The wrist and hand

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The wrist and hand

  1. 1. The Wrist and Hand Maribel G. Castro, MD CPU College of Medicine
  2. 2. Bones of the Wrist and Hand
  3. 3. <ul><li>Carpal groove – anterior concavity of the carpus </li></ul><ul><li> - converted into an osseoufibrous carpal tunnel by the flexor retinaculum, which is attached to the scaphoid and trapezium laterally and to the pisiform and hook of the hamate bone medially </li></ul><ul><li>Carpal Tunnel Syndrome – due to compression of the median nerve in the carpal tunnel </li></ul>
  4. 4. <ul><li>Extensor retinaculum – transverse band on the posterior part of the wrist formed from the thickened antebrachial fascia </li></ul><ul><li> - retains the extensor tendons in position, thereby increasing their efficiency </li></ul><ul><li>Flexor retinaculum – thickened deep fascia anteriorly </li></ul><ul><li> - converts the anterior concavity of the carpus into a carpal tunnel through which the flexor tendons pass </li></ul>
  5. 5. The Hand <ul><li>Fascia of the Palm </li></ul><ul><li>- continuous proximally with the antebrachial fascia and at the borders of the palm with the fascia on the dorsum of the hand </li></ul><ul><li>- thin over the thenar and hypothenar eminences </li></ul><ul><li>- thick in the palm where it forms the palmar aponeurosis and in the digits where it forms the fibrous digital sheaths </li></ul>
  6. 6. The Hand <ul><li>Palmar Aponeurosis </li></ul><ul><li>- strong, well-defined triangular part of the deep fascia of the hand </li></ul><ul><li>- covers the soft tissues and overlies the long flexor tendons of the palm </li></ul><ul><li>- proximal end continuous with the flexor retinaculum and palmaris longus tendon </li></ul><ul><li>- distal end divides at the roots of the digits into 4 longitudinal bands </li></ul><ul><li>- each band attached to the base of the proximal phalanx and is fused with the fibrous digital sheaths </li></ul>
  7. 7. The Carpal Tunnel
  8. 8. Palmar Spaces <ul><li>- Surgically important </li></ul><ul><li>- Spaces bounded medially and laterally by fibrous septa </li></ul><ul><li>* medial septum – from the medial border of the palmar aponeurosis to the 5 th metacarpal bone </li></ul><ul><li>* lateral septum – from the lateral border of the palmar aponeurosis to the 1 st metacarpal bone </li></ul><ul><li>1. Hypothenar compartment </li></ul><ul><li>- medial to the medial septum, containing the hypothenar muscles </li></ul><ul><li>2. Thenar compartment </li></ul><ul><li>- lateral to the lateral septum containing the thenar muscles </li></ul>
  9. 9. Palmar Spaces <ul><li>3. Central compartment </li></ul><ul><li>- between the thenar and hypothenar compartments, containing the flexor tendons and their sheaths, the superficial palmar arch, and branches of the median and ulnar nerves </li></ul><ul><li>4. Adductor compartment </li></ul><ul><li>- deepest muscular plane of the palm, contains the adductor pollicis muscle </li></ul><ul><li>Midpalmar space – medial and lateral </li></ul><ul><li> - created by a fibrous septum passing obliquely and posteriorly from the lateral border of the palmar aponeurosis to the 3 rd metacarpal bone </li></ul><ul><li>Retroadductor space – between the adductor pollicis and the 1 st dorsal interosseous muscle </li></ul>
  10. 10. Muscles of the Hand <ul><li>The intrinsic muscles of the hand are on the palmar aspect and are innervated by the ulnar and median nerves </li></ul><ul><li>A. Thenar Muscles </li></ul><ul><li>- chiefly responsible for the movement of the thumb known as opposition </li></ul><ul><li>1. abductor pollicis brevis </li></ul><ul><li>- forms the anterolateral part of the thenar eminence </li></ul><ul><li>- origin: flexor retinaculum and tubercles of scaphoid and trapezium </li></ul><ul><li>- insertion: lateral side of base of proximal phalanx of thumb </li></ul><ul><li>- action: abducts thumb and helps oppose it </li></ul>
  11. 11. <ul><li>2. flexor pollicis brevis </li></ul><ul><li>- medial to the abductor pollicis brevis </li></ul><ul><li>- origin: flexor retinaculum and tubercle of trapezium </li></ul><ul><li>- insertion: lateral side of base of proximal phalanx of thumb </li></ul><ul><li>- action: flexes thumb </li></ul><ul><li>3. opponens pollicis </li></ul><ul><li>- lies deep to the abductor pollicis brevis and lateral to the flexor pollicis brevis </li></ul><ul><li>- origin: flexor retinaculum and tubercle of trapezium </li></ul><ul><li>- insertion: lateral side of 1 st metacarpal bone </li></ul><ul><li>- action: opposes thumb toward center of palm and rotates it medially </li></ul><ul><li>* opposition is the most impt. movement of the thumb </li></ul>
