Ch. 9 Lec: Articulations (Joints)

\-Structural (Anatomy)

\-Functional (Range of motion)

\-Structure determines function

Joint Classification

\-Fibrous

\-Cartilaginous

\-Bony

\-Synovial

Structural classifications

\-Synarthrosis

\-**Amphiarthrosis**

\-Diarthrosis

Functional classifications

Immovable joint

Synarthrosis

Slightly movable joint

Amphiarthrosis

Freely movable joint

Diarthrosis

–Very strong

–Edges of bones may touch or interlock

–Can be fibrous or cartilaginous

\-4 types (Synarthrotic)

Synarthrosis

•Suture

•Gomphosis

•Synchondrosis

•Synostosis

Types of Synarthrotic Joints

•Found only between bones of skull

•Edges of bones interlock

•Bound by dense fibrous connective tissue

Suture

•Binds teeth to bony sockets

•Fibrous connection (periodontal ligament)

Gomphosis

•Rigid cartilaginous bridge between two bones

•Found between vertebrosternal ribs and sternum

•Also, epiphyseal cartilage of growing long bones

Synchondrosis

•Created when two bones fuse

•Example: metopic suture of frontal bone

•And epiphyseal lines of mature long bones

Synostosis

–More movable than a synarthrosis

–Stronger than a diarthrosis

–Can be fibrous or cartilaginous

\-2 types (Amphiarthroses)

Amphiarthrosis

\-Syndesmosis

\-Symphysis

Types of Amphiarthroses

Bones connected by a ligament

Syndesmosis

Bones connected by fibrocartilage

Symphysis

\-Synovial joints (Diarthroses)

Diarthrosis

–Freely movable joints

–At ends of long bones

Surrounded by **joint capsule** (**articular capsule)**

Diarthroses

–Synovial fluid from synovial membrane

–**Articular cartilage** covers articulating surfaces

Diarthroses

Contains synovial membrane

J**oint capsule** (**articular** **capsule**)

Fills joint cavity

Synovial fluid

Prevents direct contact between bones

**Articular cartilage**

\-Synovial fluid

\-5 accessory structures

\-Mobile but relatively weak

Synovial joint

–Has the consistency of egg yolk

–Contains proteoglycans

–3 primary functions

Synovial fluid

•Lubrication

•Nutrient distribution

•Shock absorption

Primary functions: Synovial fluid

–Cartilages

\-Fat pads

–Ligaments

–Tendons

–Bursae

Accessory structures: Synovial joint

Fibrocartilage pad between opposing bones

Meniscus

Made of cartilage

Meniscus

–Adipose tissue covered by synovial membrane

–Protect articular cartilages

Fat pads

–Support and strengthen joints

**-Sprain**

Ligaments

Ligament with torn collagen fibers

Sprain

Attach to muscles around joint

Tendons

–Small pockets of synovial fluid

–Cushion areas where tendons or ligaments rub against other tissues

Bursae

•Collagen fibers of joint capsule and ligaments

•Shapes of articulating surfaces and menisci

•Other bones, muscles, or fat pads

•Tendons attached to articulating bones

S**tabilize synovial joints**

–Prevent injury by limiting the range of motion

\# of Synovial Joint Movements

19

\-Flexion

\-Extension

\-Hyperextension

Synovial Joint Movements

\-Abduction

\-Adduction

\-Circumduction

\-Rotation

Synovial Joint Movements

\-Pronation

\-Supination

\-Inversion

\-Eversion

Synovial Joint Movements

\-Dorsiflexion

\-Plantar flexion

\-Opposition

\-Reposition

Synovial Joint Movements

\-Protraction

\-Retraction

\-Depression

\-Elevation

Synovial Joint Movements

Decreases angle between articulating bones

Flexion

Increases angle between articulating bones

Extension

Extension past anatomical position

**Hyperextension**

Movement away from longitudinal axis

Abduction

Movement toward longitudinal axis

Adduction

Complete circular movement without rotation

**Circumduction**

Movements made about the longitudinal axis and in the transverse plane

Rotation

•Rotates forearm so that radius rolls across ulna

•Results in palm facing posteriorly

Pronation

•Turns palm anteriorly

•Forearm is supinated in anatomical position

Supination

Twists sole of foot medially

Inversion

Twists sole of foot laterally

Eversion

Flexion at ankle (lifting toes)

