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# ULNAR NERVE - COMPLETE PLASTIC SURGERY RESIDENT GUIDE
## References: Campbell's Operative Orthopaedics 15th Ed 2026 | Gray's Anatomy for Students | Current Surgical Therapy 14e | Adams & Victor's Neurology 12th Ed

---

# SECTION 1: ANATOMY OF THE ULNAR NERVE

## Origin and Root Value
- Root value: **C8, T1** (medial cord of brachial plexus)
- Largest branch of medial cord
- Contains both motor and sensory fibers

## Course - ARM
1. Enters arm medial to axillary artery, alongside median nerve
2. Passes medial to brachial artery in proximal arm
3. Pierces **medial intermuscular septum** at midarm level → enters posterior compartment
4. Lies anterior to medial head of triceps brachii
5. Passes **posterior to medial epicondyle** in the **cubital tunnel** (osseofibrous tunnel)
6. **NO branches in the arm**

## Cubital Tunnel Anatomy (KEY)
- Floor: medial collateral ligament + elbow joint capsule
- Roof: arcuate ligament of Osborne (Osborne's band) = aponeurosis between humeral and ulnar heads of FCU
- Contents: ulnar nerve only
- During elbow flexion: tunnel volume decreases by 55%, intraneural pressure increases dramatically
- Nerve is tethered proximally by medial intermuscular septum and distally by FCU aponeurosis

## Course - FOREARM
- Enters forearm between humeral and ulnar heads of **flexor carpi ulnaris (FCU)**
- Lies in plane between FCU (medial) and FDP (lateral)
- Ulnar artery joins nerve at distal one-third of forearm and lies LATERAL to nerve
- Enters hand superficial to flexor retinaculum, lateral to pisiform

### Branches in Forearm:
1. **Muscular branches**: FCU + medial half of FDP (ring and little finger FDP)
   - Arise soon after entering forearm
2. **Palmar cutaneous branch**: arises mid-forearm → supplies skin medial palm
3. **Dorsal cutaneous branch**: arises ~5 cm above wrist, passes deep to FCU tendon posteriorly → supplies:
   - Posteromedial dorsum of hand
   - Dorsal aspect of little finger (entirely)
   - Dorsal ulnar half of ring finger
   - Dorsal ulnar half of middle finger (variable)

## Guyon's Canal (Ulnar Tunnel)
- **Boundaries**:
  - Medial wall: pisiform bone + pisohamate ligament (hypothenar eminence)
  - Lateral wall: hook of hamate
  - Floor: flexor retinaculum
  - Roof: palmar carpal ligament (superficial part of flexor retinaculum)
- **Contents**: Ulnar nerve + ulnar artery (artery is lateral)
- **Zones of Guyon's canal** (Gross & Gelberman classification):
  - Zone I: proximal to bifurcation → Mixed (motor + sensory deficits)
  - Zone II: surrounds deep branch → Motor deficit only
  - Zone III: around superficial branch → Sensory deficit only

### Deep Branch of Ulnar Nerve (Motor):
- Curves around hook of hamate (key anatomical landmark)
- Lies deep to pisohamate ligament
- Innervates ALL hypothenar muscles, ALL interossei, medial 2 lumbricals, adductor pollicis, deep head of FPB
- Key: supplies ALL intrinsic muscles of hand EXCEPT thenar muscles (APB, OP, superficial FPB - median) and lateral 2 lumbricals (median)

### Superficial Branch (Sensory):
- Supplies: palmar surface of little finger and ulnar half of ring finger

## Muscles Supplied by Ulnar Nerve (Complete List)
| Level | Muscle | Function |
|-------|---------|----------|
| Forearm | Flexor Carpi Ulnaris (FCU) | Wrist flexion + ulnar deviation |
| Forearm | FDP - ring and little | Distal phalanx flexion |
| Hand | Abductor digiti minimi | Little finger abduction |
| Hand | Flexor digiti minimi brevis | Little finger MCP flexion |
| Hand | Opponens digiti minimi | Little finger opposition |
| Hand | Palmaris brevis | Skin wrinkling over hypothenar |
| Hand | All 4 dorsal interossei | Abduction of fingers (DAB) |
| Hand | All 3 palmar interossei | Adduction of fingers (PAD) |
| Hand | Medial 2 lumbricals (ring, little) | MCP flexion + IP extension |
| Hand | Adductor pollicis | Thumb adduction |
| Hand | Flexor pollicis brevis (deep head) | Thumb MCP flexion |

---

# SECTION 2: ULNAR NERVE COMPRESSION SYNDROMES

## A. CUBITAL TUNNEL SYNDROME

### Epidemiology
- Second most common upper limb compression neuropathy (after carpal tunnel)
- Prevalence: 1.8-5.9% in USA
- More common in males

### Etiology / Causes
- **Repeated elbow flexion** (most common)
- Cubitus valgus deformity (tardy ulnar nerve palsy - delayed palsy after old lateral condyle fracture)
- Medial epicondyle fractures
- Anconeus epitrochlearis muscle (anomalous)
- Hypertrophic medial head of triceps
- Direct pressure / occupational
- Ganglia, lipoma, bony spurs
- Cubital tunnel retinaculum laxity → subluxation of nerve

### McGowan Classification:
- Grade I: Mild - intermittent numbness/tingling, no muscle wasting
- Grade II: Moderate - persistent sensory changes, weakness
- Grade III: Severe - muscle wasting, fixed sensory loss

### Clinical Features
**Symptoms:**
- Tingling/numbness in little finger and ulnar half of ring finger
- Worse with elbow flexion
- Medial elbow pain
- Weakness of grip and pinch

**Signs:**
- **Froment's sign**: Flexion of IPJ of thumb on strong pinch (FPL compensating for weak adductor pollicis)
- **Wartenberg's sign**: Persistent abduction of little finger (extensor digiti minimi unopposed)
- **Clawing**: Ring and little fingers (more prominent in LOW lesion - Ulnar Paradox)
- Hypothenar wasting
- Interosseous wasting (first dorsal interosseous most visible)
- Loss of sensation: little finger + ulnar half of ring finger
- Tinel's sign positive at cubital tunnel

### Ulnar Paradox:
- HIGH ulnar nerve lesion (above elbow): FDP to ring/little also paralyzed → LESS clawing (no FDP pull)
- LOW ulnar nerve lesion (at wrist): FDP intact → MORE clawing of ring and little fingers
- **Therefore: more claw = lower lesion paradoxically**

### Investigations
- **EMG/NCS**: Slowed conduction velocity across elbow (<50 m/s diagnostic), denervation potentials in hand intrinsics
- X-ray: Cubitus valgus, bony spurs, elbow arthritis

### Treatment

#### Conservative (Mild-Moderate):
- Avoid prolonged elbow flexion
- Elbow extension night splint (splint with elbow near extension; NOT pronated - worsens symptoms)
- Activity modification

#### Surgical Options:
1. **Simple decompression** (in situ decompression): Release of Osborne's ligament + fascia of FCU
   - Open or endoscopic
   - Indications: Mild-moderate without subluxation
   
2. **Medial epicondylectomy**: Partial removal of medial epicondyle
   - Reduces nerve tension through elbow arc
   - Risk: medial instability

3. **Anterior transposition** (gold standard for recurrence/subluxation):
   - **Subcutaneous**: Nerve placed anterior to medial epicondyle in subcutaneous plane, held by fasciodermal flap
   - **Intramuscular**: Nerve placed within flexor-pronator mass
   - **Submuscular (Learmonth)**: Nerve placed deep to flexor-pronator mass - best decompression, but technically demanding, longer rehab
   - Indication: Subluxating nerve, recurrent symptoms, severe cases

