General Joint Biomechanics Flashcards

Vocabulary flashcards covering skeletal joint classifications, structural architecture, functional stability and flexibility, and pathologies based on Chapter 5 joint biomechanics notes.

Synarthroses

Immovable fibrous joints designed to attenuate force, which include sutures, gomphoses, and syndesmoses.

Syndesmosis

A type of synarthrodial joint held together by fibrous ligaments or bands, such as the mid-radioulnar and mid-tibiofibular joints.

Suture

A type of synarthrodial joint where bone sheets mate closely together held by fibers, such as in the skull.

Amphiarthroses

Slightly movable cartilaginous joints that attenuate forces and permit limited movement, including synchondroses and symphyses.

Synchondrosis

An amphiarthrodial joint held together by a thin layer of hyaline cartilage, such as the sternocostal joint and epiphyseal plate.

Symphysis

An amphiarthrodial joint where a thin plate of hyaline cartilage separates a disc of fibrocartilage from bone, such as intervertebral joints and the pubic symphysis.

Diarthroses

Freely movable synovial joints that permit motion in or parallel to one or more planes with defined degrees of freedom.

Gliding Joint (Arthrodial)

A synovial joint with zero degrees of freedom ($0\text{ DOF}$) allowing non-axial sliding motion only, such as intercarpal, intertarsal, and vertebral facet joints.

Hinge Joint (Ginglymus)

A uniaxial synovial joint with one degree of freedom ($1\text{ DOF}$) permitting movement in one plane, such as the humeroulnar and interphalangeal joints.

Pivot Joint (Trochoid)

A uniaxial synovial joint with one degree of freedom ($1\text{ DOF}$) that allows rotation, such as the radioulnar and atlanto-axial joints.

Ellipsoidal Joint (Condyloid)

A biaxial synovial joint with two degrees of freedom ($2\text{ DOFs}$) allowing flexion/extension, abduction/adduction, and circumduction, such as the radiocarpal and metacarpophalangeal joints.

Saddle Joint (Sellar)

A biaxial synovial joint with two degrees of freedom ($2\text{ DOFs}$) that permits movements similar to ellipsoidal joints but with greater range of motion, such as the first carpometacarpal joint of the thumb.

Ball and Socket Joint (Spheroidal)

A triaxial synovial joint with three degrees of freedom ($3\text{ DOFs}$) permitting flexion/extension, abduction/adduction, and rotation, such as the hip and glenohumeral joints.

Articular Cartilage

A dense, white connective tissue $1\text{ to }5\text{ mm}$ thick that covers articulating bone ends in diarthrodial joints to absorb load, reduce contact stress, and minimize friction.

Articular Fibrocartilage

Soft-tissue discs, labrums, or menisci (e.g., knee menisci, glenoid labrum, intervertebral discs) located between articulating bones to distribute load and improve joint fit.

Joint Stability

The ability of a joint to resist displacement, traction, shear, or movement in planes outside its intended design.

Close-Packed Position

The position of a joint where articulating surfaces achieve maximum contact area, providing peak stability (e.g., knee at full extension, ankle at dorsiflexion).

Joint Flexibility

The ranges of motion (ROM) allowed at a joint within its intended planes of motion.

Range of Motion (ROM)

The angle through which a joint moves from anatomical position (zero) to the extreme limit of segment motion.

Sprain

An injury caused by abnormal or temporary displacement of articulating bones that over-stretches or tears supporting connective tissues such as ligaments and tendons.

Dislocation (Luxation)

The semi-permanent displacement of articulating bones at a joint.

Bursitis

An overuse injury causing frictional irritation and inflammation of bursae.

Arthritis

A joint pathology characterized by joint inflammation accompanied by pain and swelling.

Goniometer

An inexpensive device used to measure relative joint angles and static/passive range of motion.