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UAG - U.L. Joints
Question | Answer |
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Joints (articulations) | unions or junctions between 2+ bones or rigid parts of the skeleton |
Classification of Joints | 1. Synovial Joints (most common) <p>2. Fibrous Joints <p>3. Cartilaginous Joints |
Synovial Joints | a joint(articular) capsule (outer fibrous layer lined by a serous synovial membrane) spanning & enclosing an articular cavity; joint cavity=potential space that contains a small amount of lubricating synovial fluid, secreted by the synovial membrane |
Fibrous Joints | fibrous tissue; amount of movement occurring @ fibrous joint depends in most cases on the length of the fibers; EX - sutures of the cranium; b/w Radius & Ulna |
Cartilaginous Joints | hyaline cartilage or fibrocartilage; primary cartilaginous joints (synchondroses) slight bending during early life; Secondary cartilaginous joints (symphyses) strong, slightly movable but no more growth |
Major Synovial Joints | 1. Plane Joints <P>2. Hinge Joints <P>3. Saddle Joints <P>4. Condyloid/Ellipsoid Joints <P>5. Ball & Socket Joints <P>6. Pivot Joints |
Plane Joints | permit gliding/sliding movements in plane of articular surface; flat or almost flat bone surface & limited movement; numerous & nearly always small |
Hinge Joints | permit flexon & extension only & uniaxial (occur in 1 plane (sagittal) around single axis transversely); joint capsule=thin & lax |
Saddle Joints | permit abduction & adduction, flexion & extension, circumduction=possible; biaxial=2 axes at right angles of each other (sagittal & frontal); 2 surfaces=concave & convex |
Condyloid/Ellipsoid Joints | permit flexion, extension, abduction & adduction; biaxial; movement in 1 plane (sagittal) is usually greater (freer) than the other; circumduction=possible but more restricted than saddle joints |
Ball & Socket Joints | movement in multiple axes & planes (flexion/extension/abduction/adduction/medial & lateral rotation/circumduction)=multi-axial joints |
Pivot Joints | uniaxial=rotation around a central axis; rounded process of bone rotates in sleeve or ring |
Movement of Pectoral Girdle | Involves the sternoclavicular joint, acromioclavicular joint, & glenohumeral joint; usually all move at once; provides for attachment of the superior appendicular skeleton to the axial skeleton |
Range of Motion (ROM) of Pectoral Girdle | both scapulothoracic (movement of the scapula on the thoracic wall) & glenohumeral movements must be considered |
Scapulohumeral Rhythm | Every 3° of elevation, approx 2° occurs @ glenohumeral & 1° @ physiological scapulothoracic. EX: when upper limb has been elevated vertically at the side of the head (180° of arm abduction/flexion), 120° @ glenohumeral & 60° @ scapulothoracic |
Sternoclavicular Joint | saddle type but functions as ball & socket, strong; only joint b/w upper limb & Axial skeleton (palpable) <P>1. articular disc - divides SC joint into 2, attached to anterior & posterior sternoclavicular ligaments & interclavicular ligamet; absorbs shock |
Sternoclavicular Joint - articulation | sternal end of clavicle articulates w/manubrium & 1st costal cartilage (covered with fibrocartilage) |
Sternoclavicular Joint - ligaments | Anterior/posterior sternoclavicular lig. reinforce the joint capsule anteriorly/posteriorly <P>interclavicular lig strengthens the capsule superiorly <P>costoclavicular lig. anchors inferior surface of sternal end of clavicle to 1st rib & costal cartila |
Acromioclavicular Joint | plane type; located 2-3 cm from the “point” of the shoulder formed by the lateral part of the acromion <P>Articulation - acromial end of clavicle articulates w/acromion of scapula |
Acromioclavicular Joint - ligaments | acromioclavicular lig=fibrous band from the acromion to clavicle, strengthens AC joint superiorly +extrinsic lig's <P>coracoclavicular lig=strong pair of bands uniting coracoid process of scapula to clavicle;conoid & trapezoid ligaments separated by burs |
Glenohumeral (Shoulder) Joint | ball & socket; permits wide range of movement but relatively unstable <P>Articulation - large/round humeral head w/relatively shallow glenoid cavity of scapula (glenoid labrum) covered w/hyaline cartilage;glenoid cavity=1/3+ humeral head by "rotator cuff |
Glenohumeral Joint - ligaments | Glenohumeral=3 fibrous bands, internal aspect, reinforce anterior part of joint, radiate laterally & inferiorly from glenoid labrum<P>Coracohumeral=strong broad band from coracoid process to anterior greater tubercle of humerus |
Glenohumeral Joint - ligaments II | Transverse humeral=broad fibrous band running obliquely from greater to the lesser tubercle of humerus, converts groove into canal=synovial sheath & biceps brachii tendon<P>Coraco-acromial arch=extrinsic, protective structure |
Ankylosis | stiffening or fixation of the pectoral girdle joints; more restricted ROM even if glenohumeral joint is normal |
Muscles of Glenohumeral Joint | Axioappendicular muscles=act indirectly on the joint (on pectoral girdle)<P>Scapulohumeral muscles=act directly on glenohumeral joint<P>other muscles resist dislocation w/o producing movement at joint |
