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Anatomy > Hand & Wrist > Flashcards

Hand & Wrist Flashcards

1
Q

`Describe the blood supply to the scaphoid? What is the main supply?

A

Dorsal carpal branch of the radial artery is the main - supplies 80% Also: Superficial palmar branch of the radial artery

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2
Q

Which ligament is violated and must be repaired in the volar approach to the scaphoid?

A

Radioscaphocapitate ligament

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3
Q

Which ligament is the strongest ligament that resists perilunate dislocations in the wrist?

A

Long radiolunate ligament

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4
Q

What is the weakest point in the volar wrist?

A

Space of Poirier

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5
Q

What is the significance of the Space of Poirier?

A

It is the weakest point in the volar wrist and is where volar lunate dislocations occur most often.

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6
Q

Where is the Space of Poirier located?

A

Volar wrist at the junction of the Lunate and Trapezium/Trapezoid

Bordered by the Radiocapitate & Radiolunotriquetral ligaments (aka long radiolunate)

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7
Q

What “ligament” in the wrist is actually a neurovascular bundle?

A

Radioscapholunate ligament

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8
Q

What are the components of the radioscapholunate ligament?

A

Vascular branches of the anterior interosseous and radial arteries Nerve branches of the anterior interosseous nerve

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9
Q

Where is the radioscapholunate ligament found?

A

Between the long and short radiolunate ligaments, piercing the joint capsule

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10
Q

What are the components of the TFCC?

A

Triangular fibrocartilage disc (articular disc)

Meniscus homolog (disc-carpal ligaments)

Volar Ulnocarpal ligaments (ulnolunate & ulnotriquetral)

Dorsal and volar Radioulnar ligaments (palmar & dorsal, each with a superficial & deep component)

ECU subsheath

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11
Q

What is the ligament of Testut?

A

Radioscapholunate ligament. Actually a neurovascular bundle with no contribution to carpal stability

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12
Q

What are the contents of the anatomical snuffbox?

A

Radial artery Sensory branch of the radial nerve Wrist joint capsule Fat

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13
Q

What are the borders of the anatomical snuffbox?

A

Trianglr: Anterior: EPB, ABL Posterior: EPL (extensor compartments 1&3) Base: radial stylus process Floor: scaphoid & trapezium

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14
Q

What are the stabilizers of the DRUJ?

A

Extrinsic:

ECU tendon & Subsheath

Pronator quadratus

Interosseous membrane

Joint capsule

TFCC

Intrinsic:

Bony contact

Superficial radioulnar ligaments - origina at ulnar styloid

Deep radioulnar ligaments (ligamentum subcruentum) origin at fovea

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15
Q

What are the components of the scapholunate ligament?

A

Dorsal (strongest) Palmar Proximal (thin, membranous)

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16
Q

What is a lesser arc injury?

A

Purely ligamentous perilunate injury

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17
Q

What is a greater arc injury?

A

Fracture around the lunate - scaphoid, capitate, hamate, triquetrum

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18
Q

What are the extrinsic ligaments of the dorsal wrist?

A

Dorsal radiocarpal ligaments Dorsal intercarpal ligaments

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19
Q

What is Kienbock’s disease?

A

Avascular necrosis of the lunate.

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20
Q

Why do perilunate dislocations usually NOT end up in AVN?

A

Because it has a rich blood supply including: Dorsal and volar radial branches Branches of the dorsal and volar intercarpal arch Anterior interosseous artery

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21
Q

How many articulations does the scaphoid have?

A

5 Radius, capitate, lunate, trapezoid, trapezium

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22
Q

What is intersection syndrome?

A

Overuse condition affecting the second dorsal compartment - ECRL and ECRB

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23
Q

What is DeQuervain’s tenosynovitis?

