a&p 1 exam 2 full set

joint (articulation)

any point where two bones meet, whether or not the bones are moveable at that interface

arthology

science of joint structure, function, and dysfunction

kinesiology

the study of musculoskeletal movement

how are joints named

from the bones involved- ex: atlanto-occipital joint, radioulnar joint

how are joints classified

structure- manner in which bones are bound together; function- how freely bones move

synostosis- bony joints

an immovable joint formed when the gap between two bones ossifies and two bones become one; also form by ossification of fibrous or cartilagenous joints; ex- left and right mandibular bones fuse in infancy, cranial sutures in elderly people

synarthrosis- fibrous joints

adjacent bones are bound by collagen fibers that emerge from one bone and penetrate into the other; three types- sutures, gomphoses, syndesmoses

sutures- synarthrosis

immobile or slightly mobile fibrous joints in which short collagen fibers bind the bones of the skull to each other; serrate- interlocking wavy lines; lap (squamous)- overlapping beveled edges; plane (butt)- straight non-overlapping edges

gomphosis- synarthrosis

attachment of tooth to socket; held in place by fibrous periodontal ligament- collagen fibers attach tooth to jaw bone, allows the tooth to move a little under the stress of chewing

syndesmosis- synarthrosis

a fibrous joint at which two bones are bound by long collagen fibers- gives bone more mobility; very mobile example- interosseous membrane joining radius to ulna allowing supination; less mobile example- joint between tibia and fibula

synchondrosis- cartilagenous joint

bones joined by hyaline cartilage; temporary joints in the epiphyseal plates in children; first rib attachment to sternum- other costal cartilage joined by synovial joints

symphysis- cartilagenous joints

two bones joined by fibrocartilage; pubic symphysis joins right and left pubic bones with interpubic discs; bodies of vertebrae joined by intervertebral discs, only slight movements between adjacent vertebrae

diarthrosis- synovial joints

joint in which two bones are separated by a joint cavity, most are freely moveable, most structurally complex type of joint

articular cartilage

layer of hyaline cartilage that covers the facing surfaces of two bones

joint (articular) cavity

separates articular surfaces

synovial fluid

slippery lubricant in joint cavity; nourishes articular cartilage and removes waste; makes movement of synovial joint almost friction free

joint (articular) capsule

connective tissue that encloses the cavity and retains the fluid; outer fibrous capsule- continuous with periosteum of adjoining bones; inner (cellular) synovial membrane- composed mainly of fibroblast-like cells that secrete synovial fluid and macrophages that remove debris from the joint cavity

articular disc- general anatomy of synovial joints

forms a pad between articulating bones that crosses the entire joint capsule; ex- temporomandibular joint

meniscus- synovial joint

moon shaped cartilage in knee, extend inward from the left and right; these cartilages absorb shock and pressure; guides bones across each other and improve their fit together; stabilizes the joint, reducing the chance of dislocation

tendon- synovial joint

strip of collagenous tissue attaching muscle to bone

ligament- synovial joint

strip of collagenous tissue attaching one bone to another

bursa- synovial joint

fibrous sac filled with synovial fluid, located between muscles, where tendons pass over bone and skin

tendon sheath- synovial joints

elongated cylindrical bursa wrapped around a tendon

lever

any elongated, rigid object that rotates around a fixed point called a fulcrum; rotation occurs when an effort applied overcomes resistance (load) at some other point; resistance arm and effort arm described relative to fulcrum

first kind of advantage conferred by a lever

exerting more force against a resisting object than the force applied to the lever; moving a heavy object with help of crowbar

second kind of advantage conferred by a lever

moving the resisting object farther or faster than the effort arm is moved; movement of rowing a boat

relationship between exerting more force and moving resisting object faster or farther

indirect, as one increases the other decreases

mechanical advantage (MA) of a lever

the ratio of its output force to its input force; calculated from length of effort arm divided by length of resistance arm

MA > 1.0

lever produces more force but less speed and distance than force exerted on it

MA < 1.0

lever produces more speed or distance but less force than input; ex- contraction of brachialis muscle puts more power into lever than we get out of it, but hand moves faster and farther than spot of brachialis attachment

first class lever

has fulcrum in the middle between effort and resistance (EFR);ex- atlanto-occipital joint lies between the muscles on the back of the neck (applying effort) and the weight of the face (resistance); loss of muscle tone occurs when you nod off in class (seesaw)

second class lever

resistance between fulcrum and effort (FRE); ex- when bouncing a baby on your knee, hip is fulcrum, baby’s weight is resistance, and effort is applied at the tibia (wheelbarrow)

third class lever

effort between the resistance and fulcrum (REF); most joints of the body; the effort of a biceps curl is applied to the forearm between the elbow joint (fulcrum) and the weight in the hand (resistance) (rowing a boat)

range of motion (ROM)

the degrees through which a joint can move; aspect of joint performance; physical assessment of patient’s joint flexibility

