Ch9 Joints - goodwinmedia.org · PDF file– More movable than a condyloid or hinge joint forming ... ankle, and vertebral column ... Classes of Synovial Joints • Hinge joints

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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Chapter 9Joints/ Articulation

Lecture AP1Goodwin College

9-2

Joints

• Joint (articulation)—any point where two bones meet, whether or not the bones are movable at that interface

• Function: Joints link the bones of the skeletal system, permit effective movement, and protect the softer organs

• Arthrology—science of joint structure, function, and dysfunction

• Kinesiology—the study of musculoskeletal movement

– A branch of biomechanics, which deals with a broad variety of movements and mechanical processes in the body, including the physics of blood circulation, respiration, and hearing

• Joint name—typically derived from the names of the bones involved– Atlanto–occipital joint, glenohumeral joint, radioulnar joint

© Gerard Vandystadt/Photo Researchers, Inc.

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9-3

Joints and Their Classification

• Joints classified according to the manner in which the adjacent bones are bound to each other, with differences in how freely the bones can move

• Four major joint categories– Bony joints– Fibrous joints– Cartilaginous joints– Synovial joints

9-4

Bony Joints (Synostosis)

• An immovable joint formed when the gap between two bones ossifies, and the bones become, in effect, a single bone

– Frontal and mandibular bones in infants

– Cranial sutures in elderly

• Can occur in either fibrous or cartilaginous joint

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9-5

Types of Fibrous Joints

• Synarthrosis, or Synarthrodial joint—a point at which adjacent bones are bound by collagen fibers that emerge from one bone, cross the space between them, and penetrate into the other

• Three kinds of fibrous joints

– Sutures

– Gomphoses

– Syndesmoses

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• Immovable or slightly movable fibrous joints that closely bind the bones of the skull to each other

• Sutures can be classified as:

– Serrate: interlocking wavy lines• Coronal, sagittal, and lambdoid

sutures

– Lap: overlapping beveled edges• Temporal and parietal bones

– Plane: straight, non-overlapping edges

• Palatine processes of the maxillae

Type of Fibrous Joint / Sutures

Figure 9.2a

Fibrous connective tissue

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Types of SuturesCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Wood

Dovetail joint Miter joint Butt joint

Bone

Serrate suture Lap suture Plane suture

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Figure 9.3

9-8

Type of Fibrous Joint / Gomphoses

Gomphosis: attachment of a tooth to its socket

• Held in place by fibrous periodontal ligament

– Collagen fibers attach tooth to jawbone

– Allows the tooth to move a little under the stress of chewing


Fibrous connective tissue

(b) GomphosisFigure 9.2b

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9-9

A fibrous joint at which two bones

are bound by longer collagenous

fibers than in a suture or

gomphosis giving the bones

more mobility

• Most movable syndesmosis– Interosseus membranes unite

radius to ulna allowing supination and pronation

• Less movable syndesmosis– Tibia to fibula

Type of Fibrous Joint / SyndesmosesFibrous connective tissue

(c) Syndesmosis

Figure 9.2c

9-10

Cartilaginous Joints

Cartilaginous joint, amphiarthrosis, or

amphiarthrodial joint—two bones are linked by

cartilage

• Two types of cartilaginous joints

– Synchondroses

– Symphyses

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9-11

Synchondroses

Bones are bound by hyaline cartilage

• Binds epiphysis and diaphysis of long bones

• First rib attachment to sternum

• Other costal cartilages are joined to sternum by synovial joints

Figure 9.4a,b

Pubic symphysis

Clavicle

Rib 1

(a)

(b)

Sternum

Costalcartilage

Interpubic disc(fibrocartilage)


9-12

Symphyses

Bones joined by fibro-cartilage

– Pubic symphysis in which right and left pubic bones joined by interpubic disc

– Bodies of vertebrae and intervertebral discs

• Only slight amount of movement between adjacent vertebrae

• Collective effect of all 23 discs gives spine considerable flexibility Pubic symphysis

Body of vertebra(c)

(b)

Interpubic disc(fibrocartilage)

Intervertebraldisc (fibrocartilage)

Figure 9.4b,c

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9-13

Synovial Joints

Diarthrosis or Diarthrodialjoint—two bones are separated by a space called a joint cavity

