Week 7-Articulations Flashcards
Joint aka articulation
-place of contact between bones, between bone and cartilage, or between bones and teeth
-bones articulate with each other at a joint
Arthrology
scientific study of joints
Classification of Joints
-classified by structural and functional characteristics
1) Fibrous joint
2) Cartilaginous joint
3) Synovial joint
Fibrous joint
Structural characteristics: no joint cavity and holds bones together with dense regular (fibrous) connective tissue
Structural categories: gomphosis, suture, syndesmosis
Functional classification: synarthrosis (immobile) or amphiarthrosis (slightly mobile)
Cartilaginous joint
Structural characteristics: no joint cavity and pad of cartilage wedged between ends of bones
Structural categories: synchondrosis, symphysis
Functional classification: synarthrosis (immobile) or amphiarthrosis (slightly mobile)
Synovial joint
Structural characteristics: joint cavity filled with lubricating fluid that seperates articulating surfaces of bones, articulating surfaces are enclosed with connective tissue capsule, and bones attached to each other by ligaments
Structural categories: plane, hinge, pivot, condylar, saddle, and ball-and-socket
Functional classification: diarthrosis (freely mobile)
Synarthrosis
-Immobile joint
-2 types of fibrous and 1 type of cartilaginous
Amphiarthrosis
-Slightly mobile joint
-1 type of fibrous and 1 type of cartilaginous
Diarthrosis
-Freely mobile joint
-all synovial joints
Function of fibrous joints
Hold 2 bones together
Examples of fibrous joints
-articulations of teeth in their sockets
-sutures between skull bones
-articulations between radius and ulna or tibia and fibula
Types of fibrous joints
1) Gomphoses
2) Sutures
3) Synesmoses
Gomphosis
-resembles peg in a socket
-only found as articulations of roots of individual teeth with alveolar processes of mandible and maxillae
-tooth is held firmly in place by fibrous periodontal membranes
-synarthrosis (immobile)
Sutures
-fibrous joints found between certain skull bones
-synarthroses (immobile joints)
-have distinct interlocking, usually irregular edges that increase their stability and decrease number of fractures at these articulations
-permit skull to grow as brain increases in size during childhood
-sutures become ossified in adulthood, fusing skull bones (fully fused sutures= synostoses)
Syndesmoses
-fibrous joints in which articulating bones are joined by long stands of dense regular connective tissue only
-allow for slight mobility (amphiarthroses)
-found between radius and ulna and between tibia and fibula
-shaft of 2 bones bound by interosseous membrane (provides pivot where 2 bones can move relative to one another)
Types of Cartilaginous Joints
1) Synchondroses
2) Symphyses
Synchondroses
-articulation in which bones are joined by hyaline cartilage
-synarthroses (immobile)
Examples of synchondroses
-hyaline cartilage of epiphyseal plates in children bind epiphyses and diaphysis of long bones
-spheno-occipital synchondrosis between body of sphenoid and basilar part of occipital bone
-costochondral joint (between each bony rib and its respective costal cartilage)
-first sternocostal joint (attachment of first rib to manubrium of sternum by costal cartilage, provides stability to rib cage)
Symphysis
-has pad of fibrocartilage between articulating bones
-amphiarthroses (slight mobility)
Examples of symphyses
-Pubic symphysis: between right and left pubic bones
-Intervertebral joints: bodies of adjacent vertebrae are both separated and united by intervertebral discs
Synovial joint anatomy
-articular capsule
-joint cavity
-synovial fluid
-articular cartilage
-ligaments
-nerves
-blood vessels
-accessory structures: bursae and fat pads
Articular capsule
-double layered capsule
-outer layer= fibrous layer
-inner layer= synovial membrane
Fibrous layer
-formed from dense connective tissue
-strengthens joint to prevent bones from being pulled apart
Synovial membrane
-specialized type of connective tissue that contains cells which help produce and secrete synovial fluid
-covers all internal joint surfaces not covered by cartilage
-lines articular capsule
Articular cartilage
-thin layer of hyaline cartilage that covers articulating surfaces of bones
-lacks perichondrium
-avascular (no blood vessels to bring nutrients to or remove wastes from) therefore compression and expansion that occurs during exercise is vital to maintaining this because this action enhances obtaining nutrients and removing waste
Functions of articular cartilage
-reduce friction in joint during movement
