Skeletal System: Articulations

Comprehensive flashcards covering classifications, anatomy, specific examples, and movements of human skeletal joints based on the provided lecture notes.

Articulations

Joints where bones meet, classified structurally by connective tissue type and functionally by the amount of movement allowed.

Fibrous joint

Bones held together by dense connective tissue without a joint cavity.

Cartilaginous joint

Bones joined by hyaline cartilage or fibrocartilage and lacking a joint cavity.

Synovial joint

Bones joined by ligaments with a fluid-filled joint cavity separating bone surfaces; functionally classified as diarthroses.

Synarthroses

Immobile joints that can be either fibrous or cartilaginous.

Amphiarthroses

Slightly mobile joints that can be either fibrous or cartilaginous.

Diarthroses

Freely mobile joints; includes all synovial joints.

Gomphoses

A 'peg in a socket' fibrous joint where periodontal membranes hold teeth in place; functionally classified as synarthroses.

Sutures

Fibrous joints found between some skull bones with interlocking, irregular edges that increase strength and function as synarthroses.

Syndesmoses

Fibrous joints bound by an interosseous membrane, found between the radius and ulna and between the tibia and fibula; they function as amphiarthroses.

Synchondroses

Cartilaginous joints where bones are joined by hyaline cartilage, such as the epiphyseal plate and costochondral joints; they are immobile synarthroses.

Symphyses

Cartilaginous joints with pads of fibrocartilage between articulating bones that resist compression and allow slight mobility (amphiarthroses).

Articular capsule

A double-layered capsule in synovial joints consisting of an outer fibrous layer of dense connective tissue and an inner synovial membrane.

Fibrous layer

The outer layer of the articular capsule formed from dense connective tissue that strengthens the joint to prevent bones from being pulled apart.

Synovial membrane

The inner layer of the articular capsule that covers internal joint surfaces not covered by cartilage and helps produce synovial fluid.

Articular cartilage

Avascular hyaline cartilage on bone surfaces at a joint that reduces friction, absorbs compression, and prevents damage to bone ends.

Joint cavity

The space between articulating bones lined by a synovial membrane that secretes synovial fluid.

Synovial fluid

A viscous, oily substance that lubricates articular cartilage, nourishes chondrocytes, removes wastes, and acts as a shock absorber.

Ligaments

Dense regular connective tissue that connects one bone to another to stabilize and reinforce synovial joints.

Tendons

Composed of dense regular connective tissue, these attach muscle to bone and help stabilize joints but are not part of the synovial joint itself.

Bursae

Pockets of synovial membrane and fluid that alleviate friction where bones, ligaments, muscles, skin, or tendons overlie each other.

Fat pads

Protective packing material located in the joint periphery that can fill spaces when the joint shape changes.

Tendon sheaths

Elongated bursae that wrap around tendons where friction is excessive, common in the wrist and ankle.

Glenohumeral Joint

A ball-and-socket joint formed by the head of the humerus and the glenoid cavity; it has the greatest range of motion but is the most unstable joint.

Glenoid labrum

A fibrocartilage ring that encircles the socket of the glenohumeral joint.

Rotator cuff muscles

A group of muscles whose tendons encircle the glenohumeral joint and fuse with the articular capsule to hold the humeral head in the glenoid cavity.

Hip Joint

Articulation between the head of the femur and the acetabulum; it is more stable and less mobile than the glenohumeral joint.

Acetabular labrum

A fibrocartilaginous ring that deepens the socket of the hip joint.

Knee Joint

The largest and most complex diarthrosis, primarily a hinge joint capable of slight rotation and lateral gliding when flexed.

Menisci

C-shaped fibrocartilage pads (medial and lateral) deep to the articular capsule of the knee that provide cushioning between articular surfaces.

Anterior cruciate ligament (ACL)

Extends from the posterior femur to the anterior tibia; prevents hyperextension and anterior displacement of the tibia.

Posterior cruciate ligament (PCL)

Extends from the anteroinferior femur to the posterior tibia; prevents hyperflexion and posterior displacement of the tibia.

Arthritis

A group of inflammatory or degenerative diseases of the joints characterized by swelling, pain, and stiffness.

Gouty arthritis (Gout)

Joint disease typically seen in middle-aged or older males due to increased levels of uric acid.

Osteoarthritis

A degenerative condition in older individuals due to the wearing down of articular cartilage; commonly affects fingers, hips, and knees.

Rheumatoid arthritis

An autoimmune disorder seen in younger to middle-aged adults that starts with inflammation of the synovial membrane.

Uniaxial joint

A synovial joint where bone moves in just one plane or axis.

Biaxial joint

A synovial joint where bone moves in two planes or axes.

Multiaxial joint

A synovial joint where bone moves in multiple planes or axes.

Plane joint

The simplest, least mobile synovial articulation featuring flat surfaces for uniaxial gliding; found in the ankle, wrist, and sacroiliac joint.

Hinge joint

A uniaxial synovial joint where a convex surface fits into a concave depression, such as the elbow or interphalangeal joints.

Pivot joint

A uniaxial synovial joint involving a rounded surface fitting into a ligament ring, allowing rotation such as at the atlantoaxial joint.

Condylar joint

A biaxial synovial joint with an oval, convex surface articulating with a concave surface, such as the metacarpophalangeal joints.

Saddle joint

A biaxial synovial joint with convex and concave surfaces resembling a saddle, such as the joint between the trapezium and the first metacarpal.

Ball-and-socket joint

A multiaxial synovial joint where a spherical head fits into a cuplike socket; it is the most freely mobile joint type.

Gliding

A limited sliding motion typically occurring along plane joints, such as between carpals or tarsals.

Flexion

An angular motion that decreases the angle between bones in the anterior-posterior plane (bending).

Extension

An angular motion that increases the angle between articulating bones in the anterior-posterior plane (straightening).

Hyperextension

Extension of a joint more than $180^{\circ}$ or beyond the anatomical position.

Lateral flexion

Movement of the trunk of the body laterally in the coronal plane, occurring between vertebrae in the cervical and lumbar regions.

Abduction

Lateral movement of a body part away from the midline.

Adduction

Medial movement of a body part toward the midline.

Circumduction

A movement where the distal end of an appendage describes a cone.

Rotation

Movement where a bone pivots on its own longitudinal axis; can be lateral or medial.

Pronation

Medial rotation of the forearm so the palm of the hand faces posterior.

Supination

Lateral rotation of the forearm so the palm of the hand faces anterior.

Depression

Inferior movement of a body part.

Elevation

Superior movement of a body part.

Dorsiflexion

Movement where the foot is lifted toward the shin.

Plantar flexion

Movement where one stands on the toes.

Inversion

Movement where the sole of the foot turns medially.

Eversion

Movement where the sole of the foot turns laterally.

Protraction

Anterior movement from the anatomic position.

Retraction

Posterior movement from the anatomic position.

Opposition

Movement of the thumb toward the tips of the fingers which enables grasping.