KNH244: Exam 2

Module 2, Part2; Module 3, and Module 4 (slide 15)

What is an articulation?

joint

What determines the limit of movement of a joint?

configuration of the bones that form an articulation and the reinforcing ligaments

What is a joint?

junction or pivot between bones

What is the major function of joints?

movement

What are some factors that can affect the structure and function of joints?

trauma, immobilization, disease, aging, exercise

What are three characteristics of joints?

weight bearing, shock absorption, stability-mobility tradeoff

What is the stability-mobility tradeoff?

a continuum in which a joint can be very stable or very mobile

What is simple joint?

a joint that joins 2 bones

What is a compound joint?

a joint that joins 3 or more bones

What determines structural classifcation of a joint?

the soft tissue that connects cones determines classification

What is a functional joint?

a joint that has no soft tissue connection

What are the three structural classifications of joints?

fibrous, cartilaginous, and synovial

What the three types of functional classifications of joints?

synarthrotic, amphiarthrotic, and diarthrotic

What does a fibrous structural classification mean?

dense fibrous tissue joins the bones

What does a cartilaginous structural classification mean?

fibrocartilage or hyaline cartilage joins bones

What does a synovial structural classification mean?

joint capsule joins bones

What does a synarthrotic (fibrous) functional classification mean?

little/no movement at the joint

What does a amphiarthrotic (cartilaginous) functional classification mean?

moderate/little movement at the joint

What does a diarthrotic (synovial) functional classification mean?

the joint is freely moveable

What structures are always present at a diarthrotic (synovial) joint?

synovial fluid, articular cavity, articular cartilage, articular capsule, synovial membrane, ligaments, blood vessels and sensory nerves

What is synovial fluid?

fluid that is found inside the articular cavity

What is the articular cavity?

the space between two bones

What is a fibrous/articular capsule?

binds the articular capsule so fluid does not come through

What is articular cartilage?

cartilage that lines the surface of the bone and gives bone flexibility, strength and protection

What is synovial membrane?

membrane that produces fluid to fill the articular cavity, and filter the blood so only certain things enter the capsule

What structures are sometimes found at diarthrotic (synovial) joints?

menisci, fat pads, labrum, synovial plicae

What are menisci?

structures found in the knees that act as cushions

What are fat pads?

provide protection, and insulation

What is a labrum?

fibrous, soft tissue connection that increase joint space

What are synovial plicae?

remints of the synovial membrane

What is a plane joint/nonaxial/gliding joint?

joints are flat or slightly curved surfaces, that permits gliding/sliding movements (no axis)

What are uniaxial joints?

joint that has one degree of freedom

What the two types of uniaxial joints?

hinge and pivot

What is a hinge joint (uniaxial)?

have a convex/cave surface that permits flexion/extension (one degree of freedom) ex. humeroulnar joint

What is a pivot joint (uniaxial)?

have a peg and ring (one degree of freedom) ex. atlas and axis in the neck

What is a condyloid joint (biaxial)?

oval or egg shape convex surface fitting into a reciprocal concave surface, permits flexion/extension, abduction/adduction and circumduction, ex. carpometacarpal joint

What a saddle joint (biaxial)

modification of condyloid, both surfaces are convex and concave and permits flexion/extension, abduction/adduction and circumduction ex. base of thumb, and sternoclavicular joint

What is a ball and socket joint (triaxial)?

head of one bone fits into the cup of the other bone

What are the types of fibrous joints?

syndesmosis, suture, and gomphosis

What is a syndesmosis (fibrous) joint?

soft tissue connections, ex. between the radius and the ulna

What is a suture joint?

joints between two skull bones

What is a gomphosis joint?

joint between the mandible and the teeth

What are the two types of cartilaginous joints?

symphysis and synchrondrosis

What are symphysis joints?

fibrocartilage discs in the spine and pubic

What are synchrondosis joints?

hyaline cartilage in the costal cartilage or the growth plate

What is the main and secondary functions of joints?

main function of joints to provide movement, and the secondary function is provide the movement with some degree of stability

What is Emerson’s law?

for everything that is given, something is taken

What is the relationship between movement and stability?

inverse relationship, more movement means less stability

How is joint stability defined?

resistance to displacement

What are the three main factors that are responsible for the stability of bones?

shape of bone, ligaments/joint capsule/muscle

What is the closed-packed position of the joint?

the most stable position of the joint ex. the femur on the tibia in full extension with as much of the femur touching the tibia as possible

What is an open-packed position of a joint?

