Musculoskeletal System Joints
articular capsule
outside dense irregular connective tissue; synovial membrane is inside lining of capsule that makes synovial fluid to lubricate and nourish joint, does not cover cartilage
synovial joint condyloid movement
oval articular surfaces permit both flexion/extension, abduction/adduction, and rotation
arthritis
over 100 kinds
muscles
when contracted they hold the bone tight within a socket; helps stabilize joints by keeping tension on tendons
sprain
a stretching or tearing of a ligament; joint becomes less stable
strain
a stretching or tearing of a tendon or muscle
talocalcaneal joint
ankle and foot joint; joint between talus and calcaneus allows inversion/eversion
tibiotalus joint
ankle and foot joint; joint between tibia and talus only allows plantar and dorsiflexion
tarsometatarsal joints
ankle and foot joint; joints between tarsals/metatarsals allow gliding and help maintain arch
rheumatoid arthritis
autoimmune disease causing chronic inflammation of synovial membranes leading to swelling of joints and joint damage
glenohumeral (shoulder) joint
ball and socket type; most freely movable joint in body but least stable; synovial joint; glenoid labrum deepens glenoid cavity; articular capsule thin and loose; bursa and tendon sheaths of arm and shoulder muscles reduce friction; bicipital groove with long head biceps; rotator cuff muscle tendons contribute to joint stability
acetabulofemoral (hip) joint
ball-and-socket joint; head of femur articulates with acetabulum; movement occur in all axes, limited by ligaments, depth of acetabulum, and acetabular labrum; stability chiefly from acetabulum and capsular ligaments; muscle tendons contribute to stability; hip joint more stable than shoulder joint but less mobile
functional classification
based on amount of movement permitted; immovable joints, slightly moveable joints, freely movable joints
structural classification
based on type of material between two bones; solid: fibrous, cartilaginous; synovial
humeroulnar (elbow) joint
bone structure only allows flexion and extension; humerus' articulation with trochlear notch of ulna forms hinge; tendon of biceps and triceps brachii provide stability
syndesmosis
bones are connected by ligaments (bands of connective tissue); the longer the band the more movement
synovial joint saddle movement
both surfaces are concave and convexed allowing flexion/extension and abduction/adduction
bursae and tendon sheaths
closed sacks of synovial fluid protecting bone from rubbing tendons, ligaments, and muscles; reduce friction between body elements
knee injuries
common in sports activities; often due to excessive lateral force when foot is planted and knee is twisted
medial (deltoid) ligament
comprised of three small lateral ligaments between medial malleous of tibia and bones of foot; easily torn with over eversion
extrinsic ligaments
connect bone to bone outside the fibrous capsule
intrinsic ligaments
connect bone to bone, thickening of fibrous capsule
tendons
connect muscle to bone; dense regular connective tissue reinforce the joint capsule
unhappy triad
damage to tibial collateral ligament, medial meniscus (connected to tibial collateral ligament), anterior cruciate ligament
function of menisci of knee
deepen articular surface; act as shock absorbers
cartilaginous joints
different depending on type of cartilage between the two bones; synchondrosis, symphysis
gouty arthritis
elevated uric acid blood levels leads to crystals forming in synovial membranes causing joint inflammation and severe pain
tendon sheath
elongated bursa that wraps around a tendon
characteristics of synovial joints
ends of bones covered by hyaline cartilage; space (synovial cavity) between two bones; space surrounded by a capsule; may or may not have intervening fibrocartilagenous disc; support may come from shape of bones creating articular surface/amount of movement between bones, extrinsic and intrinsic ligaments, surrounding muscles
fibrous joints
no joint cavity, very stable with little or no movement; sutures, syndesmosis, gomphosis
fibrocartilagenous discs and labrums
occur where two bones, with different surface shapes, articulate; helps deepen the socket
strength and mobility
opposing characteristics; increase strength decrease mobility and vice versa
synovial joint ball and socket movement
multiaxial (e.g. shoulder and hip joints)
bursa
flattened fibrous sac lined by synovial membrane
synovial joint hinge movement
flex and extend (e.g. elbow, knee, and ankle)
rotator cuff
four muscles and their associated tendons: subscapularis, supraspinatus, infraspinatus, teres minor; injuries are common shoulder injuries; shoulder dislocation pops out into axilla, inferiorly
patella
glides across distal femur; increases leverage quadriceps tendon exerts on tibia; V-shaped posterior surface of patella faces knee joint cavity; stabilizes flexed knee joint by fitting in groove of femoral condyles
synovial joint plane movement
gliding type (e.g. carpal bones)
synchondrosis
immovable, stable joints between bone and hyaline cartilage (epiphyseal plate); epiphyseal plates, joint between first rib and manubrium
bursitis
inflammation of bursa due to injury or friction
factors influencing synovial joint stability
inverse relationship between amount of motion at joint and stability of joint; articular surfaces - shapes of articulating surfaces determine movements possible; ligaments - joint capsules and ligaments prevent excessive motions, in general the more ligaments the stronger the joint; muscle tone of skeletal muscles whose tendons cross the joint
symphysis
joint where fibrocartilage unites bones (pubic symphysis, intervertebral disc); resists tension and compression
articulation (joint)
junction between two or more bones, or parts of bones, of the skeleton
tibiofemoral (knee) joint
largest and most complex joint; hinge joint; flexion and extension with limited capacity for rotation; two fibrocartilage menisci within joint cavity
ligaments surrounding hip joint capsule
ligament arrangement makes extended thigh most stable joint position, lateral rotation and flexion of hip least stable joint position; hip dislocation easier when hip is flexed
ligament to femoral head
ligament within joint connects acetabulum to head of femur; helps hold femur in socket; provides route for major nutrient artery to supply femoral head
knee joint stability
ligaments: tibial and fibular collateral ligaments; medial and lateral menisci; muscles, tendons, and capsule; patella
fibular and tibial collateral ligaments
located external the fibrous joint capsule
anterior and posterior cruciate ligaments
located within fibrous capsule; named for position on tibia; each extends between proximal tibia to distal femur and cross each other like "X"
temporomandibular joint (TMJ)
modified hinge joint where head of mandible articulates with temporal bone; movements: hinge-like movement, gliding of superior surface anteriorly, lateral excursion is side-to-side
osteoarthritis (degenerative arthritis)
most common type; "wear and tear" arthritis; characterized by pitting and erosion of cartilage
synovial joints
most movable type of joint; hyaline cartilage covers the ends of the articulating bones; gliding surface, absorbs compression, protects bone
gomphosis
peg-in-socket joint (between the teeth and bone)
anterior cruciate ligament
prevents anterior sliding of tibia
posterior cruciate ligament
prevents posterior sliding of tibia
nerves and blood supply to joints
rich supply of sensory nerves: detect pain, most monitor stretching of capsule; rich blood supply: supply synovial membrane, extensive capillary beds produce synovial fluid
synovial joint pivot movement
rotate (e.g. radius/ulnar joint)
sutures
seams where bones are interconnected and tightly bound to one another by fibrous tissue
menisci of knee
semilunar wedge-shaped fibrocartilages within knee joint; medial and lateral bathed in synovial fluid and connected to joint capsule; most likely to be torn with rotation of femur
anular ligament
surrounds head of radius permitting rotational movement
ankle ligaments
thin capsule but supported by thickened ligaments
lateral ligaments
three bands connecting lateral malleous of fibula to bones of foot; easily sprained or torn when ankle is over inverted
elbow ligaments
ulnar and radial collateral ligaments; anular ligament