  12. 12. <ul><li>4. adductor pollicis </li></ul><ul><li>- has 2 heads that are separated by a gap through which the radial artery passes </li></ul><ul><li>- origin: oblique head – bases of 2 nd and 3 rd metacarpals, capitate, and adjacent carpal bones </li></ul><ul><li> transverse head – anterior surface of body of 3 rd metacarpal bone </li></ul><ul><li>- insertion: medial side of base of proximal phalanx of thumb </li></ul><ul><li>-action: adducts thumb towards middle digit </li></ul>
  13. 13. Thenar Muscles
  14. 14. <ul><li>B. Hypothenar Muscles </li></ul><ul><li>- concerned with movements of the 5 th digit </li></ul><ul><li>- produce the hypothenar eminence or the ball of the 5 th digit </li></ul><ul><li>1. abductor digiti minimi </li></ul><ul><li>- most superficial of the 3 hypothenar muscles forming the hypothenar eminence </li></ul><ul><li>- origin: pisiform bone </li></ul><ul><li>- insertion: medial side of base of proximal phalanx of 5 th digit </li></ul><ul><li>- action: abducts digit 5 </li></ul><ul><li>2. flexor digiti minimi </li></ul><ul><li>- lateral to the abductor digiti minimi </li></ul><ul><li>- origin: hook of hamate and flexor retinaculum </li></ul><ul><li>- insertion: medial side of base of proximal phalanx of digit 5 </li></ul><ul><li>- action: flexes proximal phalanx of digit 5 </li></ul>
  15. 15. <ul><li>3. opponens digiti minimi </li></ul><ul><li>- lies deep to the abductor and flexor muscles of the 5 th digit </li></ul><ul><li>- origin: hook of hamate and flexor retinaculum </li></ul><ul><li>- insertion: medial border of 5 th metacarpal bone </li></ul><ul><li>- action: draws 5 th metacarpal bone anteriorly and rotates it, bringing digit 5 into opposition with thumb </li></ul><ul><li>**4. palmar brevis </li></ul><ul><li>- lies in the fascia deep to the skin of the hypothenar eminence </li></ul><ul><li>- a relatively unimportant muscle except that it covers and protects the ulnar nerve and artery </li></ul><ul><li>- origin: flexor retinaculum and palmar aponeurosis </li></ul><ul><li>- insertion: skin on the medial side of the palm </li></ul><ul><li>- action: wrinkles the skin on the medial side of the palm and deepens the hollow of the palm, as in cupping of the hand, thereby aiding the grip </li></ul>
  16. 16. Hypothenar Muscles
  17. 17. <ul><li>C. Lumbrical Muscles </li></ul><ul><li>- named as such because of their elongated wormlike form </li></ul><ul><li>1. Lumbricals 1 and 2 </li></ul><ul><li>- origin: lateral 2 tendons of flexor digitorum profundus </li></ul><ul><li>2. Lumbricals 3 and 4 </li></ul><ul><li>- origin: medial 3 tendons of flexor digitorum profundus </li></ul><ul><li>- insertion: lateral sides of extensor expansions of digits 2 to 5 </li></ul><ul><li>- action: flex digits at MCP joints and extend IP joints </li></ul>
  18. 18. <ul><li>D. Interosseous Muscles </li></ul><ul><li>- located between the metacarpal bones </li></ul><ul><li>- arranged in 2 layers: 3 palmar and 4 dorsal </li></ul><ul><li>- located between bones </li></ul><ul><li>1. dorsal interossei 1 to 4 </li></ul><ul><li>- origin: adjacent sides of 2 metacarpal bones </li></ul><ul><li>- insertion: extensor exapnsions and bases of proximal phalanges of digit 2 to 4 </li></ul><ul><li>- action: abducts digits and assit lumbricals </li></ul><ul><li>2. palmar interossei 1 to 3 </li></ul><ul><li>- origin: palmar surfaces of 2 nd , 4 th and 5 th metacarpal bones </li></ul><ul><li>- insertion: extensor expansion of digits and bases of proximal phalanges of digits 2, 4, and 5 </li></ul><ul><li>- action: adducts digits and assist lumbricals </li></ul>
  19. 19. Lumbricals and Interossei
  20. 20. Nerves <ul><li>medial, ulnar and radial nerves supply the hand </li></ul><ul><li>A. Median Nerve </li></ul><ul><li>- enters the hand through the carpal tunnel </li></ul><ul><li>- supplies motor fibers to the 3 thenar muscles and the 1 st and 2 nd lumbricals </li></ul><ul><li>- sends cutaneous sensory fibers to the lateral palmar surface, the sides of the first 3 digits, the lateral half of the 4 th digit, and the dorsum of the distal halves of these digits </li></ul><ul><li>Carpal tunnel syndrome </li></ul><ul><li>- caused by any lesion that significantly reduces the size of the carpal tunnel (e.g. inflammation of the flexor retinaculum), resulting to compression of the median nerve </li></ul>
  21. 21. The Carpal Tunnel
