Fundamentals of Anatomy & Physiology Frederic H. Martini Unit 2 Support and Movement Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint ® Lecture Slides prepared by Professor Albia Dugger, Miami–Dade College, Miami, FL Professor Robert R. Speed, Ph.D., Wallace Community College, Dothan, AL

Chapter 9: Articulations

Articulations Body movement occurs at joints (articulations) where 2 bones connect

Joint Structure Determines direction and distance of movement (range of motion) Joint strength decreases as mobility increases

What are the major categories of joints, and the structure and function of each category?

Functional Classification Table 9–1

Functional Classifications Synarthrosis: –no movement Amphiarthrosis: –little movement Diarthrosis: –more movement

Synarthroses Also called immovable joints Fibrous or cartilaginous connections May fuse over time

Amphiarthroses Also called slightly moveable joints Fibrous or cartilaginous connections

Diarthroses Synovial joints Also called freely moveable joints Subdivided by type of motion

Structural Classification Table 9–2

Structural Classifications Bony Fibrous Cartilaginous Synovial

Synarthroses (Immovable Joints) Are very strong Edges of bones may touch or interlock

4 Types of Synarthrotic Joints Suture Gomphosis Synchondrosis Synostosis

Suture Bones interlocked Are bound by dense fibrous connective tissue Are found only in skull

Gomphosis Fibrous connection (periodontal ligament) Binds teeth to sockets

Synchondrosis Is a rigid cartilaginous bridge between 2 bones: –epiphyseal cartilage of long bones –between vertebrosternal ribs and sternum

Synostosis Fused bones, immovable: –metopic suture of skull –epiphyseal lines of long bones

Amphiarthroses More moveable than synarthrosis Stronger than freely movable joint

2 Types of Amphiarthroses Syndesmosis: –bones connected by ligaments Symphysis: –bones separated by fibrocartilage

What is the basic structure of a synovial joint, and what are the common accessory structures and their functions?

Synovial Joints (Diarthroses) Also called moveable joints At ends of long bones Within articular capsules Lined with synovial membrane

Articular Cartilages Pad articulating surfaces within articular capsules: –prevent bones from touching Smooth surfaces lubricated by synovial fluid: –reduce friction

Synovial Fluid Contains slippery proteoglycans secreted by fibroblasts

Functions of Synovial Fluid 1.Lubrication 2.Nutrient distribution 3.Shock absorption

Synovial Joints: Accessory Structures Cartilages Fat pads Ligaments Tendons Bursae

Cartilages Cushion the joint: –fibrocartilage meniscus (articular disc)

Fat Pads Superficial to the joint capsule Protect articular cartilages

Accessory Ligaments Support, strengthen joints Sprain: –ligaments with torn collagen fibers

Tendons Attach to muscles around joint Help support joint

Bursae Pockets of synovial fluid Cushion areas where tendons or ligaments rub

Synovial Joints: Stabilizing Factors Prevent injury by limiting range of motion: –collagen fibers (joint capsule, ligaments) –articulating surfaces and menisci –other bones, muscles, or fat pads –tendons of articulating bones

Injuries Dislocation (luxation): –articulating surfaces forced out of position –damages articular cartilage, ligaments, joint capsule Subluxation: –a partial dislocation

What are the dynamic movements of the skeleton?

Types of Dynamic Motion Linear motion (gliding) Angular motion Rotation

Linear Motion Pencil maintains vertical orientation, but changes position Figure 9–2a, b

Angular Motion Pencil maintains position, but changes orientation Figure 9–2c

Circumduction Circular angular motion Figure 9–2d

Rotation Pencil maintains position and orientation, but spins Figure 9–2e

Planes (Axes) of Dynamic Motion Monaxial (1 axis) Biaxial (2 axes) Triaxial (3 axes)

Types of Movements at Synovial Joints Terms describe: –plane or direction of motion –relationship between structures

Linear Motion Also called gliding 2 surfaces slide past each other: –between carpal or tarsal bones

Flexion Figure 9–3a

Flexion Angular motion Anterior–posterior plane Reduces angle between elements

Extension Angular motion Anterior–posterior plane Increases angle between elements