### Endoscopic Decompression Technique (Campbell's):
1. 2-3 cm incision posterior to medial epicondyle
2. Elevate adipose tissue off fascia proximally and distally
3. Identify nerve by palpation posterior to medial epicondyle
4. Incise roof of cubital tunnel (Osborne's band)
5. Confirm no anconeus epitrochlearis; if present, incise over canal
6. Insert cannula, advance proximally between nerve and roof
7. Use scope to visualize nerve throughout cannula length
8. Divide fascia with blade along superior slot of cannula
9. Repeat distally
10. Deflate tourniquet, confirm release, close with subcuticular sutures
11. Infiltrate 0.5% bupivacaine + epinephrine

**Post-op**: Gentle ROM, full ROM expected within 5-7 days

---

## B. GUYON'S CANAL SYNDROME (Ulnar Tunnel Syndrome)

### Etiology:
- Ganglia (most common - 30-40%)
- Hook of hamate fracture
- Hypothenar hammer syndrome (occupational - repetitive trauma to ulnar artery)
- Anomalous muscles
- Lipoma
- Ulnar artery thrombosis/aneurysm (true fusiform or false saccular aneurysm)

### Clinical Features:
- Tingling/numbness in little and ring fingers (Zone I, III)
- Weakness in hand, poor grip, weak pinch (Zone I, II)
- Difficulty opening/closing fingers (later)
- Note: **Dorsum of hand sensation PRESERVED** (dorsal cutaneous branch leaves proximal to canal)

### Treatment:
- Find and remove cause (ganglia excision, hamate hook excision)
- For ulnar artery aneurysm/thrombosis: segmental resection + vein graft replacement
- Recovery of intrinsic muscles: 3-12 months after surgery

---

# SECTION 3: ULNAR NERVE PALSY - FUNCTIONAL DEFICITS AND RECONSTRUCTION

## Functional Deficits - LOW Ulnar Nerve Palsy (at wrist):
1. **Claw deformity** (ring + little fingers) - prominent due to intact FDP
2. Loss of intrinsic function → loss of MCP flexion, IP extension of ring/little
3. Loss of power pinch (adductor pollicis paralyzed)
4. Weak grip (50% reduction)
5. Loss of abduction/adduction of fingers
6. Hypothenar wasting
7. **Froment's sign positive**
8. **Wartenberg's sign** (little finger abduction)

## Additional Deficits in HIGH Ulnar Nerve Palsy (above elbow):
- Loss of FDP to ring and little fingers (weakened grip)
- Loss of FCU (wrist deviates radially with flexion)
- Less claw deformity (Ulnar Paradox)

---

# SECTION 4: SURGICAL RECONSTRUCTION OF ULNAR NERVE PALSY

## PRINCIPLES OF TENDON TRANSFER:
1. Adequate passive range of motion before surgery
2. Donor muscle must be expendable
3. Donor must have sufficient strength (MRC Grade 4+)
4. Straight line of pull preferred
5. One tendon = one function
6. Adequate soft tissue coverage
7. Patient compliance for rehabilitation

---

## A. RESTORATION OF INTRINSIC FUNCTION (Anti-Claw Procedures)

### Static Procedures (Block MCP hyperextension):
- **Zancolli Lasso procedure**: FDS slip looped around A1 pulley → blocks MCP hyperextension
  - Indications: When no suitable motors available or combined with dynamic transfer
  - Advantage: Simple, reliable
  
- **Volar plate advancement** (capsulodesis): Advancement of volar plate of MCP to block hyperextension

### Dynamic Procedures (Restore active intrinsic function):

#### 1. STILES-BUNNELL Transfer (Classic):
- Motor: Flexor digitorum sublimis (FDS) of middle finger
- Route: Through lumbrical canals (volar to deep transverse metacarpal ligament)
- Insertion: Lateral bands of extensor aponeurosis (radial side)
- Achieves: MCP flexion + IP extension
- Disadvantage: Swan neck risk if not carefully tensioned; FDS deficit

#### 2. FOWLER Transfer (EIP Transfer - Fig. 76.20):
- Motor: Extensor indicis proprius (EIP)
- Route: Dorsal to volar → through intermetacarpal space
- Insertion: Lateral bands (radial side) of ring and little fingers
- Advantage: Preserves FDS function

#### 3. RIORDAN Modification (FCR Transfer - Fig. 76.21):
- Motor: Flexor carpi radialis (FCR)
- Route: Free tendon graft extended, passed through carpal tunnel + lumbrical canals
- Note: Risk of carpal tunnel crowding and median nerve compression

#### 4. BRAND Transfer (ECRB):
- Motor: Extensor carpi radialis brevis (ECRB) or longus (ECRL)
- Extended with: 4-tailed free graft
- Route: Volar to forearm → through carpal tunnel and lumbrical canals
- Insertion: Radial lateral band of extensor aponeurosis of each finger
- For severe clawing with wrist flexion (Fig. 76.22-76.24)

#### 5. BURKHALTER Transfer:
- Motor: Brachioradialis or ECRL extended by free grafts
- Route: Dorsally → through intermetacarpal area, volar to transverse metacarpal ligament
- Insertion: Directly into BONE of proximal phalanx diaphysis
- Advantage: Greater lever arm; more secure attachment

#### 6. OMER Procedure (One-stage for LOW ulnar palsy):
- Arthrodese MCP of thumb
- Split FDS ring finger into 2 slips:
  - Slip 1: Across palm parallel to adductor pollicis → thumb adduction
  - Slip 2: Split into 2 tails → through lumbrical canals → radial extensor aponeurosis of ring and little fingers
- Plus: Brachioradialis (prolonged with free graft) through 3rd interosseous space → adductor pollicis insertion

---

## B. RESTORATION OF THUMB ADDUCTION (Adductor Pollicis Paralysis)

### Available Motors:
1. **FDS of ring finger** (deep to finger flexors, across palm) - Brown's transfer
2. **Extensor indicis proprius** (around 3rd metacarpal, transversely across palm, parallels adductor) - Brown
3. **Brachioradialis** (prolonged with free graft through 3rd interosseous space) - Burkhalter/Omer
4. If MCP joint unstable: **Arthrodesis of thumb MCP joint** (increases pinch power)
5. **FPL advancement** (if IP joint hyperextension also present): Advance A1 pulley proximally, advance FPL

### Key Point:
- Transfer must parallel fibers of adductor pollicis (transverse pull across palm)
- Attachment at MCP joint area of thumb

---

## C. HIGH ULNAR NERVE PALSY - Additional Reconstructions

### Additional to above (for high lesion):
1. **FDP restoration**: Side-to-side suture of ring/little FDP to middle FDP (FDP of middle = median nerve, unaffected)
2. **FCU replacement**: Usually not reconstructed separately as other wrist flexors compensate

---

## D. COMBINED LOW MEDIAN AND ULNAR NERVE PALSY (at wrist):

### Deficits:
- Loss of all intrinsic muscles
- Loss of thenar muscles (APB, OP, FPB superficial)
- Complete loss of opposition and intrinsics
- Clawing all fingers (but variable)

### Reconstruction:
- Use brachioradialis, ECRL, ECRB (all radial nerve supplied), extensor tendons
- Priority: Opposition restoration + anti-claw

---

## E. NERVE TRANSFER FOR ULNAR NERVE PALSY

### Principle:
- Sacrifice expendable fascicle of functioning nerve to reinnervate distal target
- Advantage over tendon transfer: Restores native muscle function, no donor deficit from tendon
- Disadvantage: Requires nerve regeneration time (1mm/day or 1 inch/month)
- Best results when reinnervation occurs before muscle fibrosis (within 12-18 months)

