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Ortho Anatomy ft. MM > Elbow/Forearm > Flashcards

Elbow/Forearm Flashcards

1
Q

Claw Hand (What is the posture, what is the cause, and which muscles are causing imbalance?)

A

Clawing of the ulnar 2 digis

  • MCP Hyperextension: unopposed extensors with loss of lumbricals
  • IP Flexion: unopposed long flexors with loss of lumbricals

Only appears in low ulnar n. palsy, as high ulnar nerve palsy will knock out FDS as well.

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2
Q

Orientation of the Distal Humerus (sagittal, coronal, axial)

A
  • Sagittal: 30 degrees flexed/anterior tilt
  • Coronal: 6-8 degrees valgus
  • Axial: 5 degrees IR
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3
Q

Sites of Compression of the Ulnar N.

A
  1. Medial intramuscular septum
  2. Arcade of Struthers
  3. Medial Epicondyle (osteophytes)
  4. Cubital Tunnel: osbournes ligaments, anconeus epitrochlearis
  5. Arcuate Ligament (aponeurosis between FCU heads
  6. Ligament of Spinner (aponeurosis between FDS of D4 and Humeral arm of FCU)
  7. Deep flexory/pronator aponeurosis
  8. Guyon’s Canal (3 zones)
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4
Q

What is the plane and angle of the capitellum?

A

Sits 30 degrees extended. The center of the curve lies 60 f.rom the anterior humreral line

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5
Q

Boundaries & Contents of the Antecubital Fossa

A
  • Superior: Transepicondylar Line
  • Medial: Pronator Teres
  • Latera: Brachioradialis

Contents (lat to med):

  1. Biceceps Tendon
  2. Brachial A.
  3. Median N.
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6
Q

Force transmittance from wrist to elbow

A
  • Wrist: Radius (80%, Ulna 20%)
  • Elbow: Radius (60%, Ulna 40%)

Force is transmitted via the IOM

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7
Q

Providers of Elbow Valgus Stability

A
  • 20-120 Degrees- Anterior Bundle (not band) of MCL
  • <20 & >120 - intrinsic bony restraint
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8
Q

Radial Tunnel Syndrome

A
  • Lateral proximal forearm pain
  • 3-4cm distal to the lateral epicondyle
  • Extasturbated with elbow forearm pronation, elbow extension and wrist flexion
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9
Q

Pronator Syndrome

A

Compression neuropathy of the median n. at the elbow.

  • Will have weakness in AIN as well as median n. proper distribution
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10
Q

Cubital Tunnel Boundaries

A
  • Floor: MCL & joint capsule
  • Roof: Arcuate Ligament of Osbourne (aponeurosis between two heads of FCU
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11
Q

Safe Zone for Fixation in Radial Head

A

90 degree arc between radial styloid and lister’s tubercle. Essentially area that does not articulate with the sigmoid notch.

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12
Q

Medial Ligaments of the Elbow

A

MCL

  1. Anterior Bundle: medial epicondyle to sublime tubercle. Primary stabilizer against valgus force from 20-120 degrees of elbow ROM.
    • Anterior Band: opposes valgus stress in extension
    • Central Band: isometric
    • Posterior Band: opposes valgus stress in flexion
  2. Posterior Bundle: 2nd restraint in deep flexion
  3. Transverse Bundle: function unknown, does not cross elbow joint.
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13
Q

Baumann’s Angle

A

Angle between humeral shaft and lateral condyle physis.

  • Normal ~72 +/- 5 degrees
  • Only applicable in skeletally immature patients.
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14
Q

Sites of Compression of PIN

A
  1. Fibrous bands- anterior to radiocapitellar joint between brachialis and brachioradialis
  2. Recurrant vessles: Leash of Henry
  3. ECRB leading edge
  4. Arcade of Frosche- proximal end of supinator
  5. Supinator - distal edge
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15
Q

Bare Area of the Ulna

A

Non articular portion of the ulna, between olecranon articular facet and coracoid articular facet.

  • ~2cm distal to the triceps insertion
  • Between FCU and ECU
  • Spot you aim for when doing an olecranon osteotomy
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16
Q

Proximal Ulna Dorsal Angulation (PUDA)

A

~5.7 degrees, located ~47mm from the tip of the olecranon.

