Chapter 9: Joints

Question 1

Define articulation (arthorsisi)

Answer 1

A joint - point of contact between two bones, between bone and cartilage, or between bone and teeth

Question 2

Classify joints based on structure and function

Answer 2

Structural (3): presence of a space (synovial cavity)
1. Fibrous: no synovial cavity bound by dense connective tissue rich in collagen

2. Cartilangous: no synovial cavity bound by cartilage
3. Synovial: has a synovial cavity

Functional (3): relates to degree of movement

1. Synarthorsis: immoveable
2. Amphiarthoris: slightly moveable
3. Diarthrosis: freely moveable

Question 3

Describe the structure and function of the 3 types of fibrous joints

Suture
Syndesmoses
Interosserous membrane

Answer 3

Suture : occurs only between bones in the skull

Syndesmoses: greater distance between articulating surfaces and more connective tissue than a suture (limited movement)

Interosserous membrane: substantial sheet of connective tissue that binds neighbouring bone bones (ex. between diaphysis of fibula and tibia)

Question 4

Define synostosis and frontal/metopic structure

Answer 4

A suture of a bony joint tin which there is a complete fusion of 2 separate bones into one

If fusion of bones persists past 6yrs it is known as a frontal/metopic structure

Question 5

A gomphosis (denotalveolar joint) in which a cone-shaped peg fits into a socked is an example of a _________

Answer 5

syndesmosis joint

Question 6

Describe the structure and functions of the 2 types of cartilaginous joints

Synchondrosis
Symphysis

Answer 6

Synchondrosis: connecting material is hyaline cartilage (Ex. growth plate)

Symphysis: ends of articulating bones are covered with hyaline cartilage but a broad, flat disc of fibrocartilage connects the bones
(occurs in all bones in midline of the body)

Question 7

Describe synovial joints and the following components:

Articular capsule 
Synovial fluid 
Extracapsular and intracapsular ligaments 
Articular disc 
Labrum

Answer 7

Synovial joints are diarthrothsis that are covered in articular cartilage that makes the surfaces slippery but does not bind them

Articular capsule: surrounds synovial joint/cavity and unites the articulating bones. Comprised of 2 layers:
1. Fibrous membrane (outer): consist of irregular connective tissue and sometimes arranged in bundles called ligaments to provide flexibility/strength

2. Synovial membrane (inner): areolar connective tissue that accumulates adipose tissue called articular fat pads

Synovial fluid: clear/pale-yelow fluid consists inf hyalurionic acid and ISF that lubcricates the joints and absorbs shocks, and supplies nutrients

Extracapsular (outside capsule) and intracapsular ligaments (within capsule)

Articular disc (not all joints): bind strongly to inside of fibrous membrane and subdivide the cavity, allowing for seperate movements

Labrum: prominent in ball-and-socket joints, helps deepen the socket and increases area of contact

Question 8

How are synovial joints supplied with blood and nerves?

Answer 8

Although many components are avascular surrounding arteries send out branches that penetrate the ligaments and articular capsule

Question 9

Bursae vs. Tendon sheaths

Answer 9

Bursae: sac-like structures that alleviate friction as they are filled with fluid that cushions movement

Tendon sheath: tube-like bursae that wrap around tends that experience friction to protect them as they slide back and forth

Question 10

What are gliding movements?

Answer 10

Nearly flat bone surfaces move back and forth and side to side

Question 11

What are angular movements?

Answer 11

There is an increase or decrease in angle

Flexion (decrease angle) 
Extension (restore angle)
Hypertension (increase angle) 
Abuduction (away from midline) 
Adduction (towards midline) 
Circumduction (circular): continuous sequence of flexion, abductions, extension, adduction, and rotation of the joint

Question 12

What are rotation movements?

Answer 12

Bone revolves around its own longitudinal axis

Medial: rotation is turned inwards
Lateral: rotation is turned outwards

Question 13

Describe the following movements:

Elevation
Depression

Answer 13

Elevation: superior movement of a body part (closing mouth)

Depression: inferior movement of a body part (opening mouth)

Question 14

Describe the following movements:

Protraction
Retraction

Answer 14

Protraction: anterior movement of body in transverse plane (thrusting jaw forward)

Retraction : posterior movement of body in transverse plane (returning jaw)

Question 15

Describe the following movements:

Inversion
Eversion

Answer 15

Inversion: Medial movement of sole
Eversion: Lateral movement of sole

(think of rolling your ankle in heels)

Question 16

Describe the following movements:

Dorsiflexion
Plantar flexion

Answer 16

Dorsiflexion: flexing foot

Plantar flexion: pointing foot

Question 17

Describe the following movements:

Supination
Pronation

Answer 17

Supination : palms up

Pronation: palms down

Question 18

Describe the following movements:

Opposition

Answer 18

Movement of thumb across palm to touch fingers

Question 19

Describe the 6 types of synovial joints:

Plane 
Hinge 
Pivot 
Condyloid 
Saddle 
Ball-and-socket

Answer 19

Plane: back and forth or side to side on flat surfaces (blocks moving back and forth) - biaxial or triaxial

Hinge: opening/closing motion (doors) - unaxial

Pivot: think of a turning pole - uniaxial

Condyloid: convex oval shape bone fits into a depression (biaxial)

Saddle: biaxial

Ball-and-socket: triaxial

Question 20

Define the knee joint

Answer 20

aka tibofermoral joint is the larger and complex joint of the body: it is a modified hinge joint that conceits of 3 joints within 1 synovial cavity:

1. Laterally is a tibofemoral joint between lateral condyle of femur, lateral meniscus, and lateral condyle of tibia
2. Medially is another tibofemoral joint between medial condyle of femur, medial meniscus, and medial condyle of tibia
3. Intermediate patellofermoral joint between the patella and patellar surface of femur

Question 21

Describe the anatomical components of the knee joint:

Articular capsule 
Patellar ligament 
Tibial collateral ligament 
Fibular collateral ligament 
ACL 
PCL 
Medial & lateral miniscus

Answer 21

Articular capsule

Patellar ligament: continuation of common tendon that extends from patella to tibial tuberosity

Tibial collateral ligament: flat ligaments of medial surface that attached to medial meniscus

Fibular collateral ligament : rounded ligament on lateral surface that attaches to fibula

ACL: limits hyperextension of prevents anterior sluing of the tibia and femur

PCL: prevents posterior sliding of the tibia when knee is flexed (important for walking down inclines)

Medial (c-shaped fibrocartilage) & lateral (O-shaped fribocartlilage) miniscus: attached to tibia

Question 22

Rheumatism

Answer 22

Any painful disorder of the supporting structures of the body – bones, ligaments, tendons, or muscle – that is not caused by infection of injury

Arthritis is a form of rheumatism in which joints are swollen, stiff, and painful

Question 23

Osteoartritis

Answer 23

degenerative joint disease in which joint cartilage is gradually lost restricting movement

Most common arthritis referred to as ‘wear-and-tear’

Progressive disorder of synovial joints

Question 24

Rheumatoid arthritis (RA)

Answer 24

autoimmune disease in which the immune system attacks cartilage and joint linings

Attacks small joints first

Question 25

Gouty arthritis

Answer 25

sodium urate crystals are deposited in the soft tissues of the joint especially the joints of the feet and base of big toe

Question 26

Lyme disease

Answer 26

a bacteria transmitted mainly by deer ticks that typically causes a bulls-eye target rash -Other symptoms include joint stiffness, nausea, and low back pain