengthens a synovial joint; may be extracapsular or intracapsular.

Articular Disc (Meniscus)

Fibrocartilage pad within some synovial joints (e.g., knee, TMJ) that distributes load and improves fit.

Bursa

Flattened, synovial-fluid-filled sac that reduces friction between moving structures outside the joint capsule.

Tendon Sheath

Elongated bursa that wraps around a tendon, reducing friction.

Gliding Movement

Sliding motion between flat bone surfaces, as in carpals, tarsals, or vertebral articular processes.

Flexion

Angular movement that decreases the angle between two bones, usually in the sagittal plane.

Extension

Angular movement that increases the angle between two bones, returning to anatomical position.

Abduction

Movement of a limb away from the body’s midline in the frontal plane.

Adduction

Movement of a limb toward the body’s midline in the frontal plane.

Circumduction

Cone-shaped movement combining flexion, extension, abduction, and adduction.

Medial Rotation

Turning a bone toward the median plane; inward rotation.

Lateral Rotation

Turning a bone away from the median plane; outward rotation.

Elevation

Lifting a body part superiorly (e.g., shrugging shoulders).

Depression

Moving an elevated body part inferiorly.

Protraction

Anterior movement of a body part (e.g., jutting mandible forward).

Retraction

Posterior movement of a body part back to anatomical position.

Pronation

Medial rotation of the forearm so the palm faces posteriorly; radius crosses ulna.

Supination

Lateral rotation of the forearm so the palm faces anteriorly; radius and ulna are parallel.

Opposition

Movement of the thumb across the palm to touch fingertips.

Inversion

Turning the sole of the foot medially.

Eversion

Turning the sole of the foot laterally.

Dorsiflexion

Lifting the foot so its superior surface approaches the shin.

Plantar Flexion

Depressing the foot, elevating the heel (pointing the toes).

Plane Joint

Synovial joint with flat articular surfaces allowing short nonaxial gliding (e.g., intercarpal joints).

Hinge Joint

Synovial joint where a cylindrical bone end fits into a trough; uniaxial flexion-extension (e.g., elbow, ankle).

Pivot Joint

Synovial joint where a rounded bone end rotates within a ring; uniaxial rotation (e.g., atlantoaxial joint).

Condylar Joint

Synovial joint with oval surfaces permitting biaxial movement—flexion/extension and abduction/adduction (e.g., wrist, knuckle).

Saddle Joint

Synovial joint with concave-and-convex surfaces on each bone; biaxial (e.g., first carpometacarpal allowing opposition).

Ball-and-Socket Joint

Synovial joint in which a spherical head fits into a round socket; multiaxial movement (e.g., shoulder, hip).

Glenoid Labrum

Fibrocartilaginous rim that slightly deepens the glenoid cavity of the scapula.

Rotator Cuff

Group of four shoulder muscles/tendons (Subscapularis, Supraspinatus, Infraspinatus, Teres minor) stabilizing the glenohumeral joint.

Coracohumeral Ligament

Strong superior ligament supporting the weight of the upper limb at the shoulder joint.

Humeroulnar Joint

Elbow hinge joint between the trochlea of humerus and trochlear notch of ulna; allows flexion and extension.

Radial Collateral Ligament

Lateral ligament of the elbow preventing side-to-side movement.

Ulnar Collateral Ligament

Medial ligament of the elbow preventing side-to-side movement.

Radiocarpal Joint

Condylar joint between the radius and proximal carpals (scaphoid and lunate); enables wrist motions.

Intercarpal Joint

Plane joints between rows of carpal bones allowing gliding.

Acetabular Labrum

Fibrocartilaginous rim that deepens the acetabulum, enhancing hip joint stability.

Meniscus (Knee)

C-shaped fibrocartilage pad in the knee that distributes load and stabilizes the joint.

Anterior Cruciate Ligament (ACL)

Intracapsular knee ligament preventing forward sliding of the tibia.

Posterior Cruciate Ligament (PCL)

Intracapsular knee ligament preventing forward sliding of the femur.

Unhappy Triad

Combined injury of the tibial collateral ligament, medial meniscus, and ACL—often from a lateral blow to the knee.

Deltoid Ligament (Ankle)

Strong medial ligament stabilizing the ankle joint.

Tibiofibular Ligaments

Anterior, posterior, and interosseous ligaments binding distal tibia and fibula; stabilize ankle mortise.

Osteoarthritis

Degenerative "wear-and-tear" arthritis in which articular cartilage softens, frays, and deteriorates.

Rheumatoid Arthritis

Chronic autoimmune inflammation of joints leading to synovial membrane thickening and cartilage erosion.

Gouty Arthritis (Gout)

Joint inflammation due to uric acid crystal accumulation; may lead to bone fusion if untreated.