1. Anatomy Review Session Summer 2009

2. Approach to Anatomy • Osteology • Arthrology • Nerves • Vessels • Approaches • Questions

3. References • Miller • Self assessment exams • OITE References • Primary articles • Hoppenfeld

4. Upper extremity Shoulder Arm Forearm Wrist Spine Lower extremity Hip Thigh Knee and leg Ankle and foot Format

5. Shoulder

6. Osteology • Clavicle • First bone to ossify (5 weeks) • Last to fuse (medial epiphysis at 25 years old) • Fracture of clavicle  most common birth injury

7. Osteology • Scapula • Glenoid retroverted 5 degrees • Humerus retroverted 30 degrees • Attachments: 17 muscles, 4 ligaments

8. Coracoid • Coracoid attachments • Coracoacromial ligament • Coracoclavicular ligs • Conoid (medial) • Trapezoid (lateral) • Conjoined tendon • Coracobrachialis • Short head of biceps • Pec Minor

9. Notches • Suprascapular notch • Superior transverse scapular ligament • Nerve below • Artery above • Spinoglenoid notch • Inferior transverse scapular ligament • Nerve and artery below ** Compression (ganglion/cyst) = infraspinatus atrophy

10. Arthrology • Glenohumeral joint • Key stabilizers

11. Static Articular anatomy Glenoid Labrum Negative Pressure Capsule Ligaments Dynamic Rotator cuff Biceps tendon Scapulothoracic motion Static/Dynamic restraints

12. Arthrology • Acromioclavicular joint • Incomplete intra-articular disc (arthritis) • AC ligaments provide A-P stability • CC ligaments provide sup-inf stability • Sternoclavicular joint • Complete intra-articular disc • Rotates 30 deg w/shoulder flexion

13. Arthrology • Scapulothoracic joint • 2:1 ratio of GH:ST motion • Coracoacromial ligament – superior-anterior restraint in rotator cuff deficient shoulder • Acromial branch of thoracoacromial artery runs on the medial aspect of the CA lig (caution during subacromial decompression)

14. Muscles • Greater tuberosity • Supraspinatus (ant) • Infraspinatus (mid) • Teres minor (post) • Lesser tuberosity • Subscapularis • IR stronger than ER • Posterior shoulder dislocations occur with seizures/electrical shock

15. Brachial Plexus • Ventral rami C5-T1 • Under clavicle between scalenus anterior and scalenus medius • Roots (5) / Trunks (3) / Divisions (6) / Cords (3) / Branches (“Ron Taylor Drinks Cold Beer”) • 4 preclavicular branches • Dorsal Scapular nerve • Long Thoracic nerve • Suprascapular nerve • Nerve to the subclavius

16. Brachial Plexus

17. Cord terminations • Lateral • Musculocutaneous • Posterior • Radial and axillary nerve • Medial • Ulnar nerve • Medial and Lateral • Median nerve

18. Brachial Plexus Palsies • Erb-Duchenne Palsy • Roots C5-6 • Deficit: Deltoid, RTC, elbow flexors, wrist/hand extensors (“Waiter’s tip”) • Klumpke Palsy • Roots C8-T1 • Deficit: Wrist flexors/intrinsic Horner’s syndrome • Total plexus • C5-T1 • Deficit: flaccid arm

19. Scapular winging • Scapular trapezius winging (lateral) • Injury to the spinal accessory nerve • Shoulder depression, scapular translation laterally • Inferior angle rotated laterally due to unopposed pull of serratus anterior • Serratus anterior scapular winging (medial) • Injury to the long thoracic nerve • Shoulder elevation, scapular translation medially • Inferior angle rotated medially

20. Axillary artery • 3 parts based on relationship to pec minor

21. Axillary artery • Part 1 • Supreme thoracic- medial • Part 2 • Thoracoacromial (four branches) • deltoid, acromial (SAD at CA lig), pectoral, clavicular • Lateral thoracic • Part 3 (Most vulnerable to traumatic injury) • Subscapular (2 branches) • Thoracodorsal • Circumflex scapular triangular space • Anterior humeral circumflex: main supply to humeral head • Posterior humeral circumflex – with axillary nerve in quadrangular space

22. Axillary Artery

23. Shoulder Approaches • Anterior approach • Deltopectoral (Interval: Axillary nerve and Med/Lat Pectoral nerves) • Axillary nerve along inferior border of subscap • Musculocutaneous nerve: 5-8cm below coracoid – terminal branch is lateral antebrachial cutaneous • Adduction/ER of arm protects axillary nerve • Lateral approach • Deltoid split • Axillary nerve is 5 cm below tip of acromion

24. Shoulder Approaches • Posterior approach • Between infraspinatus (suprascapular n.) and teres minor (axillary n.) • Quadrangular space • Axillary nerve, posterior humeral circumflex artery • Triangular space • Circumflex scapular artery • Triangular interval • Radial nerve, Profunda Brachii artery

25. Axillary nerve Post humeral circumflex artery Circumflex scapular artery Radial nerve Profunda Brachii artery

26. Elbow

27. Osteology • Spiral groove 13cm above articular surface of trochlea • Normal carrying angle of elbow • 7 degrees valgus • Maximal distension of capsule at 70-80 deg flexion