A

Inflammation of the tenosynovium of the abductor pollicis longus and extensor pollicis brevis tendons

Affects 1st dorsal compartment

Diagnosed with Finklestein’s test - Increase in pain when the thumb is held in palm and wrist is ulnarly deviated - Pain is over the radial side of the wrist (1st dorsal compartment)

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24
Q

What is Wartenberg’s Syndrome

A

Radial neuritis - Neuritis of the superficial branch of the radial nerve - Inflammation due to stretch, compression or direct blow - Compression occurs between the brachioradialis and ECRL

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25
Q

Describe Eaton’s classification of the radiographic stages of thumb CMC OA

A

1: Normal
2: Joint spacer narrowing, osteophytes 2mm
3: Joint space narrowing, osteophytes >2mm
4: pantrapezial arthritis

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26
Q

What is the bony articulation of the distal radioulnar joint?

A

Sigmoid notch of the radius articulation with the ulna

i.e. “lesser” sigmoid notch

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27
Q

What are the stabilizers of the distal radio-ulnar joint (DRUJ)?

A
  • Bony integrity between sigmoid notch of the radius and ulna - Interosseous membrane - TFCC - Joint capsule - Pronator quadratus - Extensor carpi ulnaris
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28
Q

What are the muscular attachments of the proximal row of the carpal bones?

A

None

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29
Q

What carpal bones do not contribute to carpal motion?

A

Pisiform: it’s a sesamoid bone of the flexor carpi ulnaris

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30
Q

The Pisiform is a sesamoid bone for what tendon?

A

Flexor carpi ulnaris (FCU)

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31
Q

What are the contents of the carpal tunnel?

A

9 flexor tendons: - 4 for flexor digitorum superficialis - 4 for flexor digitorum profundus - Flexor pollicis longus Median nerve

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32
Q

What are the borders of the carpal tunnel?

A

Radially: scaphoid & Trapezium Ulnar: Pisiform & hamate Roof: flexor retinaculum/transverse carpal ligament Floor: proximal carpal row & radiocarpal ligaments

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33
Q

During carpal tunnel release, what nerve is most at risk when cutting the transverse carpal ligament? How do you avoid it?

A

Recurrent motor branch of the median nerve Avoid it by making your cut as ulnar as possible - Ulnar side of the 4th digit when flexed to the palm

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34
Q

What are the borders of Guyon’s Canal?

A

Roof: volar carpal ligament

Floor: Transverse carpal ligament & hypothenar uscles

Radial: Hook of hamate

Ulnar: Pisiform, pisohamate ligament, abductor digiti minimi muscle belly

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35
Q

How is Guyon’s Canal divided? What is the pathology of damaging each division?

A

3 zones:

Zone 1: proximal to the bifurcation of the ulnar nerve - Causes mixed motor and sensory symptoms

Zone 2: surrounds deep motor branch of the ulnar nerve - It is more radial - Causes only motor symptoms

Zone 3: Surrounds superficial sensory branch of the ulnar nerve - It is more ulnar - Causes only sensory symptoms

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36
Q

what is the major contributor to the superficial palmar arch?

A

Ulnar artery - Radial has minor contributions

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37
Q

What is the major contributor to the deep and superficial palmar arches?

A

Radial artery: deep

ulnar artery: superficial

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38
Q

What muscles attach to the scaphoid>?

A

None

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39
Q

How much of the scaphoid is covered in articular cartilage?

A

70%

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40
Q

name the intrinsic hand muscles of the thenar eminence and their function:

A

Abductor pollicis brevis - Abducts thumb at CMC & MCP Flexor pollicis brevis - Flexes thumb at CMC & MCP Opponens pollicis - Opposition of thumb

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41
Q

What is the innervation of flexor pollicis brevis?

A

Dual innervation - Superficial: median - Deep: ulnar

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42
Q

What are the intrinsic hand muscles of the hypothenar eminence and their actions?

