Anatomy of forearm

anatomy of forearm

1. ANATOMY OF FOREARM ESSEX LOPRESSETI INJURY PLASTIC DEFORMATION OF FOREARM APPROACHES TO FOREARM PRESENTER : DR. SANDEEP TRIPATHI MODERATOR : PROF.SURENDHER KUMAR

2. Bon Articulations and ligament Muscles Nerve and blood vessels Anatomy

3. Sigmoid/semilunar/ trochlear notch Anteriorly composed of coronoid process Posteriorly composed of olecranon process Articulates with trochlea of humerus Ulna

4. Radial head articulates with capitulum Radial neck tapers to radial tuberosity which is insertion for biceps brachii tendon Radial Anatomy

5. Elbow consists of 3 articulations : Ulnohumeral (elbow flexion/extension ) Radiohumeral (forearm pronation/supination ) Radioulnar (forearm pronation/supination) Elbow Joint Articulation

6. Muscles acting on elbow Anterior arm Posterior arm Muscles originating at elbow, acting on forearm, wrist and hand Flexor/pronator group (hand reference) Extensor/supinator group (3 medial, 3 lateral, 3 “outcropping”, 3 “accessory”) Muscular Anatomy

7. Flexor/pronator group Pronator teres Flexor carpi radialis Flexor digitorum superficialis Flexor digitorum profundus Palmaris longus Flexor carpi ulnaris Pronator quadratus Flexor pollicus longus Muscular Anatomy – Elbow Origin

8. Origin: common flexor tendon at medial epicondyle and medial coronoid process Insertion: lateral surface of radial shaft Innervation: median nerve Action: forearm pronation Pronator Teres

9. Origin: common flexor tendon at medial epicondyle Insertion: base of 2 nd and 3 rd metacarpals Innervation: median nerve Action: flexes and abduction /radial deviate the wrist Flexor Carpi Radialis

10. Present in approximately 70% of population Origin: common flexor tendon at medial epicondyle Insertion: palmar aponeurosis Action: flexes wrist and tenses palmar aponeurosis Palmaris Longus

11. Origin: common flexor tendon at medial epicondyle and proximal 2/3 of posterior ulnar border Insertion: pisiform, hamate and 5 th metacarpal Innervation: ulnar Action: flexes and adduction/ulnar deviate the wrist Flexor Carpi Ulnaris

12. Origin: common flexor tendon at medial epicondyle, medial aspect of coronoid process and oblique line of radius Insertion: sides of middle phalanges of 2 nd – 5 th digits Innervation: median nerve Action: flexes PIP joints, assists flexion of MCP and wrist joints Flexor Digitorum Superficialis

13. Origin: anteriomedial proximal ulna Insertion: bases of distal phalanges (anteriorly) of 2 nd -5 th digits Innervation: 1 st and 2 nd tendons by anterior interosseous nerve (median nerve), 3 rd and 4 th tendons by ulnar nerve Action: flexes DIP joints, assists in flexion of PIP and MCP joints Flexor Digitorum Profundus

14. Flexor Pollicus Longus Origin: anterior radius Insertion: palmar surface of base of distal phalanx of thumb Innervation: palmar interosseous nerve Action: flexion of 1 st interphalangeal and metacarpophalangeal joints

15. Pronator Quadratus Origin: anterior, distal ulna Insertion: lateral, distal radius Innervation: anterior interosseous nerve (median nerve) Action: forearm pronation

16. Muscular Anatomy – Elbow Origin Extensor/supinator group Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Extensor carpi ulnaris Extensor digitorum Extensor digiti minimi Supinator Anconeus Extensor indicis Extensor pollicus longus Extensor pollicus brevis Abductor pollicus longus

17. Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Lateral Muscles

18. Brachioradialis Brachioradialis Origin: lateral supracondylar ridge of humerus Insertion: lateral aspect of radial styloid process Innervation: radial nerve Action: elbow flexion, especially w/ forearm in neutral position

19. Extensor Carpi Radialis Longus Origin: lateral supracondylar ridge of humerus Insertion: dorsal base of 2 nd metacarpal Innervation: radial nerve Action: extend and abduct/radial deviate the wrist

