What is the recommended depth for placing a suture on the thenar eminence of the hand in an adult patient?

Proper Suture Depth for Thenar Eminence Wounds

Sutures placed on the thenar eminence should incorporate the dermis and superficial subcutaneous tissue to a depth of approximately 3-5mm, avoiding deeper placement that risks injury to the underlying motor branch of the median nerve, thenar muscles, and neurovascular structures.

Critical Anatomic Considerations

The thenar eminence presents unique challenges due to its specialized anatomy:

• The motor branch of the median nerve lies relatively superficial beneath the thenar muscles, making deep suture placement particularly hazardous 1
• Hand wounds are inherently high-risk compared to other body locations due to complex anatomy, higher infection rates, and functional consequences of complications 1
• The thenar musculature (abductor pollicis brevis, flexor pollicis brevis, opponens pollicis) sits immediately deep to the subcutaneous tissue, and suture penetration into muscle increases infection risk and causes unnecessary tissue trauma 2, 3

Recommended Suture Technique

Depth Guidelines

• For simple lacerations: Place sutures through the dermis only (2-3mm depth), using buried dermal sutures with absorbable material (5-0 or 6-0 polyglactin) to reduce tension, followed by superficial skin approximation 4, 3
• For wounds requiring deeper closure: If subcutaneous dead space exists, place deep sutures at 3-5mm depth maximum, ensuring bites remain superficial to the thenar muscle fascia 4, 2
• Avoid muscle penetration: Never place sutures through the thenar muscles themselves, as this increases infection risk, causes unnecessary inflammation, and may damage motor function 1, 2

Technical Execution

• Evert skin edges properly without excessive tension to prevent suture marks and ensure optimal healing 4
• Use non-absorbable monofilament (5-0 or 6-0 nylon or prolene) for skin closure on the thenar eminence, as these materials minimize tissue reaction and infection risk 2, 3
• Maintain uniform tensile strength along wound edges by spacing sutures evenly (typically 3-5mm apart) 4
• Avoid strangulating tissue with overly tight sutures, which compromises microcirculation and delays healing 5, 2

Timing Considerations for Thenar Wounds

Hand wounds require earlier closure compared to other body locations due to higher infection risk:

• Optimal closure window: Within 8 hours of injury for hand wounds, though up to 12-24 hours may be acceptable if the wound is clean and well-vascularized 5
• Pre-closure assessment is mandatory: Check for active infection signs (increasing pain, erythema, purulent drainage), contamination level, and devitalized tissue 5
• Infected wounds must never be closed primarily, regardless of timing 1, 5

Common Pitfalls to Avoid

Depth-Related Errors

• Placing sutures too deep risks nerve injury (motor branch of median nerve), muscle damage, and increased infection risk 1, 2
• Inadequate depth (too superficial) leads to wound edge inversion, poor approximation, and increased scarring 4
• Penetrating the palmar fascia or thenar muscle compartment dramatically increases complication rates 1, 2

Technical Errors

• Excessive tension on sutures causes tissue strangulation, ischemia, and delayed healing 5, 2
• Poor wound preparation: Failure to adequately irrigate and remove superficial debris before closure increases infection risk 1, 5
• Premature closure of contaminated wounds or wounds with devitalized tissue that cannot be adequately debrided 1, 5

Post-Closure Management

• Elevation is critical: Keep the hand elevated during the first few days, especially if swelling is present, to accelerate healing 1
• Dressings remain undisturbed for minimum 48 hours unless leakage occurs 5, 6
• 24-hour follow-up (phone or office visit) is recommended for hand wounds 5
• Monitor for infection signs: Increasing pain, redness, swelling, or discharge warrant immediate evaluation 5, 6
• Pain disproportionate to injury severity may suggest deeper complications such as tendon injury, compartment syndrome, or deep infection 1

Suture Removal Timing

• Thenar eminence sutures should be removed at 10-14 days, as this location experiences moderate tension during hand use 6
• Earlier removal (7-10 days) may be considered if wound healing is excellent and tension is minimal 7
• Never leave sutures beyond 14 days on the hand, as this increases risk of suture tract infection and poor cosmetic outcome 6, 7