Joints by dr. armaan singh

1. ANATOMY OF JOINTS
By- Dr. Armaan SinghBy- Dr. Armaan Singh

2. CLASSIFICATION OF JOINTS
 Functional classification
(Focuses on amount of movement)
 Synarthroses (immovable joints)
 Amphiarthroses (slightly movable joints)
 Diarthroses (freely movable joints)
 Structural classification
(Based on the material binding them and presence or absence of a
joint cavity)
 Bony fusion
 Fibrous
 Cartilagenous
 Synovial

3. TABLE OF JOINT TYPES
Functional across
Structural down
Synarthroses
(immovable joints)
Amphiarthroses
(some movement)
Diarthroses
(freely movable)
Bony Fusion Synostosis
(frontal=metopic
suture; epiphyseal
lines)
Fibrous Suture (skull only)
-fibrous tissue is
continuous with
periosteum
Gomphoses (teeth)
-ligament is
periodontal ligament
Syndesmoses
-ligaments only
between bones; here,
short so some but not
a lot of movement
(example: tib-fib
ligament)
Syndesmoses
-ligament longer
(example: radioulnar
interosseous
membrane)
Cartilagenous
(bone united by
cartilage only)
Synchondroses
-hyaline cartilage
(examples:
manubrium-C1,
epiphyseal plates)
Sympheses
-fibrocartilage
(examples: between
discs, pubic
symphesis
Synovial Are all diarthrotic

4. FIBROUS JOINTS
 Bones connected by fibrous tissue: dense regular connective tissue
 No joint cavity
 Slightly immovable or
not at all
 Types
 Sutures
 Syndesmoses
 Gomphoses

5. SUTURES
 Only between bones of skull
 Fibrous tissue continuous with periosteum
 Ossify and fuse in middle age: now
technically called “synostoses”= bony
junctions

6. SYNDESMOSES
 In Greek: “ligament”
 Bones connected by
ligaments only
 Amount of movement
depends on length of
the fibers: longer than
in sutures

7. GOMPHOSES
 Is a “peg-in-socket”
 Only example is tooth
with its socket
 Ligament is a short
periodontal ligament

8. CARTILAGENOUS JOINTS
 Articulating bones united by cartilage
 Lack a joint cavity
 Not highly movable
 Two types
 Synchondroses (singular: synchondrosis)
 Sympheses (singular: symphesis)

9. SYNCHONDROSES
 Literally: “junction of cartilage”
 Hyaline cartilage unites the bones
 Immovable (synarthroses)
 Examples:
 Epiphyseal plates
 Joint between first rib’s costal cartilage and manubrium of the sternum

10. SYMPHESES
 Literally “growing together”
 Fibrocartilage unites the bones
 Slightly movable (amphiarthroses)
 Resilient shock absorber
 Provide strength and flexibility
 Hyaline cartilage on articular surfaces of bones to reduce
friction
 Examples
 Intervertebral discs
 Pubic symphysis of the pelvis

11. SYNCHONDROSES AND SYMPHESES
Also pubic symphsis

12. SYNOVIAL JOINTS
 Include most of the body’s joints
 All are diarthroses (freely movable)
 All contain fluid-filled joint cavity

13. GENERAL STRUCTURE OF SYNOVIAL
JOINTS
1. Articular cartilage
 Hyaline
 Spongy cushions absorb
compression
 Protects ends of bones from
being crushed
2. Joint (synovial) cavity
 Potential space
 Small amount of synovial fluid

14. GENERAL STRUCTURE OF SYNOVIAL JOINTS
(CONT.)
3. Articular (or joint) capsule
 Two layered
 Outer*: fibrous capsule of dense
irregular connective tissue
continuous with periosteum
 Inner*: synovial membrane of
loose connective tissue (makes
synovial fluid)
 Lines all internal joint surfaces not
covered by cartilage*
*
*
*

15. GENERAL STRUCTURE OF SYNOVIAL JOINTS
(CONT.)
4. Synovial fluid
 Filtrate of blood
 Contains special glycoproteins
 Nourishes cartilage and functions as
slippery lubricant
 “Weeping” lubricatioin
5. Reinforcing ligaments (some joints)
 Capsular (most) – thickened parts of
capsule
 Extracapsular
 Intracapsular

16. GENERAL STRUCTURE OF SYNOVIAL JOINTS
(CONT.)
6. Nerves
 Detect pain
 Monitor stretch (one of the ways
of sensing posture and body
movements)
7. Blood vessels
 Rich blood supply
 Extensive capillary beds in
synovial membrane (produce the
blood filtrate)

17. GENERAL STRUCTURE OF SYNOVIAL
JOINTS

18. SOME JOINTS…
 Articular disc or
meniscus
(literally “crescent”)
 Only some joints
 Those with bone
ends of different
shapes or fitting poorly
 Some to allow two kinds of movement (e.g. jaw)
 Of fibrocartilage
 Examples: knee
TMJ (temporomandibular joint)

19. BURSAE AND TENDON SHEATHS
 Contain synovial fluid
 Not joints but often associated with them
 Act like ball bearings
 Bursa means “purse” in Latin
 Flattened sac lined by synovial membrane
 Where ligaments, muscles, tendons, or bones overlie each other and rub together
 Tendon sheath
 Only on tendons subjected to friction