the least stable position of the joint ex. the femur on the tibia in flexion, with less of the femur touching the tibia

How are the hip and shoulder different in terms of stability?

the hip is more stable than the shoulder because the hips socket is deeper than the glenoid cavity, the ligaments at the hip tend to be bigger and the muscles are the hip tend to be stronger (shape, ligaments, muscle)

What factors contribute to the mobility/stability of a joint?

shape of the bony structure, ligament arrangements, and muscular arrangement

How can the shape of a bony structure influence the mobility/stability of the joint?

may refer to the type of joint (ex. hinge vs. ball and socket), or other characteristics of the a joint (ex. depth of a socket)

How can ligamentous arrangements influence joint mobility/stability?

help maintain relationship of bones, check movements at normal limits of joints, resist movements for movements which the joint is not constructed

How does muscular arrangement influence mobility/stability of a joint?

muscles that span joints aid in stability

What are some factors affecting the range of motion ?

shape of articular surfaces, restraining effect of ligaments, and muscles and tendons

Flexibility at the joint should not exceed what?

muscle’s ability to maintain integrity at the joint

What are some additional factors that influence range of motion?

gender, body build, heredity, occupation, exercise and age

How do you assess a joint’s range of motion?

measure the degrees from starting position to its maximal movement

How would you use a goniometer to measure range of motion?

axis is placed over center of the joint, one arm held stationary and the other arms held moving segment

How would you use a film or videotape to assess a joint’s range of motion?

center of joints are marled to be visible in image, and segment action must occur in picture plane

What are the two types of muscle classifications?

axial and appendicular muscles

What are axial muscles?

muscles of the head, neck and trunk

What are appendicular muscles?

muscles of the limbs

What type of muscles tend to have similar functions?

muscles on one side of a joint and those in the same compartment

How do muscles attach to bones?

attachments/tendons

What is the proximal end of a tendon called?

origin of the muscle

What is the distal end of the tendon called?

insertion of the muscle

What part of the muscle shortens and creates tension which pulls the tendons and bones?

the “belly” of the muscle

What is the ultimate force generator in the body?

muscles

Movement of muscles means what about the forces?

forces are not equal

Stability of muscles means what about the forces?

forces are equal

What are some functions of muscle?

pression metabolic processes, major heat, waste and expression

What is the difference between skeletal muscles and cardiac and smooth muscle?

skeletal muscle is voluntary, while cardiac and smooth muscle are involuntary

What are some properties of skeletal muscle?

extensibility and elasticity, excitability (irritability), conductivity and contractility

What does extensibility (stretch) and elasticity (recoil) mean?

means that the muscle is able to be stretched and returned to normal length

What does excitability (irritability) mean?

stimulation produces electrical charge

What does conductivity mean?

conduction of electrical excitation (via muscle stimulation) along membrane initiating contraction

What does contractility mean?

ability to shorten and produce tension

What is fascia?

sheet of fibrous tissue that compartmentalizes groups of muscles

What does the tendon do?

connects muscle to bone

How is the muscular system organized?

skeletal muscle, muscle fascicle, muscle fiber, myofibrils, and sarcomere

What does epimysium do?

fascia that surrounds the whole muscle

What does perimysium do?

binds muscle fascicles (fiber bundles)

What does endomysium do?

surrounds each muscle fiber fiber or cell

What does sarcolemma do?

surrounds the outside of the sarcomere (cell membrane) that is excitbale because there is a difference in charge between inside and the outside of the cell

What are openings into the transverse tubules?

little holes in the sarcolemma

What does the sarcoplasmic reticulum do?

releases calcium when stimulated, which then causes proteins within the sarcomere to bind the actin and mysoin

What is actin?

light band/thin filament (myofilament)

What is myosin?

dark band/thick filament (myofilament)

How do the myofilaments actin and myosin interact?

cross-bridges

If you do not have cross bridges then you cannot do what?

you cannot produce force

The more cross-bridges you have active at any time means what?

means that greater force within a muscle

The force a muscle can exert is proportional to what?

it’s physiological cross-section, meaning that thicker muscle has greater force potential

What is another factor (in addition to cross-section) that determines force?

pennation angle or angle of orientation between muscle fibers and tendon also determines force

If muscle fibers attach parallel to tendon (0 degrees) then what happens to the force?

all force that is generated is transmitted

Which is stronger, a pennate muscle or a longitudinal muscle at the same thickness?

a pennate muscle of the same thickness as a longitudinal muscle can exert greater force