1. Learning Plan 4--Ch. 8 Joints
Pages , ,
Michael Aprill
Lakeshore Technical College

2. Joints (Articulations)
Articulation—site where two or more bones meet
Functions of joints:
Give skeleton mobility
Hold skeleton together

3. Functional Classification of Joints
Based on amount of movement allowed by the joint
Three functional classifications:
Synarthroses—immovable
Amphiarthroses—slightly movable
Diarthroses—freely movable

4. Structural Classification of Joints
Based on material binding bones together and whether or not a joint cavity is present
Three structural classifications:
Fibrous
Cartilaginous
Synovial

5. Bones held together by fibrous CT. No joint cavity
Fibrous Joints
Bones held together by fibrous CT.
No joint cavity
Most are synarthrotic (immovable)
Some are amphiathrotic
Three types:
Sutures
Syndesmoses
Gomphoses

6. Fibrous Joints: Sutures (Fig. 8.1A)
Unites bones of skull.
Allow for growth during youth
In middle age, sutures ossify and are called synostoses
Synarthrotic (completely immovable)

7. Fibrous Joints: Syndesmoses (Fig. 8.1B)
Bones connected by ligaments (bands of fibrous tissue)
Movement varies from immovable to slightly movable
Examples:
Synarthrotic distal tibiofibular joint
Diarthrotic interosseous connection between radius and ulna

8. Fibrous Joints: Gomphoses
Peg-in-socket joints of teeth in alveolar sockets
Fibrous connection is the periodontal ligament

9. Bones united by cartilage No joint cavity Two types:
Cartilaginous Joints
Bones united by cartilage
No joint cavity
Two types:
Synchondroses
Symphyses

10. Cartilaginous Joints: Synchondrose (Fig. 8.2A)s
A bar or plate of hyaline cartilage unites the bones
All are synarthrotic
Ex. Epiphyseal plate
Ex. Joint between ribs/sternum

11. Cartilaginous Joints: Symphyses (Fig. 6.2B)
No synovial cavity.
Connected by disc of fibrocartilage.
Ex. Intervertebral discs.
Ex. Pubic Symphysis

12. Include all limb joints; most joints of the body
Synovial Joints
All are diarthrotic
Include all limb joints; most joints of the body
Distinguishing features:
Articular cartilage: hyaline cartilage->absorbs compression placed on joint, preventing bone form being crushed.
Joint (synovial) cavity: small potential space
Articular (joint) capsule:
Outer fibrous capsule of dense irregular connective tissue

13. Distinguishing features:
Synovial Joints
Distinguishing features:
Synovial fluid:
Lubricates & nourishes articular cartilage
Reinforcing ligaments
Rich nerve & blood vessel supply

14. Synovial Joints: Friction-Reducing Structures (Fig. 8.4A)
Bursae:
Flattened, fibrous sacs lined with synovial membranes
Commonly act as “ball bearings” where ligaments, muscles, skin, tendons, or bones rub together

15. Synovial Joints: Friction-Reducing Structures
Tendon sheath:
Elongated bursa that wraps completely around a tendon

16. Synovial Joints: Range of Motion
Nonaxial—slipping movements only
Uniaxial—movement in one plane
Biaxial—movement in two planes
Multiaxial—movement in or around all three planes

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

18. Angular Movements Movements that occur along the sagittal plane:
Flexion—decreases the angle of the joint
Extension— increases the angle of the joint
Hyperextension—excessive extension beyond normal range of motion

19. Hyperextension
Extension
Flexion

20. Angular Movements Movements that occur along the frontal plane:
Abduction—movement away from the midline
Adduction—movement toward the midline
Circumduction—flexion + abduction + extension + adduction of a limb so as to describe a cone in space

21. The turning of a bone around its own long axis
Rotation
The turning of a bone around its own long axis
Examples:
Between C1 and C2 vertebrae
Rotation of humerus and femur

22. Movements of radius around ulna:
Special Movements
Movements of radius around ulna:
Supination (SEE DIAGRAM)
Pronation (SEE DIAGRAM)

23. Special Movements Movements of the foot:
Dorsiflexion (upward movement)
Plantar flexion (downward movement)

24. Special Movements Movements of the foot:
Inversion (turn sole medially)
Eversion (turn sole laterally)

25. Movements in a transverse plane:
Special Movements
Movements in a transverse plane:
Protraction (anterior movement)
Retraction (posterior movement)

26. Special Movements
Elevation (lifting a body part superiorly)
Depression (moving a body part inferiorly)

27. Opposition of the thumb
Special Movements
Opposition of the thumb
Movement in the saddle joint so that the thumb touches the tips of the other fingers

28. Classification of Synovial Joints
Six types, based on shape of articular surfaces:
Plane
Hinge
Pivot
Condyloid
Saddle
Ball and socket