20. BURSAE AND TENDON SHEATHS

21. JOINT STABILITY
 Articular surfaces
 Shape usually plays only minor role
 Some deep sockets or grooves do provide stability
 Ligaments
 Usually the more, the stronger the joint
 Can stretch only 6% beyond normal length before tear
 Once stretched, stay stretched
 Muscle tone
 Constant, low level of contractile force
 Keeps tension on the ligaments
 Especially important at shoulders, knees, arches of foot

22. MOVEMENTS ALLOWED BY SYNOVIAL
JOINTS
 Gliding
 Angular movements: or  the angle between two bones
DO TOGETHER
 Flexion
 Extension
 Abduction
 Adduction
 Circumduction
 Rotation
 Special movements

23.  Pronation
 Supination
 Dorsiflexion
 Plantar flexion
 Inversion
 Eversion
 Protraction
 Retraction
 Elevation
 Depression
 Opposition
SPECIAL MOVEMENTS

24. JOINT MOVEMENTS PICS
(FROM MARIEB, 4TH
ED.)

30. SYNOVIAL JOINTS
CLASSIFIED BY SHAPE
(OF THEIR ARTICULAR
SURFACES)
 Plane (see right)
 Hinge (see right)
 Pivot
 Condyloid
 Saddle
 Ball-and-socket

32. SHOULDER
(GLENOHUMERAL)
JOINT
 Stability sacrificed for mobility
 Ball and socket: head of
humerus with glenoid cavity of
scapula
 Glenoid labrum: rim of
fibrocartilage
 Thin, loose capsule
 Strongest ligament:
coracohumeral
 Muscle tendons help stability
 Disorders
Selected synovial joints
Rotator cuff muscles add to stability
Biceps tendon is intra-articular

33. ELBOW JOINT
 Hinge: allows only flexion and
extension
 Annular ligament of radius
attaches to capsule
 Capsule thickens into:
 Radial collateral ligament
 Ulnar collateral ligament
 Muscles cross joint
 Trauma

34. WRIST JOINT
TWO MAJOR JOINT SURFACES
SEVERAL LIGAMENTS
STABILIZE
1. Radiocarpal joint
 Between radius and
proximal carpals
(scaphoid and lunate)
 Condyloid joint
 Flexion extension
adduction, abduction,
circumduction
1. Intercarpal or midcarpal
joint
 Between the proximal and
distal rows of carpals

35. HIP (COXAL) JOINT
 Ball and socket
 Moves in all axes but
limited by ligaments and
deep socket
 Three ext. ligaments
“screw in” head of femur
when standing
 Iliofemoral
 Pubofemoral
 Ischiofemoral

36.  Acetabular labrum
diameter smaller than
head of femur
 Dislocations rare
 Ligament of head of femur
supplies artery
 Muscle tendons cross joint
 Hip fractures common in
elderly because of
osteoporosis

37. Right hip, AP view

38. KNEE JOINT
 Largest and most complex joint
 Primarily a hinge
 Compound and bicondyloid: femur and tibia both have 2 condyles
 Femoropatellar joint shares joint cavity
 At least a dozen bursae
 Prepatellar
 Suprapatellar

39.  Lateral and medial menisci
 “torn cartilage”
 Capsule absent anteriorly
 Capsular and extracapsular
ligaments
 Taut when knee extended to
prevent hyperextension

40.  Patellar ligament
 Continuation of quad
tendon
 Medial and lateral
retinacula
 Fibular and tibial
collateral ligaments
 Called medial and
lateral
 Extracapsular
 Oblique popliteal
 Arcuate popliteal

41. CRUCIATE LIGAMENTS
 Cross each other (cruciate
means cross)
 Anterior cruciate (ACL)
 Anterior intercondylar area of
tibia to medial side of lateral
condyl of femur
 Posterior cruciate
 Posterior intercondylar area of
tibia to lateral side of medial
condyl
 Restraining straps
 Lock the knee

42. CRUCIATE LIGAMENTS

43. KNEE INJURIES
 Flat tibial surface
predisposes to horizontal
injuries
 Lateral blow: multiple tears
 ACL injuries
 Stop and twist
 Commoner in women
athletes
 Heal poorly
 Require surgery

44. NKLE JOINT
 Hinge joint
 Distal tibia and fibula to talus
 Dorsiflexion and plantar flexion only
 Medial deltoid ligament
 Lateral ligaments: 3 bands
 Anterior talofibular
 Posterior talofibular
 Calcaneofibular
 Anterior and posterior tibiofibular
(syndesmosis)

45. RIGHT ANKLE, LATERAL VIEW

48. TEMPOROMANDIBULA
R JOINT (TMJ)
 Head of mandible articulates with
temporal bone
 Disc protects thin mandibular
fossa of temporal bone
 Many movements
Demonstrate movements together
 Disorders common

49. STERNOCLAVICULAR
JOINT
 Saddle joint
 Only other example is trapezium and
metacarpal 1 (thumb), allowing
opposion
 Sternum and 1st
costal (rib) cartilage
articulate with clavicle
 Very stable: clavicle usually breaks
before dislocation of joint
 Only bony attachment of axial skeleton
to pectoral girdle
Demonstrate movements together

50. DISORDERS OF JOINTS
 Injuries
 Sprains
 Dislocatios
 Torn cartilage
 Inflammatory and degenerative conditions
 Bursitis
 Tendinitis
 Arthritis
 Osteoarthritis (“DJD” – degenerative joint disease)
 Rheumatoid arthritis (one of many “autoimmune” arthritites)
 Gout (crystal arthropathy)