joints aka: articulations. classification of joints functional classification (arthr = joints)...
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Jointsaka: articulations
Classification of Joints Functional classification (arthr = joints)
(Focuses on amount of movement) Synarthroses (immovable joints) – most common in
the axial skeleton Amphiarthroses (slightly movable joints) – most
common in the axial skeleton Diarthroses (freely movable joints) – most common
in the appendicular skeleton
Classification of Joints Structural classification
(Based on the material binding them and presence or absence of a joint cavity)
Fibrous Cartilagenous Synovial
Fibrous joints
Bones connected by fibrous tissue: dense regular connective tissue
No joint cavity Slightly movable or immovable Types
Sutures Syndesmoses
Sutures Only between
bones of skull Fibrous tissue
continuous with periosteum
Ossify and fuse in middle age:
Syndesmoses
In Greek: “ligament”
Bones connected by ligaments only
Amount of movement depends on length of the fibers: longer than in sutures
Cartilagenous joints
Articulating bones united by cartilage Lack a joint cavity Not highly movable Two types
Synchondroses (singular: synchondrosis) Sympheses (singular: symphesis)
Synchondroses
Literally: “junction of cartilage” Hyaline cartilage unites the bones Immovable (synarthroses) Examples:
Epiphyseal plates Joint between rib’s and the costal cartilage
and of the sternum
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
Synchondroses and sympheses
Also pubic symphsis
Synovial joints
Include most of the body’s joints
All are diarthroses (freely movable)
All contain fluid-filled joint cavity
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
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*
*
**
General structure of synovial joints (cont.)
4. Synovial fluid Filtrate of blood Contains special glycoproteins Nourishes cartilage and
functions as slippery lubricant “Weeping” lubriication
5. Reinforcing ligaments (some joints) Capsular (most) – thickened
parts of capsule Extracapsular Intracapsular
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)
General structure of synovial 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) Made of fibrocartilage Examples: knee
TMJ (temporomandibular joint)
sternoclavicular joint
Some joints…
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
Bursae and tendon sheaths
Synovial joints classified by shape
(of their articular surfaces)Working with a book and a
partner or alone create a chart that Names, describes and provides examples of the following synovial joints
Plane Hinge Pivot Condyloid Saddle Ball-and-socket
• When you are finished describe the following inflammatory disorders:
• Bursitis• Arthritis (Osteo, Rhumatoid and
Gouty)• Tendonitis
6 synovial joints
Classified by the shape of their articular surface Plane Hinge Pivot Condyloid Saddle Ball-and-socket
Types of JointsHinge- Rounded process fits into concave
surface. Uniaxial.
Ball and Socket- Spherical head fits into deep concave surface. Multiaxial. They are found in the hips and shoulders. (Hip, Shoulder)
Gliding- In a gliding or plane joint flat bones slide past each other. Mid-carpal and mid-tarsal joints are gliding joints. Non-axial. (Hands (intercarpal), Feet (intertarsal))
Saddle- Both surfaces of the bones have both concave and convex regions with the shapes of the two bones complementing one other and allowing a wide range of movement. (carpals and metacarpal of the Thumb)
• Pivot Joint: Round end of bone fits into a sleeve or ring of bones concave. Uniaxial.
• Condyloid Joint: oval or egg shaped end fits into a concave shape. Reduced ball and socket joint. Biaxial.
The following slides show specific joints. You are not
responsible for this on a quiz or test.
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
Selected synovial joints
Rotator cuff muscles add to stability
Biceps tendon is intra-articular
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
Wrist joint
Two major joint surfacesSeveral ligaments stabilize
1. Radiocarpal joint Between radius and
proximal carpals (scaphoid and lunate)
Condyloid joint Flexion extension
adduction, abduction, circumduction
2. Intercarpal or midcarpal joint Between the proximal
and distal rows of carpals
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
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
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
Lateral and medial menisci “torn cartilage”
Capsule absent anteriorly
Capsular and extracapsular ligaments Taut when knee
extended to prevent hyperextension
Patellar ligament Continuation of
quad tendon Medial and lateral
retinacula
Fibular and tibial collateral ligaments Called medial and
lateral Extracapsular
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 condoyle
Cruciate ligaments
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
Ankle 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 (syndesmoses)
Right ankle, lateral view
Temporomandibular joint (TMJ)
Head of mandible articulates with temporal bone
Disc protects thin mandibular fossa of temporal bone
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
Disorders of joints
Injuries Sprains Dislocations Torn cartilage
Inflammatory and degenerative conditions Bursitis Tendonitis Arthritis
Osteoarthritis (“DJD” – degenerative joint disease) Rheumatoid arthritis (one of many “autoimmune” joint
disorders) Gout (crystal arthropathy)
Arthritis
Bursitis• Inflammation of the Bursa (fluid
filled sac surrounding the joint).• A bursa can become inflamed from
injury, infection (rare in the shoulder), or due to an underlying rheumatic condition.
• Bursitis is typically identified by localized pain or swelling, tenderness, and pain with motion of the tissues in the affected area.
Tendonitis• Sometimes the tendons become inflamed
for a variety of reasons, and the action of pulling the muscle becomes irritating. If the normal smooth gliding motion of your tendon is impaired, the tendon will become inflamed and movement will become painful. This is called tendonitis, and literally means inflammation of the tendon.
• The most common cause of tendonitis is overuse.