Articulation & Body Movements

Articulation

joints

place of contact btwn bones, bone and cartilage, bone and teeth

Structural Classification of Joints

Fibrous joint, Cartilaginous joint, Synovial joint

Fibrous Joint

no joint cavity

held tg by dense regular CT

Cartilaginous joint

no joint cavity

bones are joined by cartilage

Synovial Joint

Does have joint cavity > filled with lubricating fluid

separates articulating surfaces of bones

Ex: Glenohumeral joint, temporomandibular joint, elbow joint, knee joint

Structure: articular capsule, articular cartilage, joint cavity, synovial fluid, ligaments, nerves, and blood vessels

Functional Classification of Joints

Based on extend of movement:

Synarthrosis, Amphiarthrosis, Diarthrosis

Synarthrosis

immobile joint > does not move

Amphiarthrosis

slightly mobile joint

Diarthrosis

freely mobile joint

Fibrous Joint Classifications

Structure: Gomphosis, suture, syndesmosis

Function: Synarthrosis or amphiarthrosis

Cartilaginous Joint Classifications

Structure: Synchondrosis, symphysis

Function: Synarthrosis or amphiarthrosis

Synovial Joint Classifications

Structure: Plane, Hinge, Pivot, Condylar, Saddle, Ball and Socket

Function: Diarthrosis

Uniaxial, biaxial, multiaxial

Gomphosis

periodontal membranes hold a tooth to bony jaw (synarthrosis)

joined by ligaments

Suture

Connects skull bones (synarthrosis)

joined by short fibers

Syndesmosis

interosseous membranes btwn bones (amphiarthrosis)

Synostoses

complete fusion of bones across suture lines

Craniosynostosis

premature fusion or closing of 1 or more cranial sutures

Sagittal synosthosis

premature fusion of sagittal suture

skull grow forwards/backwards, or anteroposterior fashion > scaphocephaly

Coronal synosthosis

premature fusion of coronal suture

abnormally short and wide

Synchondroses

contain hyaline cartilage (synarthroses)

Symphyses

contain fibrocartilage (amphiarthroses)

Synovial fluid

lubricate, nourish chondrocytes, shock absorber

Uniaxial

bone moves 1 plane or axis

Biaxial

bone moves 2 planes or axis

Multiaxial

bone moves in multiple planes or axes

Plane Joints

(planar/gliding joints)

flattened or slightly curved faces slide across 1 another

least mobile joint

uniaxial

Ex: intertarsal joint (ankle), intercarpal joint (wrist)

Hinge Joints

convex surface of 1 bone articulates with concave surface of another

uniaxial

Ex: elbow and knee joints

Pivot Joints

formed by articulating bone and rounded surface (ring) - most commonly by a ligament and another bone

uniaxial

Ex: annular ligament permitting a pivot action of radial head

Condylar Joints

not hinge

biaxial

Ex: metacarpophalangeal joints in digitals 2-5 (knuckles)

Saddle Joint

appears like a saddle

greater range of motion compared to condylar

biaxial

Ex: carpometacarpal joint

Ball and Socket Joints

Spherical articulating head of 1 bone fits into rounded “cup-like” structure of another bone

multi-axial

Ex: hip joints, shoulder joints

Anterior cruciate ligament

prevent hyperextension of the leg

Posterior cruciate ligament

prevents hyperflexion of the leg

Menisci

fibrocartilage pads on the condyles of the tibia to partially stabilize the joint and act to cushion the articular surfaces of femur and tibia

Flexion

decreases the angle btwn 2 bones

Extension

increases angle btwn 2 bones

Hyperextension

extension past the anatomical postition

Abduction

occur in frontal plane

moves limb away from median plane

Adduction

moves limb toward the median plane

Circumduction

moves distal end of a limb in a a circle

Pronation

rotates radius over ulna

Supination

rotates radius and ulna parallel

Opposition

brings tip of thumb in contact with any finger on the same hand

Dorsiflexion

moves superior surface of foot toward the shin (standing on heel)

Planter Flexion

moves superior surface of foot farther away from shin (pointing your toes)

Inversion

turns sole of foot medially

Eversion

turns sole of foot laterally

Elevation

moves mandible up (closing the mouth)

Depression

moves mandible down (opening the mouth)

Protraction

moves mandible forward

Retraction

moves mandible back