A&P Lesson 10-11

Suture

-bones interlocked -are bound by dense fibrous connective tissue -are found ONLY in skull

Saddle joint

have complex articular faces and fit together like a rider in a saddle. Each face in concave along one axis and convex along the other. movement- angular, biaxial examples- First carpometacarpal joint

Ball-and-socket joint

in a ball-and-socket joint, the round head of one bone rests within a cup-shaped depression in another movement- angular circumduction, and rotation, triaxial examples- Shoulder joint and hip joint

Most common Knee Injury

lateral surface of leg struck pushing it medially (tears medial meniscus) -May lead to chronic problems, development of "trick knee" - feeling of knee being unstable

The Knee Joint

-A complicated hinge joint -Transfers weight from femur to tibia

The elbow joint

-A stable hinge joint -With articulations involving humerus, radius, and ulna

Synarthroses (Immovable joints)

- are very strong - edges of bones may touch or interlock -four types of synarthrotic joints: 1) Suture 2) Gomphosis 3) Synchondrosis 4) Synostosis

Processes of the Shoulder Joint

-Acromion (clavicle) and coracoid process (scapula) -Project laterally, superior to the humerus -Help stabilize the joint

Fat Pads

-Adipose tissue superficial to the joint capsule -protect articular cartilages

The Hip Joint

-Also called COXAL joint -Strong ball-and-socket diarthrosis -Wide range of motion

Intervertebral ligaments

-Bind vertebrae together -Stabilize the vertebral column

Bone and Aging

-Bone mass decreases -Bones weaken -Increases risk of hip fracture, hip dislocation, or pelvic fracture

Disorders in other body systems can cause:

-Bone tumors -Osteoporosis -Arthritis -Rickets (vitamin D deficiency)

intervertebral joints

-C2 to L5 spinal vertebrae articulate: -At inferior and superior articular processes (gliding joints) -Between adjacent vertebral bodies (symphyseal joints); adjacent vertebral bodies separated by fibrocartilage intervertebral discs; little gliding occurs here.

injuries (regarding synovial joints)

-DISLOCATION (luxation) - caused by extreme stress on joint -articulating surfaces forced out of position -damages articular cartilage, ligaments, joint capsule -Shoulder joint most prone to this injury SUBLUXATION -a partial dislocation note: "double jointed" people have weakly stabilized joints that are prone to dislocation or partial dislocation

rotation of synovial joints

-Direction of rotation from anatomical position -relative to longitudinal axis of body -LEFT and RIGHT rotation -MEDIAL rotation (inward rotation); rotates toward axis; ex. bend arm at elbow, move hand to chest -LATERAL rotation (outward rotation); rotates away from axis; ex. bent arm at elbow, move hand away from chest -PRONATION; rotates forearm, radius over ulna -SUPINATION; forearm in anatomical position note: pronation and supination are not the same as medial rotation and lateral rotation, respectively

Gomphosis

-Fibrous connection (periodontal ligament) -Binds teeth to sockets

Structures of the Hip Joint

-Head of femur fits into sockets of acetabulum of coxal bone Which is extended by fibrocartilaginous acetabular labrum - increases joint cavity depth and helps seal in synovial fluid -Hip fractures of femoral neck or between trochanters more common than dislocations

Articulations of the elbow

-Humeroulnar joint- Strongest and largest joint at elbow; Trochlea of humerus and trochlear notch of ulna; Limited movement -Humeroradial joint- Smaller joint; Capitulum of humerus and head of radius

Synchondrosis

-Is a rigid cartilaginous bridge between two bones: -Epiphyseal cartilage of long bones -Between vertebrosternal ribs and sternum

Arthritis

-Joint inflammation -all forms of rheumatism that damage articular cartilages of synovial joints -can be caused by bacterial/viral infection, injury, physical stress, metabolic problems

Planes (Axes) of Dynamic Motion

-Monaxial (1 axis)- ex. forward/backwards -Biaxial (2 axes)- ex. forward/backwards, & side to side -Triaxial (3 axes)- ex. forward/backwards, side to side, & angular

Amphiarthroses

-More movable than synarthrosis -Stronger than freely movable joint (diarthrosis) Two types of amphiarthroses: 1) Syndesmosis- bones connected by ligaments (ex. distal end of tibia and fibula) 2) Symphysis- Bones separated by fibrocartilage (ex. Pubic symphysis connects left and right coxyl bones)

Factors that stabilize synovial joints

-Prevent injury by limiting range of motion 1) Collagen fibers (joint capsule, ligaments) 2) Shape of articulating surfaces and menisci 3) Presence of other bones, muscles, or fat pads 4) Tension in the tendons of articulating bones Note: pain receptors ARE NOT found on the inside of synovial joints. Pain felt due to joint damage results from nerve that monitor the capsule, ligaments, and tendons.