A

Abductor digiti minimi brevis - Abducts 5th digit at MCP Flexor digiti minimi - Flexes 5th digit at MCP Opponens digiti minimi - Opposition of 5th digit

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43
Q

Name the intrinsic hand muscles of the hypothenar eminence and their nervous innervation

A

Abductor digiti minimi Flexor digiti mimini brevis Opponens digiti minimi - All innervated by ulnar nerve

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44
Q

Name the intrinsic muscles of the thenar eminence and their nervous innervation:

A

Abductor pollicis brevis - Median nerve Flexor pollicis brevis - Dual innevation - Superficial: median nerve - Deep: ulnar nerve Opponens pollicis - Median nerve

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45
Q

What are the muscles of the hand innervated by the median nerve?

A

LOAF - Lumbricals (radial 2 aka 1 & 2) - Opponens pollicis - Abductor pollicis brevis - Flexor pollicis brevis - note this has dual innervation - Superficial: median - Deep: ulnar

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46
Q

What is the only muscle to originate and insert onto a tendon? Which tendons does it originate and insert into?

A

Lumbricals - Originate from tendons of flexor digitorum profundus - Insert into extensor expansion on dorsal aspect of each digit’s radial side

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47
Q

What is the function of the dorsal and palmar interossei?

A

Dorsal: Abduct the fingers Palmar: Adduct the fingers - Remember DAB and PAD

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48
Q

What is the OINA of the palmar interossei?

A

O: They originate on the side facing the long finger

1st: ulnar side of 2nd MC
2nd: radial side of 4th MC
3rd: radial side of 5th MC

I: Extensor expansion of 2,4,5 digits

N: ulnar

A: adduction of 1,2,4,5th digits

nb: adduction/abduction is named relative to long finger

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49
Q

What is the OINA of the dorsal interossei?

A

O:

1st medial head: radial side of 2nd MC

1st lateral head: ulnar side of 1st MC

2nd, 3rd, 4th: space between the MC bones

I:

1st: radial sid of 2nd proximal phalanx
2nd: radial side of 3rd PP
3rd: ulnar side of 3rd PP

4th ulnar side of 4th PP

N: ulnar

A: ABduction of 2,3,5 fingers (away from midline)

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50
Q

What are the O, I, N, A of the lumbricals?

A

O: tendons of flexor digitorum profundus

I: extensor expansion on dorsal aspect of each digit’s radial side

N: 1/2: median, 3/4: ulnar

A: flexion of MCP of digist 2-5 - Extension of DIP & PIP of digits 2-5

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51
Q

What is the OINA of the palmaris brevis?

A

O: Flexor retinaculum I: Palmar surface of skin on ulnar side of hand N: Ulnar A: Wrinkles skin on ulnar side of hand

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52
Q

Describe the safe position of the hand. Why is it safe?

A

Intrinsic plus position: - Wrist extended 10 deg - MCP Flexion to 70 deg - IP extended It’s safe b/c with the MCPs in flexion, the collaterals are tight (at their longest) - So they will not get tight in a shortened position (short/lax in extension)

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53
Q

What are the components of the extensor hood?

A

Central tendon

Lateral Bands

Dorsal/palmar interossei

Lumbricals

Oblique retinacular ligaments

Sagittal bands

Works on both the MCP and IP joints

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54
Q

Describe the flexor zones of the hand?

A

1: Distal of FDS insertion (Jersey finger) 2: DIP to distal palmar crease (no man’s land) 3: Palm (Assoc w/ neurovasc injury) 4: Carpal tunnel (post-op adhesions) 5: Wrist to forearm: (Assoc w/ neurovasc injury) Thumb: Early ROM NOT better, like other fingers - T1, T2, T3

55
Q

Describe the pulley system of the fingers and thumb

A

Fingers:

5 annular pulleys: - A1, A3, A5 at MCP, PIP, DIP - A2, A4 at proximal and distal phalanx. These are most important in preventing bowstringing

3 cruciate pulleys - C1: at distal end of proximal phalanx - C2: at middle phalanx - C3: at distal end of middle phalanx

Thumb: A1 at MCP, A2 at IP Oblique between them at proximal phalanx

56
Q

Where does the superficial branch of the radial nerve emerge from at the wrist?