ROM determined by

structure of articular surfaces: elbow- olecranon of ulna fits into olecranon fossa of humerus;

strength and tautness of ligaments and joint capsules: strengthening of ligaments increases ROM; double jointed people have long or slack ligaments;

action of the muscles and tendons: nervous system monitors joint position and muscle tone (state of tension maintained in resting muscles)

axis of rotation

a moving bone has a relatively stationary axis of rotation that passes through the bone in a direction perpendicular to the plane of movement; multiaxial, biaxial, monoaxaial

multiaxial joint

shoulder joint has three degrees of freedom or axes of rotation

ball and socket joints- synovial joints

smooth, hemispherical head fits into cup-like socket; only multiaxial joints in the body; ex- head of femur fits into acetabulum of hip, head of humerus fits into glenoid cavity of scapula

condylar (ellipsoid) joints- synovial joints

oval convex surface of one bone fits into a complementary shaped depression on another; biaxial joints- radiocarpal joint where radius meets carpal of wrist, metacarpophalangeal joints where metacarpals meet phalanges in hand

saddle joints- synovial joints

both bones have an articular surface that is shaped like a saddle, one concave, one convex; biaxial joints- trapeziometacarpal (opposable thumb), sternoclavicular joint between sternum and clavicle

plane (gliding) joints- synovial joints

flat articular surfaces, bones slide over each other, relatively limited movement; usually biaxial joints- between carpal bones of wrist/tarsal bones of ankle, also between articular processes of vertebrae

hinge joints- synovial joints

one bone with convex surface fits into a concave depression; monoaxial joints- move freely in one plane; ex- elbow (ulna and humerus), knee (femur and tibia), joints within fingers and toes

pivot joints- synovial joints

a bone spins on its longitudinal axis; monoaxial joints; ex- atlantoaxial joint has transverse ligament (C1 and C2), proximal radioulnar joint has annular ligament

zero position- synovial joints

the position of joint when a person in standard anatomical position; joint movements described as deviating from the zero position or returning to it

flexion- synovial joints

movement that decreases joint angle; common in hinge joints

extension- synovial joints

movement that straightens a joint and returns body part to zero position

hyperextension- synovial joints

extension of a joint beyond the zero position; flexion and extension occur at nearly all diarthroses, limited to a few

abduction- synovial joints

movement of a body part in the frontal plane away from midline; hyperabduction- raise arm over back or front of head

adduction- synovial joint

movement in the frontal plane back toward midline; hyperadduction -crossing fingers, crossing ankles

elevation- synovial joints

movement that raises a body part vertically in frontal plane

depression- synovial joints

movement that lowers a body part in the same plane

protraction- synovial joint

the anterior movement of a body part in the transverse plane

retraction- synovial joint

posterior movement of a body part in the transverse plane

circumduction- synovial joint

one end of an appendage remains stationary while other end makes a circular motion; ex- an artist circumducts their upper limb when painting a circle

rotation- synovial joint

movement in which a bone spins on its longitudinal axis; rotation of trunk, thigh, head, or arm; medial (internal)- turns bone inward; lateral (external)- turns bone outward

supination- synovial joint

forearm movement that turns palm to face anteriorly or upward; forearm supinated in anatomical position; radius parallel to ulna

pronation- synovial joints

forearm movement that turns palm to face either posteriorly or downward; head of radius spins; radius crosses stationary ulna like an X

flexion- special movements of head and trunk

forward bending movements at waist or neck

extension- special movement of head and trunk

straightens trunk or neck

hyperextension- special movement of head and trunk

bending over backwards

lateral flexion- special movement of head and trunk

tilting head or trunk to right or left at midline

lateral excursion- special movements of the mandible

right or left movement from the zero position

medial excursion- special movements of the mandible

movement back to median, zero position; side to side grinding during chewing

radial flexion- special movement of the hand and digits

tilting hand toward thumb

ulnar flexion- special movements of the hand and digits

tilting hand toward little finger

abduction vs adduction of the fingers

spreading them apart vs bringing them together

flexion vs extension of the fingers

curling vs straightening them

palmar abduction

moving thumb away from hand and pointing it anteriorly

radial abduction

moving thumb away from the index finger (90 degrees)

