Chapter 8 Flashcards
Introduction to Articulations
Define articulation
the meeting place of two or more bones; also called a joint
Define articulate
to connect with a joint or something that is like a joint
Describe the relationship between joint stability and joint mobility
there is an inverse relationship between joint stability and joint mobility; the more freely a joint can move (increased joint mobility), the less stable the joint is and the more prone to injury the joint is
Explain the difference between the functional classification of joints and the structural classification of joints
functional classification - classifies joints by the amount of movement allowed
structural classification - classifies joints by the type of connective tissue connecting the bones
Define the fibrous structural joint type and give an example
joints where connective tissue fibers (primarily collagen) connect bones; length of fibers + opposing shapes of articulating bones determine whether no or slight movement is allowed
Examples: suture (coronal, sagittal, lambdoid sutures), syndesmosis (interosseous membranes between radius/ulna and tibia/fibula, distal tibiofibular joint), gomphosis (dentoalveolar joints)
Define the cartilaginous structural joint type and give an example
joints where bones are connected by either hyaline cartilage or fibrocartilage
Examples: synchondrosis (epiphyseal plate, 1st sternocostal joint), symphysis (intervertebral disc, pubic symphysis joints)
Define the synovial structural joint type and give an example
freely movable joints (diarthroses) that are characterized by a joint cavity containing synovial fluid; the most common joints in the adult appendicular skeleton
Examples: shoulder, elbow, wrist, hip, knee
Define the synarthrosis functional joint type and give an example
immovable joints that allow no movement in normal conditions
Examples: cranial suture joints (coronal, sagittal, lambdoid sutures), gomphosis joints (dentoalveolar joints), synchondrosis joints (epiphyseal plate, 1st sternocostal joint)
Define the amphiarthrosis functional joint type and give an example
slightly movable joints
Examples: syndesmosis joints (interosseous membranes between radius/ulna + tibula/fibula, distal tibiofibular joint), symphysis joints (intervertebral disc, pubic symphysis joints)
Define the diarthrosis functional joint type and give an example
freely movable joints
Examples: synovial joints (shoulder, elbow, wrist, hip, knee)
Specify the locations of suture joints
connect the membranous bones of the skull
Specify the locations of syndesmosis joints
bones are connected by an interosseous ligament; located between the distal portions of the tibia + fibula, as well as the interosseous membranes between the radius + ulna and tibia + fibula
Specify the locations of gomphosis joints
joints of the teeth
Describe the differences between synchondroses and symphyses and give examples of each type of joint
synchondroses - unites the bones with hyaline cartilage; also known as a primary cartilaginous joint
Example: sternum; costal (rib) cartilage
symphyses - unites the bones with a disc of fibrocartilage; also known as a secondary cartilaginous joint
Example: pubic symphysis (between two pubic bones), intervertebral disc joint (located between adjacent vertebral bodies)
Identify ligament
reinforce the joint capsule; may provide support and limit movement
Identify joint capsule
stabilizes the joint by limiting movement, and varies in thickness according to the stress it encounters; outer layer is made of dense fibrous connective tissue that is continuous with the periosteum of the articulating bones
Identify synovial membrane
soft connective tissue lining of the joint capsule; composed of loose connective tissue that includes blood and lymphatic vessels within a collagen matrix; secretes a small amount of synovial fluid into the joint cavity
Identify joint cavity
a cavity in the joint formed by enclosing the articulating bones with a joint capsule
Identify articular cartilage
dense, fibrous collagen fibers that provide a cushion between articulating bones
Identify synovial fluid
a fluid located in the joint cavity that functions as a biological lubricant by reducing friction in moving joints; also acts as a shock absorber, provides nutrients and oxygen to the articular cartilage, and removes waste from them
List an example of hinge synovial joints
hinge - articulation between a concave surface of one bone with a convex surface of another bone; a uniaxial joint; allows flexion and extension (which occur in the antero-posterior plane)
Examples: ulnohumeral joint (joint of elbow between trochlear notch of ulna and trochlea of the humerus) and interphalangeal joints of fingers and toes
List an example of pivot synovial joints
pivot - rotate about a longitudinal axis and feature an articular surface shaped like a cylinder, which rotates within a ring formed of bone and ligament; a uniaxial joint; allows pronation and supination (in the forearm), as well as rotation left and right (between C1 and C2 vertebrae)
Examples: atlanto-axial joint (between C1 and C2 cervical vertebrae), proximal radioulnar joint (head of radius and radial notch of ulna and annular ligament)
List an example of ball and socket synovial joints
ball and socket - feature a spherical surface articulating with a cup-shaped socket; triaxial joint; allows three planes of movement: rotation about a longitudinal axis, flexion and extension, abduction and adduction, and circumduction (found in biaxial joints)
Examples: shoulder, hip
List an example of plane (gliding) synovial joints
plane (gliding) - describes joints that have no identifiable axis of rotation, and thus categorized as “nonaxial”; instead, allow slight gliding movements in many directions
Example: joints between articular facets on vertebral arches, between most carpal and tarsal bones, and between ribs and vertebrae
Define the abduction joint movement and give an example
movement away from the midline that occurs in a frontal plane
Example: moving hand upwards so arm forms a “T” shape
Define the adduction joint movement and give an example
movement towards the midline that occurs in a frontal plane
Example: moving hand from higher position back to anatomical position
Define the flexion joint movement and give an example
movement along the sagittal plane that decreases the joint angle between the moving segment and its proximal segment; can also be considered a forward movement (beginning from anatomical position)
Example: bending of elbow bringing hand towards shoulder
Define the extension joint movement and give an example
movement along the sagittal plane that increases the joint angle between the moving segment and its proximal segment; can also be considered a backward movement (beginning from anatomical position)
Example: straightening elbow bringing hand away from shoulder
Define the pronation joint movement and give an example
rotation of the radius and ulna that results in crossed bones and palm facing posterior
Example: rotation at proximal and distal radioulnar joints
Define the supination joint movement and give an example
rotation of the radius and ulna that results in uncrossed bones and palm facing anterior
Example: rotation at proximal and distal radioulnar joints
Define the rotation joint movement and give an example
Rotation. - movement around the longitudinal axis of the moving segment
Example: shaking head “no”, rotation of intervertebral joints of spine (“cracking your back”), rotation at ball and socket joints
Define the supination special joint movement
rotation of the radius and ulna that results in uncrossed bones and palm facing anterior
Define the pronation special joint movement
rotation of the radius and ulna that results in crossed bones and palm facing posterior
Define the dorsiflexion special joint movement
moves dorsum of the foot from anatomical position towards the leg
Define the plantarflexion special joint movement
moves the plantar surface (sole) of the foot in an inferior direction (as in standing on toes; equivalent of extension)
Define the inversion special joint movement
moves the plantar surface (sole) of the foot medially
Define the eversion special joint movement
moves the plantar surface (sole) of the foot laterally
Define the opposition special joint movement
movement of the hand in which the thumb contacts any of the fingers (but typically the second finger); also known as the “pincer grasp”
Define the protraction special joint movement
movement in the anterior direction possible at the temporomandibular (jaw) and scapulothoracic joints that occurs in the transverse plane
Define the retraction special joint movement
movement in the posterior direction possible at the temporomandibular (jaw) and scapulothoracic joints that occurs in the transverse plane
Define the elevation special joint movement
movement upwards (or superiorly)
Define the depression special joint movement
movement downwards (or inferiorly)
