BIO: CHP 9 RS

Joint (articulation)

point where two bones meet

Arthrology

study of joint structure, function & dysfunction

Kinesiology

• Study of musculoskeletal movement;

• branch of biomechanics.

• Includes physics of blood circulation, respiration & hearing.

Three categories of joint classification by anatomy

• fibrous

• cartilaginous

• synovial

Three categories of joint classification by mobility

• synarthroses (immovable),

• amphiarthroses (slightly movable)

• diarthroses (most mobile)

Fibrous joints

• Bound by collagen fibers

• Emerge from the matrix of 1 bone, cross the space between them & penetrate the matrix of another bone

• sutures, syndesmoses, gomphoses

Fibrous joints: Sutures

• bind bones of skull (only found here) to each other

• Immobile or slightly Mobil

• serrate, lap & plane sutures

Serrate sutures

• Join bones with serrated margins (dovetail wood joint)

• Adjoining bones firmly interlock by their serrated margins (lke jigsaw puzzle.)

• Ex: coronal, sagittal, lambdoid sutures

Lap (squamous) sutures

• join bones that have overlapping beveled edges

• Ex: squamous suture

Plane (butt) sutures

• Join bones that have straight, nonoverlapping edges

• Ex: intermaxillary suture in the roof of the mouth

Fibrous joints: Sydesmoses

• bind bones with relatively long collagen fibers;

• more mobility than sutures

• 
  

Sydesmoses Example

• raidius and ulna joined by interosseous membrane, allow for pronation and supination of forearm.

• Interosseous membrane in LE less mobile

Fibrous joints: Gomphoses

bind teeth to jaw

Cartilaginous joints

• joint where adjacent bones bound by cartilage

• include: synchondroses and symphyses

Cartilaginous joint: Synchondrosis

• Bones bound by hyaline cartilage

• immoveable or slightly movable

Synchondrosis Example:

• Joint between first rib and sternum (slightly movable) in child or adolescent

• Epiphysis and diaphysis joined by cartilaginous epiphyseal plate (immovable)

Cartilaginous joints: Symphyses

• bones joined by fibrocartilage

• slightly moveable

Symphyses Example:

pubic symphysis

• L& R pubic bones joined by a cartilaginous interpubic disc.

• Allows adjoining hip bones to move slightly during childbirth

• Facilitates passage of infant’s head

Symphyses Example:

joints between bodies of adjacent vertebrae

• united by intervertebral discs

• covered with hyaline cartilage

• slight movement

• effect of all 23 discs gives the spine considerable flexibility

Synovial joint

• Bones held together by fibrous joint capsule w thin film of lubricating synovial fluid between the bones. Ends of bones covered in articular cartilage

• Most common type of joint

• Freely mobile diarthroses; some are amphiarthroses w limited mobility

Synovial joint examples

knee, elbow, knuckles

Synovial joints are separated by a gap called

joint (articular) cavity

In synovial joints, the joint (articular) cavity is filled with….

a vscous, slippery, lubricatng synovial fluid

Synovial fluid and articular cartilages make the movement of synovial joints almost

friction free (property lost in arthritis)

Synovial fluid also nourishes the articular cartilages and removes their

wastes

In synovial joints bone surfaces are covered in _____ and composed of _____

In synovial joints, bone surfaces are covered in articular cartilage and composed of hyaline cartilage

in synovial joints What encloses the joint cavity

double layered joint (articular) capsule

What are the two layers of the joint (articular) capsule

Synovial membrane

fibrous capsule

Synovial membrane

• inner layer

• Consists mainly of fibroblast-like cells that secrete synovial fluid

• Populated by macrophages that remove debris from the joint cavity

Fibrous capsule

• outer layer

• dense fibrous connective tissue

• surrounds synovial membrane

What may be found between bones n some synovial joints

fibrocartilage

What is articular disc

fibrocartilage structure that crosses the entire capsule

What is a meniscus?

fibrocartilage structure that extends inward but does not cross the joint

Describe the meniscus in the knee

The knee has two cartilages that extend inward from the left and right but dont entirly cross the joint.