• Most familiar type of joint

• Most are freely movable

• Most structurally complex type of joint

• Most likely to develop painful dysfunction

Periosteum

Ligament

Bone

Proximalphalanx

Joint cavitycontainingsynovial fluid

Fibrouscapsule

Articularcartilages

Jointcapsule

Middlephalanx

Synovialmembrane

Figure 9.5

9-14

General Anatomy of Synovial Joints

• Articular cartilage—layer of hyaline cartilage that covers the facing surfaces of two bones

• Joint (articular) cavity—separates articular surfaces

• Synovial fluid—slippery lubricant in joint cavity

– Rich in albumin and hyaluronic acid

– Gives it a viscous, slippery texture like raw egg whites

– Nourishes articular cartilage and removes waste

– Makes movement of synovial joints almost friction free

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9-15

General Anatomy of Synovial Joints

Articular capsule—connective tissue that encloses the cavity and retains

the fluid

– Outer fibrous capsule: continuous with periosteum of adjoining bones

– Inner, cellular, synovial membrane: composed mainly of fibroblast-like cells that secrete synovial fluid and macrophages that remove debris from the joint cavity

– Articular disc forms a pad between articulating bones that crosses the entire joint capsule

• Temporomandibular joint, distal radioulnar joints, sternoclavicularand acromioclavicular joints

– Meniscus: in the knee, two cartilages extend inward from the left and right but do not entirely cross the joint

• These cartilages absorb shock and pressure

• Guide bones across each other

• Improve the fit between bones

• Stabilize the joints, reducing the chance of dislocation

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Accessory structures associated with synovial joints

Tendon: a strip or sheet of tough collagenous

connective tissue that attaches muscle to bone• Most important structures in stabilizing a joint

Ligament: similar tissue that attaches one bone to

another

Bursa: a fibrous sac filled with synovial fluid, located

between adjacent muscles, Cushions muscles, helps tendons slide more easily over

joints, modifies direction of tendon pull

Tendon sheaths: elongated cylindrical bursae wrapped around a tendon. In hand and foot

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9-17

Tendon Sheaths & BursaCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Tendon of flexor pollicis longus

Radial bursa (cut)

Flexor retinaculum (cut)

Ulnar bursa (cut)

Lumbrical muscles

Tendon of flexor carpi radialis

Tendon sheaths

Tendon sheath (opened)

Tendon of flexor digitorumsuperficialis

Tendon of flexor digitorumprofundus

Tendons of flexor digitorum superficialisand flexor digitorum profundus

Tendons of flexor digitorumsuperficialis

Figure 9.6

Exercise and Articular Cartilage

• Repetitive compression of nonvascular cartilage during exercise squeezes fluid and metabolic waste out of the cartilage

• When weight removed, cartilage absorbs synovial fluid like a sponge taking in oxygen and nutrients to the chondrocytes

• Without exercise, cartilage deteriorates more rapidly from inadequate nutrition and waste removal

• Warm-up period before vigorous exercise helps protect cartilage from undue wear and tear

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9-19

Joints and Lever Systems

• Long bones act as levers to enhance the speed or power of limb movements

• Lever—any elongated, rigid object that rotates around a fixed point called a fulcrum

• Rotation occurs when an effort applied overcomes resistance (load) at some other point– Resistance arm and effort arm are described relative to fulcrum


Resistance arm

F

RE

Effort arm

Fulcrum

Effort

Resistance(load)

Figure 9.7

9-20

Types of Levers

First-class lever

– Has fulcrum in the middle between effort and resistance (EFR)

– Atlanto–occipital joint lies between the muscles on the back of the neck and the weight of the face

– Loss of muscle tone occurs when you nod off in class


F

E

Fulcrum

Resistance Effort

(a) First-class lever

R

R

F

E

Fulcrum

Effort

Resistance

Resistance Effort

F

Figure 9.9a

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9-21

Types of Levers

Second-class lever– Resistance between fulcrum and effort (FRE)– Resistance from the muscle tone of the temporalis muscle lies

between the jaw joint and the pull of the digastric muscle on the chin as it opens the mouth quickly