### Common Nerve Transfers for Ulnar Nerve Palsy:

#### 1. AIN to Deep Motor Branch Transfer (Oberlin-type / Distal nerve transfer):
- **Donor**: Anterior Interosseous Nerve (AIN) - branch of median nerve - supplies FPL and pronator quadratus
- Terminal motor branch of AIN transferred to ulnar nerve motor branch (deep branch)
- At wrist/distal forearm level
- Indication: High ulnar nerve injury with intact median nerve
- Advantage: Short regeneration distance to hand intrinsics
- Donor morbidity: Sacrifice of PQ (mild - pronation still functional via PT)

#### 2. Median Nerve Fascicle Transfer (OBERLIN Transfer - for motor):
- Originally described for biceps reinnervation in brachial plexus
- Adapted: Motor fascicle of median nerve (to FCU or FDP) → deep branch of ulnar nerve
- Requirement: Median nerve function must be intact (CRITICAL)

#### 3. Supinator Branch to AIN Transfer:
- For combined median-ulnar high injuries (less commonly needed for ulnar alone)

#### 4. Triceps Branch to Axillary Nerve (analogous concept for brachial plexus)

### Key Principle from Current Surgical Therapy 14e:
- "At the level of the middle or proximal third of the arm, a functioning ulnar nerve fascicle is used" for certain transfers
- Nerve transfers are preferred when nerve repair gap is too large, or when injury level means regeneration distance to targets is too long for tendon transfer alone

---

## F. MUSCLE TRANSFER FOR ULNAR NERVE PALSY

### Indications:
- When no suitable tendon transfer donors available
- Severe combined nerve palsies
- Long-standing palsy with muscle fibrosis
- Failed tendon transfers

### Options:
1. **Gracilis free muscle transfer**:
   - Donor muscle: Gracilis (thigh, medial compartment)
   - Neurovascular pedicle: Anterior branch of obturator nerve + medial circumflex femoral artery
   - Used for intrinsic replacement in severe palsy
   - Anastomose vessels to radial or ulnar vessels; coaptate nerve to AIN or motor branch

2. **Pectoralis minor** (rarely used)

3. **Extensor digitorum brevis** (EDB) - free muscle transfer:
   - Used in spastic/paralytic hand reconstruction

### Steps of Free Muscle Transfer (Gracilis):
1. Identify and harvest gracilis with obturator nerve and MFCA pedicle
2. In hand: Identify recipient vessels (radial/ulnar artery and vein)
3. Attach gracilis origin to appropriate proximal structure
4. Weave tendons through appropriate pulleys
5. Microvascular anastomosis
6. Neurorrhaphy to appropriate motor nerve
7. Set tension appropriately

---

# SECTION 5: FLOWCHARTS

## FLOWCHART 1: APPROACH TO CUBITAL TUNNEL SYNDROME

```
Patient with elbow medial pain + ulnar paresthesia
              ↓
Clinical Assessment (McGowan Grade)
              ↓
        ┌─────┴──────┐
    Grade I-II      Grade III
    (Conservative)  (Surgery)
        ↓               ↓
  Night splint      EMG/NCS confirm
  Activity mod.     + Image (X-ray/MRI)
        ↓               ↓
  Reassess 3 months  ┌──┴──────────────┐
        ↓            No subluxation   Subluxation/
  Failure?           ↓                Recurrent
    ↓Yes            Simple            ↓
   Surgery          Decompression     Anterior
                    (open/endoscopic) Transposition
                                     (Subcutaneous/
                                      Intramuscular/
                                      Submuscular)
```

## FLOWCHART 2: APPROACH TO ULNAR NERVE PALSY RECONSTRUCTION

```
Ulnar Nerve Palsy Confirmed
              ↓
   Is nerve repairable/graftable?
       ↓YES              ↓NO (or long gap)
  Repair/Graft       Consider Nerve Transfer
  (primary if <6wks)  (AIN → deep ulnar motor branch)
       ↓
  Wait for reinnervation (1yr)
       ↓
  No recovery? → Tendon/Muscle Transfer
              ↓
   LEVEL OF LESION?
   ┌──────────────────────────────────┐
   LOW (wrist)              HIGH (above elbow)
   ↓                                 ↓
  Intact FDP              Lost FDP ring+little
  More clawing            Less clawing
       ↓                           ↓
  Anti-claw + Adductor    Side-to-side FDP suture
  Pollicis restoration    + Anti-claw + Adductor
       ↓
  Anti-Claw Options:
  Static: Zancolli lasso / Capsulodesis
  Dynamic: Stiles-Bunnell / Fowler / Brand /
           Burkhalter / Riordan / Omer
       ↓
  Adductor Pollicis:
  FDS ring / EIP / Brachioradialis
```

## FLOWCHART 3: GUYON'S CANAL SYNDROME APPROACH

```
Ulnar symptoms at wrist (sensory/motor)
              ↓
Check: dorsal hand sensation preserved? (YES = below Guyon's)
              ↓
Locate Zone (I/II/III) by clinical examination
              ↓
     MRI / Ultrasound wrist
              ↓
  ┌──────────────────────────┐
Ganglion (most common)   Hook of Hamate Fx
     ↓                         ↓
 Excision                Hamate Hook Excision
              ↓
         Ulnar Artery lesion?
              ↓
   Vein graft reconstruction
```

---

# SECTION 6: CRISP POINTS TO REMEMBER

## Anatomy:
1. Root: C8, T1 | Medial cord of brachial plexus
2. NO branch in arm
3. Passes POSTERIOR to medial epicondyle (not anterior)
4. Osborne's ligament = arcuate ligament = roof of cubital tunnel
5. Dorsal cutaneous branch leaves ~5 cm ABOVE wrist → preserved in Guyon's canal syndrome
6. In Guyon's canal: nerve MEDIAL, artery LATERAL (opposite to most other sites)
7. FDP: BOTH lateral AND medial half → median + ulnar dual innervation
8. Adductor pollicis = PURE ulnar nerve (no dual innervation)
9. All interossei = ulnar nerve (DAB = Dorsal Abduct, PAD = Palmar Adduct)
10. 2 medial lumbricals = ulnar; 2 lateral lumbricals = median

## Clinical:
11. Froment's sign = pathognomonic of adductor pollicis weakness
12. Wartenberg's sign = persistent little finger abduction (EDM unopposed)
13. Ulnar paradox: MORE claw = LOWER lesion
14. First DIO wasting = most visible sign of intrinsic wasting
15. Cubital tunnel: worst with elbow flexion (volume decreases 55%)
16. Check DORSAL hand sensation to distinguish cubital tunnel vs Guyon's canal

## Surgery:
17. Submuscular transposition (Learmonth) = most effective but most complex
18. Zancolli lasso = static anti-claw; easiest and most reliable
19. Stiles-Bunnell = dynamic intrinsic replacement; uses FDS middle finger
20. Brand transfer = ECRB/ECRL with 4-tailed free graft
21. Fowler = EIP transfer (preserves FDS)
22. For adductor pollicis: transfer must parallel adductor fibers (transverse in palm)
23. FDS ring finger = most commonly used motor for combined adduction + intrinsic restoration
24. High palsy: Side-to-side FDP suture to middle FDP (median innervated)
25. Nerve transfer: AIN → deep motor branch of ulnar = best option for high ulnar injury
26. Free gracilis = option when no tendon transfer motors available

---

# SECTION 7: VIVA QUESTIONS AND HOW TO ANSWER

## Q1: What is the root value of the ulnar nerve?
**Answer:** "The ulnar nerve arises from the medial cord of the brachial plexus with root values C8 and T1. It is the largest terminal branch of the medial cord."

