Elbow, wrist and hand

• Function of the elbow

  • To shorten and lengthen the arm
  • To allow the hand to be moved towards and away from the body
• Bones of the elbow

  • Humerus - trochlea medially and capitulum laterally
  • Radius - radial head, radial tuberosity
  • Ulna - coronoid process, olecranon process
• Carrying angle

  • The inside angle formed between the long axis of the humerus and the long axis of the forearm
  • Due to the longer medial flange of the trochlea
  • Normally it is 5-15 degrees
• Joints of the elbow complex

  • Humero-ulnar (modified hinge)
  • Humero-radial (modified hinge)
  • Superior radio-ulnar (pivot)
• Radio-ulnar joint

  • The ulna does not move, the radius moves around the ulna
  • It allows supination and pronation
• Elbow Movements

  • Flexion (0-145 degrees)
  • Hyperextension (0-15)
  • Supination-pronation (90 degrees each)
• Ligaments of the elbow

  • Medial Collateral Ligament - runs from medial epicondyle of humerus to the medial side of coranoid process and olecranon process
  • Lateral collateral ligament - attaches proximally to the lateral epicondyle and distally to the lateral ulna and annular ligament
  • Annular Ligament - encompasses radial head at the radial notch and hold it against the ulna
  • Interosseous membrane - broad flat membrane is located between the radius and ulna for most of their length
• Collateral Ligaments

  • Resist varus and valgus strain
  • MCL - med epicondyle to coronoid and olecranon process of ulna
  • LCL - lat epicondyle to annular lig
• Bursae of the elbow

  • Biceps Bursa
  • Olecranon Bursa
• Muscles of the elbow

  • Brachialis - attaches distal half of the humerus to the coronoid process and ulnar tuberosity of ulna
  • Biceps Brachii - Long head-supraglenoid tubercle, through bicipital groove, joins with the Short head- comes from the coracoid process, Both combine to inset onto the radial tuberosity
  • Brachioradilis - attached to humerus just slightly above the lateral epicondyle, crosses the elbow anterior and lateral to attach on the styloid process of the radius
  • Triceps brachii - Entire muscle mass of posterior arm, It attaches to the olecranon process when all 3 heads of the muscle combine
  • Anconeus - Helps the triceps with extension, Keeps the annular ligament out of the olecranon fossa
  • Pronator teres - Cordlike shape is teres, Pronation is its pimary action, Mostly superficial muscle
  • Pronator quadratus - Small flat quadrilateral muscle, Pronates the wrist, Deep muscle at distal end of forearm
  • Supinator - Deep muscle that wraps around the elbow joint laterally from posterior to anterior surfaces
• Musculature attached to common flexor origin

  • Pronator teres
  • Flexor carpi radialis
  • Palmaris longus
  • Flexor digitorum sup
  • Flexor carpi ulnaris
• Musculature attached to common extensor origin

  • Ext carpi ulnaris
  • Ext dig minimi
  • Ext digitorum
  • Ext carpi radialis brev
  • Supinator
• Nerve supply

  • Dermatomes - C5/6 front of elbow, C7 back of elbow
  • Myotomes - C5 biceps and brachialis, C6 Pronator teres and supinator, C7 Triceps
  • Median nerve - medial to biceps tendon
  • Ulnar Nerve - behind medial epicondyle
  • Radial nerve + posterior interosseous nerve - lateral to the biceps
• Functions of the hand

  • Gripping / grasping
  • Manipulation
  • Weight bearing / Stabiliser
  • Feeling / Sensory organ
  • Emotional expression / communicator
• Articular system of the hand

  • Hand skeleton has many articulations
  • No single joint acts in isolation
  • Together form a functional group arranged in kinetic chains
• Bones of the hand

  • Distal phalanges
  • Middle phalanges
  • Sesamoid bones
  • Proximal phalanges
  • Metacarpals
  • Carpals
• Joints of the hand

  • Distal interphalangeal (DIP)
  • Proximal interphalangeal (PIP)
  • Metacarpophalangeal (MCP)
  • Carpaometacarpal (CMC)
  • Midcarpal
  • Radiocarpal
• Wrist function

  • Control efficiency of extrinsic muscles
  • Controls length-tension relationships in the multi-articular hand muscles
  • Controls fine adjustments of grip
• Carpal bones

  • Scaphoid, Lunate, Triquetral, Pisiform
  • Trapezium, Trapezoid, Capitate, Hamate
• Radiocarpal (RC) Joint

  • Compound biaxial joint
  • Distal articular surfaces - Convex, Bones - SC, LU, TQ
  • Proximal articular surfaces - Concave, Bones - Radius, TFCC (triangular fibrocartilagenous complex)
• Ligaments for RC and MC Joints

  • Capsule
  • Extrinsic ligaments - Volar Radiocarpal ligament, Volar Ulnocarpal ligament, Dorsal Radiocarpal ligament, Radial Collateral ligament, Ulnar Collateral ligament
  • Intrinsic ligaments
• ROM of Wrist Complex (RC and MC joints)

  • Palmarflexion ~ 0-85º
  • Dorsiflexion ~ 0-80º
  • Radial deviation ~ 0-20º
  • Ulnar deviation ~ 0-45º
  • Close packed position - full extension and full radial deviation
• Carpometacarpal Joint

  • Articulations - Base of metacarpal, Distal row of carpal bones
  • Type - 1st and 5th saddle joints, 2-4th plane joints
• Ligaments of CMC joints

  • Capsule
  • Transverse MC ligaments - strong
  • Longitudinal ligaments - volar and dorsal, weak
• ROM of CMC joints

  • 1st & 5th - flexion/extension, abduction/adduction, limited opposition
  • 2nd & 3rd - relatively immobile
  • 4th - perceptible flexion/extension
• Function of CMC joints

  • Contribute to palmar arches
  • Mobile distal transverse arch
  • Fixed proximal transverse arch
  • Longitudinal arch
  • Assist in moulding the palm around objects
• Metacarpophalangeal Joints

  • Articulations - Convex metacarpal head, Concave base of proximal phalanx
  • Type - Condyloid joint
• Ligaments of MCP joint

  • Capsule
  • 2 collateral ligaments
  • Deep transverse ligament
  • Volar plate - Proper, Accessory
• ROM of MCP joint

  • Flexion/extension (0 - 90/100°)
  • Hyperextension (0-15°)
  • Abduction/adduction (in extension 0-10°)
• Interphalangeal (IP) joints

  • Articulations - Head of the more proximal phalanx (convex), Base of the more distal phalanx (concave)
  • Proximal articular surface > distal articular surface
  • Type - Plane joints
• Ligaments of IP joint

  • Capsule
  • 2 Collateral ligs
  • Volar plate
• ROM of IP joints

  • PIP joint flexion ~ 0-110°, ~ 135° little finger
  • DIP joint flexion ~ 0 - 80°, ~ 90° little finger
• Interossei muscles

  • Dorsal - Abduction (Dab)
  • Palmar - Adduction (Pad)
• Grasps

  • Hook
  • Pincer
  • Power
  • Precision
  • Key