Effort Effort

FE E

FulcrumF

Fulcrum

Resistance

(b) Second-class lever

R

R

Resistance

Effort

Resistance

F

Figure 9.9b

9-22

Types of Levers

Third-class lever– Effort between the resistance and the fulcrum (REF)

– Most joints of the body

– The effort applied by the biceps muscle is applied to the forearm between the elbow joint and the weight of the hand and the forearm

Figure 9.9c


Effort

Fulcrum

Resistance Effort

(c) Third-class lever

E

FFulcrum

RE

F

RResistance

EffortResistance

F

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9-23

Range of Motion

The degrees through which a joint can move– Aspect of joint performance

– Physical assessment of a patient’s joint flexibility

• ROM determined by:– Structure of the articular surfaces

• Elbow—olecranon of ulna fits into olecranon fossa of humerus

– Strength and tautness of ligaments and joint capsules• Stretching of ligaments increases range of motion

• Double-jointed people have long or slack ligaments

– Action of the muscles and tendons• Nervous system monitors joint position and muscle tone

• Muscle tone—state of tension maintained in resting muscles

9-24

Axes of Rotation

A moving bone has a relatively stationary axis of rotation that passes through the bone in a direction perpendicular to the plane of movement• Multiaxial joint: shoulder joint has three degrees of freedom or

axes of rotation• Monoaxial or Biaxial joints: other joints


(b) Flexion of arm

(a) Abduction of arm

(c) Internal rotationof arm

Figure 9.10

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9-25

Classes of Synovial Joints

Head of humerus

Scapula

Carpal bone

Metacarpal bone PhalanxMetacarpalbone

Humerus

Ulna Carpal bones

Radius

Ulna

Ball-and-socket joint(humeroscapular)

Pivot joint(radioulnar)

Saddle joint(trapeziometacarpal)

Hinge joint(humeroulnar)

Plane joint(intercarpal)

Condylar joint(metacarpophalangeal)

Figure 9.11

9-26


• Ball-and-socket joints

– Smooth, hemispherical head fits within a cuplike socket

– Shoulder joint: head of humerus into glenoid cavity of scapula

– Hip joint: head of femur into acetabulum of hip bone

Only multiaxial joints in the body

• Condylar (ellipsoid) joints

– Oval convex surface on one bone fits into a complementary-shaped depression on the other

– Radiocarpal joint of the wrist

– Metacarpophalangeal joints at the bases of the fingers

Biaxial joints—movement in two planes

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• Saddle joints– Both bones have an articular surface that is shaped

like a saddle, concave in one direction and convex in the other

– Trapeziometacarpal joint at the base of the thumb

– Sternoclavicular joint: clavicle articulates with sternum

• Biaxial joint– More movable than a condyloid or hinge joint forming

the primate opposable thumb

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• Plane (gliding) joints– Flat articular surfaces in which bones slide over each

other with relatively limited movement

• Usually biaxial joint– Carpal bones of wrist– Tarsal bones of ankle– Articular processes of vertebrae

• Although any one joint moves only slightly, the combined action of the many joints in wrist, ankle, and vertebral column allows for considerable movement

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• Hinge joints– One bone with convex surface that fits into a concave

depression on other bone

– Elbow joint: ulna and humerus

– Knee joint: femur and tibia

– Finger and toe joints

• Monoaxial joint—move freely in one plane

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• Pivot joints– One bone has a projection that is held in place by a

ringlike ligament

Bone spins on its longitudinal axis– Atlantoaxial joint (dens of axis and atlas)

• Transverse ligament

– Proximal radioulnar joint allows the radius to rotate during pronation and supination

• Anular ligament

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9-31

Movement of Synovial Joints

Vocabulary of movements of synovial joints used in kinesiology, physical therapy, and other medical fields– Many presented in pairs with opposite or contrasting

meanings

– Need to understand anatomical planes and directional terms

• Zero position—the position of a joint when a person is in the standard anatomical position– Joint movements are described as deviating from the

zero position or returning to it

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Flexion and Extension

• Flexion—movement that decreases joint angle– Common in hinge joints

• Extension—movement that straightens a joint and generally returns a body part to the zero position

• Hyperextension—further extension of a joint beyond the zero position– Flexion and extension occur at

nearly all diarthroses, hyperextension is limited to a few

Figure 9.12a


(a)

