Articulations

Question 1

Joint classification

Answer 1

1. Structural - based on presence of fluid filled joint space and type of connective tissue
2. Functional - based on tupe of movement allowed at joint

Question 2

Fibrous Synarthroses

Answer 2

• no joint cavity
• bones fit closely together
• little to no movement
• 3 types (syndesmoses, sutures, and gomphoses)

Question 3

Syndesmoses

Answer 3

Joints in which ligaments connect two bones

• slightly moveable (ligament flexibility)
• radius and ulna

Question 4

Sutures

Answer 4

Found only in skull

• thin layer of fibrous connective tissue
• adjacent bones interlock
• immovable in adults, slight movement in children

Question 5

Gomphoses

Answer 5

• formed between root of tooth and the sockets (alveoli) of mandible or maxillae
• immovable joint when healthy
• fibrous tissue between root and bone called periodontal membrane

Question 6

Cartilaginous amphiarthroses

Answer 6

• no joint cavity
• bones of joints are joined together by hyaline cartilage or fibrocartilage
• no motion or very little motion
• 2 types (synchondroses and symphyses)

Question 7

Synchondroses

Answer 7

• connecting material between articulating bones is hyaline cartilage
• immovable
• 1st rib and manubrium

Question 8

Symphyses

Answer 8

Joint with a pad or disc of fibrocartilage between two bones

• most occur in midline of body
• slight movement
• pubic symphysis
• between vertebrae

Question 9

Synovial joints

Answer 9

Freely moveable joints

• diarthroses
• comprise of majority of joints in appendicular skeleton

Question 10

7 structures of synovial joints

Answer 10

1. Joint capsule
2. Synovial membrane
3. Articular cartilage
4. Joint cavity
5. Menisci (articular discs)
6. Ligaments
7. Bursae/tendon sheath

Question 11

Joint capsule

Answer 11

• forms complete casing around synovial joint

- extension of the periosteum of each of the articulating bones

Question 12

Synovial membrane

Answer 12

• lines the inner surface of joint capsule
• arranges to the margins of the articular cartilage
• secretes synovial fluid (lubricates and nourishes)

Question 13

Articular cartilage

Answer 13

• thin layer of hyaline cartilage that covers the articular surfaces of bones
• reduces friction during movement and absorbs shock

Question 14

Joint cavity

Answer 14

• small space between bones

- allows for extensive movement

Question 15

Menisci (articular disks)

Answer 15

• pads of fibrocartilage located between articulating bones
• usually divide the joint cavity into two separate spaces allowing separate movements
• Functions:
  
  1. Shock absorption
  2. Better fit between articulating bones
  3. Larger contact surface for weight bearing
  4. Synovial fluid distribution across joint surfaces

Question 16

Labrum

Answer 16

• fibrocartilaginous lip that extends form joint socket
• deepens joint socket of shoulder and hip
• increases contact area between articulating bones

Question 17

Ligaments

Answer 17

Strong cords of dense, regular fibrous tissue that hold bones of synovial joint together more firmly

Question 18

Bursae

Answer 18

• saclike structure surrounded by synovial membrane
• filled with synovial fluid
• between skin and bones, tendons and bones, or ligaments and bones
• cushion joint or facilitate movement of tendons

Question 19

Tendon (synovial) sheaths

Answer 19

• tubelike bursae that wrap around tendons that receive a lot of wear and tear
• extension of joint capsule but wraps around tendon
• protects tendon as it slides back and forth with movement

Question 20

Types of synovial joints

Answer 20

1. Uniaxial: hinge and pivot
2. Biaxial: saddle and condyloid
3. Multiraxial: ball-and-socket and gliding

Question 21

Uniaxial joints

Answer 21

Synovial joint that permit movement around one axis and only one plane

1. Hinge: elbow
2. Pivot: head of radius against ulna

Question 22

Hinge joint

Answer 22

• uniaxial

- convex surface of one bone fits into the concave surface of another bone

Question 23

Pivot joint

Answer 23

• uniaxial

- projection of one bone articulates with a ring or notch of another bone

Question 24

Biaxial joints

Answer 24

Synovial diarthroses that permit movement around two perpendicalar axes in two perpendicular planes

• saddle
• condyloid

Question 25

Saddle joint

Answer 25

Biaxial - articulating ends of the bones resemble reciprocally shaped miniature saddles - only in the thumb (1st cmc joint)

Question 26

Condyloid (ellipsoidal) joint

Answer 26

Biaxial - condyloid fits into an elliptical socket - condyloid of the occiput in the elliptical depressions of the atlas - the dental end of the radius fitting into the depression of the carpal bones (scaphoid, lunate, and triquitrum)

Question 27

Multiraxial joint

Answer 27

Synovial joints that permit movements around 3+ axes in 3+ planes - ball and socket - gliding

Question 28

Ball and socket joint

Answer 28

Multiaxial - most movable joint - ball-shaped head of one bone fits into a concave depression - shoulder/hip

Question 29

Gliding joint

Answer 29

Multiaxial - relatively flat articulating surfaces that allow sliding movements along various axes - intervertebral joints

Question 30

Synovial Gliding movements

Answer 30

- nearly flat bones move back and forth from side to side - limited in range secondary to support structures and joint capsule - can be combined with rotational movements - examples include intercapral and intertarsal joints

Question 31

Synovial Angular movements

Answer 31

- increase or decrease in the angle between the bones | - flexion, extension, abduction, adduction, and lateral flexion

Question 32

Synovial Special movements

Answer 32

- occur only in certain joints - include: elevation/depression, protraction/retraction, inversion/eversión, Doris flexion/plantarflexion, supination/pronation, and opposition