Chapter 9: Joints

Question 1

What are the 2 categories of joint classification?

Answer 1

1) Presence/absence of space between articulating bones and 2) Type of connective tissue binding them together

Question 2

What are the 6 types of joints?

Answer 2

• Fibrous joints (No synovial cavity. Bones held together by irregular dense connective tissue)
• Cartilaginous joints (No synovial cavity. Bones held together by cartilage).
• Synovial joints (Has a synovial cavity. Bones united by dense irregular connective tissue of an articular capsule and accessory ligaments)
• Synarthrosis (Immovable joint)
• Amphiarthrosis (slightly movable joint)
• Diarthrosis (Freely movable joint. All are synovial joints)

Question 3

What are the 3 types of fibrous joints?

Answer 3

Sutures, syndesmoses, and interosseous membranes

Question 4

What are sutures?

Answer 4

Thin layer of dense irregular connective tissue only between bones of the skull. Irregular interlocking edges of sutures give them added strength and decrease chance of fracturing. Synarthroses in adults (immovable) and amphiathroses in infants (slightly movable). Shock absorpion. Synostosis = complete fusion of 2 bones into 1.

Question 5

What are syndesmoses?

Answer 5

Fibrous join where there’s a greater distance between the articulating surfaces and more dense irregular connective tissue then in a suture. Dense irregular conn tissue arranged in a bundle (ligament) so limited movement. Example: Distal tibiofibular joint which permits slight movement. Example 2: Gomphosis (cone-shaped peg fits into a socket)… articulations between roots of teeth and their sockets (alveoli).. permits no movement.

Question 6

What is the interosseous membrane?

Answer 6

Final category of fibrous joint. Substantial sheet of dense irregular connective tissue that binds neighbouring long bons and permits slight movement (ie betwee radius and ulna, and tibia and fibula)

Question 7

What are 2 featuers of cartilaginous joints and what are the 2 types?

Answer 7

Lacks synovial cavity and little to no movement. 2 Types: Synchondroses and symphyses

Question 8

What are synchrondroses?

Answer 8

Cartilaginous joint. Connecting material is hyaline cartilage. Epiphyseal (growth) plate that connects the epiphysis and diaphysis. When bone elongation ceases, bone replaces the hyaline cartilage and the synchondrosis becomes a synostosis (a bony joint). Ie between rib and manubrium of sternum.

Question 9

What is a symphyss?

Answer 9

Cartilaginous joint. Ends of articulating bones are covered with hyaline cartilage but broad flat disc of fibrocartilage connects the bones. Usually at midline of body. Ie pubic symphysis; junction of manubrium and body of sternum; intervertebral joints between vertebrae. Slightly movable.

Question 10

What are synovial joints and what is the cartilage called that covers them?

Answer 10

They have a space called a synovial cavity. Freely moveaby and covered by a layer of hyaline cartilage called articular cartilage.

Question 11

What is the function of articular cartilage on synovial joints?

Answer 11

Reduces friction between bones at joint during movement and helps absorb shock.

Question 12

What is the articular capsule?

Answer 12

Aka joint capsule. Surrounds synovial joint, encloses synovial cavity and united articulating bones

Question 13

What are the 2 layers that articular capsules are composed of?

Answer 13

Fibrous membrane (outer) and inner synovial membrane

Question 14

What does the fibrous membrane of articular capsule do?

Answer 14

Dense irregular connective (mainly collagen fibres)and attaches to periosteum of articulating bones. Helps prevent bones from dislocating due to great tensile stregnth (can stretch), moveable.

Question 15

What is the synovial membrane of articular capsule?

Answer 15

Composed of areolar connective tissue with elastic fibres. Accumulations of adipose tissue called articular fat pads (ie fat pad in the knee)

Question 16

How are some people double jointed?

Answer 16

Have a greater flexibility in their articular capsules and ligaments

Question 17

What does synovial fluid look like?

Answer 17

Viscous, clear or pale yelllow fluid. Consists of hyaluronic acid secreted by synovial cells in synovial membrane and interstitial fluid filtered from blood plasma.

Question 18

What does synovial fluid do?

Answer 18

Forms a thin film over surfaces within articular capsule. Reduces friction by lubricating joint, absorbing shocks, and supplying O2 and nutrients to and removing CO2 and waste from chondrocytes. Contains phagocytic cells to remove microbes and debris. If immobile, fluid becomes viscous. If mobile, less viscous

Question 19

What are 2 types of accessory ligaments contained in synovial joints?