*Can compare to other side when doing a reconstruction

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17
Q

Axial Stabiliziers of the Elbow

A
  1. Radial Head
  2. IOM
  3. TFCC
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18
Q

Martin-Gruber Anastomosis

A

Most common nervous anastamosis in the upper extremity. Main trunk of median n. or AIN joins the ulnar n. and will innervate hand intrinsics in absense of ulnar innervation.

  • 20-25% of patients
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19
Q

Label the Diagram Below

A
  1. Ulna
  2. Anconeus
  3. ECU
  4. Supinator
  5. EDC
  6. ECRL
  7. Brachioradialis
  8. Radius
  9. Brachialis
  10. Pronator Teres
  11. FCR
  12. FDS
  13. FCU
  14. FDP
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20
Q

Tendon Transfers in High Median N. Palsies

A
  • Thumb IP Flexion: BR to FPL
  • Index & Long Finger Flexion: FDP of ring and small finger to FDP of first and middle (side to side)
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21
Q

Attachments in Proximity to the Coranoid

A
  • 6mm capsule
  • 12mm brachialis
  • 18mm MCL

*nothing inserts directly onto the coranoid

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22
Q

Whartonberg Syndrome

A

Cheiralgia Paresthetica: Superificial radial nerve comrpession. Pain over forearm. Tinels sign along superficial radial nerve.

  • Most common compression point is at brachioradialis
  • No motor loss
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23
Q

Muscles Innervated by PIN

A
  1. ECRL
  2. Extensor Pollicis Longus
  3. Extenstor Digitorum Communus
  4. Extensor Carpi Ulnaris
  5. Extensor Indicis
  6. Abductor Pollicis Longus
  7. Supinator
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24
Q

AIN Syndrome

A

Compression and Damage to the AIN. Causes pain in the forearm and weakness in AIN distribution (thumb flexion, wrist pronation and DIP flexion of the 1st and 2nd digits)

25
Q

Sites of Compression of the Median N.

A
  1. Supracondylar Process (Ligament of Struthers)
  2. Lacterus Fibrosis
  3. Pronator Teres
  4. Sublimus Bridge
26
Q

Tendon Transfers in Lower Median N. Palsy

A
  • Thumb Opposition and Abduction: FDS to base of proximal phalanx or APB tendon, use FCU as pulley
    • Bunnels Oppenensplasty**​
  • EIP to ABP Pulley
27
Q

PIN Syndrome

A

Motor Loss in PIN distribution without pain

  • Causes:
    • Benign tumors
    • Peri-elbow synovitis
    • Post-traumatic
    • Vasculitis
28
Q

Muscles Innervated by the Ulnar N.

A

Superficial:

  1. FCU
  2. FDP (ulnar 2 digits)

Deep:

  1. Abductor Digiti Minimi
  2. Flexor Digiti Minimi
  3. Opponens Digiti Minimi
  4. Adductor Pollicis
  5. 3rd and 4th lumbrical
  6. Palmar and Dorsal Interossei
  7. FPB (deep head)
29
Q

Whartonberg’s Sign

A

Cannot abduct 5th digit. Sign of ulnar neuropathy.

30
Q

Course of the Musculocuntaneous Nerve

A
  1. Pierces conjoint tendon (coracobrachialis) 5-8 cm distal from coracoid
  2. Runs between biceps and brachialis
  3. Terminates as LABCN
31
Q

Tendon Transfers for Ulnar N. Palsy

A
  • Thumb Adduction: FDS or ECRB to Add. Pollicis
  • Finger Abduction: APL, ECRL, EIP to 1st dorsal interossei
  • Reverse Claw: FDS, ECRL (pass volar to the transverse metacarpal ligament) to lateral bands of ulnar digits
32
Q

Anconeus Epitrochlearis

A

Anomalous muscle from medial olecranong to medial epicondyle.

*Clinically a site of compression of the ulnar n.

33
Q

Ulnar Paradox

A

High ulnar n. lesion can cuse a more normal looking hand, despite being worse pathologically. Takes out FDS causing less IP joint flexion posturing.