20. Extensor Carpi Radialis Brevis Origin: common extensor tendon at lateral epicondyle Insertion: dorsal base of 3 rd metacarpal Innervation: radial nerve Action: extend and abduct/radial deviate the wrist

21. Extensor digitorum Extensor carpi ulnaris Extensor digiti minimi Medial Muscles

22. Extensor Digitorum Origin: common tendon from lateral epicondyle Insertion: bases of middle and distal phalanges via bands of 4 tendons Innervation: radial nerve Action: MCP/IP joint extension

23. Extensor Carpi Ulnaris Origin: common extensor tendon at lateral epicondyle Insertion: ulnar side of base of 5 th metacarpal Innervation: radial nerve Action: extend and adduct/ulnar deviate the wrist

24. Extensor Digiti Minimi Origin: common extensor tendon at lateral epicondyle Insertion: base of the 5 th proximal phalanx Innervation: posterior interosseous (radial) nerve Action: extension of 5 th MP joint

25. Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis “Outcropping” Muscles

26. Abductor Pollicis Longus Origin: posterior, distal radius and ulna Insertion: base of 1 st metacarpal Innervation: median nerve Action: extension, abduction of 1 st carpometacarpal joint

27. Extensor Pollicis Longus/Brevis Origin: longus – posterior, middle ulna, brevis – posterior, distal radius Insertion: dorsal aspect of base of distal phalanx of thumb Innervation: deep radial nerve Action: extension of 1 st carpometacarpal and metacarpophalangeal joints

28. Supinator Anconeus Extensor indicis “Accessory” Muscles

29. Supinator Origin: lateral epicondyle, annular ligament/RCL and supinator crest of ulna Insertion: lateral proximal 1/3 of radius Innervation: posterior interosseous nerve (deep branch of radial nerve) Action: forearm supination

30. Anconeus Anconeus Origin: lateral epicondyle of humerus Insertion: lateral aspect of olecranon and posterior ulna Innervation: radial nerve Action: assists elbow extension

31. Extensor Indicis Origin: distal, lateral ulna Insertion: dorsal aspect of 2 nd proximal phalanx Innervation: posterior interosseous (radial) nerve Action: index finger extension and assists with wrist extension

32. Brachial artery Radial artery Ulnar artery Elbow vascular anastamosis Vascular Structures

33. Vascular Structures Brachial artery Descends along arm along medial aspect of brachialis muscle Enters antecubital fossa medial to biceps brachii tendon and lateral to median nerve Terminates at radial head as radial/ulnar arteries

34. Vascular Structures Radial artery Originates at radial head, emerges from antecubital fossa between brachioradialis and pronator teres muscles Continues laterally along forearm deep to brachioradialis muscle

35. Vascular Structures Ulnar artery Originates at radial head, continues medially down forearm

36. Elbow Vascular Anastamosis Laterally – profunda brachii artery meets radial recurrent artery Medially – inferior ulnar collateral artery meets anterior ulnar recurrent artery and superior ulnar collateral artery meets posterior ulnar recurrent artery

37. Terminal branches of brachial plexus Axillary Musculocutaneous Median Radial Ulnar Anterior interosseous nerve Dermatomes and myotomes Neurological Structures

38. Musculocutaneous/Axillary Nerves Musculocutaneous nerve Innervates biceps brachii, coracobrachialis and brachialis muscles Sensory distribution is anterior arm and lateral forearm Axillary nerve Innervates deltoid and teres minor muscles Sensory distribution is lateral arm

39. Median Nerve Median nerve Enters antecubital fossa medial to biceps brachii tendon and brachial artery Courses down medial forearm to hand/wrist distribution Sensory distribution is pad of index finger

40. Radial Nerve Radial nerve Enteres antecubital fossa posterior to brachialis muscle Divides into superficial and deep (posterior interosseous) branches Courses down lateral forearm to hand/wrist distribution Sensory distribution is 1 st dorsal webspace

41. Ulnar Nerve Ulnar nerve Courses in cubital tunnel posterior to medial epicondyle Superficial and susceptible to compression or entrapment Courses down medial forearm to hand/wrist distribution Sensory distribution is pad of little finger