-acts as cushion to absorb compression placed on joint
-prevents damage to articulating ends of the bones
Joint cavity
-Space that permits separation of articulating bones
-articular cartilage and synovial fluid within cavity reduce friction as bones move at synovial joint
Synovial fluid
-viscous, oily substance located within synovial joint
-product of both synovial membrane cells and filtrate formed from blood plasma
Functions of Synovial Fluid
1) Lubricates: lubricates articular cartilage in surface of articulating bones
2) Nourishes chondrocytes:
-must be circulated continually to provide nutrients to
and remove wastes from articular cartilage’s
chondrocytes
-compression and re expansion of articular cartilage
occurs during movement and circulates fluid in and
out of cartilage matrix
3)Acts as shock absorber: distributes stresses and force evenly across articular surface when pressure in joint suddenly increases
Ligaments
-composed of dense regular connective tissue
-connect bone to bone
-stabilize, strengthen, and reinforce most synovial joints
Intrinsic ligaments
-thickening of articular capsule
-include extracapsular ligaments outside articular capsule and intracapsular ligaments within capsule
Extrinsic ligaments
outside of and physically separate from articular capsule
Blood vessels
all synovial joints have numerous blood vessels to transport oxygen and nutrients to tissue and to remove wastes
Sensory receptors
-innervate articular capsule and associated ligaments
-include proprioceptors that detect movement, stretch, and positioning of joint (detect change in posture and adjust body movements through nervous system)
-nociceptors detect painful stimuli in joint (detect possible injury to joint)
Tendons
-attach muscle to bone
-dense regular connective tissue
-not actually part of synovial joint itself
-when muscle contracts, tendon from that muscle moves the bone it’s attached to, causing movement at joint
-help stabilize joint because they pass across and around a joint to provide mechanical support
-sometimes limit range or amount of movement permitted at joint
Bursa
-fibrous, saclike structure that contains synovial fluid and is lined internally by a synovial membrane
-numerous in body
-associated with most synovial joints
-where bones, ligaments, muscles, skins, or tendons overlie each other and rub together
-may be connected to joint cavity or completely separate
-alleviate friction resulting from various body movements such as where a tendon or ligament ribs against bone
Tendon sheath
-type of elongated bursa
-wraps around tendon where there may be excessive friction
-especially common in confined spaces of wrist and ankle
Fat pads
-often distributed along periphery of synovial joint
-act as packing material and provide some protection for joint
-often fill spaces that form when bones move and joint cavity changes shape
Movement of bone at synovial joint
1) Uniaxial: bone moves in just one plane or axis
2) Biaxial: bone moves in 2 planes or axes
3) Multiaxial or triaxial: bones moves in multiple planes or axes
6 Types of Synovial Joints
1) Plane joints
2) Hinge joints
3) Pivot joints
4) Condylar joints
5) Saddle joints
6) Ball-and-socket joints
Plane joint
-aka planar or gliding joint
-simplest synovial articulation and least mobile type of diarthrosis
-uniaxial
-allows only for limited side to side movements in a single plane
-articular surfaces of bones are flat or planar
-examples: intercarpal and intertarsal joints
Hinge joint
-formed by convex surface of one bone fitting into concave depression on other bone in joint
-uniaxial
-movement similar to hinge of a door
-examples: elbow joint (trochlear notch of ulna fits directly into trochlea of humerus so forearm can only be moved anteriorly toward the arm or posteriorly away from arm), knee joint, and interphalangeal joints
Pivot joint
-uniaxial
-one bone with rounded surface fits into ring formed by ligament or another bone
-first bone rotates on longitudinal axis relative to second bone
-examples: proximal radioulnar joint (rounded head of radius pivots along ulna and permits radius to rotate) and atlantoaxial joint(between atlas and axis, rounded dens of axis fits snugly against articular facet on anterior arch of atlas, allows you to shake head “no”)
Condylar joint
-biaxial
-oval, convex surface on one bone articulates with concave articular surface of another bone of joint
-example: metacarpophalangeal joints (knuckles) of finger 2-5 (can flex and extend, and move fingers apart and closer together)
Saddle joint
-bones have convex and concave regions that resemble shape of a saddle