Answer 19

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

Question 20

What are articular discs/menisci?

Answer 20

Crescent shaped pads of fibrocartilage that lie between th articular surfaces of the bones are attached to the fibrous capsule. Lateral and medial menisci or knee joint. Divides synovial cavity into 2 spaces, allowing separate movement in each (ie TMJ)

Question 21

What are the 5 functions of menisci?

Answer 21

1) Shock absorption
2) Better fit between articulating bones
3) Providing adaptable surfaces for combined movements
4) Weight distribution over a greater contact surface
5) Distribution of synovial lubricant across the articular surfaces of the joint

Question 22

What is the labrum? Functions?

Answer 22

Fibrocartilaginous lip that extends from edge of joint socket. Prominent in ball-and-socket joints of shoulder and hip. Labrum help deepen the joint socket and increase area of contact between the socket and ball-like surface of the head of the humerus or femur

Question 23

Where do synovial joints get their blood supply?

Answer 23

They contain many nerve endings that are distributed to the articular capsule and associated ligaments. Veins remove CO2 an waste from joints. Chondrocytes in articular cartilage of a synovial joint receive O2 and nutrients from synovial fluid derived from blood

Question 24

What are bursae and tendon sheaths?

Answer 24

Sac life structures called bursae are situated to aleviate friction in some joints like shoulder and knee joints. Walls consist of outer fibrous membrane of thin, dense connective tissue lined by synovial membrane. FIlled with a small amount of fluid similar to synovial fluid. Located between skin and bones, tendons and bones, muscles and bones, or ligaments and bones… cushions movement of these bony parts against one another.

Question 25

What do tendon sheaths do?

Answer 25

Reduce friction at joints. Tubelike burssae. Wrap around certain tendons that experience lots of friction. Visceral layer (inner) is atatched to surface of tendon. Parietal layer (out) is attached to the bone.

Question 26

What are the 4 main categories that synovial joints are grouped in?

Answer 26

1) Gliding 2) Angular 3) Rotation 4)special movements (occur at certain joints)

Question 27

What are gliding joints and what are examples?

Answer 27

Nearly flat bone surfaces move back and forth and side to side. Examples are intercarpal and intertarsal

Question 28

What are angular movements and what are the 7 types?

Answer 28

There’s an increase/decrease in the angle between articulating bones. THe types are: flexion, extension, lateral flexion, hyperextension, abduction, adduction and circumduction

Question 29

What is flexion and extension and what are examples?

Answer 29

USUALLY occurs along sagittal plane. Flexion is a decrease in the angle between articulating bones. Extension is an increase in the angle between articulating bones often to restore a part of the body to the anatomical position after being flexed. Examples: Bending head toward chest, bending trunk forward at intervertebral joints (crunches), moving humerus forward at shoulder joint (ie swinging arms), moving forearm toward arm at elbow joint (bending elbow), moving palm toward forearm at wrist or radiocarpal joint, bending digits of hand at the interphalangeal joints between phalanges (ie clenching fingers), moving femur forward at hip joint between femur and hipbone (ie walking) and moving heal toward butt at tibiofemoral joint between tibia ,femur, and patella (ie bending the knee)

Question 30

What are some examples of flexion and extension NOT along the sagittal plane?

Answer 30

Movement of thumb medially accross palm at carpometacarpal joint, movement of trunk sideways left to right at waste (occurs along frontal plane and involves intervertebral joints… called lateral flexion)

Question 31

WHat is hyperextension and what are some examples?

Answer 31

Continued extension beyond anatomical position. Examples: bending head back at atlanto-occipital and cervical intervertebral joints, bending trunk back at intervertebral joints (backbend), moving humerus back at shoulder joint as in swinging the arms, moving palm back at wrist joint, moving femur back at hip joint

Question 32

What is abduction and adduction?

Answer 32

Usually along the frontal plane. Abduction is movement of bone away from midline. Adduction is movement of bone toward midline. Usually adduction returns to anatomical position

Question 33

What is circumduction? Examples?