Dorsiflexion

Extension at ankle (pointing toes)

**Plantar flexion**

Movement of thumb toward palm or other fingers

**Opposition**

Opposite of opposition

**Reposition**

Anterior movement in horizontal plane (forward)

Protraction

Opposite of protraction (pulling back)

**Retraction**

Moving a structure inferiorly (down)

**Depression**

Moving a structure superiorly (up)

Elevation

\-Plane (gliding)

\-Hinge

\-Condylar (ellipsoid)

Classification: Synovial Joints

\-Saddle

\-Pivot

\-Ball-and socket

Classification: Synovial Joints

–First two cervical vertebrae are joined by a synovial joint

–Synovial joints lie between adjacent articular processes

–Adjacent vertebral bodies form symphyses

**Intervertebral joints**

Separates vertebral bodies

**Intervertebral disc**

–**Anulus fibrosus**

–**Nucleus pulposus**

–**Vertebral end plates** of cartilage

**Intervertebral disc: Components**

\-Tough outer layer of fibrocartilage

\-Attaches disc to vertebrae

**Anulus fibrosus**

•Elastic, gelatinous core

•Absorbs shocks

**Nucleus pulposus**

Cover superior and inferior surfaces of disc

**Vertebral end plates** of cartilage

\-Bulging disc

\-Herniated disc

**Intervertebral disc: Damage**

•Bulge in anulus fibrosus

•Invades vertebral canal

Bulging disc

•Nucleus pulposus breaks through anulus fibrosus

•Compresses spinal nerves

Herniated disc

\-Flexion

\-Extension

\-Lateral flexion

\-Rotation

Vertebral movements

Elbow joint is what type of joint?

Hinge joint

\-Humerus

\-Radius

\-Ulna

Elbow joint: Articulations involved

–Complex hinge joint

–Transfers weight from femur to tibia

–3 articulations

Knee joint

\-2 femur, tibia articulations (At medial and lateral condyles)

\-1 between patella and patellar surface of femur

Knee joint: Articulations

–Ball-and-socket diarthrosis

–Between head of humerus and glenoid cavity of scapula

–Greatest range of motion of any joint

Shoulder joint (glenohumeral joint)

–Most frequently dislocated joint

–Supported by skeletal muscles, tendons, and ligaments

Shoulder joint (glenohumeral joint)

–Between head of femur and acetabulum of hip bone

–Strong ball-and-socket diarthrosis

Hip joint

–Wide range of motion

–Acetabular labrum

Hip joint

•Rim of fibrocartilage

•Increases depth of joint cavity

•Seals in synovial fluid

Acetabular labrum

–**Rheumatism**

**-Arthritis (joint inflammation)**

\-__**Osteoarthritis**__

–**Rheumatoid arthritis**

–**Gouty arthritis**

Joints: Degenerative changes

Pain and stiffness in musculoskeletal system

**Rheumatism**

All rheumatic diseases that affect synovial joints

**Arthritis (joint inflammation)**

•Caused by wear and tear of joint surfaces, or genetic factors affecting collagen formation

•Generally affects people over age 60

__**Osteoarthritis**__

•An inflammatory condition

•Immune system attacks joint tissues

**Rheumatoid arthritis**

Crystals of uric acid form within synovial fluid

**Gouty arthritis**

–Muscles attach to bones

–Bones are controlled by endocrine system

Other systems interact with skeletal system

–Digestive and urinary systems provide calcium and phosphate minerals to bones for growth

–Skeleton serves as a reserve for calcium, phosphate, and other minerals

Other systems interact with skeletal system

Suture

Gomphosis

Sychondrosis

Synostosis

Syndesmosis

Symphysis

Synovial joint

Medullary cavity

Articular cartilages

Metaphysis

Spongy bone

Periosteum