42. Anterior Interosseous Nerve Anterior interosseous nerve (branch of median nerve) Passes between 2 heads of pronator teres muscle, may be impinged upon Anterior interosseous nerve syndrome characterized by abnormal pinch deformity (inability to extend DIP of thumb and index finger)

43. Dermatomes C5 – lateral arm C6 – lateral forearm, thumb and index finger C7 – posterior forearm and middle finger C8 – medial forearm, ring and little fingers T1 – medial arm

44. Myotomes C5 – shoulder abduction C6 – elbow flexion, wrist extension C7 – elbow extension, wrist flexion C8 – finger flexion/grip strength T1 – finger abduction/adduction

45. Olecranon Bursa Most frequently injured bursa in the elbow Lays between skin and olecranon process Allows unrestricted/fluid movement of skin over olecranon process

46. Essex – Lopresti injury OR longitudinal radioulnar dissociation

47. is a complex injury that includes fracture of the radial head rupture of the interosseusmembrane of the forearm impaired integrity of the distal radioulnar joint

48. Essex – Lopresti lesion leads to instability of the forearm central migration of the radius. restriction of the radiocarpal motion reduction of the grip strength and wrist pain.

49. Radial head replacement TREATMENT

50. Distal radio ulnar joint reduction(pinning)

51. APPROACHES TO FOREARM

52. VOLAR APPROACH TO RADIUS(HENRY) INDICATIONS RADIAL OSTEOTOMY TUMOR / ABSCESS BIOPSY AND EXCISION ORIF OF RADIUS FIXATION ANTERIOR EXPOSURE OF BICIPITAL TUBEROSITY

53. POSITION PLACE SUPINE ON TABLE AND SUPINATE ARM AND PLACE ON ARMBOARD EXSANGUINATE ARM INCISION LONGITUDINAL INCISION BEGIN JUST LATERAL TO BICEPS TENDON ON FLEXOR CREASE OF ELBOW END AT RADIAL STYLOID PROCESS 

54. Internervous Plane  Proximally between: brachioradialis  (radial nerve)    pronator teres  (median nerve)  Distally between: brachioradialis  (radial nerve)  FCR  (median nerve) 

55. SUPERFICIAL DISSECTION INCISE THE DEEP FASCIA IN LINE WITH SKIN INCISION DEVELOP A PLANE BETWEEN BR AND FCR DISTALLY MOVE PROXIMAL TO DEVELOP PLANE BETWEEN PT AND BR IDENTIFY THE SUPERFICIAL RADIAL NERVE BENEATH BR LIGATE THE BRANCHES OF THE RADIAL ARTERY TO AID LATERAL RETRACTION OF BR

56. DEEP DISSECTION - PROXIMAL THIRD FOLLOW THE BICEPS TENDON TO ITS INSERTION ON THE BICIPITAL TUBEROSITY  RADIAL TO THE INSERTION OF BICEPS TENDON INCISE THE BURSA TO GAIN ACCESS TO THE PROXIMAL PART OF RADIUS  FULLY SUPINATE THE FOREARM TO DISPLACE THE PIN RADIALLY AND BRING THE ORIGIN OF THE SUPINATOR MUSCLE INTO THE ANTERIOR ASPECT OF THE RADIUS INCISE THE SUPINATOR MUSCLE ALONG THE LINE IF ITS BROAD INSERTION AND CONTINUE SUBPERIOSTEAL DISSECTION LATERALLY

57. DEEP DISSECTION - MIDDLE THIRD PRONATE THE FOREARM TO BRING THE INSERTION OF THE PRONATOR TERES, ALONG THE RADIAL ASPECT OF THE RADIUS, INTO VIEW DETACH THE PRONATOR INSERTION FROM BONE AND RETRACT MEDIALLY DEEP DISSECTION - DISTAL THIRD PARTIALLY SUPINATE THE FOREARM DISSECT THE PERIOSTEUM OFF THE LATERAL ASPECT OF THE DISTAL THIRD OF THE RADIUS, LATERAL TO THE PRONATOR QUADRATUS AND FLEXOR POLLICIS LONGUS