Extension

Flexion

© The McGraw-Hill Companies, Inc./Timothy L. Vacula, photographer


(b)

Extension

Flexion

Hyperextension

Figure 9.12b


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9-33

Flexion and Extension

Figure 9.12c

Figure 9.12d


(c)

Flexion

Hyperextension



(d)

Hipflexion

Kneeflexion

Extension


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Abduction and Adduction

• Abduction—movement of a body part in the frontal plane away from the midline of the body– Hyperabduction: raise arm over back or front of head

• Adduction—movement in the frontal plane back toward the midline– Hyperadduction: crossing fingers, crossing ankles

Figure 9.13a,b


(a) Abduction (b) Adduction© The McGraw-Hill Companies, Inc./Timothy L. Vacula, photographer

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9-35

Elevation and Depression

• Elevation—movement that raises a body part vertically in the frontal plane

• Depression—movement that lowers a body part in the same plane

Figure 9.14a,b


(a) Elevation (b) Depression© The McGraw-Hill Companies, Inc./Timothy L. Vacula, photographer

9-36

Protraction and Retraction

• Protraction—the anterior movement of a body part in the transverse (horizontal) plane

• Retraction—posterior movement


(a) Protraction

(b) Retraction

Figure 9.15a,b


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9-37

Circumduction

• Circumduction—one end of an appendage remains stationary while the other end makes a circular motion

• Sequence of flexion, abduction, extension, and adduction movements– Baseball player

winding up for a pitch

Figure 9.16



9-38

Rotation

• Rotation—movement in which a bone spins on its longitudinal axis– Rotation of trunk,

thigh, head, or arm

• Medial (internal) rotation turns the bone inward

• Lateral (external) rotation turns the bone outward

Figure 9.17a,b


(b) Lateral (external) rotation(a) Medial (internal) rotation© The McGraw-Hill Companies, Inc./Timothy L. Vacula, photographer

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9-39

Supination and Pronation

• Primarily forearm movements

• Supination—forearm movement that turns palm to face anteriorly or upward– Forearm supinated in

anatomical position

– Radius is parallel to the ulna

• Pronation—forearm movement that turns palm to face either posteriorly or downward– Radius spins on capitulum of

humerus

Figure 9.18a,b


(a) Supination (b) Pronation


9-40

Special Movements of Head and Trunk

• Flexion—forward-bending movements at the waist

• Extension—straightens trunk or neck

• Hyperextension—bending over backward

• Lateral flexion—tilting the head or trunk to the right or left at the midline

Figure 9.19a,b,c


(a) Flexion (b) Hyperextension (c) Lateral flexion


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9-41

Special Movements of Head and Trunk

• Right and left rotation of trunk and head

Figure 9.19d,e



9-42

Special Movements of the Mandible

• Lateral excursion—right or left movement from the zero position

• Medial excursion—movement back to the median, zero position – Side-to-side grinding during chewing

• Protraction–retraction

• Elevation–depression

Figure 9.20


(a) Protraction (b) Retraction

(c) Lateral excursion (d) Medial excursion


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9-43

Special Movements of Hand and Digits

• Ulnar flexion—tilts the hand toward the little finger

• Radial flexion—tilts the hand toward the thumb

• Flexion of fingers—curling them

• Extension of fingers—straightening them

Figure 9.21


(a) Radial flexion (b) Ulnar flexion

(d) Palmar abduction of thumb (e) Opposition of thumb

(c) Abduction of fingers



• Abduction of the fingers—spreads them apart

• Adduction of the fingers—brings them together again

• Flexion of thumb—tip of thumb directed toward palm

• Extension of thumb—straightening the thumb

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• Radial abduction—moves thumb away from index finger 90°

• Palmar abduction—moves thumb away from hand and points it anteriorly

• Adduction of thumb—moves it to the zero position

• Opposition—moves thumb to touch tips of any of the fingers

• Reposition—returns thumb to the zero position

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9-46

Special Movements of the Foot

• Dorsiflexion—elevation of toes as you do while swinging foot forward to take a step (heel strike)

• Plantar flexion—extension of foot so that toes point downward as in standing on tiptoe (toe-off)

• Inversion—movement in which the soles are turned medially


Figure 9.22


Dorsiflexion

Zeroposition

(c) Eversion(b) Inversion

Plantar flexion

(a) Flexion of ankle

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Special Movements of the Foot