## Q2: Name the structures forming the cubital tunnel.
**Answer:** "The cubital tunnel is an osseofibrous tunnel at the elbow. The floor is formed by the medial collateral ligament and elbow joint capsule. The roof is formed by Osborne's ligament, also called the arcuate ligament, which is the aponeurosis stretching between the humeral and ulnar heads of flexor carpi ulnaris. The medial epicondyle forms the medial wall."

## Q3: What is Froment's sign? What does it indicate?
**Answer:** "Froment's sign is elicited by asking the patient to hold a piece of paper between the thumb and index finger. When the examiner pulls the paper, the patient with adductor pollicis weakness will flex the interphalangeal joint of the thumb - this is because the flexor pollicis longus, which is supplied by the anterior interosseous nerve (median), compensates for the weak adductor pollicis. A positive Froment's sign indicates weakness of the adductor pollicis, which is supplied by the deep branch of the ulnar nerve."

## Q4: What is the Ulnar Paradox?
**Answer:** "The ulnar paradox refers to the observation that a HIGH ulnar nerve lesion produces LESS claw deformity than a LOW lesion, which is counterintuitive since the high lesion is more severe. This is because in a high lesion, the FDP to ring and little fingers is also paralyzed - so there is no flexor force acting on the DIP and PIP joints to produce clawing. In a low lesion, FDP is intact and creates the flexion deformity at IP joints, with the paralyzed intrinsics unable to extend them."

## Q5: What are the zones of Guyon's canal?
**Answer:** "Guyon's canal is divided into three zones based on the Gross and Gelberman classification. Zone I is proximal to the bifurcation of the ulnar nerve, and a lesion here causes BOTH motor and sensory deficits. Zone II surrounds the deep motor branch, so a lesion causes MOTOR deficit only. Zone III surrounds the superficial sensory branch, causing SENSORY deficit only. An important clinical point is that in all three zones, the dorsal hand sensation is preserved because the dorsal cutaneous branch of the ulnar nerve arises about 5 cm proximal to the wrist, well above the canal."

## Q6: What is Wartenberg's syndrome/sign?
**Answer:** "Wartenberg's sign is the persistent abduction of the little finger seen in ulnar nerve palsy. It occurs because the extensor digiti minimi, which is supplied by the radial nerve, acts unopposed in the absence of the third palmar interosseous muscle - the normal adductor of the little finger. Wartenberg's SYNDROME is a separate entity involving entrapment of the superficial sensory branch of the radial nerve."

## Q7: Describe the Stiles-Bunnell tendon transfer.
**Answer:** "The Stiles-Bunnell transfer is a dynamic procedure to restore intrinsic function of the fingers in ulnar nerve palsy. The motor used is the flexor digitorum sublimis of the middle finger. The FDS is divided at its insertion and split into the required number of slips. Each slip is passed through the lumbrical canal, which is the space volar to the deep transverse metacarpal ligament, and attached to the radial lateral band of the extensor aponeurosis of the ring and little fingers. This recreates the action of the intrinsic muscles - flexion at the metacarpophalangeal joint and extension at the interphalangeal joints. A drawback is the risk of swan neck deformity if tension is excessive."

## Q8: What is the Fowler transfer?
**Answer:** "The Fowler transfer uses the extensor indicis proprius as the motor to restore intrinsic function. The EIP tendon is passed from dorsal to volar through the intermetacarpal space and then through the lumbrical canals, with attachment to the lateral bands of the extensor aponeurosis. The advantage over the Stiles-Bunnell transfer is that it preserves FDS function."

## Q9: What nerve transfer is used for high ulnar nerve palsy?
**Answer:** "For high ulnar nerve palsy, the most commonly used nerve transfer is the anterior interosseous nerve to the deep motor branch of the ulnar nerve - sometimes called a distal Oberlin-type transfer. The AIN is the terminal motor branch of the median nerve, supplying the flexor pollicis longus and pronator quadratus. At the distal forearm or wrist level, the AIN is divided and coapted to the deep motor branch of the ulnar nerve within or just distal to Guyon's canal. This allows reinnervation of the intrinsic muscles of the hand over a short distance. The donor morbidity is minimal as pronation is still provided by the pronator teres. The key advantage is the short regeneration distance compared to repair at the level of injury."

## Q10: What are the principles of tendon transfer?
**Answer:** "There are several fundamental principles for a successful tendon transfer. First, the hand must have adequate passive range of motion before surgery - contractures must be corrected first. Second, the donor muscle must be expendable - its loss should not create significant functional deficit. Third, the donor must have adequate strength, typically grade 4 or above on the MRC scale. Fourth, the line of pull should be as straight as possible toward the target. Fifth, one tendon should perform one function. Sixth, there must be adequate soft tissue cover. Finally, patient compliance and ability to participate in rehabilitation is essential."

## Q11: What are the surgical options for cubital tunnel syndrome?
**Answer:** "Surgical options include: First, simple decompression - either open or endoscopic - releasing all constricting tissue including Osborne's ligament and the fascia of FCU. This is preferred for mild to moderate cases without subluxation. Second, medial epicondylectomy, which reduces nerve tension through the arc of elbow motion. Third, anterior transposition of the ulnar nerve - this can be subcutaneous, intramuscular, or submuscular. Subcutaneous transposition places the nerve anterior to the epicondyle in subcutaneous tissue held by a fasciodermal flap. Submuscular transposition, the Learmonth procedure, places the nerve deep to the flexor-pronator mass - this provides the best mechanical decompression but is technically more demanding."

## Q12: What is the difference between low and high ulnar nerve palsy?
**Answer:** "Low ulnar nerve palsy is a lesion at the wrist or in Guyon's canal. Deficits include: clawing of ring and little fingers - which is PROMINENT because FDP is intact, loss of all intrinsic muscles, hypothenar wasting, Froment's and Wartenberg's signs, and sensory loss limited to the palmar aspect of little finger and ring finger. Dorsal hand sensation is PRESERVED. High ulnar nerve palsy is at or above the elbow. In addition to all the above, there is: loss of FDP to ring and little fingers causing weak DIP flexion, loss of FCU causing radial deviation of wrist on flexion, and paradoxically LESS clawing due to FDP paralysis. The dorsal cutaneous branch is also affected so dorsal hand sensation is LOST."

---

# SECTION 8: THEORY PAPER WRITING GUIDE

## For Theory Paper: "Ulnar Nerve Anatomy, Compression, and Reconstruction"

### Recommended Structure:
1. **Introduction** (2-3 lines): Root value, origin, clinical importance
2. **Anatomy** with subheadings:
   - Course in arm (mention cubital tunnel)
   - Course in forearm + branches
   - Guyon's canal anatomy + zones
   - Motor supply (table format)
   - Sensory supply (diagram)
3. **Compression Syndromes**:
   - Cubital tunnel: Definition, etiology, classification (McGowan), features, treatment (algorithm)
   - Guyon's canal: Zones, etiology, features, treatment
4. **Ulnar Nerve Palsy**:
   - Low vs High (comparison table)
   - Ulnar paradox
   - Functional deficits
5. **Reconstruction**:
   - Static anti-claw: Zancolli
   - Dynamic anti-claw: Stiles-Bunnell, Fowler, Brand, Burkhalter, Omer (table)
   - Thumb adduction restoration
   - Nerve transfer (AIN to deep branch)
   - Muscle transfer (Gracilis free flap)
6. **Conclusion**: Individualize treatment based on level of lesion and available motors

