Week 7: Joints

Fibrous Joints

-Bones joined by dense fibrous connective tissue -No joint cavity -Most are immovable -Depends on length of connective tissue fibers

General Structure of Synovial Joints

1. Articular Cartilage 2. Joint (synovial) Cavity 3. Articular (joint) capsule 4.Synovial Fluid: 5. Different types of reinforcing ligaments 6. Nerves and Blood Vessels

Factors Influencing Stability of Synovial Joints

3 factors determine stability of joints to prevent dislocations: 1. Shape of Articular Surface **Shallow surfaces less stable than ball-and-socket 2.Ligament number and location (limited role) **The more ligaments, the stronger the joint 3.Muscle tone keeps tendons taut as they cross joints (most important)

Bursae and Tendon Sheaths

Bags of synovial fluid that act as lubricating "ball bearing" Not strictly part of synovial joints, but closely associated

Synovial Joints

Bones separated by fluid-filled joint cavity All are diarthrotic (freely movable) Include almost all limb joints

Cartilaginous Joints

Bones united by cartilage Like fibrous joints, have no joint cavity Not highly movable Two types: Synchondroses & Symphyses

Synchondroses

Bones united by hyaline cartilage. Almost all are synarthrotic (immovable) Examples: -Temporary epiphyseal plate joints. Become synostoses after plate closure -Cartilage of 1st rib with manubrium of sternum

WHAT IS A FLATTENED SAC THAT REDUCES FRICTION BETWEEN ADJACENT STRUCTURES DURING JOINT ACTIVITY CALLED?

Bursae

Reinforcing Ligaments (general structure)

Capsular: thickened part of fibrous layer Extracapsular: outside the capsule Intracapsular: deep to capsule; covered by synovial membrane

LYME DISEASE IS

Caused by bacteria Borrelia burgdorferi

THE SITE WHERE TWO OR MORE BONES MEET IS CALLED A(N) __________.

articulation site

articular discs (menisci) (general structure)

Fibrocartilage separates articular surfaces to improve "fit" of bone ends, stabilize joint, and reduce wear and tear

Symphyses

Fibrocartilage unites bone in symphysis joint Symphyses are strong, amphiarthrotic (slightly movable) joints Examples:Intervertebral joints & Pubic symphysis

Periodontal Ligament

Fibrous connection that holds the tooth in the socket

WHICH OF THE FOLLOWING CORRECTLY LISTS THE THREE STRUCTURAL TYPES OF JOINTS?

Fibrous, cartilaginous, synovial

What joints show evidence of degeneration in nearly all individuals as aging progresses?

Knees and hips, shoulders, elbows

THE KNEE JOINT IS MOST SUSCEPTIBLE TO INJURY WHEN __________ BLOWS ARE APPLIED TO THE KNEE.

Lateral

THE __________ THE LIGAMENT FIBERS OF A SYNDESMOSIS, THE __________ THE DEGREE OF MOVEMENT.

Longer; greater

THE GREATEST DEGREE OF MOTION THAT SYNOVIAL JOINTS DISPLAY IS DESCRIBED AS __________.

Multiaxial Movement

Nerves & Blood Vessels (general structure)

Nerves detect pain; monitor joint position and stretch Capillary beds supply filtrate for synovial fluid

Range of motion allowed by synovial joints

Nonaxial—slipping movements only Uniaxial—movement in one plane Biaxial—movement in two planes Multiaxial—movement in or around all three planes

Gliding Movements

One flat bone surface glides or slips over another similar surface Examples: -Intercarpal joints -Intertarsal joints -Between articular processes of vertebrae

POINTING YOUR TOES DOWNWARD IS DESCRIBED AS WHICH TYPE OF MOVEMENT?

Plantar flexion

Planta Flexion

Pointing Toes

Tendon Sheaths

elongated bursae wrapped completely around tendons subjected to friction

articular cartilage:

hyaline cartilage that reduces friction between bones

Synarthroses

immovable joints

Arthrology

is the scientific study of joints.