-biaxial
-allows greater range of movement than condylar or hinge joints
-example: carpometacarpal joint of thumb(between trapezium and 1st metacarpal, permits thumb to move toward other finger so we can grasp objects)
Ball-and-socket joints
-multiaxial (permits movement in 3 planes)
-spherical head of one bone fits into rounded, cuplike socket of 2nd bone
-examples: coxal (hip) and glenohumeral (shoulder) joints
Gliding
-Simple movement in which 2 opposing surfaces slide slightly back and forth or side to side with respect to one another in any direction
-angle between bones does not change
-occurs along plane joints
Angular motion
-increases or decreases angle between 2 bones
-occurs at many synovial joints
-includes: flexion and extension, lateral flexion, abduction and adduction, and circumduction
Flexion
-movement in anterior-posterior plane of body that decreases the angle between bones
-bones are brought closer together as angle between them decreases
-bending fingers toward palm, bending of forearm toward arm at elbow, flexion at shoulder when arm is raised anteriorly, and looking down at your feet
Extension
-movement on anterior-posterior plane of body that increases angle between bones
-straightening actions
-straightening fingers after making fist, straightening forearm after bending toward forearm
Hyperextension
-extension of joint beyond its normal range of motion
-may occur if someone has extensively mobile joints or injury at that joint
Lateral flexion
-occurs when trunk of body moves in coronal plane laterally away from body
-occurs primarily between vertebrae in cervical and lumbar regions of vertebral column
Abduction
Lateral movement of body part away from midline
Adduction
Medial movement of body part toward midline
Circumduction
Proximal end of appendage remains relatively stationary while distal end makes a circular motion
Rotation
-pivoting motion in which a bone turns on its own longitudinal axis
-limb rotations include lateral and medial rotations
Protonation
-medial rotation of forearm so palm of hand is directed posteriorly or inferiorly
-radius and ulna are crossed to form a X
Supination
-forearm rotates laterally so that palm faces anteriorly or posteriorly
-forearm is supinated in anatomic position
Depression
-Inferior movement of body part
-Opening mouth to chew food and moving shoulders in inferior direction
Elevation
-Superior movement of body part
-Closing mouth and shrugging your shoulders
Dorsiflexion
-limited to ankle joint
-occurs when talocrural (ankle) joint is bent such that the dorsum (superior surface) and toes move toward leg
Plantar flexion
-limited to ankle joint
-movement of foot at talocrural joint so that toes point inferiorly
Eversion
-occurs only at intertarsal joints
-sole of foot turns to face laterally or outward
Inversion
-occurs only at intertarsal joints
-sole of foot turns medially or inward
Protraction
-anterior movement of body part from anatomic position
-example: jutting your jaw out
Retraction
-posteriorly directed movement of body part from anatomic position
Opposition
-thumb moves toward palmar tips of fingers as it crosses palm of hand
-enables hand to grasp objects
Reposition
Opposite movement of opposition
Axial Skeleton Joints
-Suture
-Temporomandibular joint
-Atlanto-occipital joint
-Atlantoaxial joint
-Intervertebral joint
-Vertebrocostal joint
-Lumbosacral joint
-Sternocostal joint
Anatomy of Temporomandibular joint
Articular capsule: surrounds joint and promotes extensive range of motion
Articular disc: thick pad of fibrocartilage separating articulating bones and extending horizontally to divide synovial cavity into 2 chambers (TMJ is really 2 synovial joints)
Supported by several ligaments:
-Sphenomandibular ligament: thin band that extends
anteriorly and inferiorly from sphenoid to medial
surface of mandibular ramus
-Temporomandibular ligament: 2 short bands that
extend inferiorly and posteriorly from articular tubercle
of temporal bone to mandible
Articulation Components of TMJ
-head of mandible and mandibular fossa of temporal bone
-head of mandible and articular tubercle of temporal bone
Structural Classification of TMJ
Synovial (hinge, plane) joints
Functional Classification of TMJ
Diarthrosis
Movement of TMJ
Depression, elevation, lateral displacement, protraction, retraction, slight rotation of mandible
Pectoral Girdle and Upper Limb Joints
-Sternoclavicular joint
-Acromioclavicular joint
-Glenohumeral joint
-Elbow joint
-Radioulnar joint
-Radiocarpal joint
-Intercarpal joint
-Carpometacarpal joint
-Metacarpophalangeal joint
