Lecture detailOutline Ch 8 Joints aka Bone Articulations
Define joint =
What limits the range of motion at a bone joint
a)
b)
c)
Kinds of joints: Classified in two ways
1 based on their functional characteristics
2 based on their anatomical (structural) characteristics
functional:
structural:
(functionally = {SYNARTROSiS} )
Examples:
sutures/synostoses: "sutr" = seam..." a fibrous joint with a thin layer of dense fibrous ct uniting bones of the skull. EX: any of the cranial sutures, sacroiliac joint (in adults) (functionally = {SYNARTROSiS} )
syndesmoses: "syndesmo = band or ligament..." a fibrous joint with a greater distance between the articulating bones (more ct than in a suture arranged in a bundle of ligament or a sheet of interosseous membrane) b/c fibers are longer a little "give" allowed for movement. EX: tibiofibular (distal tibia to fibula) , radius to ulna at shaft (functionally amphiarthroses)
gomphoses: "gomphosis = bolt or nail.." a fibrous joint with a peg shaped part fitting into a boney socket. EX: roots of teeth connected to bone (alveoli) by a periodontal ligament (functionally = {SYNARTROSiS} )
2. cartilaginous most have slight movement & have cartilage (hyaline or fibrous) connecting the two bones. Types are: symphysis, synchrondrosis
Examples:
symphysis: "symph = growing together.." a cartilaginous with the ends of the articulating bones covered with hyaline cartilage + a broad flat disc of fibrocartilage connecting the two bones EX: intervertebral between vertebral bodies, pubic symphysis between pubic bones (functionally {AMPHIARTHROSES} )
synchrondrosis: "syn = together, chondro = cartilage..." a cartilaginous joint with the connecting material being hyaline cartilage. EX: epiphyseal plate between epiphysis and diaphysis of a growing bone (functionally {synarthrosis}), sternocostal between sternum and rib 1 (functionally {AMPHIARTHROSES} )
3. synovial "syn = together, ov = egg) all have a joint capsule filled with fluid (synovial fluid) between the connecting bones with a variety of bone shapes. 6 sib-Types depending on the shape of the articulating surfaces and the various types of movements permitted are: plane/gliding, hinge, pivot, condyloid/ellipsoidal, saddle, ball & socket All are functionally {DIARTHROSIS}
Typical Synovial Bone joint parts:
a) synovial cavity space allowing joints to be freely moveable
b) articular cartilage hyaline cartilage smooth, slippery surface reduces friction and absorbs shock
c) articular capsule sleeve like encloses the synovial cavity and unites the articulating bones. consists of fibrous capsule and synovial membrane
d) fibrous capsule composed of two layers an outer fibrous capsule (IRDFCT) connecting the periosteum of the two bones...sometimes arranged as ligaments
e) synovial membrane and an inner synovial membrane (areolar ct)
f) synovial fluid appearance and consistency of uncooked egg white lubricates and reduces friction in the joint, supplies nutrients to and removes metabolic wastes from the chondrocytes of the articular cartilage, consists of hyaluronic acid ( imbibe water and are responsible for the resilience of cartilage), IF (filtered from blood plasma), phagocytes to remove microbes and debris of wear and tear. Changes consistency from very viscous gel like to watery with warm up. Warm up stimulates production and secretion of synovial fluid
Accessory parts include:
g) ligaments (extracapsular (outside the articular capsule) and intracapsular (inside the articular capsule) Examples: anterior and posterior cruciate ligaments
h) bursa sacklike structures (connective tissue lined by synovial membrane and filled with fluid similar to synovial fluid. situated at friction points such as between skin and bone, between tendons and bones, muscles and bone, ligaments and bones and inside articular capsules. Cushion the movement of one body part over another.