29. Flat articular surfaces Short gliding movements
Plane Joints
Nonaxial joints
Flat articular surfaces
Short gliding movements
Ex. Intercarpal & Intertarsal
Ex. Sternoclavicular
Ex. Vertebrocostal

30. Motion along a single plane Flexion and extension only
Hinge Joints
Uniaxial joints
Motion along a single plane
Flexion and extension only
Ex. Knee, elbow, ankle, interphalangeal

31. Uniaxial movement only
Pivot Joints
Rounded end of one bone conforms to a “sleeve,” or ring of another bone
Uniaxial movement only
Ex. Radioulnar

32. Condyloid (Ellipsoidal) Joints
Biaxial joints
Both articular surfaces are oval
Permit all angular movements
Ex. Carpals over digits 3-5 & radius

33. Saddle Joints
Biaxial
Allow greater freedom of movement than condyloid joints
Each articular surface has both concave and convex areas
Ex. Metacarpal of thumb with carpal

34. Ball-and-Socket Joints
Multiaxial joints
The most freely moving synovial joints
Ex. Shoulder & Hip

35. Knee Joint Largest, most complex joint of body
Three joints surrounded by a single joint cavity:

36. (c) Anterior view of right knee
Quadriceps
femoris muscle
Tendon of
quadriceps
femoris muscle
Patella
Medial patellar
retinaculum
Lateral patellar
retinaculum
Tibial collateral
ligament
Fibular
collateral
ligament
Patellar ligament
Fibula
Tibia
(c) Anterior view of right knee
Figure 8.8c

37. (d) Posterior view of the joint capsule, including ligaments
Femur
Tendon of
adductor magnus
Articular capsule
Oblique popliteal
ligament
Medial head of
gastrocnemius
muscle
Lateral head of
gastrocnemius
muscle
Popliteus
muscle (cut)
Bursa
Fibular collateral
ligament
Tibial collateral
ligament
Arcuate popliteal
ligament
Tendon of
semimembranosus
muscle
Tibia
(d) Posterior view of the joint capsule, including ligaments
Figure 8.8d

38. Posterior cruciate ligament Fibular collateral ligament Medial condyle
Tibial collateral
ligament
Lateral condyle
of femur
Anterior cruciate
ligament
Lateral
meniscus
Medial meniscus
Tibia
Patellar ligament
Fibula
Patella
Quadriceps tendon
(e) Anterior view of flexed knee, showing the cruciate ligaments (articular capsule removed, and quadriceps tendon cut and reflected distally)
Figure 8.8e

39. Shoulder (Glenohumeral) Joint
Ball-and-socket joint: head of humerus and glenoid fossa of the scapula
Stability is sacrificed for greater freedom of movement

40. (c) Anterior view of right shoulder joint capsule
Acromion
Coracoid
process
Coracoacromial
ligament
Articular
capsule
reinforced by
glenohumeral
ligaments
Subacromial
bursa
Coracohumeral
ligament
Subscapular
bursa
Greater
tubercle
of humerus
Tendon of the
subscapularis
muscle
Transverse
humeral
ligament
Scapula
Tendon sheath
Tendon of long
head of biceps
brachii muscle
(c) Anterior view of right shoulder joint capsule
Figure 8.10c

41. Elbow Joint
Radius and ulna articulate with the humerus
Hinge joint formed mainly by trochlear notch of ulna and trochlea of humerus
Flexion and extension only

42. Anular ligament—surrounds head of radius
Elbow Joint
Anular ligament—surrounds head of radius
Two capsular ligaments restrict side-to-side movement:
Ulnar collateral ligament
Radial collateral ligament

43. (b) Lateral view of right elbow joint
Humerus
Anular
ligament
Radius
Lateral
epicondyle
Articular
capsule
Radial
collateral
ligament
Olecranon
process
Ulna
(b) Lateral view of right elbow joint
Figure 8.11b

44. (d) Medial view of right elbow
Articular
capsule
Anular
ligament
Humerus
Coronoid
process
Medial
epicondyle
Ulnar
collateral
ligament
Radius
Ulna
(d) Medial view of right elbow
Figure 8.11d

45. Hip (Coxal) Joint Ball-and-socket joint
Head of the femur articulates with the acetabulum
Good range of motion, but limited by the deep socket

46. Temporomandibular Joint (TMJ)
Two types of movement
Hinge—depression and elevation of mandible
Gliding—e.g. side-to-side (lateral excursion) grinding of teeth
Most easily dislocated joint in the body

47. (a) Location of the joint in the skull
Mandibular fossa
Articular tubercle
Zygomatic process
Infratemporal fossa
External
acoustic
meatus
Lateral
ligament
Articular
capsule
Ramus of
mandible
(a) Location of the joint in the skull
Figure 8.13a