  22. 22. <ul><li>B. Ulnar Nerve </li></ul><ul><li>- leaves the forearm by emerging from deep to the tendon of the flexor carpi ulnaris </li></ul><ul><li>- passes alongisde the lateral border of the pisiform bone and goes with the ulnar artery on its lateral side </li></ul><ul><li>- ulnar artery and nerve ar bridged over by a slender band of connective tissue, which forms a small tunnel ( canal of Guyon ) </li></ul><ul><li>1. palmar cutaneous branch </li></ul><ul><li>- arises just proximal to the wrist </li></ul><ul><li>- passes superficial to the flexor retinaculum and to the palmar aponeurosis </li></ul><ul><li>- supplies skin of the medial side of the palm </li></ul><ul><li>2. dorsal cutaneous branch </li></ul><ul><li>- supplies medial half of dorsum of hand, 5 th digit and the medial half of 4 th digit </li></ul>
  23. 23. <ul><li>*At the distal border of the flexor retinaculum, the ulnar nerve ends by dividing into a superficial and deep branch </li></ul><ul><li>4. superficial branch </li></ul><ul><li>- supplies cutaneous fibers to the anterior surfaces of the medial 1 ½ digits </li></ul><ul><li>5. deep branch </li></ul><ul><li>- supplies motor fibers to the hypothenar muscles, the medial 2 lumbricals, the adductor pollicis and all the interosseous muscles </li></ul><ul><li>- also supplies several joints (wrist, intercarpal, carpometacarpal and intermetacarpal) </li></ul><ul><li>* Referred to as the nerve of fine movements – innervates muscles that are concerned with fine movements </li></ul>
  24. 24. Ulnar Nerve
  25. 25. <ul><li>C. Radial Nerve </li></ul><ul><li>- supplies no hand muscles </li></ul><ul><li>- deep branch is muscular and articular in distribution </li></ul><ul><li>- superficial branch is the direct continuation of the radial nerve along the anterolateral side of the forearm and is entirely sensory </li></ul><ul><li>- pierces the deep fascia near the dorsum of the wrist and supplies the skin and fascia over the lateral 2/3 of the dorsum of the hand, the dorsum of the thumb, and proximal parts of the lateral 1 ½ digits </li></ul><ul><li>Wrist drop </li></ul><ul><li>- due to radial nerve injury producing paralysis of the extensor muscles of the forearm </li></ul><ul><li>- hand is flexed at the wrist and lies flaccid </li></ul><ul><li>- digits are also flexed at the MCP joints </li></ul>
  26. 26. Arteries <ul><li>Radial and ulnar arterues and their branches provide all the blood to the hand </li></ul><ul><li>A. Radial Artery </li></ul><ul><li>- smaller of the 2 terminal branches of the brachial artery </li></ul><ul><li>1. superficial palmar branch  superficial palmar arterial arch </li></ul><ul><li>2. princeps pollicis artery – supplies the thumb </li></ul><ul><li>3. radialis indicis – supplies lateral side of digit 2 </li></ul><ul><li>*4. deep palmar arterial arch – formed mainly by the radial artery which joins the deep branch of the ulnar artery </li></ul><ul><li>palmar metacarpal arteries – arise from the deep palmar arch </li></ul><ul><li> - run distally and join the common palmar digital arteries which arise from the superficial palmar arterial arch </li></ul>
  27. 27. <ul><li>B. Ulnar Artery </li></ul><ul><li>- larger of the 2 terminal branches of the brachial artery </li></ul><ul><li>- enters the palm on the lateral side of the ulnar nerve superficial to the flexor retinaculum </li></ul><ul><li>- passes lateral to the pisiform bone </li></ul><ul><li>1. deep palmar branch  deep palmar arterial arch </li></ul><ul><li> - passes deep through the hypothenar muscles and anastomoses with the radial artery </li></ul><ul><li>2. superficial palmar arterial arch </li></ul><ul><li>- formed mainly by the ulnar artery </li></ul><ul><li>- located distal to the deep palmar arch </li></ul><ul><li>- gives rise to the three common digital arteries that anastomoses with the palmar metacarpal arteries from the deep palmar arch </li></ul><ul><li>  each common digital artery divides into a pair of proper palmar digital arteries which run along the sides of the 2 nd to 4 th digits </li></ul>
  28. 28. Palmar Arteries
  29. 29. Superficial Palm
  30. 30. Veins <ul><li>Superficial and deep palmar arterial arches are accompanied by venae comitantes </li></ul><ul><li>Superficial venous arch </li></ul><ul><li>Deep venous arch </li></ul><ul><li>Dorsal digital veins – drain into </li></ul><ul><li>(3) Dorsal metacarpal veins – unite to form a dorsal venous network (superficial to the metacarpus, this network is prolonged proximally as the cephalic vein ) </li></ul>
  31. 31. Thank You and Good Luck! 

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