A joint's structure determines

its combination of strength and flexibility.

Syndesmosis (fibrous joint)

joint permits limited movement (distal tibia and fibula) joint held together by ligament

Elevation

lifting a body part superiorly ex) shrugging shoulders

Depression

lowering a body part

Retraction

mandible is pulled toward neck

Protraction

mandible juts out

Abduction (angular movement)

movement along frontal plane, away from the midline

Adduction (angular movement)

movement along frontal plane, toward the midline

Opposition

movement of thumb ex) touching thumb to tips of other fingers on same hand or any grasping movement

Longer fibers

offer a larger amount of movement ex.) interosseous membrane connecting radius and ulna

Short Fibers

offer little to no movement ex.) inferior tibiofibular joint

THE MOST COMMON FORM OF CHRONIC ARTHRITIS IS __________.

osteoarthritis

supination

palm face anteriorly; Radius & Ulna are parallel

pronation

palms face posteriorly; radius rotates over ulna

Gomphoses

peg-in-socket joints ex.) alveolar sockets are in teeth

AN INJURY COMMON TO BASEBALL PLAYERS IS A TORN ROTATOR CUFF. THIS COLLECTION OF MUSCLES AND TENDONS IS ASSOCIATED WITH THE __________ JOINT.

Shoulder

AN AMPHIARTHROTIC JOINT EXHIBITS WHICH LEVEL OF MOVEMENT?

Slightly movable

OF THE FOLLOWING TYPES OF JOINTS, WHICH TYPE OCCURS ONLY IN THE SKULL?

Suture

WHEN SOMEONE HAS "SLIPPED A DISC" OF THEIR VERTEBRAL COLUMN, WHICH TYPE OF JOINT HAVE THEY DISRUPTED?

Symphysis

Which of the following joints is a site of long bone growth?

Synchrondrosis

What structure of a synovial joint allows it to be classified as a diarthrosis?

Synovial Cavity

WHICH OF THE FOLLOWING SYNOVIAL JOINT COMPONENTS IS RESPONSIBLE FOR SECRETING SYNOVIAL FLUID?

Synovial Membrane

Articular Cartilage (general structure)

consists of hyaline cartilage covering ends of bones Prevents crushing of bone ends

Synovial Fluid (general structure)

Viscous, slippery filtrate of plasma and hyaluronic acid Lubricates and nourishes articular cartilage Contains phagocytic cells to remove microbes and debris

Moving the mandible for chewing involves

depression and elevation

ALL SYNOVIAL JOINTS ARE __________.

diarthrotic (freely movable)

What are the 6 different types of synovial joints?

plane, hinge, pivot, condylar, saddle, ball and socket

bursae:

provides cushion so that bone doesn't rub against soft tissue

Bursae

reduce friction where ligaments, muscles, skin, tendons, or bones rub together

synovial fluid:

reduces friction between articulating bones

Eversion of Foot

sole of foot faces laterally

Inversion of Foot

sole of foot faces medially

THE MOST COMMON JOINT INJURIES INCLUDE:

sprains and dislocations

In the anatomical position, the palms are

supinated

saddle joints (synovial)

the articular surface of one bone is shaped like a saddle and the other bone fits into the "saddle" like a sitting rider; motion is angular around two axes (biaxial). ex.) the carpometacarpal joint between the trapezium and the metacarpal of the thumb.

plane joints (synovial)

the articulating surfaces are flat, and the bones glide back-and-forth and side-to-side (many are biaxial); they may also permit rotation (triaxial). ex.) between carpals and the joints between tarsals.

ball-and-socket joints (synovial)

the ball-shaped surface of one bone fits into the cuplike depression of another; motion is around three axes (triaxial). ex.)hips and shoulder

Hinge Joints (synovial)

the convex surface of one bone fits into the concave surface of another, and the motion is angular around one axis (uniaxial) ex.) the elbow, knee (a modified hinge joint), and ankle joints.