A

Beneath brachioradialis 7-9cm proximal to rad styloid tip

57
Q

What is the most common place for the palmar cutaneous branch of the median nerve to emerge? What is its location with respect to FCR and the carpal tunnel?

A

Ulnar to FCR - Travels outside the carpal tunnel, so not affected by CTS (you get sparing)

58
Q

Space of Parona - where is it?

A

space between pron quadratus and flextor tendons - continuous with carpal tunnel and palmar space

59
Q

Stener’s lesion

A

Ulnar collateral ligament tear with interposed adductor pollicis tendon - prevents healing so is an indiation for surgical repair

Normally, the UCL is deep to the adductor pollicis tendon

A Stener lesion is characterised by slippage of the torn end of the ulnar collateral ligament superficial to the adductor aponeurosis / adductor pollicis muscle

AKA the tendon/aponeurosis is now interposed between the ulnar collateral ligament and the MCP joint

This prevents healing and is an indication for surgical repair.

60
Q

Froment’s sign

A

Ulnar nerve injury

61
Q

Wartenberg’s sign

A

Ulnar nerve injury - Ulnar drift of small finger due to unopposed function of EDM (radial) with paralysis of palmar interossei (ulnar)

EDM attaches ulnarly so will have an ulnar/abduction moment, pulling small finger ulnarly

vs: Wartenburg’s syndrome: superficial radial nerve injury

62
Q

Why is a flexor tendon sheath infection a medical emergency?

A

B/c the most common anatomical variants have flexor sheaths 1 & 5 communicating with the wrist/carpal tunnel, so infection can easily propagate up the wrist

63
Q

What is the most common variation of the recurrent branch of the median nerve?

A

Extra ligamentous, distal to the carpal tunnel (46-95%)

64
Q

What is the last muscle innervated by the median nerve proper?

A

Second lumbrical

65
Q

Where does the dorsal branch of the ulnar nerve branch off?

A

5-12cm, average 9cm

66
Q

What nerves branch off the ulnar nerve proximal to the elbow?

A

Usually none, but if any, are just articular branches

67
Q

What is a Riche-Cannieu anastamosis?

A

Ulnar to median anastmosis in the hand. classically deep br of ulnar n to recurrent median.

i.e. ulnar n supplying thenar muscles

68
Q

Name the contents of the extensor compartments

A

1: ABL/EPB 2: ECRB/ECRL 3: EPL 4: EDC/EIP (PIN) 5: EDM 6: ECU

69
Q

Which is more distal, superficial or deep palmar arch?

A

Superficial - it is at the distal transverse palmar crease

70
Q

Where is the superficial and deep palmar arches?

A

Superficial: distal transverse palmar crease Deep: Kaplan’s cardinal line

71
Q

Describe the extensor zones of the hand and wrist

A

Odd numbers are at the joints:

I: DIP

III: PIP

V: MCP

VII: radiocarpal

IX: forarm muscle belly

72
Q

Name the contents of the extensor compartment of the wrist

A

I: APL/EPB

2: ECRB/ECRL
3: EPL
4: EDC/EIP (PIN)
5: EDM
6: ECU

73
Q

Name a syndrome or pathology for each extensor compartment of the wrist

A

1: De Quervain’s tenosynovitis
2: Intersection syndrome
3: Drummer’s wrist or traumatic rupture with DR #
4: Extensor tenosynovitis
5: Vaughn-Jackson’ syndrome (common in RA0
6: Snapping ECU

74
Q

Describe the flexor tenson injury zones:

A

Fingers:

1: FDP to FDS insertion
2: FDS to A1 pulley
3: A1 pulley to carpal tunnel
4: Carpal tunnel
5: Tendons of forearm flexors
6: Muscle bellies of forearm flexors

Thumb:

1: Distal to IP
2: IP to A1 pulley
3: thenar eminence
4: carpal tunnel
5: tendons of forearm flexors
6: muscle bellies of forearm flexors

75
Q

In what position is the radius shortest compared to the ulna (or the ulna longest compared to the radius)?

