Articulations (Chap. 8)

Protraction

moves a structure anteriorly

Depression

moves a structure inferiorly

Retraction

moves a structure posteriorly

Elevation

moves a structure superiorly

Circumduction

Combination of flexion, adduction, extension, abduction

Components of a Synovial Joint (capsule, cartilage, membrane, fluid)

-Articular capsule: Encloses the joint -Articular cartilage: Hyaline cartilage, Covers articulating surfaces -Synovial membrane: Lines the capsule -Synovial fluid: Consistency of egg whites

Dynamic motion (joints, stability, describes, importance)

-Diathrotic joints allow movement -Not as stable as synarthroses and amphiarthroses -Describe a variety of movements -Important in muscle function -Dynamic motion: Linear motion. Angular motion. Rotation

Classification of joints

-Functional: Amount of movement allowed & Range of motion. -Structural: Anatomical components. Bony, fibrous, cartilaginous, synovial.

Structural classification of joints (gliding, hinge, pivot, ellipsoidal, saddle, ball & socket)

-Gliding joints permit movement in a single plane -Hinge joints are monaxial joints permitting angular motion in one plane -Pivot joints are monaxial joints that permit rotation -Ellipsoidal joints are biaxial joints that pit one bone in an oval depression of another -Saddle joints are biaxial joints with one concave and one convex bone face -Ball-and-socket joints are triaxial joints that permit rotation and other movements

Movements of the foot (Special movement)

-Inversion and eversion -Plantar flexion - toes down, heel up (flexes plantar surface of foot) -Dorsiflexion - toes up, heel down

Diarthroses (freely movable joints)

-Joint is enclosed -Joint space is filled with fluid -Can also be called a synovial joint -Most joints of the appendicular skeleton

Rotational Movements of forearm (Pronation & Supination)

-Pronation: Palm up to down (front to back). Start in anatomical position. -Supination: Palm down to up (back to front). Return to the anatomical position.

4 major types of Synarthroses (immovable joints)

-Suture = skull bones bound together by dense connective tissue -Gomphosis = teeth bound to bony sockets by periodontal ligaments -Synchondrosis = two bones bound by rigid cartilaginous bridge -Syntosis = two bones completely fused

Diarthroses

A functional classification -Freely moveable joints -synovial *Diarthroses Most joints in the adult body are diarthroses. The singular form is diarthrosis. In this type of joint, the ends of the opposing bones are covered with hyaline cartilage, the articular cartilage, and they are separated by a space called the joint cavity. The components of the joints are enclosed in a dense fibrous joint capsule. The outer layer of the capsule consists of the ligaments that hold the bones together. The inner layer is the synovial membrane that secretes synovial fluid into the joint cavity for lubrication.

Synarthroses

A functional classification. -Immovable joints -fibrous / cartilagenous -Bony *The singular form is synarthrosis. In these joints, the bones come in very close contact and are separated only by a thin layer of fibrous connective tissue. The sutures in the skull are examples of immovable joints

Amphiarthroses

A functional classification. -Slightly moveable joints -fibrous / cartilagenous *The singular form is amphiarthrosis. In this type of joint, the bones are connected by hyaline cartilage or fibrocartilage. The ribs connected to the sternum by costal cartilages are slightly movable joints connected by hyaline cartilage. The symphysis pubis is a slightly movable joint in which there is a fibrocartilage pad between the two bones. The joints between the vertebrae and the intervertebral disks are also of this type. *

Inflammatory and Degenerative Conditions

Bursitis - An inflammation of a bursa, usually caused by a blow or friction • Treated with rest and ice and, if severe, anti-inflammatory drugs Tendonitis - Inflammation of tendon sheaths typically caused by overuse • Symptoms and treatment similar to bursitis

Angular Movements

Flexion: Decreases the angle between two parts Extension: Increasing the angle between two parts Hyperextension: Extending beyond the anatomical position

Rotational movement

Left or right: head Medial (internal) or lateral (external): Arms and legs

Synovial fluid functions:

Lubrication, Nutrient distribution, Shock absorption

Synovial joint additional structures

Menisci (knee), Fat pads, Accessory ligaments, Bursae

Arthritis: Inflammatory or degenerative diseases that damage joints

Most widespread crippling disease in the U.S. Symptoms; pain, stiffness, and swelling of a joint Acute forms: caused by bacteria, treated with antibiotics Chronic forms: osteoarthritis, rheumatoid arthritis, and gouty arthritis

Abduction

Movement away from the body's midline

Adduction

Movement towards the body's midline

Movements of the thumb (Special movement)

Opposition - movement towards palm, grasping

2 major types of Amphiarthroses (slightly movable joints)

Syndesmosis = bones connected by a ligament Symphysis = bone separated by fibrocartilage

Gliding motion (type of movement)

Two surfaces slide past one another: Carpals, tarsals

Articulations

Where two bones interconnect

Lateral flexion

bends the vertebrae to one side

Common Joint Injuries

• Sprains- The ligaments are stretched or torn • Partial tears slowly repair themselves • Complete ruptures require prompt surgical repair • Cartilage tears - Due to compression and shear stress, Fragments may cause joint to lock or bind • Cartilage rarely repairs itself • Repaired with arthroscopic surgery Dislocations (luxations) - Occur when bones are forced out of alignment • Accompanied by sprains, inflammation, and joint immobilization Caused by serious falls or playing sports - Subluxation—partial dislocation of a joint