Answer 33

Movement of distal end of body part in a circle. Continuous sequence of abduction, flexion, extension, adduction and rotation of the joint. Examples: moving humerous in a circle at shoulder joint, moving hand in a circle at wrist joint, moving thumb in a circle at metacarpophalangeal joints, moving femur in a circle at hip joints. Shoulder amd hip joints permit circumduciton

Question 34

What is rotation and what are examples?

Answer 34

Bone revolves around its own longitudinal axis. Examples: turning head from side to side at atlanto-axial joint, turning trunk from side to side at intervertebral joints

Question 35

What is medial and lateral rotation?

Answer 35

Medial rotation: Anterior ssurface of bone of the limb is turned toward midline (medially rotate at humerus at the shoulder).

Lateral rotation: If anterior surface of a bone of a limb is turned AWAY from midline

Question 36

What are some special movements of joints?

Answer 36

Elevation, depression, protraction, retraction, inversion, eversion, dorsiflexion, plantar flexion, supination, pronation and opposition

Question 37

WHat is elevation and what are examples?

Answer 37

Superior movement of a part of the body. Closing the mouth at TMJ to elevate the mandible. Shrugging the shoulders at the acromioclavicular joint to elevate the scapula and clavicle. OPposng movment is depression

Question 38

What is depression and what are examples?

Answer 38

Inferior movement of a part of the body like opening the mouth to depress the mandible. Returning shrugged shoulders to anatomical position

Question 39

What is protraction and what are examples?

Answer 39

Movement of part of body anteriorly at the transverse plane. Like protracting your mandible by thrusting it outward or protracting clavicles by crossing your arms. Its opposing movement is retraction

Question 40

What is retraction and what are examples?

Answer 40

Moving protracted part back to anatomical position

Question 41

What is inversion?

Answer 41

Movement of sole medially at intertarsal joints between tarsals. Opposing movement is eversion. Inversion combined with plantar flexion is supination

Question 42

What is eversion?

Answer 42

Movement of sole laterally at the intertarsal joints. Eversion combined with dorisflexion is pronation

Question 43

What is dorisflexion?

Answer 43

Bending the foot at the talocrural joint in the direction of the dorsum (superior surface). Like when you stand on your heals.. Opposing movement is plantar flexion

Question 44

What is plantar flexion?

Answer 44

Bending at the foot and ankle joint in direction of plantar or inferior surface (ie standing on toes)

Question 45

What is supination?

Answer 45

Movement of forearm at the proximal and distal radioulnar were palm is turned anteriorly . Opposing movement is pronation

Question 46

What is pronation?

Answer 46

Movement of forearm at the proximal and distal radioulnar joints where the distal end of the radius crosses over the distal end of the ulna and palm is turned posteriorly.

Question 47

What is opposition movement?

Answer 47

Movement of thumn at the carpometacarpal joint where the thumb moves across the palm to touch the tips of the fingers on the same hand

Question 48

Synovial joints are divided into 6 categories based on movement. What are these categories?

Answer 48

Plane, hinge, pivot, condyloid, saddle, and ball-and-socket.

Question 49

What are plane joints and what are some examples?

Answer 49

Back and forth, and side to side movement is between flat surfaces of bones. Many are biaxial (movement on 2 axes) some are triaxial (rotates in addition to sliding). Examples: intercarpal joints, intertarsal joints, sternoclavicular joints, acromioclavicular joints, sternocostal joints, and vertebrocostal joints

Question 50

What are hinge joints and what are examples?

Answer 50

Convex surface of one bone fits into concave surface of another. Angular opening and closing motion like a hinged door. Uniaxial (motion around single axis… only flexion and extension). i.e., knee, elboe, ankle and interphalangeal joints

Question 51

What are pivot joints and what are examples?

Answer 51

Rounded or pointed surface of one bone articulates with a ring formed partly by another bone and partly by a ligament. Uniaxial (rotation only around own longitudinal axis). I.e., atlanto-axial joint (atlas rotates around axis and allows head to move from side to side), radioulnar joints enable the palms to turn anteriorly and posteriorly as head of the radius pivots around its long axis in the radial notch of the ulna)

Question 52

What are condyloid joints and what’s an example?

Answer 52

Convex oval shaped projection of one bone fits into the oval shaped depression of another. Biaxial (flexion-extension and abduction-adduction) plus limited circumduction. Examples: Radiocarpal (wrist) and metacarpophalangeal joints of the 2nd through 5th digits

Question 53

What are saddle joints and what are examples?