A

In pronation

THINK: supination is anatomic position so bones are uncrossed. In pronation, radius must cross over ulna, shortening it compared with the ulna

That’s why positive ulnar variance is mostly detected in pronation x-rays

76
Q

What ligaments are the main restraint to subluxation of the DRUJ in supination and pronation?

A

Supination:

Deep dorsal radioulnar ligament is the main restraint to dorsal subluxation of the radius

Pronation:

Deep volar radioulnar ligament is the main restraint to volar subluxation of the radius

77
Q

Name the 9 palmar and 5 dorsal intrinsic carpal ligaments

A

see picture

Palmar:

scapholunate

lunotriquetral

triquetrohamate

triquetrocapitate

capitohamate

capitotrapezoidal

trapeziotrapezoidal

scaphotrapeziotrapezoidal

scaphocapitate

Dorsal:

scapholunate

lunotriquetral

trapeziotrapezoidal

capitotrapezoidal

capitohamate

78
Q

What carpal bones do the following MC align with?

1st MC

2 MC

3 MC

4/5th MC

A

1st MC: Trapezium

2nd MC: Trapezoid

3rd MC: Capitate

4th/5th MC: Hamate

79
Q

Name the Volar extrensic Wrist ligaments (6)

A

Radioscaphocapitate

Radioscapholunate

Long radiolunate

Short radioluate

Ulnolunate

Ulnotriquetral

80
Q

What is the strongest wrist ligament?

A

Radioscaphocapitate

**Note that the long radiolunate is the primary restraint to perilunate dislocations but not the strongest volar wrist ligament

81
Q

What are the components of the scapholunate ligament?

A

Dorsal (strongest)

Palmar

Membranous (intraosseous, proximal)

82
Q

Name the extrinsic dorsal wrist ligaments

A

Dorsal radiocarpal

Dorsal intercarpal

These converge on the triquetrum and can be used in the Mayo ligament sparing approaach that Gammon uses

83
Q

What type of joints are the 1st - 5th CMC joints?

A

1st: saddle

2-4: plane/synovial

5th???

84
Q

What are the components of the deep flexor retinaculum of the wrist?

A

Starts as: antebrachial fascia

Becomes: Transverse carpal ligament

Becomes Thenar & Hypothnar aponeurosis/Deep palmar fascia

85
Q

What are the components of the superficial wrist retinaculum?

A

Carpal ligament and palmar ligament

86
Q

What are the contents of the Guyon’s canal?

A

Ulnar nerve

Ulnar artery

87
Q

Name the bands affected & not affected by Dupuytren’s Disease

A

Affected:

Pretendinous

Spiral

Natatory

Lateral

Grayson’s

Not Affected:

Trasnverse fibers

Cleland’s ligaments

(Some say only Cleland’s is not affected)

88
Q

What are the positions of Grayson’s and Clelands Ligaments with respect to each other

A

Grayson’s: (grip) are volar to the NV bundle

Cleland’s (ceiling) are dorsal to the NV bundle

89
Q

What are the variants of the flexor tendon sheath anatomy?

Why is this important?