Hyperextension Angular motion Extension past anatomical position Angular Movements (Flexion, Extension, Hyperextension) PLAY

Abduction Figure 9–3b, c

Abduction Angular motion Frontal plane Moves away from longitudinal axis

Adduction Angular motion Frontal plane Moves toward longitudinal axis

Circumduction Circular motion without rotation Angular motion Figure 9–3d

Rotation Figure 9–4

Rotation Direction of rotation from anatomical position Relative to longitudinal axis of body

Rotation Left or right rotation Medial rotation (inward rotation): –rotates toward axis Lateral rotation (outward rotation): –rotates away from axis

Pronation and Supination Pronation: –rotates forearm, radius over ulna Supination: –forearm in anatomical position

Inversion and Eversion Figure 9–5a

Inversion and Eversion Inversion: –twists sole of foot medially Eversion: –twists sole of foot laterally

Dorsiflexion and Plantar Flexion Figure 9–5b

Dorsiflexion and Plantar Flexion Dorsiflexion: –flexion at ankle (lifting toes) Plantar flexion: –extension at ankle (pointing toes)

Opposition Thumb movement toward fingers or palm (grasping) Figure 9–5c

Protraction and Retraction Figure 9–5d

Protraction and Retraction Protraction: –moves anteriorly –in the horizontal plane (pushing forward) Retraction: –opposite of protraction –moving anteriorly (pulling back)

Elevation and Depression Figure 9–5e

Elevation and Depression Elevation: –moves in superior direction (up) Depression: –moves in inferior direction (down)

Lateral Flexion Bends vertebral column from side to side Figure 9–5f

What are the types of synovial joints, and the relationship of motion to structure?

Classification of Synovial Joints by Shape Gliding Hinge Pivot Ellipsoidal Saddle Ball-and-socket A Functional Classification of Synovial Joints PLAY

Gliding Joints Flattened or slightly curved faces Limited motion (nonaxial) Figure 9–6 (1 of 6)

Hinge Joints Angular motion in a single plane (monaxial) Figure 9–6 (2 of 6)

Pivot Joints Rotation only (monaxial) Figure 9–6 (3 of 6)

Ellipsoidal Joints Oval articular face within a depression Motion in 2 planes (biaxial) Figure 9–6 (4 of 6)

Saddle Joints 2 concave faces, straddled (biaxial) Figure 9–6 (5 of 6)

Ball-and-Socket Joints Round articular face in a depression (triaxial) Figure 9–6 (6 of 6)

KEY CONCEPT A joint can’t be both mobile and strong The greater the mobility, the weaker the joint Mobile joints are supported by muscles and ligaments, not bone-to-bone connections

How do vertebrae in the vertebral column articulate?

Intervertebral Articulations Figure 9–7

Intervertebral Articulations C 2 to L 5 spinal vertebrae articulate: –at inferior and superior articular processes (gliding joints) –between adjacent vertebral bodies (symphyseal joints)

Intervertebral Discs Intervertebral discs: –pads of fibrocartilage –separate vertebral bodies

Disc Structure Anulus fibrosus: –tough outer layer –attaches disc to vertebrae Nucleus pulposus: –elastic, gelatinous core –absorbs shocks

Verterbral Joints Also called symphyseal joints As vertebral column moves: –nucleus pulposus shifts –disc shape conforms to motion

Intervertebral Ligaments Bind vertebrae together Stabilize the vertebral column

Damage to Intervertebral Discs Figure 9–8

Damage to Intervertebral Discs Slipped disc: –bulge in anulus fibrosus –invades vertebral canal Herniated disc: –nucleus pulposus breaks through anulus fibrosus –presses on spinal cord or nerves

Movements of the Vertebral Column Flexion: –bends anteriorly Extension: –bends posteriorly Lateral flexion: –bends laterally Rotation

What are the structures and functions of the shoulder, elbow, hip, and knee joints, and what is the relationship between joint strength and mobility?