58. DANGERS POSTERIOR INTEROSSEOUS NERVE   THE POSTERIOR INTEROSSEOUS NERVE ENTERS THE SUPINATOR MUSCLE SUPERFICIAL RADIAL NERVE  VULNERABLE WITH MANIPULATION OF MOBILE WAD OF THREE DAMAGE TO IT CAN CAUSE A PAINFUL NEUROMA RUNS DOWN FOREARM UNDER BODY OF BRACHIORADIALIS RADIAL ARTERY RUNS DOWN MIDDLE OF FOREARM UNDER BRACHIORADIALIS

59. DORSAL APPROACH TO RADIUS(THOMPSON) ACCESS PROVIDES EXPOSURE TO PROXIMAL 1/3 OF RADIUS INDICATIONS ORIF OF RADIAL FRACTURES TREATMENT OF NONUNION ACCESS TO THE PIN AS IT PASSES THROUGH THE ARCADE OF FROHSE FOR NERVE PARALYSIS RESISTANT TENNIS ELBOW RADIAL OSTEOTOMY OSTEOMYELITIS AND BONE TUMORS

60. INTERNERVOUS PLANE PROXIMALLY BETWEEN ECRB (RADIAL NERVE) AND EDC (PIN NERVE)  DISTALLY BETWEEN ECRB (RADIAL NERVE) AND EPL (PIN NERVE) DISTALLY  APPROACH

61.  POSITION PLACE PATIENT SUPINE IF ARM IS ON ARM BOARD, THEN PRONATE THE FOREARM IF ARM IS ACROSS CHEST, THE SUPINATE THE FOREARM INCISION STRAIGHT OR GENTLY CURVED INCISION FROM POINT( 1.5) ANTERIOR TO THE LATERAL EPICONDYLE OF THE HUMERUS TO POINT JUST DISTAL TO LISTER'S TUBERCLE( mid point of the wrist)

62. SUPERFICIAL DISSECTION PROXIMALLY DEVELOP INTERVAL BETWEEN ECRB AND THE EDC PROXIMALLY EXPOSE PROXIMAL THIRD OF THE RADIUS AND OVERLYING SUPINATOR DISTALLY DEVELOP PLANE BETWEEN THE ECRB AND EPL AND EXPOSES LATERAL ASPECT OF DISTAL THIRD OF THE RADIUS

63. DEEP DISSECTION - PROXIMAL THIRD  PRONATE ARM TO EXPOSE ANTERIOR ASPECT OF RADIUS AND MOVE PIN AWAY FROM ORIGIN OF SUPINATOR DETACH SUPINATOR MUSCLE AT INSERTION ON ANTERIOR ASPECT OF RADIUS SUBPERIOSTEALLY STRIP SUPINATOR TO EXPOSE PROXIMAL THIRD OF RADIUS

64. DEEP DISSECTION - MIDDLE THIRD MAKE INCISION ALONG SUPERIOR AND INFERIOR BORDERS OF APL AND EPB AND RETRACT THEM OFF BONE TO EXPOSEMIDDLE THIRD OF RADIUS DANGERS POSTERIOR INTEROSSEOUS NERVE INJURY USUALLY FROM RETRACTION IN 25% OF PATIENTS THE NERVE ACTUALLY TOUCHES THE DORSAL ASPECT OF THE RADIUS PLATES PLACED HIGH ON THE DORSAL SURFACE MAY TRAP THE NERVE PIN MUST BE IDENTIFIED WITHIN THE SUPINATOR MUSCLE

65. APPROACH TO ULNA INIDICATIONS ORIF OF ULNAR SHAFT FXS ULNAR OSTEOTOMY ULNAR LENGTHENING (KIENBOCK'S DISEASE) ULNAR SHORTENING (FOR RADIAL MALUNION) OSTEOMYELITIS AND TUMORS OF ULNA INTERNERVOUS PLANE BETWEEN ECU AND  FCU   POSITION PLACE SUPINE ON TABLE PLACE ARM ACROSS CHEST TO EXPOSE SUBCUTANEOUS BORDER OF ULNA