28. Coranoid attachments • Anterior bundle of MCL (18mm distal to tip) • Brachialis (11mm distal to tip) • Anterior capsule (6mm distal to tip) • Coranoid is intra-articular

29. Elbow ligaments • MCL • Anteroinferior portion of medial epicondyle to sublime tubercle • Anterior bundle: most important in resisting valgus force • **Valgus stability w/arm pronated = intact anterior bundle of MCL • LCL: most important is the LUCL • Deficiency = posterolateral rotatory instability • From lateral epicondyle to ulna crista supinatoris

30. Elbow Ligaments LATERAL MEDIAL

31. Nerves • Musculocutaneous – pierces CB 5-8cm below insertion, LABC • Radial – 21cm from medial epicondyle and 14cm from lateral • Found at the BR/ brachial interval • Dual innervation to brachialis (MC/radial) • Median – crosses lateral to medial over brachial artery, no branches in the arm • Ulnar- no branches to arm

32. Surgical Approaches • Anterolateral approach to humerus: splits brachialis • Dual innervation (Radial and MC) • Radial n. (Brachialis and BR interval) • Kocher approach • Ancones (radial n.) and ECU (PIN) • Pronate arm to protect PIN • 38mm in pronation / 22mm in supination

33. Elbow arthroscopy • Direct lateral portal • “soft spot” in triangle (joint insufflation) • Anterolateral portal • 2-3cm distal to lateral epicondyle and 1cm anteriorly • WATCH FOR RADIAL NERVE/PIN • Medial portal • 2cm distal and 2cm anterior to medial epicondyle • WATCH FOR MEDIAL ANTEBRACHIAL CUTANEOUS NERVE • Posterior portal • 3cm prox to tip of olecranon and 2cm lateral • Pohling portals • 2cm proximal and anterior to medial epicondyle (anterior to septum)

34. FOREARM

35. Osteology/Arthrology • Radius is convex laterally • Restoration of radial bow important in ORIF of shaft fractures • DRUJ most stable in supination • Volar wrist ligaments stronger than dorsal • Radial styloid and radial tuberosity are 180 deg rotated from one another

36. TFCC • TFCC • Dorsal and volar radioulnar ligaments • Articular disc • Meniscal homologue • UCL (ulnolunate/ulnotriquetral) • ECU

37. Radial nerve • Between BR and brachialis • Supplies BR, ECRL, ECRB (mobile wad) • PIN supplies the rest • Order of reinnervation • Supinator, ECU, EDC, EDM, APL, EPL, EPB, EIP last to return w/PIN palsy (most distally innervated) • Wartenberg’s syndrome – pain from radial sensory nerve entrapment at wrist • Superficial radial nerve: between BR & ECRL

38. PIN compression • Potential sites of PIN compression (FREAS) • Fibrous bands • Recurrent leash of Henry • ECRB (site of tennis elbow) • Arcade of Frohse (proximal edge supinator) • Supinator distal margin

39. Median nerve • Splits two heads of the pronator teres • Runs between FDS and FDP • Supplies PT, FCR, PL, FDS, thenars, FPB (supinator head), 1st and 2nd lumbrical

40. AIN • Runs between FPL and FDP • Supplies PQ, FPL and FDP to index and long

41. AIN compression • Potential sites of AIN Compression • Deep head of PT • FDS • Aberrant vessels • Gantzer’s muscle (accessory FPL)

42. Ulnar nerve • Cubital tunnel (ulnar groove, fascial arch, muscles of FCU) • Between FCU and FDP (supplies ulnar ½) • Distally at Guyon’s—more superficial • Supplies FCU, ulnar ½ of FDP, hypothenars, 3rd and 4th lumbrical, deep head of FPB

43. Ulnar nerve compression • Potential sites of ulnar nerve compression • Arcade of Struthers • band from medial head of triceps to medial IM septum8cm prox to med epicondyle • Medial IM septum • Medial epicondyle • Cubital tunnel • Proximal edge of FCU (Osborne’s fascia) • Deep flexor pronator aponeurosis

44. Cutaneous nerves • LABC – continuation of musculocutaneous nerve, lateral to bicep at elbow • MABC – arises from medial cord, crosses 6cm proximal to 4cm distal from medial epicondyle • PABC – arises from radial nerve, crosses from posterior to anterior compartment

45. Nerves splitting muscles • PIN splits supinator • Median nerve splits pronator teres • Ulnar nerve splits FCU

46. Nerve anastomoses • Martin-Gruber anastomosis • Between median and ulnar nerve in forearm • Riches-Cannieu anastomosis • Between ulnar and median nerve in the palm

47. Vessels • Radial artery • Splits at level of radial neck • Between BR and PT proximally and between BR and FCR distally • Ulnar artery • Between FDS and FDP proximally • On FDP between FDS and FCU distally

48. Forearm approaches • Henry (anterior) • BR (radial n.) and PT (median n.) proximally • BR and FCR (median n.) distally • Elevate PQ off radius • Thompson (dorsal) • ECRB (radial n.) and EDC (PIN) proximally • ECRB and EPL (PIN) distally • Excessive retraction of the supinator can injure PIN

49. Wrist and Hand

50. Osteology • Carpal bones • Ossification begins at capitate (1 year of age) and runs counterclockwise • Pisiform (9 years) **Last to ossify