### Diagrams to Draw in Theory Paper:
1. **Brachial plexus with ulnar nerve origin** (simplified - show medial cord → ulnar nerve C8T1)
2. **Cross-section of cubital tunnel** (label: floor = MCL, roof = Osborne's ligament, nerve)
3. **Guyon's canal anatomy** (zones I, II, III with boundaries and what each affects)
4. **Sensory map of ulnar nerve** (hand dorsum and palm - what areas are supplied)
5. **Froment's sign diagram** (thumb IP flexion during pinch)
6. **Intrinsic muscle anatomy** (interossei and lumbricals - origin, insertion, action)
7. **Stiles-Bunnell transfer** (schematic of FDS → lumbrical canal → lateral band)
8. **Zancolli lasso** (FDS looped around A1 pulley)
9. **Algorithm/flowchart** for treatment of cubital tunnel syndrome
10. **High vs Low ulnar palsy comparison table**

### Key Tables to Include:
| Feature | Low Palsy (Wrist) | High Palsy (Elbow) |
|---------|-------------------|---------------------|
| FDP ring/little | Normal | Paralyzed |
| FCU | Normal | Paralyzed |
| Clawing | Prominent | Less prominent |
| Dorsal sensation | Normal | Abnormal |
| FDP for reconstruction | Available | Unavailable |

---

# SECTION 9: IMPORTANT NAMED PROCEDURES - QUICK REFERENCE

| Procedure | Motor Used | Purpose | Key Feature |
|-----------|-----------|---------|-------------|
| Stiles-Bunnell | FDS middle | Anti-claw (intrinsic) | Classic; swan neck risk |
| Fowler | EIP | Anti-claw (intrinsic) | Preserves FDS |
| Brand | ECRB/ECRL + graft | Anti-claw (intrinsic) | 4-tailed graft; for severe claw |
| Burkhalter | BR or ECRL | Anti-claw | Bony insertion in phalanx |
| Riordan | FCR | Anti-claw | Crowds carpal tunnel |
| Zancolli Lasso | FDS slip | Anti-claw (STATIC) | Simplest; loop around A1 pulley |
| Omer | FDS ring (split) | Anti-claw + adduction | One-stage combined |
| Brown | FDS ring / EIP | Thumb adduction | Transverse palm route |
| Learmonth | - | Submuscular transposition | Best decompression for cubital tunnel |
| AIN to deep branch | Nerve transfer | Reinnervation of intrinsics | Best for high ulnar palsy |
| Gracilis free transfer | Gracilis muscle | Intrinsic replacement | Last resort; microsurgery |

---

*References: Campbell's Operative Orthopaedics 15th Ed 2026 (Chapters 76, 77, 82); Gray's Anatomy for Students (Chapter 7); Current Surgical Therapy 14e (Chapter on Muscle and Tendon Transfer); Adams and Victor's Principles of Neurology 12th Ed (Ulnar Nerve chapter)*

*Note: Neligan's Plastic Surgery (latest edition) was not available in the digital library at the time of preparation. The content above is drawn from equivalent authoritative surgical texts. For Neligan-specific content, refer to Volume 6 (Hand and Upper Limb) Chapters on Nerve Injuries, Compression Neuropathies, and Tendon Transfers.*

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<header>
  <h1>🫱 Ulnar Nerve – Visual Reference Collection</h1>
  <p>Compiled for Plastic Surgery Residents | Sources: Campbell's Operative Orthopaedics 15th Ed 2026 · Gray's Anatomy for Students · Current Surgical Therapy 14e</p>
</header>

<div class="toc">
  <h2>Contents</h2>
  <a href="#anatomy">1. Anatomy</a>
  <a href="#clinical">2. Clinical Signs</a>
  <a href="#compression">3. Compression / Guyon's Canal</a>
  <a href="#intrinsic">4. Intrinsic Replacement Transfers</a>
  <a href="#thumb">5. Thumb Adduction / Pinch Restoration</a>
  <a href="#operative">6. Operative Techniques – Step Detail</a>
  <a href="#nerve">7. Nerve Repair / Graft Principles</a>
</div>

<!-- ===== SECTION 1: ANATOMY ===== -->
<section id="anatomy">
  <div class="section-header">
    <span>1. ANATOMY OF THE ULNAR NERVE IN THE HAND</span>
    <span class="badge">Gray's Anatomy for Students</span>
  </div>
  <div class="section-body">
    <div class="img-grid">

      <div class="img-card wide">
        <img src="https://cdn.orris.care/cdss_images/e7c9b70673af9abed57cbaae89e07b72c8215a47e1c8fd9f33c9a65f1f1ecec6.png" alt="Ulnar Nerve in the Right Hand">
        <div class="caption">
          <div class="fig-label">Fig. 7.113 · Gray's Anatomy for Students</div>
          <div class="fig-title">Ulnar Nerve in the Right Hand – Palmar dissection showing bifurcation into deep and superficial branches lateral to pisiform. Insets show sensory distribution on palmar (green = superficial branch area) and dorsal views (orange = dorsal cutaneous branch area).</div>
          <div class="key-point">🔑 Key: Ulnar nerve enters hand <strong>superficial to flexor retinaculum</strong>, lateral to pisiform. Deep branch curves around hook of hamate → supplies ALL intrinsics. Artery is lateral to nerve at this level.</div>
          <div class="source">Source: Gray's Anatomy for Students, Block 4, line 3464</div>
        </div>
      </div>

    </div>
  </div>
</section>

<!-- ===== SECTION 2: CLINICAL SIGNS ===== -->
<section id="clinical">
  <div class="section-header">
    <span>2. CLINICAL SIGNS OF ULNAR NERVE PALSY</span>
    <span class="badge">Gray's Anatomy for Students</span>
  </div>
  <div class="section-body">
    <div class="img-grid">

      <div class="img-card">
        <img src="https://cdn.orris.care/cdss_images/75c67e95c67ce2eeb0eaf2140dde4be8615727eb4391b64e2cd7029501e7bb99.png" alt="Claw Hand – Ulnar Nerve Palsy">
        <div class="caption">
          <div class="fig-label">Fig. 7.114 · Gray's Anatomy for Students</div>
          <div class="fig-title">Typical "Clawed Hand" appearance due to ulnar nerve lesion. Ring and little fingers show MCP hyperextension with IP flexion due to loss of intrinsic muscles. Index and middle fingers less affected as their lumbricals are median-innervated.</div>
          <div class="key-point">🔑 Ulnar Paradox: LOW lesion (wrist) = MORE claw (FDP intact). HIGH lesion (elbow) = LESS claw (FDP also paralyzed).</div>
          <div class="source">Source: Gray's Anatomy for Students, Block 4, line 3485</div>
        </div>
      </div>

    </div>
    <div class="divider"></div>
    <h3 style="color:#0f3460; margin-bottom:12px; font-size:0.95rem;">ALLEN TEST – Ulnar Artery Patency (Guyon's Canal Assessment)</h3>
    <div class="img-grid">
      <div class="img-card wide">
        <img src="https://cdn.orris.care/cdss_images/daac2d602dd0f8601015c0e461bdf83009242163584132bd7179eb299b1c9ea4.png" alt="Allen Test">
        <div class="caption">
          <div class="fig-label">Figure 75.1 · Campbell's Operative Orthopaedics 15th Ed</div>
          <div class="fig-title">Allen Test for patency of radial and ulnar arteries. (A) Patient elevates hand and makes fist while examiner occludes both arteries. (B) Patient extends fingers – blanching seen. (C) Radial artery alone released – normal colour returns. (D) Ulnar artery thrombosis – hand remains blanched when ulnar released alone. Positive Allen test = occluded ulnar artery.</div>
          <div class="key-point">🔑 Positive Allen test = Guyon's canal / hypothenar hammer syndrome. Important pre-op assessment for all wrist nerve compressions.</div>
          <div class="source">Source: Campbell's Operative Orthopaedics 15th Ed, Block 39, line 634</div>
        </div>
      </div>
    </div>
  </div>
</section>