Answer 53

Articular surface of one bone is saddle shaped and the articular surface of the other fits into the saddle like a ride. Biaxial plus limited circumduction. I.e., carpometacarpal joint between trapezium of the carpus and metacarpal of the thumb

Question 54

What are ball-and-socket joints?

Answer 54

Ball like surface fits into a cup like depression of another bone. Triaxial (flexion-extension, abduction-adduction, and rotation). I.e., shulder (humerus fits into glenoid cavity of scapula) and hip joints (femur fits into acetabulum)

Question 55

What are the factors that affect the range of motion (ROM) of a joint?

Answer 55

1) Structure / shape of articulating bones: Determines how close they can fit together. Obvious at hip joint.
2) Strength and tension (tautness) of joint ligaments: Tense ligaments restrict range of motion and direct movement of articulating bones with respect to one another. In hip joints, certain ligaments become taut when standing and more firmly attach the head of the femur to the acetabulum of the hip bone.
3) Arrangement of tension of the muscles: Muscle tension reinforces the restraint placed on a joint by its ligaments and therefore restricts movement
4) Contact of soft parts: The point where a body surface contacts another may limit mobility
5) Hormones: May affect joint flexibility. I.e., relaxin increases flexibility of fibrocartilage of pubic symphysis, and loosens ligaments between sacrum, hip bone and coccyx.
6) Disuse: Restrcited movement because not used of a long period like when a joint is in a cast. Results in decreased synovial fluid, less flexibility of tendons and ligaments and muscular atrophy

Question 56

What is the temporamandibular joint (TMJ)?

Answer 56

A combined hinge and place joint formed by the condylar process of the mandible and the mandibular fossa and articular tubercle of the temporal joint. Only freely movable joint between skulls (excluding the ear ossicles).

Question 57

What is the articular disc (meniscus)?

Answer 57

Fibrocartilage disc separating the synovial cavity into superior and inferior parts each with a synovial membrane

Question 58

What is the articular capsule?

Answer 58

Thin loose envelope around circumference of joint

Question 59

What’s the lateral ligament?

Answer 59

Extends inferiorly and posteriorly from inferior border and tubercle of the zygomatic process to the lateral and posterior aspect of the neck of the mandible. Covered by the parotid gland and helps strengthen the joint laterally and prevent displacement of mandible

Question 60

What is the sphenomandibular ligament?

Answer 60

Thin band extending inferiorly and anteriorly from spine of sphenoid bone to ramus of mandible. Doesn’t contribute significantly to strength

Question 61

What’s the stylomandibular ligament?

Answer 61

Thick band of cervical fascia extends from styloid process to the inferior and posterior border of the ramus of the mandible. Separates parotid gland from submandibular gland. Limits movement of mandible at TMJ

Question 62

What is the articular capsule?

Answer 62

Thin loose sac that envelopes the joint

Question 63

What’s the Coracohumeral ligament?

Answer 63

Strong broad ligament that stregnthens the superior part of the articular capsule and extends from the coracoid process of scapula to the greater tubercle of humerus

Question 64

What’s the glenohumeral ligaments?

Answer 64

3 thickenings of the articularcapsule over the anterior surface of the joint that extends from the glenoid cavity to the lesser tubercle and anatomical neck of humerus. Provides minimal strength. Role in joint stebilization when the humerus approaches or exceeds its limits of motions

Question 65

What’s the transverse humeral ligament?

Answer 65

Narrow sheet extending from greater to lesser tubercle of the humerus. Holds the long head of the biceps brachii muscle

Question 66

What is the glenoid labrum?

Answer 66

Narrow rim of fibrocartilage around edge of glenoid cavity that slightly deepens and enlarges glenoid cavity

Question 67

What is bursae?

Answer 67

4 associated with shoulder joint (subscapular bursa, subdeltoid bursa, subacromial bursal and subcoracoid bursa).

Question 68

What forms the elbow joint?

Answer 68

Hinge joint formed by trochlea and capitulum of humerus, trochlear notch of ulna and head of radius

Question 69

What are the anatomical components of the elbow joint?

Answer 69

Articular capsule, ulnar collateral ligament (part of it deepens the socket for the trochlea of the humerus), radial collateral ligament (strong triangular ligament), anular ligament of radius (Strong band encircling head of radius… Holds the head of the radius in the notch of the ulna),

Question 70

What forms the hip joint?