34
Q

Position of Immobilization for MCL & LCL Injury

A
  • MCL - supination
  • LCL - pronation

*thumb points towards the uninjured side

35
Q

Course of the AIN

A
  1. Branches from median n. at pronator teres
  2. Passess between two heads of PT
  3. Runs on volar aspect of IOM
36
Q

Explain the Stages of the Hori Cycle

A

Circle of disruption around the elbow. Begins on the lateral side of the elbow & progresses to the medial side in three stages:

  1. Stage 1 (PLRI)Lateral collateral ligament is partially or completely disrupted
    • Rupture of LUCL
    • Results in posterolateral rotatory subluxation of the elbow which can reduce spontaneously (see below)
      1. Stage 2 (perched ulna)
  • Additional disruption anterior & posterior capsule
  • Incomplete posterolateral dislocation with subluxation/ dislocation of radial head & the medial edge of ulna resting on the trochlear (AP film) & coranoid perched on the trochlear (lateral film)
  • Dislocation reduced with minimal force
  1. Stage 3 (dislocated)
  • Elbow dislocates & coranoid lies posterior to trochlear
  • 3A - AMCL intact
    • All soft tissue sleeve including posterior part of medial collateral ligament disrupted (anterior medial collateral ligament intact)
    • Elbow pivots on intact AMCL
    • Reduction performed by recreating deformity with supination & valgus stress, followed by application of traction, varus stress, & pronation simultaneously
    • often seen with radial head and coronoid fracture
    • AMCL provides stability if forearm remains pronated
  • 3B - no ligaments
    • Entire MCL (including AMCL) disrupted
    • Varus, valgus & rotatory instability all present following reduction
    • Immobilise in cast 90 flexion
    • Need to be flexed > 30 - 40o to be stable
  • 3C - no ligaments, no flex/pronator mass
    • Soft tissues stripped off entire distal humerus (including the flexor-pronator & common extensor origins)
    • Grossly unstable even in flexion (need to flex > 90)
37
Q

Anatomic Bowing of the Radius

A
  • Coronal Plane:
    • ~10mm, apex radial
    • Max radial bow located at around 60% from proximal end (measured from radial tuberosity)
    • Max radial bow is usisally located in the middle 1/3 of the radial shaft and around 7% of total radial length.
  • Sagittal:
    • 4.7 degrees apxex dorsal, proximal radial shaft
38
Q

Course of the Radial Nerve

A
  1. Posterior Cord
  2. Triangleular Interal
  3. Runs in posterior compartment, in spiral groove entering 14cm proximal to the medial epicondyle on the medial side, and exiting 10cm proximal to the lateral epicondyle
  4. Peirces the lateral intramuscular septum and travels anteriorly
  5. Branches at supinator, deep branch goes on as PIN
  6. Superficial branch goes on as superficial radial nerve deep to brachioradialis.
39
Q

Course of the Ulnar Nerve

A
  1. Medial Cord
  2. Travesl emdial to brachial a. in anterior compartment
  3. Dives into the posterior compartment through medial intramuscular septum 8-10 cm proximal to medial epicondyle
  4. Enters the cubital tunnel
  5. Travels between two heads of FCU
  6. Travels in the arm, radial to the ulnar A., between FCU and FDS, ontop of FDP
  7. To the wrist via guyon’s canal
40
Q

Muscles Innervated by AIN

A
  1. Pronator Quadratus
  2. Flexor Pollicis Longus
  3. Flexor Digitorum Profundus (Radial 2 Heads)
41
Q

Order of Elbow Ossificiation

A

CRITOE

  1. Capitellum: 1 year
  2. Radial Head: 3 years
  3. Internal (Medial) Epicondyle: 5 years
  4. Trochlea: 7 years
  5. Olecranon: 9 years
  6. External (Lateral) Epicondyle: 11 years
42
Q

Lateral Ligaments of the Elbow (Name, Origin & Insertion)

A
  1. Annular Ligament: Around sigmoid notch and radial head
  2. Lateral Radial Collateral Ligament (LRCL): distal lateral epicondyle to annular ligament
  3. Lateral Ulnar Collateral Ligament (LUCL): distal lateral epicondyle to crestor supinatorae.
    • Deficient in PLRI
    • Usually tears proximally
  4. Acessory Lateral Collateral Ligament: from annular ligament to crestor supinatorae
43
Q