Bursae | sac-like cavities w/capillary films of synovial fluid are near the glenohumeral joint<P>located where tendons rub against bone, ligaments or other tendons & where skin moves over a bony prominence |
Subscapular Bursa | located b/w tendon of subscapularis & neck of the scapula<P>protects tendon where it passes inferior to root of the coracoid process & over neck of scapula<P>communicates w/cavity of glenohumeral joint |
Subacromial Bursa | "subdeltoid"<P>located b/w acromion, coraco-acromial ligament & deltoid superiorly & the supraspinatus tendon & glenohumeral joint capsule inferiorly |
Musculotendinous Rotator Cuff | SITS, muscles that help hold the humeral head in the glenoid cavity<P>1. Supraspinatus<p>2. Infraspinatus<P>3. Teres Minor<P>4. Subscapularis |
Elbow Joint | hinge type<P>located 2-3 cm inferior to the epicondyles of humerus<P>trochlea (spool-shaped) & capitulum (spheroidal) of humerus articulate w/ trochlear notch of ulna & head of radius (slightly concave superior aspect); b/w pronation & supination |
Elbow Joint - ligaments | collateral lig.=strong triangular bands, medial & lateral thickenings of fibrous layer of joint capsule<P>radial collateral ligament=from lateral epicondyle of humerus & blends distally w/anular ligament |
Elbow Joint - ligaments II | anular lig of radius=encircles & holds head of radius in radial notch of ulna=(proximal radio-ulnar);pronation/supination<P>ulnar collateral lig=medial/triang. & extends from medial epicondyle of humerus to coronoid process & olecranon of ulna(3bands) |
Elbow Joint - Bursae | 1. Intratendinous olecranon bursa <P>2. Subtendinous olecranon bursa <P>3. Subcutaneous olecranon bursa |
Intratendinous olecranon bursa | sometimes present in the tendon of triceps brachii |
Subtendinous olecranon bursa | b/w the olecranon & triceps tendon, just proximal to its attachment to the olecranon |
Subcutaneous olecranon bursa | in the subcutaneous connective tissue over the olecranon |
Proximal (Superior) Radio-Ulnar Joint | pivot joint allows movement of head of radius on the ulna<P>head of radius articulates w/ radial notch of ulna<P>held in place by anular ligament of radius |
Proximal Radio-Ulnar Joint - movements | head of radius rotates within the collar formed by the anular ligament & radial notch of ulna during pronation/supination<P>supination=turns palm anteriorly/superiorly when are is flexed<P>pronation=turns palm posteriorly/inferiorly when arm is flexed |
Distal (Inferior) Radio-Ulnar Joint | pivot joint; radius moves around ~fixed distal end of ulna; rounded head of ulna articulates w/ulnar notch on medial side of distal end of radius |
Articular disc of the distal Radio-Ulnar Joint | fibrocartilaginous, triangular disc (triangular lig) binds ends of ulna & radius together & is the main uniting structure; attached to medial edge of ulnar notch of the radius; apex is attached to lateral said of base (ulna styloid process) |
Wrist (Radiocarpal) Joint | condyloid/ellipsoid joint; positioned approx by a line joining the styloid processes of the radius & ulna (proximal wrist crease); ulna not in wrist joint but distal end of radius & articular disc of distal radio-ulnar w/proximal row of carpal bones |
Wrist Joint - ligaments | palmar radiocarpal lig=from radius to 2 rows of carpals, strong & directed so hand follows during supination<P>dorsal radiocarpal lig=same direction so hand follows radius during pronation |
Wrist Joint - ligaments II | ulnar collateral lig=strengthens joint capsule medially, attaching to ulnar styloid process & triquetrum<P>radial collateral lig=strengthens joint capsule laterally, attaching to radial styloid process & scaphoid |
Intercarpal (IC) Joints | plane joints<P>b/w carpal bones of proximal row<P>b/w carpal bones of distal row<P>midcarpal joint=complex joint b/w proximal & distal rows of carpal bones<P>pisotriquetral joint=articulation of pisiform w/palmar surface of triquetrum |
Carpometacarpal (CMC) and Intermetacarpal (IM) Joints | plane joints except for the CMC joint of the thumb=saddle joint<P>distal surfaces of the carpals of distal row articulate w/carpal surfaces of bases of metacarpals @ CMC joints<P>important CMC joint of thumb=b/w the trapezium & base of the 1st metacarpal |
Carpometacarpal & Intermetacarpal Joints - ligaments | palmar & dorsal CMC & IM ligaments & interosseous IM ligaments=unite the bones<P>transverse metacarpal lig.=superficial & deep; w/distal ends of metacarpals - limit movement at CMC & IM joints as they limit metacarpal head separation |
Metacarpophalangeal (MC) & Interphalangeal (IP) Joints | metacarpophalangeal=condyloid & permit movement in flexion-extension & adduction-abduction<P><P>interphalangeal=hinge & permit flexion-extension only |
Metacarpophalangeal & Interphalangeal Joints - ligaments | medial & lateral collateral ligaments:<P>denser cord like=pass distally from heads of metacarpals & phalanges to base of phalanges<P>thinner fan like=pass anteriorly to attach to fibrocartilaginous plates (palmar lig.) forming palmar aspect of joint cap |