66. APPROACH LINEAR LONGITUDINAL INCISION OVER SUBCUTANEOUS BORDER OF ULNA SUPERFICIAL DISSECTION INCISE DEEP FASCIA IN DISTAL INCISION IN LINE WITH SKIN INCISION DIVIDE PLANE BETWEEN ECU AND FCU DISSECT DOWN TO SUBCUTANEOUS BORDER OF ULNA DEEP DISSECTION INCISE PERIOSTEUM OVER ULNA PERFORM SUBPERIOSTEAL DISSECTION

67. DANGERS ULNAR NERVE PROXIMALLY PASSES THROUGH  HEADS OF FCU TRAVELS DOWN FOREARM UNDER FCU AND ON TOP OF FDP  ULNAR ARTERY TRAVELS DOWN FOREARM WITH ULNAR NERVE (RADIAL SIDE) PROTECT BY DISSECTING FCU SUBPERIOSTALLY

68. POSTERIOR APPROACH TO PROXIMAL 3 RD ULNA AND RADIAL HEAD(BOYDS) INDICATION PROXIMAL THIRD ULNA FRACTURE WITH RADIAL HEAD DISLOCATION(MONTEGGIA) ISOLATED RADIAL HEAD AND NECK FRACTURE INCISION INCISION GIVEN ABOUT 2.5 CM ABOVE ELBOW JOINT JUST LATERAL TO TRICEPS TENDON EXTEND OVER OLECRONON TO PROXIMAL AND MIDDLE 3 RD OF ULNA POSTERIORALY

69. DISSECTION DEVELOP THE INTERVAL BETWEEN THE ULNA ON MEDIAL SIDE , ANCONEUS AND ECU LATERALLY STRIP THE ANCONEUS SUBPERIOSTEALLY TO EXPOSE THE RADIAL HEAD DISTAL TO RADIAL HEAD, REFLECT THE SUPINATOR SUBPERIOSTEALLY FROM ULNA

70. FCR APPROACH TO DISTAL RADIUS INDICATIONS ORIF OF FRACTURE AND DISLOCATIONS OF DISTAL RADIUS AND CARPUS POSITION PLACE SUPINE ON TABLE SUPINATE ARM AND PLACE ON ARMBOARD APPLIED TOURNIQUET   INCISION MAKE INCISION ALONG PALPABLE FLEXOR CARPI RADIALIS (FCR) TENDON SHEATH

71. SUPERFICIAL DISSECTION INCISE SKIN FLAPS AND SUBCUTANEOUS FAT SECTION FIBERS OF VOLAR FCR TENDON SHEATH IN LINE WITH TENDON  RETRACT FCR TENDON ULNARLY AND INCISE THROUGH THE DORSAL ASPECT OF THE FCR SHEATH CAN RETRACT FCR RADIALLY IF CARPAL TUNNEL ACCESS IS NECESSARY

72. DEEP DISSECTION AND ACCESS TO VOLAR WRIST JOINT UNDERNEATH THE FCR SHEATH IS THE FLEXOR POLLICIS LONGUS (FPL) - THIS MUST BE RETRACTED ULNARLY AFTER THE FPL RETRACTED, THE PRONATOR QUADRATUS (PQ) IS SEEN  INCISE THE RADIAL AND DISTAL BORDERS OF THE PQ, ELEVATING THE MUSCLE OFF THE VOLAR RADIUS 

73. PROXIMAL EXTENSION DISSECTION EXTEND INCISION UP MIDDLE OF ARM INCISE DEEP FASCIA BETWEEN PL AND FCR RETRACT PL AND FCR TO EXPOSE FDS INDICATIONS TO FURTHER EXPOSE MEDIAN NERVE OR RADIUS MEDIAN NERVE IS IMMEDIATELY UNDER THE DEEP SURFACE OF FDS

74. DISTAL EXTENSION INDICATIONS TO FURTHER EXPOSE THE SCAPHOID DISSECTION EXTEND INCISION OBLIQUELY IN A RADIAL DIRECTION ACROSS THE FLEXOR CREASE CONTINUE THIS IN LINE WITH THE THUMB RAY ELEVATE THE THENAR MUSCULATURE OFF THE VOLAR WRIST CAPSULE OPEN CAPSULE IF NECESSARY

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