• Eversion—movement in which the soles are turned laterally

• Supination of foot—complex combination of plantar flexion, inversion, and adduction

• Pronation of foot—complex combination of dorsiflexion, eversion, and abduction

9-47

The Jaw Joint (TMJ)

Temporomandibular (jaw) joint (TMJ)—articulation of the condyle of the mandible with the mandibular fossa of the temporal bone

– Combines elements of condylar, hinge, and plane joints

– Two ligaments support joint

• Lateral ligament—prevents posterior displacement of mandible

• Sphenomandibular ligament—on the medial side

– Deep yawn or strenuous depression can dislocate the TMJ

• Condyles pop out of fossa and slip forward

• Relocated by pressing down on molar teeth while pushing the jaw backward

9-48

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The Jaw JointCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Joint capsule

Styloid process

(a) Lateral view

(c) Sagittal section(b) Medial view

Occipital bone

Sphenoid sinus

Styloid process

Joint capsule

Synovial membrane

Mandibular condyle

Superior joint cavity

Inferior joint cavity

Articular disc

Sphenomandibularligament

Lateralligament

Externalacoustic meatus

Stylomandibularligament

Mandibular fossaof temporal bone



Figure 9.23

9-49

9-50

TMJ SyndromeTemporomandibular joint (TMJ) syndrome

– May affect as many as 75 million Americans

• Signs and symptoms– Can cause moderate intermittent facial

pain– Clicking sounds in the jaw– Limitation of jaw movement– Often severe headaches, vertigo

(dizziness), tinnitus (ringing in the ears)– Pain radiating from jaw down the neck,

shoulders, and back• Cause of syndrome

– Caused by combination of psychological tension and malocclusion (misalignment of teeth)

• Treatment – Psychological management, physical

therapy, analgesic and anti-inflammatory drugs, corrective dental appliances to align teeth properly

Figure 9.23 a,c


Joint capsule

Styloid process

(a) Lateral view


Lateralligament

Externalacoustic meatus



(c) Sagittal section

Joint capsule

Synovial membrane

Mandibular condyle

Superior joint cavity

Inferior joint cavity

Articular disc

Mandibular fossaof temporal bone

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9-51

The Shoulder Joint

Glenohumeral(humeroscapular) joint

hemispherical head of humerus articulates with glenoid cavity of scapula

– Most freely movable joint in body

Figure 9.24c


Glenoid labrum

Glenoid labrum

Supraspinatus tendon

Acromion

Capsular ligament

Humerus

(c) Frontal section

Subdeltoidbursa

Deltoidmuscle Synovial

membrane

Glenoid cavityof scapula

9-52

The Shoulder Joint

Five principal ligamentssupport shoulder

– Three are called the Glenohumeral ligaments

– Coracohumeral ligament– Transverse humeral

ligament

• Four bursa occur at the shoulder- Subdeltoid, subacromial,

subcoracoid, and subscapular bursae Figure 9.24c


Glenoid labrum

Glenoid labrum


Acromion

Capsular ligament

Humerus

(c) Frontal section

Subdeltoidbursa


membrane


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9-53

The Shoulder Joint

Figure 9.24b


Acromion

Tendon sheath

Humerus

ClavicleAcromioclavicular ligament

Subacromialbursa

Supraspinatustendon

Coracohumeralligament

Subdeltoidbursa

Subscapularistendon

Transversehumeralligament

Biceps brachiitendon(long head)

(b) Anterior view

Glenohumeralligaments

Subscapularbursa

Subcoracoidbursa

Coracoidprocess

Coraco-acromialligament

Coraco-clavicularligament

9-54

Shoulder Dislocation• Very painful and sometimes causes

permanent damage

• Downward displacement of the humerus is the most common shoulder dislocation– Rotator cuff protects the joint in all

directions but inferiorly– Joint protected from above by

coracoid process, acromion, and clavicle

• Dislocations most often occur when the arm is abducted and then receives a blow from above

