Lecture Notes - Joints of the Upper Limb

1. Sternoclavicular - only bony union of upper limb to axial skeleton - multiaxial
   1. Bones - manubrium, clavicle
   2. Cartilages - articular cartilage, articular disc, costal cartilage
   3. Ligaments - capsule
   4. Weakness, etc. - none - clavicle usually breaks before dislocation occurs
2. Acromioclavicular - slightly movable planar
   1. Bones - lateral end of clavicle - articular surface of acromion
   2. Cartilages - articular, articular disc, disc often incomplete
   3. Ligaments -
      • capsular - acromioclavicular
      • accessory - coracoclavicular - actually a syndesmosis
   4. Weakness - "shoulder separation," disruption of acromioclavicular joint and coracoclavicular ligament
3. Shoulder - glenohumeral - scapulohumeral -freely movable, multiaxial - ball and socket
   1. Bones - glenoid fossa of scapula, head of humerus
   2. Cartilages - articular, glenoid labrum
   3. Ligaments -
      • capsular - glenohumeral bands (superior, middle, inferior), coracohumeral
      • accessory - coracoacromial, transverse humeral
      • accessory structures - long head of biceps, subscapular bursa, rotator cuff
   4. Weakness - anterior dislocation most common - inferior often in children, rotator cuff tear - usually the supraspinatus which often deteriorates with age - wear and tear
4. Elbow - humeroulnar & humeroradial (proximal radioulnar is included in capsule ) uniaxial - hinge
   1. Bones - trochlea and capitulum of humerus, head of radius, trochlear notch of ulna
   2. Cartilages - articular
   3. Ligaments - capsular only - ulnar and radial collateral, anular (forms proximal attachment of radial)
   4. Weakness - ulna most commonly dislocated post., epicondylitis, "pitcher's elbow", "pulled elbow"
5. Radioulnar - pivot joint, allows rotation (pronation and supination), about 135 degrees of rotation
   1. Proximal radioulnar
      • bones - head of radius, radial notch of ulna
      • ligaments - anular ligament (lined by cartilage)
   2. Interosseous membrane - a syndesmosis between the interosseous margins of radius and ulna
   3. Distal radioulnar
      • bones - head of ulna, styloid of ulna and ulnar notch of radius
      • ligaments - capsular only, none to name
      • accessory structure - articular disc - acts as a ligament between ulnar styloid and ulnar notch of radius
6. Wrist - complex joint, condyloid, planar, and ball and socket; multiaxial with limited movements
   1. Radiocarpal - "Wrist joint" between radius and ulnar disc proximally and proximal row of carpals distally
      • bones - radius, scaphoid, lunate, triquetrum (carpals act as a unit)
      • cartilages - ulnar disc, articular cartilages of participating bones
      • ligaments - dorsal and palmar radiocarpal, radial and ulnar collateral, and interosseous
   2. Midcarpal - between proximal and distal row of carpals
      • bones - scaphoid, lunate, triquetrum (prox. unit); trapezium, trapezoid, capitate, hamate (dist. unit)
      • cartilages - articular of participating bones
      • ligaments - dorsal and palmar, collateral, and interosseous
   3. Carpo-metacarpal - between distal row of carpals and combined metacarpals 2-5
      • bones - trapezium, trapezoid, capitate, hamate (prox. unit); metacarpals 2-5 (dist. unit)
      • cartilages - articular of participating bones
      • ligaments - dorsal and palmar, collateral, and interosseous
   4. Thumb - trapezial-metacarpal, multiaxial saddle joint
      • bones - trapezium, first metacarpal
      • cartilages - articular of participating bones
      • ligaments - dorsal and palmar, collateral, and interosseous
   5. Piso-triquetral - separate joint, but found at wrist, closely associated with tendon of flexor carpi ulnaris muscle; the pisiform is a sesamoid bone in its tendon; a plane joint with triquetrum
   6. Weaknesses: scaphoid fractures, lunate dislocation is common
7. Intermetacarpal - between metacarpals 2-5 (act as a functional unit) deep transverse metacarpal lig. binds together
8. Metacarpophalangeal (MP joints) - between distal ends of metacarpals and bases of proximal phalanges
9. Interphalangeal (PIP and DIP joints) - between adjacent phalanges of same digit
   Note: Both MP and IP joints are held together by palmar ligaments, and the extensor expansion, the I-P joints have collateral ligaments as well