Joint structure and function

Question 1

Arythrology

Answer 1

Study of joints

Question 2

Synarthrosis

Answer 2

Immoveable joint.

Provides stability, shock absorption, and has limited to no movement.

Question 3

Amphiarthrosis

Answer 3

Cartilaginous joint.
Provides mild mobility, designed to provide cushioned stability and shock absorption.
Ex: pubic symphysis, synchrondrosis (1st sternocostal joint).

Question 4

Diarthrosis

Answer 4

Synovial joint.

Has degrees of freedom.

Question 5

Characteristics of synovial articulations.

Answer 5

Bony end covered by hyaline cartilage.
Joint cavity and joint capsule.
Synovial membrane lines the inner surface of the joint capsule.
Synovial fluid that feeds hyaline cartilage.

Question 6

Non-axial joints

Answer 6

Gliding joints

Question 7

Gliding joints

Answer 7

2 flat bony surfaces which are placed up against each other.
One bone translates (glides) along the surface of another bone.
Little motion is possible at any one joint articulation - doesn’t move around an axis.
Usually work together in series of articulations.
Ex: face joints between vertebrae, carpal bones in wrist.

Question 8

Uniaxial joints

Answer 8

Ginglymus and trochoid

Question 9

Ginglymus

Answer 9

AKA hinge joint.
Moves in the sagittal plane.
Ex: elbow (humero-ulnar), IP joints in fingers, knee, ankle (talocrural).

Question 10

Trochoid

Answer 10

AKA pivot joint.
Motion in the transverse plane.
Ex: radioulnar, atlas-axis in neck.

Question 11

Biaxial joints

Answer 11

Condyloid and Ellipsoid

Question 12

Condyloid

Answer 12

Spherical convex surface paired with a shallow concave surface.
Moves in the sagittal and frontal planes.
Ex: MCP/MTP joints.

Question 13

Ellipsoid

Answer 13

Flattened convex surface articulating with a deeper concave surface.
Moves in sagittal and frontal planes.
Ex: radiocarpal articulation.

Question 14

Triaxial joints

Answer 14

Moves in sagittal, frontal, and transverse planes.
Ball and socket joint (enarthrodial).
Ex: hip and shoulder.

Question 15

Saddle joints

Answer 15

Sellar: both surfaces have convex and concave components.
Primary sagittal and frontal plane motions but can achieve some transverse motion.
Ex: CMC joint of thumb.

Question 16

There is always a balance of _______ and ________. More of one results in less of the other.

Answer 16

mobility

stability

Question 17

3 factors that influence mobility and stability

Answer 17

Shape of bones as a joint.
Ligament/joint capsule complex of a joint.
Musculature of a joint.

Question 18

Joint structures

Answer 18

Ligaments
Fibrocartilaginous discs
labrum
bursa

Question 19

Logaments

Answer 19

Thickenings of a joint capsule.
Function is to restrain excessive or abnormal movement.
Located in intra/extra-articular space.

Question 20

Fibrocartilaginous discs

Answer 20

Function is to increase joint surface area, increase lubrication, dissipation of joint reaction forces, and increase joint stability.
Located between joint surfaces.
Ex: tibiofemoral menisici, TMJ disc, pubic symphysis.

Question 21

Labrum

Answer 21

Function is to deepen the articular cavity and helps with joint stability.
Located inside the joint capsule at articular surface margins.
Ex: glenohumeral joint and hip joint labra.

Question 22

Bura

Answer 22

Functions is to decrease the friction of structures.
Location may or may not be in communication with the joint cavity.
Ex: subdeltoid bursa, psoas bursa.

Question 23

Functions of a joint

Answer 23

Allows movement.
Muscles create movement.
Ligaments/joint capsules limit movement.
Weight bearing.
Shock absorption.
Each joint has optimal balance between mobility and stability.

Question 24

Range of motion

Answer 24

Measurable degree of movement potential in a joint.

Measured with a goniometer in degrees of 0-360.

Question 25

Arthrokinematics

Answer 25

Accompany osteokinematic motion. Required for a joint to exhibit full ROM. Involuntary.

Question 26

Arthokinematic motions

Answer 26

Rolling - rotary or angular. Sliding - transulatory or linear. Spinning. Distraction and compression.

Question 27

Close-packed position

Answer 27

Maximum SA contact occurs. Capsuloligamentous tissues are taut. Minimal amount of accessory motion.

Question 28

Open-packed position

Answer 28

Any position but close-packed. | Joint surfaces don't fit congruently.

Question 29

Movement in the sagittal place is ________ and ________. It moves on the _________ axis.

Answer 29

Flexion Extension Frontal (x)

Question 30

Movement in the frontal plane is _________ and _________. It moves on the __________ axis.

Answer 30

Abduction Adduction Sagittal (z)

Question 31

Movement in the transverse plane is ___________ and ___________. It moves on the __________ axis.

Answer 31

Internal rotation External rotation Vertical (y)