VT111 Lec. 8 Arthrology

Types of Joints: Arthro-

• Junctions between bones

• 3 types of joints:

  • Fibrous:

    • ex: sutures of skull

    • essentially immovable (synarthrotic joint)

    • Gomphosis: teeth in socket-not a true joint

  • Cartilaginous:

    • ex: symphysis of pubis; intervertebral joints, mandibular symphyis

    • very slightly movable (amphiarthrotic joint); “rocking joints”

  • Synovial:

    • ex: joints of limbs

    • freely movable, bones separated by joint cavity containing synovial fluid (diarthrotic joint)

Type of Joint?

Fibrous joint

Type of Joint?

Cartilaginous joint

Type of Joint?

Synovial joint → Hinge joint

Structures of a Diarthrotic Joint

• Articular cartilage covers articular surface of bone

  • Hyaline cartilage

    • Teflon-like coating to reduce friction

• Joint space/cavity

  • Fluid filled

  • Surrounded by fibrous joint capsule

  • Capsule lined by vascular synovial membrane

    • Secretes joint fluid (synovial fluid)

      • “motor oil”; nutrient transport

• +/- Reinforcing ligaments

  • Fibrous connective tissue

    • Dense regular

    • Stability to joint

• Join bones to other bones

  • (tendons join muscle to bone)

Synovial (Diarthrotic) Joint

• What joint is this?

  • femorotibial joint = stifle joint

• Ligaments to stabilize

  • Connect bone to bone

  • Area of possible injury

• Meniscus

  • Made of hyaline cartilage

    • Padding

Classification of Synovial Joints

• Number of articulating surfaces

  • Simple = 2

  • Compound = >2

• Function of joint

• Shape or form of the joint

Types of Joint Movement

• Flexion: decreases angle between two bones

• Extension: increases angle between two bones

• Adduction: movement of extremity toward medial plane

• Abduction: movement away from median plane

• Rotation: twisting on its own axis

• Circumduction: distal end of extremity moves in a circle

Types of synovial joints based on movement, shape and/or form

• Hinge joint (ginglymus): movement in a single plane like a gate hinge (elbow). Only flexion and extension.

• Gliding (plane) joint: joint surfaces are flat; movement between is a rocking motion of one bone on another, like carpal joints.

• Pivot joint: rotational around a pivot point, like radio-ulnar joint or atlantoaxial joint

Types of synovial joints based on movement

• Ball and socket (spheroidal): self explanatory, like coxofemoral (hip) joint. Allows for all types of movement: adduction, abduction, circumduction etc.

• Condyloid joint (ellipsoidal): rounded projection (condyle; “knuckle-shaped”) of one bone fits depression of another bone similar to knuckle or femorotibial joints. Allows movement in two planes.

• Saddle joint: where two bones fit together like sitting in a saddle (carpometacarpal joints)

Diagram of Different Joints

What Type of Joint?

A. Atlas vertebrae → head = synovial joint = hinge joint = atlantooccipital joint = neck to head → “yes” joint

B. Atlas vertebrae → axis vertebrae = pivot joint = synovial joint = atlanto-axial joint = “no” joint

What Type of Joint?

synovial joint = Scapulohumeral = ball in socket = shoulder joint

What Type of Joint?

synovial joint = Humeroradioulnar = elbow joint = hinge joint → flexes and extends

What Type of Joint?

Cartilaginous joint = sacroiliac joint = loin/croup joint → slightly moveable

What Type of Joint?

Synovial joint = coxofemoral joint = ball in socket joint = hip joint 

What Type of Joint?

synovial joint = femorotibial joint = condyloid (elipsoidal) joint = stifle joint 

What Type of Joint?

synovial joint = tibiotarsal joint = hinge/gliding joint = hock joint

What Type of Joint?

synovial joint = Intercarpal joint = gliding joint = wrist (knee in horse) joint

What Type of Joint?

Synovial joint = Proximal metacarpophalageal joint = hinge joint = fetlock joint (horse) flexion/extension; condyloid joint in a dog

What Type of Joint?

Synovial joint = Saddle joint = Distal Interphalageal joint = coffin joint (horse)

What Type of Joint?

synovial joint = tempromandibular joint = condyloid (elipsoidal) joint = jaw joint