Skeletal System ch. 9 joints

Joints/articulations or arthrosis

*Sites or points of contact between two bones ( bones and cartilage or between bone and teeth) * Rigid elements of skeleton meet at articulations (bones to rigids to bend, movement involves) articulations and contraction.

tempormandibular joint

- modified hinge joint - head of mandible articulates with temporal bone - lateral excursion is side-side movement - Two surfaces of the articular disc allow - hinge-like movement - gliding of superior surface anteriorly

intracapsular ligaments

-anterior and posterior Cruciate ligaments: - prevent undesirable movements at knee - cross each other like an X - each cruciate ligament runs from proximal tibia to distal femur

Inflammatory and Degenerative Conditions I

Arthritis: describes over 100 kinds of joint damaging diseases - painful, stiff and swollen joints •Osteoarthritis: most common type of arthritis - joint disease where joint cartilage is gradually lost - causes: aging, obesity, irritation of joints, muscle weakness •Rheumatoid arthritis: chronic inflammatory disorder - autoimmune disease •Gouthy arthritis: uric acid buildup in soft tissues and joints due to sodium urate crystal deposition - usually affects joints of feet especially at the base of big toe - crystals irritate and erode cartilage causing

plane joints (synovial)

Articular surfaces are flat planes. Short gliding movements are allowed. Nonaxial

Severe rheumatoid arthritis

Autoimmune disease - immune system attacks cartilage and joint linings (usually bilaterally) -Characterized by inflammation of the synovial membrane with swelling, pain and loss of function -Membrane produces an abnormal granulation tissue (pannus) that adheres to the articular cartilage, eroding and destroying it - Fibrous tissue joints exposed bone ends and ossifies, fusing the joing (immovable)

Syndesmosis (fibrous joint)

Bones connected exclusively by ligments. Amount of movement depends on length of fibers.

Symphyses (Cartilaginous Joint)

Bones united by fibrocartilage. Resist tension and compression. Slightly movable joint provides strength and flexibility

ligaments (Factors influencing stability of synovial joint)

Capsules and ligaments prevent excessive motion

Muscle tone (Factors influencing stability of synovial joints)

Constant low level contractile force generated by muscles . Stabilizes joints

Supination (synovial joints)

Forearm rotates laterally, palms faces posterioriy

Pronation (synovial joints)

Forearm rotates medially, palm faces posterior

Glenohumeral (shoulder) joint:

Glenohumeral (shoulder) joint: •The most freely movable joint lacks stability •Articular capsule is thin and loose •Muscle tendons contribute to joint stability

What are the 3 basic types of movement?

Gliding, angular movement, rotation

Knee Synovial Joint

Knee Joint: •Largest and most complex joint •Acts primarily as a hinge joint •Has some capacity for rotation when leg is fixed •Structurally considered compound and bicondyloid •Two fibrocartilage menisci occur within the joint cavity •Femeropatellar joint - shares the joint cavity - allows patella to glide across the distal femur

condylar joint (ellipsoid joint)

Knuckles, wrist joints. Allow moving bone to travel.

Elevation (synovial joints)

Lifting body parts superiorly

Ligaments of the knee joint

Ligaments of the knee joint become taut when knee is extended •Extracapsular and capsular ligaments : Fibular and tibial collateral ligament •Oblique popliteal ligament •Arcuate popliteal ligament

angular movements of synovial joints

Movement changes the angle between bone. Movement involve flexion and extension. Abducted and adduction. Circumduction.

Depression (synovial joints)

Moving elevated part inferior

Protraction (synovial joints)

Nonangular movement anteriorly

Retraction (synovial joints)

Nonangular movement posteriorly

Gliding

One bone slips arcoss the surface of the other. Flat surface of two bones slip across each other

Gomphoses (fibrous joints)

Peg-in-socket joints of teeth in alveolar sockets Fibrous connection is the periodontal ligament

Pivot joints

Pivot joints allow rotation arround an axis. The neck and forearms have pivot joints.

sternoclavicular joint

Saddle joint surround with 4 ligaments. Anterior and posterior Sternoclavicular ligaments, interclavicular ligaments, costoclavicular ligaments.

Stabilizing function of cruciate ligaments

See Image

Stabilizing function of cruciate ligaments 2

See Image

Wrist joints

Stabilized by numerous ligaments •Composed of radiocarpal and intercarpal joint - radiocarpal joint- joint between radius and proximal carpals (Scaphoid and lunate) - allows for flexion, extension, adduction , abduction and circumduction - Intercarpal joint - joint between proximal and distal rows of carpals - allows for gliding movement.

synovial joints

The most movable joints of the body. Are all diarthroses. Each contain a fluid filled joint cavity

Opposition (synovial joints)

Thumbs move across the palms to touch tip of other fingers

rotation of synovial joints

Turning movement around bones long axis. The movement only allowed between atlas and axis vertebrae. Shoulder and hips.