A

Communication between 1st, 5th flexors (most common)

Communication between 1st, 2nd, 5th flexors

No communication between 1st and anywhere else

Can get horseshoe abscesses if there is communication between the 2st/5th digists

90
Q

Name the potential spaces in the hand (3) and forearm (1)

A

Hand:

Midpalmar space

Thenar space

Hypothenar space

Forearm:

Parona’s space

91
Q

Describe Parona’s Space

A

Potential space superficial to pronator quadratus

Contiguous with the midpalmar and thenar spaces (also potnetial spaces)

92
Q

Name the intrinsic hand muscles of the thenar eminence:

A

Abductor pollicis brevis

Flexor pollicis brevis

Opponens pollicis

Adductor pollicis

93
Q

Name the intrinsic hand muscles of the hypothenar eminence:

A

Abductor digiti minimi

Flexor digiti minimi

Opponens digiti minimi

94
Q

Name the OINA of Abductor Pollicis Brevis

A

O: Scaphoid tuberosity, trapezium ridge, TCL

I: Proximal 1st phalanx, lateral base

N: Median

F: ABduction of CMC & MCP of thumb

95
Q

Name the OINA of Flexor Pollicis Brevis

A

O:

  • Superficial Head: trapezium
  • Deep Head: trapezoid, capitate and palmar ligaments of distal carpal bones

I: Base of 1st proximal phalanx on radial side & extensor expansion

N:

Superficial: median

Deep: ulnar

F: CMC & MCP thumb flexion

96
Q

What is the innervation of flexor pollicis brevis?

A

Superficial head: median nerve

Deep head: ulnar nerve

97
Q

What is the OINA of opponens pollicis?

A

O: Trapezium & TCL

I: 1st MC shaft, radial side

N: median

A: Opposition

98
Q

Name the OINA for adductor pollicis

A

O:

Oblique head: capitate, base of 2/3 MC

Transverse head: proximal 2/3 of palmar surface of 3rd MC

I: base of 1st proximal phalanx, ulnar side

N: ulnar nerve

A: adduction of 1st CMC

99
Q

Name the OINA for abductor digiti minimi:

A

O: pisiform

I: base of 5th proximal phalanx, ulnar side

N: ulnar

A: Abduction of 5th MCP/digit

100
Q

Describe the OINA for flexor digiti minimi

A

O: hamate, TCL

I: Proximal 5th phalanx, ulnar side

N: ulnar

A: flexion of 5th digit/MCP

101
Q

Name the OINA for opponens digiti minimi

A

O: hook of hamate, TCL

I: 5th MC - entire ulnar border

N: ulnar

A: 5th MCP flexion and rotation of entire 5th digit

102
Q

What is a test you can do for ?Boutonniere’s Deformity

how do you do it?

A

Elson’s Test:

Tests for central slip rupture

Flex PIP to 90 deg over a table edge

get them to actively extend PIPJ

if they can, then central slip is intact

if they cannot, then central slip is disrupted - lateral bands sublux volar to axis of PIPJ and pull on extensor tendon will cause flexion instead

103
Q

Name the OINA of the lumbricals

A

O: Tendons of FDP

I: extensor expansion on dorsal aspect of each digitit’s radial side

N:

1,2: median

3,4: ulnar

A:

MCP flexion 2-5th digits

DIP & PIP extension of 2-5th digits

104
Q

How do the lumbricals exert their function?

A

They relax it’s own antagonist (FDP) when they are contracting

It originates from the FDP muscel tendon

When it is relaxed, and the FDP contracts, the IP joint flexes

When the lumbricals contract, it extends the IP joint by relaxation of the FDP tendon distal to the lumbrical origin and by proximal pull on the lateral band and dorsal aponeurosis

105
Q

Descirbe the pathoanatomy of a swan neck deformity

A

Lesion: Hyperextension of PIP + flexion of DIP

Primary lesion: Lax volar plate caused by:

  • Trauma
  • Generalized Laxity
  • RA

Secondary lesion: Imbalance of forces on PIP joint (PIP extension > PIP flexion). Causes:

  • Mallet finger: leads to transfer of DIP extension force into PIP extension forces
  • FDS rupture: eads to unopposed PIP extension combined with loss of integrity of the volar plate
  • Intrinsic contracture
  • MCPJ volar subluxation: in RA
106
Q

What is the intrinsic plus position?