-Interphalangeal joint
Joints Associated with Movement of Shoulder
Sternoclavicular, acromioclavicular, and glenohumeral joint
Anatomy of Sternoclavicular Joint
-Saddle joint
Articular disc: fibrocartilaginous disc partitions joint into 2 parts and forms 2 seperate synovial cavities, allowing for wide range of movement
-support and stability provided to this joint by fibers of articular capsule and by multiple extracapsular ligaments
Articulation Components of Sternoclavicular Joint
Manubrium of sternum and sternal end of clavicle
Structural Classification of Sternoclavicular Joint
Synovial (Saddle)
Functional Classification of Sternoclavicular Joint
Diarthrosis
Movement of Sternoclavicular Joint
Depression, elevation, and circumduction of clavicle
Anatomy of Acromioclavicular Joint
-Plane joint
-fibrocartilaginous articular disc lies within joint cavity between scapula and clavicle
-works with other shoulder joints to give upper limb full range of motion
Ligaments provide stability:
-articular capsule is strengthened superiorly by acromioclavicular ligament
-coracoclavicular ligament binds clavicle to coracoid process of scapula
Articulation Components of Acromioclavicular Joint
Acromion of scapula and acromial end of clavicle
Structural Classification of Acromioclavicular Joint
Synovial (Plane)
Functional Classification of Acromioclavicular Joint
Diarthrosis
Movement of Acromioclavicular Joint
Gliding of scapula on clavicle
Anatomy of Glenohumeral (Shoulder) Joint
-Ball and socket joint
-Permits greatest range of motion of any joint in the body (most unstable and frequently dislocated)
-Glenoid labrum: encircles and covers surface of glenoid cavity
-loose articular capsule attaches to surgical neck of humerus
-ligaments provide little support
-most of it’s strength comes from rotator cuff muscles surrounding it
-bursa decrease friction at specific places on shoulder where tendons and large muscles extend across articular capsule
Ligaments of Glenohumeral (Shoulder) Joint
1) Coracoacromial ligament: between coracoid process and acromion
2) Coracohumeral ligament: thickening of superior part of articular capsule, extends from coracoid process to humeral head
3) Glenohumeral ligaments: 3 thickenings of anterior portion of articular capsule, often indistinct or absent and provide little support
Rotator Cuff Muscles
-subscapularis, supraspinatus, infraspinatus, and teres minor
-work as a group to hold head of humerus in glenoid cavity
-tendons of these muscles encircle the joint and fuse with articular capsule
-inferior portion of joint lacks support from muscles, making area weak and prone to injury
Articulation Components of Glenohumeral (Shoulder) Joint
Glenoid cavity of scapula and head of humerus
Structural Classification of Glenohumeral (Shoulder) Joint
Synovial (Ball-and-Socket)
Functional Classification of Glenohumeral (Shoulder) Joint
Diarthrosis
Movement of Glenohumeral (Shoulder) Joint
Abduction, adduction, circumduction, flexion, extension, lateral rotation, and medial rotation of arm
Elbow joint
-Hinge joint composed of 2 articulations:
1) Humeroulnar joint
2) Humeroradial joint
-both joints enclosed in single, thick articular capsule
-bony surfaces of humerus and ulna interlock very well, providing solid bony support
-ligaments provide strong support
-very stable but not as mobile as some other joints
Ligaments of Elbow Joint
Radial Collateral Ligament: responsible for stabilizing joint at lateral surface, extends from lateral epicondyle of humerus to head of radius
Ulnar Collateral Ligament: stabilizes medial side joint, extends from medial epicondyle of humerus to both coronoid process and olecranon of ulna
Anular Ligament: surrounds neck of radius and binds proximal head of radius to ulna, helps hold head of radius in place
Articulation Components of Elbow Joint
Humeroulnar joint: trochlea of humerus and trochlear notch of ulna
Humeroradial joint: capitulum of humerus and head of radius
Structural Classification of Elbow Joint
Synovial (Hinge)
Functional Classification of Elbow Joint
Diarthrosis
Movement of Elbow Joint
Flexion and extension of forearm
Pelvic Girdle and Lower Limb Joints
-Sacroiliac
-Hip (coxal)
-Pubic symphysis
-Knee
-Tibiofibular
-Talocrural (ankle)
-Intertarsal
-Tarsometatarsal
-Metatarsophalangeal
-Interphalangeal
Coxal (Hip) Joint
-fibrocartilaginous acetabular labrum further deepens this socket
-must be more stable and less mobile because it supports body weight
-secured by strong articular capsule, several ligaments, and a number of powerful muscles