<!-- ===== SECTION 3: COMPRESSION ===== -->
<section id="compression">
  <div class="section-header">
    <span>3. COMPRESSION SYNDROMES – CUBITAL TUNNEL &amp; GUYON'S CANAL</span>
    <span class="badge">Campbell's Operative Orthopaedics 15th Ed</span>
  </div>
  <div class="section-body">
    <div style="background:#e8f4fd; border-radius:8px; padding:16px; margin-bottom:24px; font-size:0.9rem; color:#0d47a1;">
      <strong>McGowan Classification:</strong> Grade I = Mild (intermittent paresthesia, no wasting) | Grade II = Moderate (persistent sensory change + measurable weakness) | Grade III = Severe (persistent paresthesia + measurable weakness + wasting)<br><br>
      <strong>Cubital Tunnel Anatomy:</strong> Floor = Medial collateral ligament + joint capsule. Roof = Osborne's ligament (arcuate ligament). During elbow flexion → tunnel volume ↓55%, intraneural pressure ↑ dramatically. Nerve tethered by medial intermuscular septum proximally + FCU aponeurosis distally.
    </div>
    <div style="background:#fce4ec; border-radius:8px; padding:16px; margin-bottom:24px; font-size:0.9rem; color:#880e4f;">
      <strong>Guyon's Canal Zones (Gross &amp; Gelberman):</strong><br>
      Zone I (proximal to bifurcation) → Mixed motor + sensory deficit<br>
      Zone II (around deep motor branch) → Motor deficit ONLY<br>
      Zone III (around superficial sensory branch) → Sensory deficit ONLY<br>
      <em>All zones: Dorsal hand sensation PRESERVED (dorsal cutaneous branch leaves ~5cm above wrist)</em>
    </div>
  </div>
</section>

<!-- ===== SECTION 4: INTRINSIC REPLACEMENT ===== -->
<section id="intrinsic">
  <div class="section-header">
    <span>4. INTRINSIC REPLACEMENT – TENDON TRANSFER TECHNIQUES</span>
    <span class="badge">Campbell's Operative Orthopaedics 15th Ed · Ch. 76</span>
  </div>
  <div class="section-body">

    <div class="img-grid">

      <!-- Bunnell modification -->
      <div class="img-card tall">
        <img src="https://cdn.orris.care/cdss_images/29594d9d058f89616cef674600ec50d3fd6bf87389b3324074db53b52faf8a37.png" alt="Stiles-Bunnell Transfer">
        <div class="caption">
          <div class="fig-label">Figure 76.18 · Campbell's – STILES-BUNNELL TRANSFER (Modification)</div>
          <div class="fig-title">Bunnell modification to restore intrinsic function. FDS of middle finger divided, passed through lumbrical canals (volar to deep transverse metacarpal ligament), attached to lateral bands of extensor aponeurosis. Shows 4-tailed graft pattern fanning out to all fingers.</div>
          <div class="key-point">🔑 All dynamic anti-claw transfers MUST pass volar to deep transverse metacarpal ligament to mimic intrinsic action. If passed dorsal – only clawing worsens.</div>
          <div class="source">Source: Campbell's Operative Orthopaedics 15th Ed, Block 39, line 3566</div>
        </div>
      </div>

      <!-- Fowler Transfer – Fig 76.20 -->
      <div class="img-card tall">
        <img src="https://cdn.orris.care/cdss_images/a15dd2aba7485b9f602e71f9f37831440c83328e06254b17e6add6ca72d94cbb.png" alt="Fowler Transfer EIP">
        <div class="caption">
          <div class="fig-label">Figure 76.20 · Campbell's – FOWLER TRANSFER (EIP)</div>
          <div class="fig-title">Fowler transfer using Extensor Indicis Proprius (EIP) and Extensor Digiti V Proprius to restore intrinsic function. EIP tendon routed volar to deep transverse metacarpal ligament, attached to radial lateral band of ring and little fingers. Palmaris longus / plantaris graft extends to index and middle.</div>
          <div class="key-point">🔑 Fowler transfer advantage: Preserves FDS function (no swan neck risk from FDS sacrifice). EIP is expendable – index extension maintained by EDC.</div>
          <div class="source">Source: Campbell's Operative Orthopaedics 15th Ed, Block 39, line 3582</div>
        </div>
      </div>

      <!-- Riordan Transfer – Fig 76.21 -->
      <div class="img-card tall">
        <img src="https://cdn.orris.care/cdss_images/2bd4658dc4efa0ec0e0d959ca7b4dfa9ddb80b735ffc9f3f74f8b15cc97c27f2.png" alt="Riordan Modification">
        <div class="caption">
          <div class="fig-label">Figure 76.21 · Campbell's – RIORDAN MODIFICATION</div>
          <div class="fig-title">Riordan modification of Fowler/Bunnell transfer. Palmaris longus extended with free graft from plantaris. EIP tendon split and rerouted to ring and little fingers. Shows the characteristic 4-finger fan pattern through lumbrical canals with final attachment to radial lateral bands.</div>
          <div class="key-point">🔑 Riordan uses Palmaris longus as motor (if present) extended by free graft. Alternative to FCR which crowds carpal tunnel. Excellent for all-4-finger intrinsic replacement.</div>
          <div class="source">Source: Campbell's Operative Orthopaedics 15th Ed, Block 39, line 3587</div>
        </div>
      </div>

      <!-- Operative detail: threading through interosseous space -->
      <div class="img-card tall">
        <img src="https://cdn.orris.care/cdss_images/4211407298f02535921930698da3094523453c4e88c64c4176d30f763d68c898.png" alt="Threading graft volar to transverse metacarpal ligament">
        <div class="caption">
          <div class="fig-label">Figure 76.19 · Campbell's – OPERATIVE TECHNIQUE: Graft routing</div>
          <div class="fig-title">Critical operative step: Clamp threading free graft through interosseous space, volar to transverse metacarpal ligament (top panel). Lower panel shows graft tacked to side of extensor mechanism at lateral band level. This is the universal routing for ALL intrinsic replacement transfers.</div>
          <div class="key-point">🔑 MUST pass volar to transverse metacarpal ligament. Passing dorsal to it mimics extrinsics not intrinsics and fails to correct claw.</div>
          <div class="source">Source: Campbell's Operative Orthopaedics 15th Ed, Block 39, line 3571</div>
        </div>
      </div>

    </div>
  </div>
</section>

<!-- ===== SECTION 5: THUMB ADDUCTION ===== -->
<section id="thumb">
  <div class="section-header">
    <span>5. THUMB ADDUCTION / PINCH RESTORATION</span>
    <span class="badge">Campbell's Operative Orthopaedics 15th Ed · Ch. 76</span>
  </div>
  <div class="section-body">
    <div class="img-grid">