What is the principle behind this position?

A

Safe position for immobilization of the hand

Wrist in 30deg extension

MCP 70deg flexion

IP neural

Princip;s”

Wrist in extension: optimal position for grip strength

MCP flexion: MCP collateral ligament at their longest in 90 deg flexion, but this is painful so only do 70 deg

PIP collateral ligaments: at same length throughout ROM but flexors arestronger than extensors and gaining PIP flexion is easier than gaining back extension

107
Q

What are the junctura tendinae?

A

Intertendinous connections

Transverse connections between EDC tendons

EIP & EDM not typically involved, therefore allowing for independent extension of D2 and D5

Passive stabilization of extensor tendon over MC head in full flexion (fist)

108
Q

What allows for independent motion of the index and small fingers (most of the time)?

A

Generally, no junctura tendinae between EIP and EDM so they get independent motion

109
Q

What are the components of the extensor hood?

A

Combination of:

EDC tendons –> central slip

DI and PI tendons & Lumbricals –> lateral bands

Oblique retinacular ligaments

Sagittal bands

Triangular ligament

110
Q

Describe the pathoanatomy of a Boutonniere Deformity:

A

Force causing hyperflexion at PIP joint

Central slip rupture –> more force going through terminal slip –> hyperextenio of DIP, Volar subluxation of alteral bands –> PIP hyperflexion

Triangular ligament rupture –> subluxation of lateral bands –> hyperflexion of PIP –> increased extension force through DIP

111
Q

What is Camper’s Chiasm?

A

Where FDP passes through the 2 slips of FDS located at the PIP joint

112
Q

Describe the blood supply to the flexor tendons

A

From Diffusion and Vascular supply from vincular system

  • Each tendon has a short and long vinculum
113
Q

What is the blood supply to the Lunate?

A

Dorsal plexus: from radial and anterior interosseous arteries

Volar plexus: from radial, ulnar, anterior interossoues, recurrent branches of deep palmar arch

3 different vascular patterns within lunate (see picture attached)

“I” has greatest risk of AVN

114
Q

Name the course of the radial artery

A

Arises from the bifurcation of the brachial artery in the cubital fossa

Runs distally on anterior forearm winding laterally around the wrist radial to FCR

Passes through the anatomical snuff box

Then between the heads of the first dorsal interosseous muscle

It passes anteriorly between the heads of the adductor pollicis & winds around 1st MC between heads of oblique and transverse opponens pollicis

Gives off major contributions fo deep palmar arch, which joins with deep branch of ulnar artery

115
Q

Name the course of the ulnar artery

A

From brachial artery

Arises just distal to cubital fossa (5-9cm)

Deep proximally: covered by the PT, FCR, FDS; It lies on Brachialis FDP

The median nerve is in relation with the medial side of the artery for about 2.5 cm. and then crosses the vessel, being separated from it by the ulnar head of the Pronator teres.

Distally in forearm, it sits on FDP being covered by the integument and the superficial and deep fasciæ, and sits between the FCU & FDS

Runs with 2 venæ comitantes

Covered in middle 1/3 by FCU

Ulnar nerve is ulnar in distal 2/3

Palmar cutaneous branch of the nerve descends on the lower part of the vessel to the palm of the hand.

Major contributions to superficial palmar arch

116
Q

Course of the Anterior interossoues artery

A

Comes down the forearm on palmar surface of the IoM

Accompanied by palmar interosseous branch of the median nerve & overlapped by FDP & FPL giving off muscular branches and nutrient vessels to radius/ulna

At the upper border of the pronator quadratus, it pierces the IoM, winding to dorsal forearm to anastomosewith the dorsal interosseous artery.

It then descends with the terminal part of the dorsal interosseous nerve to the dorsal wrist to join dorsal carpal network.

Before it pierces the interosseous membrane the anterior interosseous sends a branch downward behind the pronator quadratus muscle to join the palmar carpal network.