Answer 70

Ball and socket joint. Formed by head of the femur and acetabulum of hip bone

Question 71

What is the knee joint?

Answer 71

Largest and most complex joint. Modified hinge joint

Question 72

The knee joint consists of 3 joints within a single synovial cavity. What are these 3 joints?

Answer 72

1) laterally is a tibiofemoral joint
2) Medially is another tibiofemoral joint
3) An intermediate patellafemoral joint

Question 73

What are the anatomical components of the knee joint?

Answer 73

Articular capsule (no complete independent capsule unites the bones of the knee joint. Some capsule fibres connect the articulating bones), medial and lateral patellar retinacula (strengthens interior surface of joint), tibial collateral ligament (firmly attached to medial meniscus), fibula collateral ligament (strengthens the lateral aspect of the joint. Covered by tendon of bicepts femoris muscle), Intracapsular ligaments (ligaments within capsule connectin tibia and fibula), and articular discs (menisci) (2 fibrocartilage discs between the tibial and femoral condyles help compensate for the irregular shapes of the bones and circulate synovial fluid)

Question 74

What are the 2 types of intracapsular ligaments?

Answer 74

1) Anterior cruciate ligament (ACL) (limits hyperextension of the knee, prevents sliding of the tibia on the femur) and 2) Posterior cruciate ligament (PCL) (prevents posterior sliding of the tibia and anterior sliding of the femur when the knee is flexed. Important when walking down stairs or a steep incline)

Question 75

Why are ACL injuries more common in women?

Answer 75

1) Less space between femoral condyle in females so space for ACL movement is limited
2) Wider pelvis of females creates greater angle between tibia and femur
3) Females’ lesser muscle strength causes them to rely more on the ACL

Question 76

What are the 2 types of articular discs (menisci) in the knee?

Answer 76

1) Medial meniscus (Semi0circular piece of fibrocartilage. C-shaped)
2) Lateral meniscus (Nearly circular piece of fibrocartilage)

Medial and lateral menisci are connected to eachother by the TRANSVERSE LIGAMENT OF THE KNEE and the margins of the head of the tibia by the CORONARY LIGAMENTS

Question 77

What does the knee joint allow?

Answer 77

The knee joint allows flexion, extension, slight medial rotation and lateral rotation of the leg in the flexed position

Question 78

What is reumatism?

Answer 78

Any painful disorder of the supporting structures of the body (bones, ligaments, tendons, muscles) not caused by infection or injury

Question 79

What is arthritis?

Answer 79

Joints are swollen, stiff and painful

Question 80

What is osteoarthritis?

Answer 80

Progressive disorder of synovial joints, mainly weight bearing joints, where joint cartilage is gradually lost. Articular cartilage deteriorates and new bone forms in the subchondral areas and at margins of joint. New bone ends become exposed, spurs (small bumps) of new osseus tissue are deposited on them in an effort by the body to protect against increased friction. These spurs derease the space of the joint cavity and restrict joint movement. Mainly affects articular cartilage

Question 81

What is rheumatoid arthritis?

Answer 81

Autoimmune disease where immune system of body attacks its own tissues (cartilage and joint linings). Inflammation of synovial membrane. If untreated, membrane thickens and synovial fluid accumulates. The membrane produces abnormal grannulation tissue called PANNUS that adheres to the surface of the articular cartilage and may erode cartilage completely. When cartilge is destroyed, fibrous tissue joints the exposed bone ends. Fibrous tissue ossifies and fuses the joint so it becomes immovable

Question 82

What is gouty arthritis?

Answer 82

Sodium urate crystals are deposited in the soft tissues of the joints. Gout most often affects the joints of the feet. The crystals irritate and erode the cartilage, causing inflammation, swelling and acute pain. Eventually the crystals destroy all joint tissue. If untreated the ends of the articulating bones fuse

Question 83

What is lyme disease?

Answer 83

Caused by spiral shaped bacterium called Borrelia Burgdorferi. Symptoms: joint stiffness, fever, chills, headache, stiff neck, nausea and lower back pain. Arthritis is a complication. Aflicts larger joints like knee, ankle, hip, elbow or wrist. Symptoms may linger for years after cure.