joint immobilization

-Reduces flow of synovial fluid -Can cause arthritis symptoms -Treated by continuous passive motion or CPM (therapy)

Bursae

-Singular, bursa, a pouch -Pockets of synovial fluid, lined by synovial membrane -Cushion areas where tendons or ligaments rub BURSITIS- inflamed bursae causing pain. -can result from repetitive motion, irritation, trauma, or infection (ex. bunions)

Bone Support Body Systems

-Support and protect other systems -Store fat, calcium, and phosphorus -Manufacture cells for immune system

Articulations of the Knee Joint

-Two femur-tibia articulations At medial and lateral condyles -One between patella and patellar surface of femur

Joints

-a joint cannot be both mobile and strong (or rolled) -The greater the mobility, the weaker the joint -Mobile joints are supported by muscles and ligaments, not bone-to-bone connections

synovial joints (diarthroses)

-also called movable joints -at ends of long bones -within articular capsules -lined with synovial membrane

Tendons

-attach to muscles around joint -Help support joint

synovial fluid

-contains slippery proteoglycans secreted by fibroblasts -resembles interstitial fluid, not much in joint (ex. knee joint only has up to 3 mL of fluid)

Cartilages (in the joints)

-cushion the joint -fibrocartilage pad called a MENISCUS (or articualr disc; plural, menisci), located between opposing bones in synovial joint

Synostosis

-fused bones, immovable -metopic suture of skull (fuses two sides of frontal bone) -epiphyseal lines of long bones

Special Movements at Synovial Joints

-include specific articulations or unusual types of movements 1) Inversion- twists sole of foot medially 2) Eversion- twists sole of foot laterally 3) Dorsiflexion- flexion at ankle (lifting toes) 4) Plantar flexion- extension at ankle (pointing toes) 5) Opposition- Thumb movement toward fingers or palm (grasping) 6)Reposition- opposite of opposition 7)Protraction- moves anteriorly; in the horizontal plane (pushing forward) 8) Retraction- opposite of protraction, moving posteriorly (pulling back) 9) Elevation- moves in superior direction (up) 10) Depression- moves in inferior direction (down) 11) Lateral flexion- bends vertebral column from side to side.

articualr cartilages

-pad articulating surfaces within articular capsules; prevents bones from touching -Smooth surfaces lubricated by synovial fluid -has consistency of heavy molasses -functions to reduce friction

Intervertebral Discs

-pads of fibrocartilage -separate vertebral bodies -Consists of: 1)ANULUS FIBROSUS- tough outer layer; attaches disc to vertebrae through collagen fibers 2)NUCLEUS PULPOSUS- Elastic, gelatinous core;absorbs shocks, gives disc resiliency Note: discs account for almost 1/4 length of vertebral column superior to sacrum. As we age, discs lose water content- less cushioning and also shortens our height

gliding movement of synovial joints

-two surfaces slide past each other ex) between carpal or tarsal bones, clavicle and sternum

angular movements of synovial joints

1) Flexion- angular motion in the anterior-posterior plane, REDUCES angle between elements 2) Extension- angular motion in the anterior-posterior plane; INCREASES angle between elements 3) Hyperextension- angular motion; extension past anatomical position ex) extension of neck when you tilt your head back & look up at the ceiling, extend your leg behind you, or flick your wrist. 4) Abduction- angular motion in the frontal plane; moves away from longitudinal axis 5) Adduction- angular motion in the frontal plane; moves toward longitudinal axis 6) Circumduction- angular motion in a circular motion without rotation

Seven Major Supporting Ligaments (of the knee joint)

1) Patellar ligament (anterior)- attaches to tibia 2&3) Two popliteal ligaments (posterior) 4&5) Anterior and Posterior Cruciate ligaments (ACL/PCL) (inside joint capsule) 6) Tibial collateral ligament (medial) 7) Fibular collateral ligament (lateral)

Structural Classifications of joints

1) bony joint - synotoses (synarthroses); joined by bone 2) fibrous joint - sutures and gomphoses (synarthroses); syndesmoses (amphiarthroses); joined by collagen fibers 3) cartilaginous joint - synchondroses (synarthroses) and symphyses (amphiarthroses) joined by cartilage 4) synovial joint - (only diarthroses) joined by thin fluid-filled space

Factors Affecting Bone Strength

1. Age 2. Physical stress 3. Hormone levels 4. Calcium and phosphorus uptake and excretion 5. Genetic and environmental factors

Classification of joints

1. Functional classification is based on range of motion of the joint 2. Structural classification relies on the anatomical organization of the joint Note: Be careful distinguishing the difference between Function and Structural classifications

What are the THREE types of dynamic motion?