Functional Classifications

three types based on movement joint allows -Synarthroses -Amphiarthroses -Diathroses

Structural

three types based on what material binds the joints and whether a cavity is present -Fibrous -Cartilaginous -Synovial

Rotation

turning of bone around its own long axis, toward midline or away from it -Medial: rotation toward midline -Lateral: rotation away from midline Examples: Rotation between C1and C2 vertebrae. Rotation of humerus and femur

Articular (joint) capsule (general structure)

two layers thick External fibrous layer: dense irregular connective tissue Inner synovial membrane: loose connective tissue that makes synovial fluid

Sutures

-Rigid, interlocking joints of skull -Allow for growth during youth **Contain short connective tissue fibers that allow for expansion -In middle age, sutures ossify and fuse **Immovable joints join skull into one unit that protects brain **Closed, immovable sutures referred to as synostoses

Movements allowed by synovial joints

All muscles attach to bone or connective tissue at no fewer than two points origin & insertion Muscle contraction causes insertion to move toward origin Movements occur along transverse, frontal, or sagittal planes Range of motion

Fatty Pads (general structure)

For cushioning between fibrous layer of capsule and synovial membrane or bone

Characteristics of synovial joints

Have six general features Have bursae and tendon sheaths associated with them Stability is influenced by three factors Allow several types of movements Classified into six different types

THIS TYPE OF SYNOVIAL JOINT IS USED WHEN YOU BEND YOUR FINGERTIPS TO HANG ONTO A CLIFF.

Hinge

Angular Movements

Increase or decrease angle between two bones Movement along sagittal plane Angular movements include: Flexion, Extension and Hyperextension Abduction, Adduction, Circumduction

Circumduction

Involves flexion, abduction, extension, and adduction of limb Limb describes cone in space

What affects the movement at a joint?

The flexibility of the ligaments. The shape of the articulating bones. The tension of associated muscles and tendons.

Kinesiology

The study of motion of the human body

pivot joints (synovial)

a round or pointed surface of one bone fits into a ring formed by another bone and a ligament, and movement is rotational (uniaxial) ex.) the atlanto-axial and radioulnar joints

Condyloid Joint (synovial)

an oval projection of one bone fits into an oval cavity of another, and motion is angular around two axes (biaxial); ex.) the writs joint and metacarpophalangeal joints of digits #2-5

Which of the following is stretched or torn in about 70 percent of all serious knee injuries?

anterior cruciate ligament

A fluid-filled sac found between skin and bone that helps reduce friction between the skin and bone is a

articular capsule

origin

attachment to immovable bone

insertion

attachment to movable bone

The shoulder joint is a ___ joint while the elbow joint is considered a ___ joint.

ball-and-socket; hinge

Dorsiflexion

bending foot toward shin

WHICH OF THE FOLLOWING IS NOT A FACTOR THAT STABILIZES JOINTS?

bursae

Shaking you head to indication "yes" involves _____________; moving your head to indicated "no" involves ____________

flexion and extension; rotation

Diarthroses

freely movable joints

Function of Joints

give skeleton mobility and hold skeleton together

3 general types of movements

gliding, angular movements, rotation

supination and pronation

rotation of radius and ulna

Shaking your head "no" is an example of ___ while nodding your head "yes" involves ___ and ___.

rotation; flexion, and extension

Joints (articulation)

sites where two or more bones meet

Amphiarthroses (Cartilaginous Joints)

slightly moveable joints

Joint (synovial) cavity (general structure)

small, fluid-filled potential space that is unique to synovial joints

3 types of fibrous joints

sutures, syndesmoses, gomphoses

What exercise is best for joints?

swimming

The joints between the vertebrae and the joint between the hip bones are examples of which joint type?

symphysis

What joint is not a synarthrosis?

symphysis