i) tendon sheath a sleeve around a tendon which allows it to freely move without friction
j) meniscus pads of fibrocartilage which modify the shape of the joint surfaces to allow a better fit, also direct the flow of synoviala fluid to areas of greatest friction
k) sometimes articular fat pads add extra cushion
Examples of synovial joints:
plane/gliding flat or slightly curved articulating surfaces: femoralpatellar (patella to femur), tibiofibular (tibia and fibula proximal end) intertarsal , intercarpal, vertebrocostal (transverse process or bodies and the ribs), sternocostal (sternum and ribs 2-7), acromioclavicular (acromion of scapula and clavicle), intervertebral (between superior and inferior articular processes),
hinge convex surface of one bone fits into the concave surface of another bone: temporomandibular (TMJ modified hinge), elbow (ulna trochlear notch with humerus trochlea), fingers and toes (adjacent phalanges), knee (modified hinge femur to tibia), ankle (tibia and fibula to talus)
pivot articulation is between the rounded jor pointed surface of one bone and a ring formed by another bone or ligament: atlantoaxial (C1 to C2), radioulnar (proximal end of radius to ulna), radioulnar (distal end of radius to ulna),
condyloid/ellipsoidal the convex oval-shaped projection of one bone fits into the oval-shaped depression of another bone: wrist radio-carpal (distal radius to scaphoid and ulna to lunate) atlanto-occipital (occipital condyles to atlas), knuckle-metacarpophalangeal (metacarpal and proximal phalanges), metatarsophalangeal (metatarsals and proximal phalanges
saddle the surface of one bone is saddle-shaped and the other bone fits as a rider would in the saddle: sternoclavicular (sternum and clavicle - shallow saddle), carpometacarpal pollex (trapezium and metacarpal 1),
ball & socket the ball-lke surface of one bone fits into a cuplike depression of another bone: shoulder-glenohumeral (scapula and humerus), hip (acetabelum and femur head),
Actions of synovial diarthrosis joints (review from Muscles)
Gliding: two flat surfaces slip over each other "back and forth"
inversion
eversion
Angular: increase/decrease angle between two joints
Flexion
Extension
Hyperextension
Abduction
Adduction
Circumduction
Rotation: turning a bone around its own long axis
medial rotation of thigh or arm
lateral rotation of thigh or arm
turning head
Special movements:
Elevation
Depression
Pronation
Supination
Protraction
Retraction
Dorsiflexion
Plantarflexion
opposition
Knee Joint Parts
tendon of quadriceps femoris muscle - strengthens joint anteriorly and externally
gastrocnemius muscle - strengthens joint posteriorly and externally
Medial meniscus semicircular fibrocartilage C-shaped attached to tibia. modify the shape of the joint surfaces to allow a better fit, also direct the flow of synoviala fluid to areas of greatest friction. Connected to lateral meniscus with transverse ligament
Lateral meniscus nearly circular fibrocartilage. modify the shape of the joint surfaces to allow a better fit, also direct the flow of synovial fluid to areas of greatest friction
Medial collateral ligament (tibial) broad flat ligament strengthens the medial aspect of the joint prohibits side to side movement
Lateral collateral ligament (fibular) strong, rounded ligament strengthens lateral aspect of joint and prohibits side-to-side movement
Anterior cruciate ligament (ACL) - passes posterior and laterally from anterior through intercondylar area of the tibia to the posterior medial surface of the lateral condyle of tibia limits hyperextension and prevents anterior sliding of tibia on femur
Posterior cruciate ligament (PCL) passes anteriorly and medially from posterior through intercondylar area to anterior medial condyle of the femur. prevents posterior sliding of tibia when knee if flexed
Patellar ligament - continuation of the quadriceps femoris tendon from patella to gibial tuberosity. Strengthens anterior portion of joint
popliteal ligament - broad flat ligament from intercondylar fossa supporst the posterior surface of the knee
suprapatellar bursa between inferior part of femur and deep surface of quadriceps femoris muscle
Infrapatellar bursa between superior part of tibia and patellar ligament
prepatellar bursa between patella and skin
Arcurate ligament Y shaped connects fibular head to popliteal muscle and gastrocnemius
Hip Joint Parts
iliofemoral ligaments 2 ligaments connecting femur to ilium *known as strongest ligament in the body that keeps trunk from falling backward when standing and relaxes to let us sit.
pubofemoral ligament connects femur to pubic bones and restricts abduction in the hip joint to prevent dislocation
ligamentum teres intracapsular and connects head of fibula from fovea capitis to acetabulum
ischiofemoral ligament connects femur to ischium and prevents medial rotation
acetabular labrum rim of fibro cartilage around the acetabulum to make a tight fit