Each meniscus is crecent shaped

Articular discs

pads across the joint

In the knee what are the 2 crescent-shaped bodies

menisci

What are accessory structures associated with synovial joints

• Tendon

• Ligaments

• Bursa

• Tendon sheath

Tendon

cord or sheet of fibrous connective tissue connecting muscle to bone

Ligament

• Similar to tendon, but connects bone to bone

• avascular

What do tendons and ligaments do

they cross synovial joints and stabilize them

Bursa

• Fibrous sac external to joint cavity and between moving parts

• filled with synovial fluid

• Cushion muscles

• help tendons slide over joints

Bursitis

inflammation of a bursa

Tendon sheath

elongated bursa wrapped over a tendon

Tendinitis

inflamed tendon sheath

What are the six types of synovial joints

• Ball and socket joints

• Condylar (ellipsoid joints)

• saddle joints

• Plane (gliding) joints

• hinge joints

• pivot joints

Ball and socket joints

• head of one bone fits into cup-like socket of the other bone

• multiaxial

Ball and socket joint example

shoulder and hip joints

Condylar (ellipoid) joints

• oval convex surface of one bone fits into complementary depression of other

• biaxial

Condylar (ellipoid) joints example

radiocarpal joint of wrist, metacarpophalangeal joints of knuckles

Saddle joints

• Saddle-shaped surface

• concave in one direction and convex in the other

• Biaxial (greater mobility than others )

Saddle joints Example

trapeziometacarpal joint at base of thumb; sternoclavicular joint

Plane (gliding) joints

• bone surfaces are flat

• usually biaxial

Plane (gliding) joints example

• between carpal bones of the wrist

• tarsal bones of ankle

• patella and femur

Hinge joints

• convex surface of one bone fits into concave depression on another bone, like a door hinge

• monoaxial

Hinge joints example

• elbow (humeroulnar)

• knee (femur & condyles of femur & slightly concave condyles of tibial plateau)

• interphalangeal (finger and toe) joints

pivot joints

One bone spins (pivots) on longitudinal axis

monoaxial

Pivot joints example

• radioulnar joint at elbow

• atlantoaxial joint between vertebrae C1 and C2

Range of motion is the action of

musces and tendons

What can limit range of motion

Muscle tensions and tone

Extension of the knee is also limited by _____ ______ on the _____ side of the ______

Extension of the knee is also limited by hamstring muscle on the posterior side of the thigh

Even a resting muscle maintains a…….

state of tension called muscle tone

muscle tone serves in many casses to

stabilize a joint

The nervous system continually monitors and adjusts joint angles and muscle tone to maintain

joint stability and limit unwanted movements

Does resting muscle maintain a little tension

yes

Temporomandibular (jaw) joint

artculation between condylke of mandble and mandibular fossa or temporal bone

Key features of TMJ

• Condylar, hinge, and plane joints

• elevation and depression of mandible

• side-to-side movements

• protraction, and retraction

• Articular surfaces covered w fibrocartilage

• Articular disc within joint

• Lateral ligament prevents posterior displacement of mandible

What can dislocate TMJ

deep yawm or other strenuous depression of mandible

what happens when TMJ dislocates and how to relocate

• Condyle pops out of fossa and slips forward

• Press down on molars while pushing jaw backward to relocate

Glenohumeral (humeroscapular) joint

• shoulder joint

• articulation between head of humerous and lenoid cavity of scapula

Key features of the shoulder joint

• Glenoid labrum - stability

• Several ligaments support the joint; tendon of the biceps brachii

• Four rotator cuff muscles have tendons that fuse with joint capsule

Ligaments of the Glenohumeral joint

• coracohumeral ligament,

• transverse humeral ligament

• three glenohumeral ligaments

Coracohumeral ligament

extends from the coracoid process of the scapula to the greater tubercle of the humerus