The Shoulder Joint Figure 9–9a

The Shoulder Joint Figure 9–9b

The Shoulder Joint Also called the glenohumeral joint: –allows more motion than any other joint –is the least stable –supported by skeletal muscles, tendons, ligaments

Structure of the Shoulder Joint Ball-and-socket diarthrosis Between head of humerus and glenoid cavity of scapula

Processes of the Shoulder Joint Acromion (clavicle) and coracoid process (scapula): –project laterally, superior to the humerus –help stabilize the joint

Shoulder Ligaments Glenohumeral Coracohumeral Coracoacromial Coracoclavicular Acromioclavicular

Shoulder Separation Dislocation of the shoulder joint

Shoulder Muscles Also called rotator cuff: –supraspinatus –infraspinatus –subscapularis –teres minor

Shoulder Bursae Subacromial Subcoracoid Subdeltoid Subscapular

The Elbow Joint Figure 9–10

The Elbow Joint A stable hinge joint With articulations between humerus, radius, and ulna

Articulations of the Elbow Humeroulnar joint: –largest articulation –trochlea of humerus and trochlear notch of ulna –limited movement Humeroradial joint: –smaller articulation –capitulum of humerus and head of radius

Elbow Muscle Biceps brachii muscle: –attached to radial tuberosity –controls elbow motion

The Hip Joint Figure 9–11a

The Hip Joint Figure 9–11b, c

The Hip Joint Also called coxal joint Strong ball-and-socket diarthrosis Wide range of motion

Structures of the Hip Joint Head of femur fits into it Socket of acetabulum Which is extended by fibrocartilage acetabular labrum

The Knee Joint Figure 9–12a, b

The Knee Joint Figure 9–12c, d

The Knee Joint A complicated hinge joint Transfers weight from femur to tibia

Articulations of the Knee Joint 2 femur–tibia articulations: –at medial and lateral condyles –1 between patella and patellar surface of femur

Menisci of the Knee Medial and lateral menisci: –fibrocartilage pads –at femur–tibia articulations –cushion and stabilize joint –give lateral support

Locking Knees Standing with legs straight: –“locks” knees by jamming lateral meniscus between tibia and femur

7 Ligaments of the Knee Joint Patellar ligament (anterior) 2 popliteal ligaments (posterior) Anterior and posterior cruciate ligaments (inside joint capsule) Tibial collateral ligament (medial) Fibular collateral ligament (lateral)

What are the effects of aging on articulations, and the most common clinical problems?

Rheumatism A pain and stiffness of skeletal and muscular systems

Arthritis All forms of rheumatism that damage articular cartilages of synovial joints

Osteoarthritis Caused by wear and tear of joint surfaces, or genetic factors affecting collagen formation Generally in people over age 60

Rheumatoid Arthritis An inflammatory condition Caused by infection, allergy, or autoimmune disease Involves the immune system

Gouty Arthritis Occurs when crystals (uric acid or calcium salts): –form within synovial fluid –due to metabolic disorders

Joint Immobilization Reduces flow of synovial fluid Can cause arthritis symptoms Treated by continuous passive motion (therapy)

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

Integration with Other Systems Figure 9–13

Bone Recycling Living bones maintain equilibrium between: –bone building (osteoblasts) –and break down (osteoclasts)

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

Bones Support Body Systems The skeletal system: –supports and protects other systems –stores fat, calcium, and phosphorus –manufactures cells for immune system

Body Systems Support Bones Disorders in other body systems can cause: –bone tumors –osteoporosis –arthritis –rickets (demineralization)

SUMMARY (1 of 6) Joint classification by motion and structure 4 types of synarthroses: –suture, gomphosis, synchondrosis, synostosis 2 types of amphiarthroses: –syndesmosis, symphysis

SUMMARY (2 of 6) Structures of diarthroses 3 forms of dynamic motion: –linear or gliding, angular, rotation 3 planes of motion: –monaxial, biaxial, triaxial

SUMMARY (3 of 6) Movements of synovial joints: –gliding, flexion, extension, abduction, rotation, pronation, inversion, dorsiflexion, opposition, protraction, depression, etc.

SUMMARY (4 of 6) 6 structural types of synovial joints: –gliding –hinge –pivot –ellipsoidal –saddle –ball-and-socket

SUMMARY (5 of 6) Structures and movements of: –intervertebral articulations –shoulder joint –elbow joint –hip joint –knee joint

SUMMARY (6 of 6) Effects of aging on joints Relationship of the skeleton to other body systems