Anatomy and Physiology: Chapter 9 - Skeletal System: Articulations

Vocabulary flashcards covering key terms, anatomical classifications, joint structures, movements, and clinical concepts from Chapter 9 of Anatomy & Physiology.

Arthrology

The scientific study of joints.

Joint (Articulation)

Places of union between bones, bones and cartilage, or bones and teeth.

Fibrous Joint

A joint where bones are held together by dense regular connective tissue with no joint cavity.

Cartilaginous Joint

A joint where bones are joined by cartilage with no joint cavity.

Synovial Joint

A joint where bones are joined by ligaments with a fluid-filled joint cavity separating the articulating surfaces.

Synarthrosis

An immobile joint; can be a fibrous or cartilaginous joint.

Amphiarthrosis

A slightly mobile joint; can be a fibrous or cartilaginous joint.

Diarthrosis

A freely mobile joint; includes all synovial joints.

Gomphosis

A peg-in-a-socket fibrous joint where teeth are held in the sockets of the mandible and maxillae by periodontal ligaments; functions as a synarthrosis.

Suture

A fibrous synarthrotic joint with short fibers connecting interlocking, irregular edges of skull bones.

Syndesmosis

A fibrous amphiarthrotic joint bound by an interosseous membrane between parallel long bones, such as between the radius and ulna or tibia and fibula.

Synchondrosis

A cartilaginous synarthrotic joint where bones are joined by hyaline cartilage, such as the epiphyseal plate and costochondral joints.

Symphysis

A cartilaginous amphiarthrotic joint containing fibrocartilage pads between articulating bones to resist compression and act as shock absorbers.

Costochondritis

Inflammation of the costochondral joints, causing localized chest pain that may be mistaken for a myocardial infarction.

Articular Cartilage

Avascular hyaline cartilage lacking a perichondrium that covers articulating bone ends in synovial joints to reduce friction and absorb compression.

Articular Capsule

A double-layered capsule surrounding synovial joints consisting of an outer fibrous layer and an inner synovial membrane.

Synovial Fluid

A viscous, oily substance secreted by the synovial membrane that lubricates cartilage, nourishes chondrocytes, and absorbs shock.

Bursa

A fibrous, saclike structure containing synovial fluid and lined internally by a synovial membrane, designed to alleviate friction where surfaces rub together.

Tendon Sheath

An elongated bursa that wraps around tendons where friction is excessive, common in the wrist and ankle.

Uniaxial Joint

A joint in which bone movement is limited to just one plane or axis.

Biaxial Joint

A joint in which bone movement occurs in two planes or axes.

Multiaxial Joint

A joint in which bone movement occurs across multiple planes or axes.

Plane Joint

The simplest and least mobile uniaxial synovial joint, having flat articular surfaces that permit side-to-side gliding movement.

Hinge Joint

A uniaxial joint where a convex surface fits into a concave depression, allowing movement similar to a door hinge.

Pivot Joint

A uniaxial joint where a bone with a rounded surface fits into a ligament ring to rotate on its longitudinal axis.

Condylar Joint

A biaxial joint featuring an oval, convex surface articulating with a concave surface.

Saddle Joint

A biaxial joint with convex and concave surfaces resembling a saddle shape.

Ball-and-Socket Joint

A multiaxial joint where a spherical head fits into a cuplike socket, forming the most freely mobile type of joint.

Flexion

Movement in an anterior-posterior plane that decreases the angle between articulating bones.

Extension

Movement in an anterior-posterior plane that increases the angle between articulating bones.

Hyperextension

Extension of a joint beyond its normal range of motion.

Lateral Flexion

Lateral movement of the trunk of the body within the coronal plane.

Abduction

Lateral movement of a body part away from the midline of the body.

Adduction

Medial movement of a body part toward the midline of the body.

Circumduction

Movement in which the proximal end of an appendage remains stationary while the distal end makes a circular motion, tracing an imaginary cone.

Pronation

Medial rotation of the forearm resulting in the palm of the hand facing posteriorly.

Supination

Lateral rotation of the forearm resulting in the palm of the hand facing anteriorly.

Depression

Inferior movement of a body part, such as lowering the mandible when opening the mouth.

Elevation

Superior movement of a body part, such as raising the mandible when closing the mouth.

Dorsiflexion

Bending of the talocrural joint so that the superior surface (dorsum) of the foot moves toward the leg.

Plantar Flexion

Bending of the talocrural joint so that the dorsum of the foot points inferiorly, as when standing on tiptoe.

Eversion

Movement at intertarsal joints that turns the sole of the foot laterally.

Inversion

Movement at intertarsal joints that turns the sole of the foot medially.

Protraction

Anterior movement of a body part from anatomic position, such as jutting the jaw forward.

Retraction

Posterior movement of a body part from anatomic position, such as pulling the jaw backward.

Opposition

Movement of the thumb toward the tips of the fingers at the carpometacarpal joint to enable grasping.

First-Class Lever

A lever system where the fulcrum is located between the effort and resistance, such as the atlanto-occipital joint.

Second-Class Lever

A lever system where resistance is situated between the fulcrum and effort, such as standing on tiptoe.

Third-Class Lever

The most common lever class in the human body, where effort is applied between resistance and fulcrum, such as at the elbow joint.

Temporomandibular Joint (TMJ)

The only mobile articulation between skull bones, formed by the head of the mandible articulating with the temporal bone.

Rotator Cuff Muscles

A group of muscles (Subscapularis, Supraspinatus, Infraspinatus, Teres minor) whose tendons encircle the glenohumeral joint to hold the head of the humerus in the glenoid cavity.

Unhappy Triad

A severe knee injury involving simultaneous damage to the tibial collateral ligament, medial meniscus, and anterior cruciate ligament (ACL).

Ankle Sprain

Stretching or tearing of ligaments around a joint without fracture; usually caused by overinversion of the foot affecting the lateral ligament.

Pott Fracture

A severe injury caused by overeversion of the foot, resulting in avulsion of the medial malleolus off the tibia and fracture of the fibula.

Osteoarthritis

A degenerative joint disease associated with aging and wear-and-tear of articular cartilage.

Rheumatoid Arthritis

An autoimmune inflammatory disorder starting in the synovial membrane that can lead to joint scar formation and ossification (ankylosis).