• Children especially prone to dislocationFigure 9.24c


Glenoid labrum

Glenoid labrum


Acromion

Capsular ligament

Humerus

(c) Frontal section

Subdeltoidbursa


membrane


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9-55

The Elbow Joint

Figure 9.25c

• Elbow is a hinge joint composed of two articulations– Humeroulnar

joint: where the trochlea of the humerus joins the trochlear notch of the ulna


(b) Sagittal section

Humerus

Trochlea

Joint capsule

Radius

Olecranon

Articular cartilage

Coronoid process

Ulna

Olecranonbursa

Figure 9.25bCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

(c) Medial view

Anular ligament

Joint capsule

Humerus

Coronoid process

Radius

Ulna

Tendon oftriceps brachii

Ulnar collateralligament

Olecranonbursa

Tendon of bicepsbrachii (cut)

9-56

The Hip Joint

• Coxal (hip) joint—point at which the head of femur inserts into the acetabulum of the hip bone

• Bears much more weight, have deeper sockets, more stable than shoulder

• Ligaments supporting hip joint

– Iliofemoral and pubofemoral—on anterior

– Ischiofemoral ligament—on posterior

– Fovea capitis ligament-pit on head of femur

Figure 9.26b


Acetabulum

Labrum

Femur

Roundligament (cut)

Foveacapitis

Head offemur

Greatertrochanter

Transverseacetabularligament

Ischialtuberosity

Obturatormembrane

(b) Lateral view, femur retracted

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9-57

The Hip Joint

Figure 9.26c,d


Ilium

Femur

Pubis

Pubofemoralligament

Iliofemoralligament

Greatertrochanter

Lessertrochanter

(c) Anterior view

Femur

(d) Posterior view

Iliofemoralligament

Ischiofemoralligament

Greatertrochanter

Ischialtuberosity


9-58

The Hip Joint

Figure 9.26a


Acetabular labrum

Acetabulum

Round ligament

Head of femur

Greater trochanter

Shaft of femur

(a) Anterior dissection© The McGraw-Hill Companies, Inc./Timothy L. Vacula, photographer

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9-59

The Knee Joint

• Tibiofemoral (knee) joint—largest and most complex diarthrosis of the body

• Primarily a hinge joint

– Capable of slight rotation and lateralgliding when knee is flexed

– Patellofemoraljoint—gliding joint

Figure 9.29c


Femur

Meniscus

Tibia

Joint cavity

Infrapatellar fat pad

Synovial membrane

Patellar ligament

Patella

Prepatellar bursa

Articular cartilage

Joint capsule


Bursa under lateralhead of gastrocnemius

Quadricepsfemoris

Quadricepsfemoris tendon

Suprapatellarbursa

Superficialinfrapatellar bursa

Deepinfrapatellar bursa

The Knee JointJoint capsule encloses only the lateral and posterior aspects of the

knee, not the anterior

– Anterior covered by patellar ligament

• Knee stabilized– Quadriceps tendon in front– Tendon of semimembranosus muscle on rear of thigh

• Joint cavity contains two C-shaped cartilages

– Lateral meniscus and medial meniscus– Joined by transverse ligament

• Absorbs shock on the knee• Prevents femur from rocking side-to-side on the tibia

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9-61

The Knee Joint

• Popliteal region of knee– Supported by a complex

array of extracapsularligaments external to joint capsule

• Prevent knee from rotating when joint is extended

• Fibular (lateral) collateral ligament

• Tibial (medial) collateral ligament

Figure 9.29c


Femur

Meniscus

Tibia

Joint cavity


Synovial membrane

Patellar ligament

Patella

Prepatellar bursa

Articular cartilage

Joint capsule



Quadricepsfemoris


Suprapatellarbursa



The Knee Joint

• Popliteal region: popliteal bursa and semimembranosus bursa

• Seven more bursae on lateral and medial sides of knee joint

• Knee joint has at least 13 bursae

9-62

Figure 9.29c


Femur

Meniscus

Tibia

Joint cavity


Synovial membrane

Patellar ligament

Patella

Prepatellar bursa

Articular cartilage

Joint capsule



Quadricepsfemoris


Suprapatellarbursa



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The Knee Joint

Figure 9.29a,b

Femur

Patellar surface

Medial condyle

Fibula

Tibia

Medial meniscus

(a) Anterior view

Lateralcondyle

Fibularcollateralligament

Lateralmeniscus

Transverseligament

Posterior cruciateligament

Anterior cruciateligament

Tibial collateralligament

Patellar ligament(cut)