      <!-- Modified Royle-Thompson – adductor restoration -->
      <div class="img-card tall">
        <img src="https://cdn.orris.care/cdss_images/6fa91bf3ce4122659771af71136e5dd5251af8f378b46f67c7431cf5e7f8fa14.png" alt="Modified Royle-Thompson Transfer – Thumb Adduction">
        <div class="caption">
          <div class="fig-label">Figure 76.15 · Campbell's – MODIFIED ROYLE-THOMPSON TRANSFER</div>
          <div class="fig-title">Tendon transfer to restore thumb adduction (adductor pollicis paralysis in ulnar nerve palsy). Shows FDS ring finger looped around 3rd metacarpal and attached to adductor pollicis insertion at MCP joint of thumb. Red arrow shows direction of adduction force. Dashed lines show thumb excursion range after transfer.</div>
          <div class="key-point">🔑 Thumb adduction transfer must parallel fibers of adductor pollicis (transverse pull across palm). Options: FDS ring / EIP around 3rd metacarpal / Brachioradialis with free graft. Froment's sign corrects after successful transfer.</div>
          <div class="source">Source: Campbell's Operative Orthopaedics 15th Ed, Block 39, line 3275</div>
        </div>
      </div>

    </div>
  </div>
</section>

<!-- ===== SECTION 6: OPERATIVE TECHNIQUES ===== -->
<section id="operative">
  <div class="section-header">
    <span>6. OPERATIVE TECHNIQUES – ZANCOLLI LASSO &amp; INTRINSIC PROCEDURES</span>
    <span class="badge">Campbell's Operative Orthopaedics 15th Ed · Ch. 76</span>
  </div>
  <div class="section-body">
    <div style="background:#e8f5e9; border-radius:8px; padding:16px; margin-bottom:20px; font-size:0.9rem; color:#1b5e20;">
      <strong>Zancolli Lasso (Static Anti-Claw):</strong> FDS slip looped around A1 pulley → blocks MCP hyperextension without restoring active intrinsic function. Simplest, most reliable procedure when no suitable motors for dynamic transfer exist. Combined with dynamic transfers when needed.
    </div>
    <div class="img-grid">

      <!-- Zancolli operative steps A-E -->
      <div class="img-card">
        <img src="https://cdn.orris.care/cdss_images/dfcadc7b507eefe2aa71ecc89fbe45bf95bb6e262269cdc2bfaf1fe936f91f25.png" alt="Zancolli Lasso A">
        <div class="caption">
          <div class="fig-label">Figure 76.29A · Campbell's – ZANCOLLI LASSO (Planning)</div>
          <div class="fig-title">Schematic showing planned route of FDS slips through lumbrical canals of ring and little fingers for Zancolli-type lasso procedure. Shows the fan-like branching pattern from wrist to individual finger lumbrical canals.</div>
          <div class="source">Source: Campbell's Operative Orthopaedics 15th Ed, Block 39, line 3824</div>
        </div>
      </div>

      <div class="img-card">
        <img src="https://cdn.orris.care/cdss_images/687a0e486f6d6bbee8c0d9350131f25100a1c4aadb4e74639730de41a072e67d.png" alt="Zancolli Lasso B">
        <div class="caption">
          <div class="fig-label">Figure 76.29B · Campbell's – ZANCOLLI LASSO (Operative planning diagram)</div>
          <div class="fig-title">Surgeon's operative planning diagram showing numbered incision sites and graft routes for Zancolli procedure on the palm and fingers.</div>
          <div class="source">Source: Campbell's Operative Orthopaedics 15th Ed, Block 39, line 3829</div>
        </div>
      </div>

      <div class="img-card">
        <img src="https://cdn.orris.care/cdss_images/c7b92f7e69a898841d0b5610c07fa4bc7effdf4ab3e6273d41b2a74959bcc824.png" alt="Zancolli Lasso C – Harvest">
        <div class="caption">
          <div class="fig-label">Figure 76.29C · Campbell's – FDS HARVESTING</div>
          <div class="fig-title">Intraoperative view: Surgical instruments harvesting FDS tendon slip from the palm. The free tendon graft segment is being obtained for use in the lasso transfer.</div>
          <div class="source">Source: Campbell's Operative Orthopaedics 15th Ed, Block 39, line 3834</div>
        </div>
      </div>

      <div class="img-card">
        <img src="https://cdn.orris.care/cdss_images/1d56859daae147a9c8474ec41d6a3160443bdac8697cd286d3c9e9e710452d55.png" alt="Zancolli Lasso D – Suture">
        <div class="caption">
          <div class="fig-label">Figure 76.29D · Campbell's – TENDON SECURED</div>
          <div class="fig-title">Intraoperative view: Forceps securing the harvested tendon graft, demonstrating the quality of the tendon and the suture material used for the lasso fixation around the A1 pulley.</div>
          <div class="source">Source: Campbell's Operative Orthopaedics 15th Ed, Block 39, line 3839</div>
        </div>
      </div>

      <div class="img-card">
        <img src="https://cdn.orris.care/cdss_images/a4ec8e964b5a26c746c3327623b862030f092dce7516c7bee66797e24849156c.png" alt="Zancolli Lasso E – Post-op splint">
        <div class="caption">
          <div class="fig-label">Figure 76.29E · Campbell's – POST-OPERATIVE SPLINTING</div>
          <div class="fig-title">Post-operative wrist splint/brace applied after intrinsic replacement procedure. MCP joints held in flexion with IP joints free. Splint maintained for 4-6 weeks post-operatively to protect the tendon transfer during healing.</div>
          <div class="key-point">🔑 Post-op position: MCP joints in 70-90° flexion, IP joints in extension. This protects the transfer and allows safe rehabilitation.</div>
          <div class="source">Source: Campbell's Operative Orthopaedics 15th Ed, Block 39, line 3844</div>
        </div>
      </div>

    </div>
  </div>
</section>

<!-- ===== SECTION 7: NERVE REPAIR ===== -->
<section id="nerve">
  <div class="section-header">
    <span>7. NERVE REPAIR &amp; GRAFT PRINCIPLES</span>
    <span class="badge">Current Surgical Therapy 14e · Ch. 10</span>
  </div>
  <div class="section-body">
    <div style="background:#f3e5f5; border-radius:8px; padding:16px; margin-bottom:20px; font-size:0.9rem; color:#4a148c;">
      <strong>Key Principles for Ulnar Nerve Transfer/Repair:</strong><br>
      • Primary repair within 6 weeks → best results<br>
      • Nerve regeneration: 1 mm/day (1 inch/month)<br>
      • Muscle fibrosis occurs after ~18 months denervation → tendon transfer preferred beyond this<br>
      • AIN → Deep motor branch of ulnar nerve = nerve transfer of choice for high ulnar palsy<br>
      • Sural nerve = most common donor for nerve graft (up to 40 cm per leg)
    </div>
    <div class="img-grid">

      <div class="img-card">
        <img src="https://cdn.orris.care/cdss_images/ae3eba2d5f6b3c7820ae94f28555459f395bdfbe53918667833806e25f24bd0b.png" alt="Sural Nerve Graft">
        <div class="caption">
          <div class="fig-label">Fig. 8 · Current Surgical Therapy 14e – SURAL NERVE GRAFT</div>
          <div class="fig-title">Sural nerve harvest for nerve graft. Shows the sural nerve bridging a "Damaged nerve" gap. The sural nerve is a purely sensory nerve supplying a small dorso-lateral foot area. Up to 40 cm available per leg; bilateral harvest possible. Used as cable grafts to bridge ulnar nerve gaps.</div>
          <div class="key-point">🔑 Sural nerve = #1 donor for nerve graft worldwide. Expendable with minimal donor morbidity. Other options: medial/lateral antebrachial cutaneous nerve, superficial radial nerve.</div>
          <div class="source">Source: Current Surgical Therapy 14e, Block 10, line 2338</div>
        </div>
      </div>