Elbow Stabilizers: Primary & Secondary

A
  • Primary
    • Ulnohumeral Articulation
    • MCL
    • LCL
  • Secondary
    • Radial Head
    • Capsule
    • Common Flexor and Extensor Origins
44
Q

Tendon Transfers for Radial N. and PIN Palsies

A
  • Elbow Extension: Deltoid, Lat Dorsi, Biceps to Triceps
  • Wrist Extension: PT to ECRB
  • Finger Extension: FDS, FCR, FCU to EDC
  • Thumb Extension: PL or FDS to EPL
45
Q

Fromet’s Sign

A

Sign of weakness of ulnar n. intrisic muscles

Patient is asked to adduct thumb- by gripping a peice of paper between their first webspace. In a positive test, the patient has no adductor pollicis function so will hyperflex their IP joint to compensate

46
Q

Sites of Compression of AIN

A
  1. Pronator Teres
  2. FDS
  3. Aberrant Vessels
  4. Gantzer’s Acessory FPL
47
Q

Course of the Axillary Nerve

A
  1. Comes off posterior cords
  2. Through quadrangular space
  3. Wraps around humeral head ~5cm distal to the tip of the acromion
  4. Innervates deltoid and teres minor
  5. Terminates as SLBCN
48
Q

Branches of the Ulnar A.

A
  1. Common Interosseus
  2. Posterir Interossesus
  3. Anterior Interosseus- travels with AIN
49
Q

Components of the Introsseus Memebrane of the Forearm

A

Proximal Membranous Portion:

  • Dorsal Oblique Accessory Cord
  • Proximal Oblique Cord

Middle Ligamentous Portion:

  • Central band
  • Acessory Band

Distal Membranous Portion:

  • Distal Oblique Band
50
Q

Superficial Veins of the Arm

A
  1. Cephalic (lateral)
  2. Basilic (medial)

Each give off a branch at the proximal forearm which join together to form the medial interbrachial v.

51
Q

Course of the Median Nerve

A
  1. Medial and lateral cords
  2. Lateral to brachial a. along medial intramuscular septum, crosses medial to brachial a. at the cubital fossa.
  3. Travels under bicipital aponeurosis
  4. Travels between FDS and FDP and then into the carpal tunnel
52
Q

O’Driscoll Classification of Coranoid Fractures

A
  1. Tip
  • 1A: Tip <2mm of height
  • 1B: Tip >2mm of height
  1. Anteromedial Facet
  • 2A Anteromedial Rim
  • 2B Atneriomedial Rim & Tip
  • 2C Anteromedial Rim & Sublime tubercle
  1. Basal
  • 3A Coranoid Base
  • 3B Transolecranon with Basal Coranoid #
53
Q

Muscles Innervated by Median N.

A

Forearm Flexors:

  1. Pronator Teres
  2. Flexor Carpi Radialis
  3. Palmaris Longus
  4. Flexor Digitorum Superficialis

Hand

  1. Thenar Muscles (Recurrent Branch)
    • Opponens Pollicis
    • Flexor Pollicis Brevis
    • Abductor Pollicis Brevis
  2. 1st and 2nd lumbricles
54
Q

Muscles Innervated by Radial Nerve

A
  1. Brachioradialis
  2. ECRB
  3. Anconeus
  4. Triceps
  5. Brachialis (along with musculocutaenous n.)
55
Q

How much of the trochlear arch is covered in cartilage?

A

300 Degrees

56
Q

Carrying Angle of the Elbow

A
  • Men 10-15 degrees valgus
  • Women 15-20 degrees valgus
57
Q

Components of the Annular Ligament

A
  1. Superior Oblique Band
  2. Inferior Oblique Band
  3. Annular Ligament Band itsefl

Attachments: Anterior and posterior portion of the sigmoid notch of the proximal radius.

58
Q

Column Theroy of the Elbow

A

Models the distal humerus after a spool (articular surface), being held by two columns (medial and lateral)

  • Medial: 45 degrees
  • Lateral: 20 degrees

*mesured from a line bisecting the humeral shaft on AP

59
Q

Where is the Medial Antebrachial Cutaneous Nerve found?

A
  • 3.5cm distal to the medial epicondyle
    • posterior branch is 1.5cm distal to the medial epicondyle

Ortho Anatomy ft. MM (10 decks)

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