117
Q

Digital nerve: volar or dorsal in the finger?

A

Nerve becomes the most volar structure in the finger

It gives off dorsal branches to innervate dorsal skin starting at ~mid P2

118
Q

Name the anatomic variants of the Million Dollar Nerve

A

Recurrent Motor branch of the Median Nerve

Variants:

Extraligamentous: most common

Subligamentous: next

Transligamentous: Rarest

119
Q

Describe the course of the palmar cutaneous branch of the median nerve. What common surgery to you have to watch out for it

A

Arises from radial border of median nerve approximately 5 to 6 cm proximal to distal transverse flexion crease of the wrist;

  • it runs along the median nerve for 2 to 3 cm, and then runs along the ulnar border of the flexor carpi radialis tendon;
  • in some cases it may run along the ulnar side of the palmaris longus tendon;
  • when the tendon enters the flexor retinaculum comparment, the nerve passes between the two layers of the forearm fascia into the root of the palmar aponeurosis;
  • after 5-10 mm, the nerve divides into three terminal branches which cross the midpalmar aponeurosis to supply deep layers of dermis

Watch out for it during Carpal Tunnel Approach and with any incision ulnar to FCR

120
Q

Where can you find the dorsal cutaneous branch of the ulnar nerve?

A

emerges from under FCU and becomes subcutaneous 5cm proximal to pisiform

0.2-2cm proximal to the ulnar styloid at the subcutaneous border of the ulna

121
Q

What is the terminal branch of the ulnar nerve and what does it supply?

A

Deep branch of ulnar nerve

Supplies 1st dorsal interossei last

122
Q

describe path of superficial radial nerve at the level of the wrist/hand:

emerges where?

branches where?

A

emerges from under BR, 7-9cm proximal to radial styloid tip on dorsoradial aspect of wrist

branches out 5cm proximal to radial styloid tip into terminal branches

123
Q

dorsal extrinsic wrist ligaments: what and where?

A

dorsal intercarpal ligament: between scaphoid and triquetrum

dorsal radiocarpal ligament: between radius (ulnar side) and triquetrum

124
Q

lunotiquetral ligament: what part is strongest?

A

volar

125
Q

Name the compartments of the hand

(not wrist)

A

there are 10

Thenar compartment

Adductor pollicis

Hypothenar compartment - may have subcompartments

4x dorsal interossei compartments

3x palmar interossei compartments

126
Q

Describe the motion of the proximal carpal row with ulnar and radial deviation of the wrist

A

Radial deviation: Proximal row flexes (think scaphoid)

Ulnar deviation: proximal row extends

127
Q

What structure is at risk during trigger thumb release?

A

Radial digital nerve because of it’s oblique orientation overlying the A1 pulley

128
Q

What is the last muscle to be reinnervated after PIN injury? Bonus marks for full order of reinnervation.

A

Last to reinnervate: EIP

Order of reinnervation: Goes proximal to distal:

ECU, EDC, EDM, APL, EPL, EPB, EIP

129
Q

The ulnar nerve is (radial/ulnar) and (volar/dorsal) to the artery at the level of the wrist

A

Ulnar nerve is ulnar and dorsal to the artery at the level of the wrist

130
Q

What amount of wrist flexion and extension occur through the midcarpal joint?

A

70 degrees

131
Q

What is the main function of the midcarpal joint?

A

radial and ulnar deviation

132
Q

What is a Martin-Gruber Anastomosis?

A

median to ulnar n anastomosis in the forearm, somtimes AIN to ulnar.

i.e. median/AIN supplies muscles normally supplied by ulnar n, so with ulnar palsy can still have intrinsic hand function

133
Q

order of carpal bone ossification?

A

capitate, hamate, triquetrum, lunate, scaphoid, trapezium, trapezoid, pisiform

i.e. starting with capitate, go clockwise on right wrist dorsum, with pisiform at end

Anatomy (13 decks)

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