1. Linear movement (gliding) 2. Angular movement 3. Rotation

Functional classifications of joints

1. Synarthrosis (immovable joint) 2. Amphiarthrosis (slightly movable joint) 3. Diarthrosis (freely movable joint)

functions of synovial fluid

1. lubrication- articular cartilage act as sponge filled with fluid. Compression of it pushes some fluid out 2. nutrient distribution- fluid circulates as joint moves, provides nutrients to chondrocytes in area 3. shock absorption- viscosity of fluid increases with increases pressure

Vertebral Joints

AKA symphyseal joints -as vertebral column moves: 1)NUCLEUS PULPOSUS shifts 2)Disc shape conforms to motion

Rheumatoid Arthritis

An inflammatory condition Caused by infection, allergy, or autoimmune disease Involves the immune system- body attacks its own tissue (the joints)

The Articular Capsule and Joint Cavity (knee joint)

Has fibrocartilage pads (medial and lateral menisci): -Located at femur-tibia articulations -Cushion and stabilize joint -Give lateral support

Bone recycling

Living bones maintain equilibrium between: -Bone building (osteoblasts) -And breakdown (osteoclasts) *refer to previous lesson on osseous tissue

Shoulder Muscles (Rotator Cuff)

Primary mechanism for supporting shoulder joint and limiting ROM. -Supraspinatus -Infraspinatus -Subscapularis -Teres minor 5 ligaments support the shoulder joint

Degenerative changes (effects of aging on joints)

Rheumatism and Arthritis

Damage to Intervertebral Discs

Slipped Disc: -Bulge in anulus fibrosus (vertebral foramen) -Invades vertebral canal -caused by weakened posterior longitudinal ligaments of the vertebrae Herniated Disc: -Nucleus pulposus breaks through anulus fibrosus -Presses on spinal cord or nerves

Types of Movement at Synovial Joints

Terms describe: -Plane or direction of motion -Relationship between structures

Rheumatism

a pain and stiffness of skeletal and muscular systems

The Shoulder Joint

aka GLENOHUMERAL JOINT -Ball-and-socket diarthrosis; between head of humerus and glenoid cavity of scapula -Allows more motion than any other joint (is less stable) -Supported by skeletal muscles, tendons, ligaments; most support provided by skeletal muscles of the rotator cuff, some support by tendons and ligaments; damage to musces common in sports that strain the shoulder (baseball/softball pitchers, quarterbacks)

osteoarthritis

aka degenerative arthritis/ degenerative joint disease (DJD) -caused by wear and tear of joint surfaces, or genetic factors affecting collagen formation -generally in people over the age of 60- 25% women, 15% men

Plane Joint

aka gliding joints, have flattened or slightly curved surfaces that slide across one another, but the amount of movement is very slight. movement- Gliding, slight, nonaxial. examples- Acromioclavicular and claviculosternal joints; intercerpal joints; vertebrocostal joints; sacro-iliac joints

Articulation

body movement occurs at joints (articulations) where two bones connect

what are the five accessory structures?

cartilage, fat pads, ligaments, tendons, bursae

Ligaments

continuous with periostea of articulating bones (no direct blood supply) -support, strengthen joints -SPRAIN- ligaments with torn collagen fibers

gouty arthritis

crystal arthritis -Occurs when crystals (uric acid or calcium salts) form within synovial fluid -Due to metabolic disorders

joint structure

determines direction and distance of movement (ROM) Joint strength decreases as mobility increases Stronger joints=less mobile

Hinge Joints

permit angular motion in a single plane, like the opening and closing of a door movement- angular, monaxial examples- Elbow joint; Knee joint; Ankle joint; Interphalangeal joint

Pivot joint

pivots joints only permit rotation movement- rotation, monaxial examples- Atlanto-axial joint; Proximal radio-ulnar joint

shoulder separation vs dislocation

shoulder separation can result from hit to superior surface of shoulder (forcing acromion downward) Shoulder separation= dislocation of the shoulder joint (at acromion of scapula and clavicle - at the acromioclavicular joint) -Relatively common Note: dislocation shoulder is different from shoulder separation. Dislocated shoulder= dislocation at glenohumeral joint between the humerus and glenoid cavity.

Condylar joint

{AKA ellipsoidal joint} oval shaped condyle of one bone fits into elliptical cavity (depression) of other bone; back and forth motion, but not rotation movement- angular, biaxial Ex: metacarpophalangeal joints 2-5; Radiocarpal joint; Metatarsophalangeal joints.