While performing a fasciotomy for compartment syndrome, the following layers are incised:

Explanation

## Correct Answer: C. Skin, Subcutaneous tissue, Superficial fascia and Deep fascia Fasciotomy for compartment syndrome requires precise anatomical knowledge of the layers that must be incised to decompress the affected compartment. The procedure involves sequential incision through: (1) **Skin**, (2) **Subcutaneous tissue** (superficial to the fascia), (3) **Superficial fascia** (also called investing fascia or fascia of Scarpa in the abdomen), and (4) **Deep fascia** (the true compartmental fascia that encloses muscle groups). The deep fascia is the critical structure creating the compartment; it must be incised longitudinally to relieve intracompartmental pressure. Importantly, muscular fibres are NOT incised during fasciotomy—the incision stops at or just through the deep fascia. Incising muscle fibres would cause unnecessary tissue damage, bleeding, and functional impairment. The goal is pressure relief, not muscle resection. In Indian surgical practice (as per Bailey & Love and standard orthopaedic protocols), fasciotomy is performed urgently when compartment pressure exceeds 30–40 mmHg to prevent muscle necrosis and rhabdomyolysis. The procedure is often performed in the operating theatre under anaesthesia, and careful layer-by-layer dissection ensures adequate decompression without iatrogenic muscle injury. ## Why the other options are wrong **A. Skin and Subcutaneous tissue** — This is wrong because it omits both the superficial and deep fascia—the very structures creating the compartment. Incising only skin and subcutaneous tissue leaves the compartmental fascia intact, providing no pressure relief. This is an incomplete procedure and would fail to treat compartment syndrome. NBE may use this to catch students who confuse fasciotomy with simple skin incision or drainage. **B. Skin, Subcutaneous tissue, Superficial fascia, Deep fascia and a few muscular fibres** — This is wrong because it includes muscular fibre incision, which is unnecessary and harmful. Fasciotomy is a decompressive procedure, not a debridement or resection. Incising muscle causes additional trauma, bleeding, and functional loss without therapeutic benefit. The incision must stop at the deep fascia to achieve adequate compartment decompression while preserving muscle integrity. **D. Skin, Subcutaneous tissue, Superficial fascia** — This is wrong because it omits the **deep fascia**, which is the actual compartmental boundary. The deep fascia is the structure that restricts expansion and causes pressure buildup in compartment syndrome. Incising only up to superficial fascia leaves the deep fascia intact, failing to decompress the compartment. This is a common trap for students who confuse the layers. ## High-Yield Facts - **Fasciotomy layers**: Skin → Subcutaneous tissue → Superficial fascia → Deep fascia (stop here; do NOT incise muscle). - **Deep fascia** is the compartmental boundary; it must be incised longitudinally to relieve pressure in compartment syndrome. - **Compartment pressure threshold**: Fasciotomy is indicated when pressure exceeds 30–40 mmHg or when clinical signs (pain out of proportion, pain on passive stretch, paresthesia, pallor, pulselessness) appear. - **Muscular fibres are NOT incised** during fasciotomy—this is a decompressive procedure, not a resection. - **Two-incision technique** is often used in leg fasciotomy (anterior and lateral compartments via anterolateral incision; posterior compartments via posteromedial incision) to ensure complete decompression. ## Mnemonics **SSDF Rule** **S**kin → **S**ubcutaneous → **D**eep fascia → **F**asciotomy complete. (Superficial fascia is between subcutaneous and deep fascia, so the full sequence is S-S-SF-DF.) **Compartment Decompression Mantra** "Cut skin, cut fat, cut fascia—stop before muscle." This reinforces that fasciotomy is layer-by-layer incision through skin, subcutaneous tissue, and fascia, but muscle is preserved. ## NBE Trap NBE pairs "muscular fibres" in option B with the correct layer sequence to trap students who know the layers but confuse fasciotomy (decompression) with muscle resection or debridement. Similarly, option D omits deep fascia to catch students who underestimate the depth of incision needed. ## Clinical Pearl In Indian emergency departments, compartment syndrome is a surgical emergency—often seen after crush injuries, severe fractures, or prolonged immobilization. Delayed fasciotomy (>6–8 hours) risks irreversible muscle necrosis and acute kidney injury from myoglobinuria. The "5 P's" (Pain, Pressure, Paresthesia, Pallor, Pulselessness) guide clinical diagnosis, but compartment pressure measurement (via needle manometry or transducer) confirms the diagnosis and guides timing of fasciotomy. _Reference: Bailey & Love's Short Practice of Surgery, Ch. 27 (Compartment Syndrome); Harrison's Principles of Internal Medicine, Ch. 330 (Rhabdomyolysis and Acute Kidney Injury)_