(b) Posterior view

Femur

Fibula

Tibia

Lateral meniscus


Fibular collateralligament

Articular cartilageof tibia

Medialcondyle

Tibialcollateralligament

Medialmeniscus

Posteriorcruciateligament

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

9-64

The Knee Joint

• Medial and lateral meniscus absorb shock and shape joint

Figure 9.29d


Medial meniscus

Lateral meniscus

(d) Superior view of tibia and menisci

Posterior cruciateligament

Synovialmembrane

Medial condyleof tibia


33

Knee Injuries and Arthroscopic Surgery

• Arthroscopy—procedure in which the interior of the joint is viewed with a pencil-thin arthroscope inserted through a small incision

– Less tissue damage than conventional surgery

– Recover more quickly

– Arthroscopic ACL repair: about 9 months for healing to be complete

• Most common injuries are to the meniscus and anterior cruciate ligament (ACL)

• Heal slowly due to scanty blood flow

9-65

The Ankle Joint

• Talocrural (ankle) joint—includes two articulations:

– Medial joint: between tibia and talus

– Lateral joint: between fibula and talus

– Both enclosed by one joint capsule

– More restricted range of motion than the wrist

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34

The Ankle Joint

• Ankle ligaments– Anterior and posterior tibiofibular ligaments: bind the

tibia to fibula

– Multipart medial (deltoid) ligament: binds the tibia to the foot on the medial side

– Multipart lateral (collateral) ligament: binds fibula to the foot on the lateral side

– Calcaneal (Achilles) tendon: extends from the calf muscle to the calcaneus

• Plantarflexes the foot and limits dorsiflexion

– Sprains (torn ligaments and tendons) are common at the ankle

• Pain and immediate swelling

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9-68

The Ankle Joint

Figure 9.31a,c,d


Posterior tibiofibularligament

Lateral malleolus

Posterior talofibularligament

Calcaneofibularligament

Calcaneus

(d) Posterior view

Medialmalleolus

Interosseousmembrane

Fibula

Tibia

Calcanealtendon

Calcaneus

Tibia

Tendons oftibialis anterior and posterior

Metatarsal I

Navicular

Medial ligament

(c) Medial view

Calcaneofibular ligament

Anterior talofibular ligament

Posterior talofibular ligament

Tendons offibularis longusand brevis

Metatarsal v

Calcaneus

Calcanealtendon

Anterior andposterior tibiofibularligaments

Tibia

Fibula

(a) Lateral view

Lateral ligament:

35

9-69

Arthritis and Artificial Joints

• Arthritis—a broad term for pain and inflammation of a joint

• Most common crippling disease in the United States

• Rheumatologists—physicians who treat arthritis and other joint disorders

• Osteoarthritis (OA)—most common form of arthritis– “Wear-and-tear arthritis”

– Results from years of joint wear

– Articular cartilage softens and degenerates

– Accompanied by crackling sounds called crepitus

– Bone spurs develop on exposed bone tissue causing pain

9-70

Arthritis and Artificial Joints

• Rheumatoid arthritis (RA)—autoimmune attack against the joint tissues– Misguided antibodies (rheumatoid factor) attack

synovial membrane, enzymes in synovial fluid degrade the articular cartilage, joint begins to ossify

– Ankylosis: solidly fused, immobilized joint

– Remissions occur, steroids and aspirin control inflammation

• Arthroplasty—replacement of diseased joint with artificial device called prosthesis

36

9-71

Rheumatoid Arthritis

Figure 9.32a,b

9-72

Joint ProsthesesCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Femur

(a)

(b)

(c)

(d)

Fibula

Femur

Prosthesis

Artificialacetabulum

Artificialfemoralhead

Tibia

a: © SIU/Visuals Unlimited; b: © Ron Mensching/Phototake; c: © SIU/Peter Arnold, Inc.; d: © Mehau Kulyk/SPL/Photo Researchers, Inc.

Figure 9.33a,b Figure 9.33c,d

Documents

Ch9 Joints - goodwinmedia.org · PDF file– More movable than a condyloid or hinge joint forming ... ankle, and vertebral column ... Classes of Synovial Joints • Hinge joints