-articular capsule extends from acetabulum to trochanters of femur, enclosing both femoral head and neck
-retinacular fibers reflect(fold over) around neck of femur and provide additional stability to capsule
-retinacular arteries: branches of the deep femoral artery located within retinacular fibers and supply almost all the blood to head and neck of femur
Ligaments of Coxal (Hip) Joint
Iliofemoral ligament: Y shaped ligament that provides strong reinforcement for anterior region of articular capsule
Ischiofemoral ligament: spiral shaped and posteriorly located
Pubofemoral ligament: triangular thickening of capsule’s inferior region
Ligament of head of femur (ligamentum teres): originates along acetabulum, attaches at fovea of head of femur, does not provide stability, contains small artery that supplies head of femur
Articulation Components of Coxal (Hip) Joint
Head of femur and acetabulum of os coxae
Structural Classification of Coxal (Hip) Joint
Synovial (Ball-and-socket)
Functional Classification of Coxal (Hip) Joint
Diarthrosis
Movement of Coxal (Hip) Joint
Flexion, extension, abduction, adduction, circumduction, medial and lateral rotation of thigh
Knee Joint
-largest and most complex diarthrosis in body
Composed of 2 Separate Articulations:
1) Tibiofemoral joint
2) Patellofemoral joint
Anatomy of Knee Joint
-articular capsule encloses medial, lateral, and posterior regions of knee joint
-quadriceps femoris muscle tendon passes over anterior surface and patella is embedded within tendon
-Patellar ligament: extends beyond the patella and continues to where it attaches on tibial tuberosity of tibia
-no single unified capsule or common joint cavity
Collateral Ligaments of Knee Joint
-on either side of knee joint and provide stability
Fibular (Lateral) Collateral Ligament: reinforces lateral surface of joint, extends from femur to fibula, and prevents hyperadduction of leg at knee
Tibial (Medial) Collateral Ligament: reinforces medial surface of joint, runs from femur to tibia, attaches to medial meniscus, and prevents hyperabduction of leg at knee
Fibrocartilage Pads of Knee Joint
-within joint is pair of C shaped fibrocartilage pads positioned on condyles of tibia
-Medial meniscus and lateral meniscus
-partially stabilize joint medially and laterally, act as cushions between articular surfaces, and continuously change shape to conform to articulating surfaces as femur moves
Cruciate Ligaments of Knee Joint
-deep to articular capsule of joint and limit anterior and posterior movement of femur on tibia
-cross each other in form of an X
Anterior Cruciate Ligament (ACL): extends from posterior femur to anterior side of tibia, prevents hyperextension of leg at knee joint, and prevents tibia from moving too far anteriorly relative to the femur
Posterior Cruciate Ligament (PCL): attaches from anteroinferior femur to posterior side of tibia, prevents hyperextension of leg at knee joint, and prevents posterior displacement of tibia relative to femur
Articulation Components of Knee Joint
Tibiofemoral joint: medial condyle of femur, medial meniscus, and medial condyle of tibia
Patellofemoral joint: patella and petellar surface of femur
Structural Classification of Knee Joint
-Synovial
-Hinge at tibiofemoral joint
-Hinge and plane at patellofemoral joint
Functional Classification of Knee Joint
Diarthrosis
Movement of Knee Joint
Flexion, extension, lateral rotation of leg in flexed position, slight medial rotation
Talocrural (ankle) Joint
-includes 2 articulations within one articular capsule
-one articulation is between distal end of tibia and talus
-other articulation between distal end of fibula and lateral aspect of talus
-medial and lateral malleoli of tibia and fibula form extensive medial and lateral margins and prevent talus from sliding side to side
Anatomy of Talocrural (Ankle) Joint
Articular capsule: covers distal surfaces of tibia, medial malleolus, lateral malleolus, and talus
Deltoid (Medial) ligament: binds tibia to foot on media side, prevents overeversion of foot, incredibly strong and rarely tears
Lateral Ligament: much thinner, binds fibula to foot on lateral side, prevents overinversion, prone to sprains and tears
Anterior and posterior ligaments: bind tibia to fibula
Articulation Components of Talocrural (Ankle) Joint
-Distal end of tibia and medial malleolus of tibia with talus
-Lateral malleolus of fibula and talus
Structural Classification of Talocrural (Ankle) Joint
Synovial (Hinge)
Functional Classification of Talocrural (Ankle) Joint
Diarthrosis
Movement of Talocrural (Ankle) Joint
Dorsiflexion and plantar flexion of the foot