Glenoid labrum

• stability

• Ring of fibrocartilage around the margin

• makes it deeper than it looks on a dried skeleton

What are the four rotator cuff muscles important for

stabilizing the glenohumeral

What are the 4 rotator cuff muscles

• SITS

• Subscapularis

• supraspinatus

• infraspinatus

• teres minor

What two articulations is the elbow composed of

humeroulnar joint and the humeroradial jointwh

what do the humeroulnar joint and the humeroradial joint both enclosed

a single joint capsule

Key features of the elbow joint

• olecranon bursa

• Side movements restricted by radial and ulnar collateral ligaments

• proximal radioulnar joint is near the elbow, but isn’t part of elbow hinge joint; at this joint the disc-like head of the radius fits into the radial notch of the ulna & is held in place the annular ligament, which encircles the head of the radius & attaches at each end of the ulna

Which ligaments restrict side-to-side movements of the elbow

the radial (lateral) and ulnar (medial) collateral ligaments

Function of the olecranon bursa

It cushions the movement of tendons over the olecranon of the ulna

Is the proximal radioulnar joint part od the elbow hinge joint?

No. its near the elbow but t is not part of the elbow hinge joint

At the proximal radioulnar joint where does the head of the radius fit?

into the radial notch od the ulna and is held in place by the annular ligament

What does the annular ligament do?

encircles the head of the radius & attaches at each end of the ulna

Coxal (hip joint)

head of femur articulates with acetabulum of hip bone

Key features of the hip joint

• Stable joint due to deep socket of acetabulum and numerous taut ligaments

• acetabular labrum present at rim of acetabulum

• Round ligament (ligamentum teres) attaches at head of femur (fovea capitis ) and lower margin of acetabulum

  • contains an artery that supplies blood to head of femur

In the Coxal join the depth of the socket is somewhat _______ than you see on dried bones because a ______________ ___ of _____, the _______ _______ is attached to its rims

In the coxal joint, the depth of the socket is somewhat greater than you see on dried bones because a horseshoe-shaped ring of fibrocartilage, the acetabular labrum, is attached to its rims

What are the ligaments that support the coxal joint

anterior side:

• iliofemoral

• pubofemoral ligaments

posterior side

• ischiofemoral ligament

What happens to the ligaments of the coxal joint when you stand up

When you stand up these ligaments become twisted and pull the head of the femur tightly into the acetabulum

Tibiofemoral (knee) joint

• Articulation between femoral and tibial condyles

• largest and most complex synovial joint in body

• prim. hinge joint

• but when flexed, can do slight rotation and lateral gliding

Key features of knee joint

• Femur articulates with patella via patellar ligament. - patellofemoral joint

• Lateral and medial menisci within joint.

• Stabilized by numerous ligaments

• Knee injuries usually involve a meniscus or anterior cruciate ligament

Describe the lateral and medial menisci within the tibiofemoral joint

• C-shaped cartilage.

• shock absorbers

• prevent femur from side-to-side motion on tibia.

• Made of fibrocartilage

What are the ligaminets the Tibiofemoral joint is stabilized by

• Oblique & arcuate popliteal ligaments

• Fibular and tibial collateral ligaments

• Anterior and posterior cruciat eligaments (they cross eachother)

• ACL:

• PCL

ACL

attaches to anterior tibia and prevents foward sliding of tibia and stops hyperextension of knee

PCL

attaches to posterior tibia & prevents backward sliding of tibia and forward sliding of femur

Talocrural (ankle) joint

Two articulations:

• joint between tibia and talus

• joint between fibula and talus

both enclosed within a single joint capsule

Key features of ankle joint

• Malleoli of tibia and fibula overhang talus, preventing side-to-side motion

• Numerous ligaments and calcaneal (Achilles) tendon offer support

  • anterior and posterior tibiofibular ligaments

  • medial (deltoid) ligament

  • lateral collateral ligament

Ankle joint

dorsiflexion and plantarflexion

Subtalar joint is between the

talus and calcaneus tarsals