Aversion (synovial joints)

Turns sole laterally

Inversion (synovial joints)

Turns sole medially

Joint cavity (synovial cavity)

Unique to synovial joints Cavity is a potential space that holds a small amount of synovial fluid

synovial fluid

Viscous fluid similar to raw egg whites. Filtrate of blood arises from capillaries in synovial membrane. Contains glycoprotein molecules secreted by fibroblast.

bursa

a flattened fibrous sac lined by a synovial membrane

cartilaginous joints

bones held together by cartilage

fibrous joints

bones joined by fibrous tissue; no joint cavity is present

synovial joints (fibrous joint)

bones separated by joint cavity

synchondroses

bones united by hyaline cartilage

hinge joints

elbow, knee, ankle/ uniaxial

tendon sheath

elongated bursa that wraps around a tendon

Diarthrosis

freely movable joint, common on the appendicular skeleton

articular cartilage of synovial joint

hyaline cartilage covers, but doesn't join articular surfaces;reduces friction, absorbs shock

Synarthrosis

immovable joint, common on the axial skeleton

Sutures (fibrous joint)

immovable or slightly movable fibrous joints that closely bind the bones of the skull to each other Bones Connected by fibrous tissue

articular capsule

joint cavity is enclosed in a two-layered capsule. Fibrous layer dense irregular connective tissue. Strengthen joint. Synovial membrane Loose connective tissue.

nerves and vessels

richly supplied with sensory nerves and blood. Detect pain. How rich blood supply. Some synovial joints contain in articular disc

Articular surface ( Factors influencing stability of synovial joints)

shape determines what movements are possible

Amphiarthrosis

slightly movable joint, common on the axial skeleton

ball and socket joint

spherical head of one bone fits into a round socket in another; i.e. shoulder and hip

Kinesiology

study of human movement

Arthology

study of joints

reinforcing ligaments

thickened parts of the fibrous capsule. Extracapsular ligments.Located outside the capsule. Intracapsule ligaments Located internal to tge capsule.

saddle joint

thumb; allows grasping and rotation, biaxial

Dorsiflexion and planter flexion (synovial joints)

up and down movements of the foot at the foot

The Joints Throughout Life

• •Synovial joints develop from mesenchyme •By week 8 of fetal development, joints resemble adult joints - outer region of mesenchyme becomes fibrous joint capsule - inner region becomes joint cavity •During youth - injury may tear an epiphysis off a bone shaft •Advancing age - osteoarthritis becomes more common •Exercise helps maintain joint health

Elbow synovial joint

•Allows flexion and extension •Articulation of humerus with trochlear notch of ulna forms the hinge •Tendons of biceps and triceps brachii provide stability •Radial & ulnar collateral ligaments - prevent lateral and medial movements

Inflammatory and Degenerative Conditions

•Bursitis: - inflammation of bursa due to injury or friction •Tendonitis: - inflammation of a tendon sheath •Rheumatism: - painful disorder of supporting structures - bones, ligaments, tendons or muscles •Lyme disease: - inflammatory disease often resulting in joint pain

capsule of knee joint

•Covers posterior and lateral aspects of the knee •Covers tibial and femoral condyles •Does not cover the anterior aspect of the knee •Anteriorly covered by three ligaments - patellar ligament - medial and lateral patellar retinacula Extracapsular ligaments: reinforces joint -fibular and tibial collateral ligaments -Oblique and arcuate popliteal ligaments Intracapsular ligaments: stabilizes joint -Anterior and posterior cruciate ligaments

Ankle Synovial Joint

•Hinge joint between united inferior ends of tibia and fibula and talus of the foot •Allows dorsiflexion and plantar flexion only movements •Medially and laterally stabilized by ligaments: - medial (deltoid) ligament and lateral ligaments • Inferior ends of tibia and fibula are joined by ligaments: - anterior and posterior tibiofibular ligaments

The Unhappy Triad

•Lateral blow to the knee can tear: - Tibial collateral ligament and medial meniscus - Anterior cruciate ligament

Hip Synovial Joint

•Movements occur in all axes but limited by ligaments and acetabulum •Head of femur articulates with acetabulum •Stability comes chiefly from acetabulum and capsular ligaments •Muscle tendon contributes somewhat to stability •Iliofemoral, pubofemoral and ischiofemoral ligaments increase stability

Disorders of the Joints

•Structures of joints make them prone to traumatic stress •Function of joints make them subject to friction and wear •Affected by inflammatory and degenerative processes Joint injuries: •Torn cartilage: - common injury to meniscus of knee joint •Sprains: - ligaments of a reinforcing joint are stretched or torn •Disclocation: - occurs when bones of joint are forced out of alignment

Glenohumeral (Shoulder)joint: Rotator Cuff

•The Rotator cuff is made up of four muscles and their associated tendons-contribute to most of joint stability - Subscapular - Supraspinatus - Infraspinatus - Teres minor •Rotator cuff injuries are common shoulder injuries