      <div class="img-card">
        <img src="https://cdn.orris.care/cdss_images/a12be6063e3b21f7b86f61b43f2830fa2ee3de7d1fa24641914b4d680ea6b2ed.png" alt="Nerve Fascicle Alignment">
        <div class="caption">
          <div class="fig-label">Fig. 7 · Current Surgical Therapy 14e – FASCICLE ALIGNMENT</div>
          <div class="fig-title">Cross-section diagram showing nerve fascicle alignment at coaptation site. Proximal fascicles (left, blue circles) must align with corresponding distal fascicles (right, red circles). The yellow-orange central cylinder represents the nerve trunk. Mismatch leads to errant innervation, synkinesis, or dyskinesis.</div>
          <div class="key-point">🔑 For ulnar nerve repair: Motor fascicles (to deep branch) must be aligned with motor fascicles distally. Intraoperative nerve stimulation and fascicle staining help confirm alignment.</div>
          <div class="source">Source: Current Surgical Therapy 14e, Block 10, line 2333</div>
        </div>
      </div>

      <div class="img-card">
        <img src="https://cdn.orris.care/cdss_images/a43f06a5f87fe27f5bd028adce3dcea78e7fc70e5f43e6a75b04879adfc9c3e1.png" alt="Conduit / Tube nerve repair">
        <div class="caption">
          <div class="fig-label">Fig. 6 · Current Surgical Therapy 14e – NERVE CONDUIT / CABLE GRAFT</div>
          <div class="fig-title">Diagram showing a nerve repair using cable graft technique. Parallel horizontal lines represent individual nerve graft strands within a conduit, with circular markers indicating the proximal and distal coaptation points. Used when gap is too large for primary repair.</div>
          <div class="key-point">🔑 Cable grafts: Multiple parallel sural nerve strands used to match the diameter of larger nerve trunks like the ulnar nerve. Each strand sutured individually at each end with 9-0 or 10-0 nylon.</div>
          <div class="source">Source: Current Surgical Therapy 14e, Block 10, line 2343</div>
        </div>
      </div>

    </div>
  </div>
</section>

<!-- SUMMARY TABLE -->
<section id="summary" style="margin-bottom:60px;">
  <div class="section-header">
    <span>📋 QUICK REFERENCE – Named Transfers at a Glance</span>
    <span class="badge">Summary</span>
  </div>
  <div class="section-body">
    <div style="overflow-x:auto;">
      <table style="width:100%; border-collapse:collapse; font-size:0.9rem;">
        <thead>
          <tr style="background:#0f3460; color:white;">
            <th style="padding:10px 14px; text-align:left;">Procedure</th>
            <th style="padding:10px 14px; text-align:left;">Motor Used</th>
            <th style="padding:10px 14px; text-align:left;">Purpose</th>
            <th style="padding:10px 14px; text-align:left;">Route</th>
            <th style="padding:10px 14px; text-align:left;">Key Point</th>
          </tr>
        </thead>
        <tbody>
          <tr style="background:#f8f9fa;">
            <td style="padding:9px 14px; font-weight:600;">Zancolli Lasso</td>
            <td style="padding:9px 14px;">FDS slip</td>
            <td style="padding:9px 14px;">Static anti-claw</td>
            <td style="padding:9px 14px;">Loop around A1 pulley</td>
            <td style="padding:9px 14px; color:#e94560;">Simplest; blocks MCP hyperextension</td>
          </tr>
          <tr>
            <td style="padding:9px 14px; font-weight:600;">Stiles-Bunnell</td>
            <td style="padding:9px 14px;">FDS middle finger</td>
            <td style="padding:9px 14px;">Dynamic anti-claw</td>
            <td style="padding:9px 14px;">Lumbrical canals → lateral band</td>
            <td style="padding:9px 14px; color:#e94560;">Classic; swan neck risk if over-tensioned</td>
          </tr>
          <tr style="background:#f8f9fa;">
            <td style="padding:9px 14px; font-weight:600;">Fowler</td>
            <td style="padding:9px 14px;">EIP + EDV proprius</td>
            <td style="padding:9px 14px;">Dynamic anti-claw</td>
            <td style="padding:9px 14px;">Dorsal → volar → lumbrical canal</td>
            <td style="padding:9px 14px; color:#e94560;">Preserves FDS; no swan neck risk</td>
          </tr>
          <tr>
            <td style="padding:9px 14px; font-weight:600;">Riordan</td>
            <td style="padding:9px 14px;">Palmaris longus + graft</td>
            <td style="padding:9px 14px;">Dynamic anti-claw</td>
            <td style="padding:9px 14px;">Through carpal tunnel + lumbrical canals</td>
            <td style="padding:9px 14px; color:#e94560;">Can crowd carpal tunnel → CTS risk</td>
          </tr>
          <tr style="background:#f8f9fa;">
            <td style="padding:9px 14px; font-weight:600;">Brand</td>
            <td style="padding:9px 14px;">ECRB or ECRL + 4-tailed graft</td>
            <td style="padding:9px 14px;">Dynamic anti-claw</td>
            <td style="padding:9px 14px;">Volar forearm → carpal tunnel → lumbrical canals</td>
            <td style="padding:9px 14px; color:#e94560;">For severe claw + wrist flexion deformity</td>
          </tr>
          <tr>
            <td style="padding:9px 14px; font-weight:600;">Burkhalter</td>
            <td style="padding:9px 14px;">BR or ECRL + free graft</td>
            <td style="padding:9px 14px;">Dynamic anti-claw</td>
            <td style="padding:9px 14px;">Dorsal → volar to transverse metacarpal ligament</td>
            <td style="padding:9px 14px; color:#e94560;">Bony insertion in phalanx; greater lever arm</td>
          </tr>
          <tr style="background:#f8f9fa;">
            <td style="padding:9px 14px; font-weight:600;">Royle-Thompson / Brown</td>
            <td style="padding:9px 14px;">FDS ring or EIP</td>
            <td style="padding:9px 14px;">Thumb adduction</td>
            <td style="padding:9px 14px;">Around 3rd metacarpal → transverse to adductor insertion</td>
            <td style="padding:9px 14px; color:#e94560;">Must parallel adductor fibers for correct pull</td>
          </tr>
          <tr>
            <td style="padding:9px 14px; font-weight:600;">AIN → Deep branch (nerve transfer)</td>
            <td style="padding:9px 14px;">AIN (terminal motor branch)</td>
            <td style="padding:9px 14px;">Reinnervation of intrinsics</td>
            <td style="padding:9px 14px;">Distal forearm/wrist level coaptation</td>
            <td style="padding:9px 14px; color:#e94560;">Best for high ulnar palsy; short regeneration distance</td>
          </tr>
          <tr style="background:#f8f9fa;">
            <td style="padding:9px 14px; font-weight:600;">Free Gracilis transfer</td>
            <td style="padding:9px 14px;">Gracilis (free flap)</td>
            <td style="padding:9px 14px;">Intrinsic replacement</td>
            <td style="padding:9px 14px;">Microsurgical anastomosis</td>
            <td style="padding:9px 14px; color:#e94560;">Last resort when no tendon donors available</td>
          </tr>
        </tbody>
      </table>
    </div>
  </div>
</section>

<footer style="background:#1a1a2e; color:#aaa; text-align:center; padding:20px; font-size:0.8rem;">
  Visual Reference Collection – Ulnar Nerve Plastic Surgery Study Guide | 
  Images sourced from: Campbell's Operative Orthopaedics 15th Ed 2026 · Gray's Anatomy for Students · Current Surgical Therapy 14e |
  Compiled for educational use. Not for clinical decision-making without textbook verification.
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