flexion of thumb

tip of thumb directed toward palm

extension of thumb

straightening the thumb

opposition- special movements of the hand and digits

moving thumb to touch tip of a finger

reposition- special movements of the hand and digits

returning thumb to the zero position

dorsiflexion

elevating toes while swinging foot forward to take a step (heel strike)

plantarflexion

extending foot so toes point downward as in standing on tiptoe (toe-off)

foot inversion

movement in which the soles are turned medially

foot eversion

movement in which the soles are turned laterally

supination of foot

complex combination of plantar flexion, inversion, and adduction

pronation of foot

complex combination of dorsiflexion, eversion, and abduction

temporomandibular (jaw) joint (TMJ)

articulation of the condyle of the mandible with the mandibular fossa of the temporal bone; two ligaments support joint: lateral ligament- prevents posterior displacement of mandible, sphenomandibular- ligament on medial side; deep yawn or strenuous depression can dislocate

the shoulder joint

supported by biceps brachii tendon anteriorly and rotator cuff tendons; tendons fuse to joint capsule and strengthen it; supraspinatus, infraspinatus, teres minor, subscapularis; five principle ligaments support shoulder: three are called the glenohumeral ligaments, coracohumeral ligament, transverse humeral ligament; four bursae at shoulder- subdeltoid, subacromial, subcoracoid, subscapular bursae

the elbow joint

a hinge that includes 2 articulations- humeroulnar joint, humeroradial joint, has olecranon bursa, radial (lateral) collateral ligament, ulnar (medial) collateral ligament, proximal radioulnar joint

the hip joint

coxal joint: head of femur inserts into acetabulum of hip bone- bears weight, has deeper socket, more stable than shoulder

the knee joint

tibiofemoral joint: largest and most complex diarthrosis of the body; primarily a hinge joint- capable of slight rotation and lateral gliding when knee is flexed; has 13 bursae; ability to lock and unlock knees is important in human bipedalism- ACL allows locking, popliteus contracts and rotates femur to unlock

acetabulum labrum- hip joint

horseshoe shaped ring of fibrocartilage that deepens socket

ligaments supporting hip joint

iliofemoral and pubofemoral (anterior), ischiofemoral ligament (posterior)- when standing, ligaments become twised and pull head of femur tightly into acetabulum, transverse acetabulum ligament bridges gap on inferior margin of acetabulum labrum

fovea capitis- hip joint

pit on head of femur where round ligament attaches

round ligament (ligamentum teres)- hip joint

arises from fovea capitis and attaches to lower margin of acetabulum

humeroulnar joint- elbow joint

trochlea of humerus joins trochlear notch of ulna

humeroradial joint- elbow joint

capitulum of humerus meets head of radius

olecranon bursa- elbow joint

on posterior side of elbow and eases movements of tendons

radial (lateral) collateral ligament and ulnar (medial) collateral ligament

restrict side to side motions

proximal radioulnar joint- elbow joint

functions as a pivot, not a hinge; head of radius fits into radial notch of ulna; held in place by annular ligament encircling radial head; allows for pronation and supination

patellofemoral joint- knee joint

gliding joint

joint capsule- knee joint

encloses only the lateral and posterior aspects of the knee; anterior aspect covered by patellar ligament and lateral and medial retinacular ligament

knee stabilized by

quadriceps tendon in front, tendon of semimembranosus muscle on rear thigh

lateral and medial meniscus- knee joint

c-shaped cartilages within joint capsule; absorb shock and prevent side to side rocking, joined by transverse ligament

the knee joint- popliteal (posterior) region

extracapsular ligaments- fibular (lateral) collateral ligament, tibial (medial) collateral ligament; intracapsular ligaments cross each other to form an X- anterior cruciate ligament (ACL) prevents hyperextension of knee when ACL is pulled tight and is a common site of injury, posterior cruciate ligament (PCL) prevents femur from sliding off tibia

knee injuries and arthroscopic surgery

highly vulnerable to rotation and horizontal stress, most common injuries to menisci and anterior cruciate ligament (ACL), heal slowly due to lack of blood flow

arthroscopy

procedure in which interior of joint is viewed with a pencil-thin arthroscope inserted through small incision; less invasive damage than a conventional surgery, recover quicker