# Leg Ulcer > Leg ulcer for FMGE Surgery: venous gaiter ulcer, ABI before compression, arterial and neuropathic ulcer sites, TIME wound care and Marjolin change. - Canonical URL: https://prepelephant.com/topics/fmge/surgery/leg-ulcer-fmge - Exam / course: FMGE · Subject: Surgery - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Leg Ulcer", PrepElephant, https://prepelephant.com/topics/fmge/surgery/leg-ulcer-fmge ## Direct answer Site predicts aetiology in lower-limb ulceration: a shallow, granulating ulcer in the gaiter area above the medial malleolus, ringed by pigmented skin and oedema, is venous — seven in ten leg ulcers; punched-out ulcers over the toes, foot or pressure points with absent pulses and rest pain are arterial; a painless deep ulcer beneath a callus at a metatarsal head belongs to the neuropathic, usually diabetic, foot. The single measurement that must precede every compression bandage is the ankle-brachial index — compression against an ischaemic limb is how ulcers become amputations. Ulcers that fail to heal within three months deserve a biopsy, because Marjolin's ulcer — squamous carcinoma arising in a chronic wound — is the malignant end of neglect. ## What you must remember - **Venous ulcer profile:** gaiter area, shallow with sloping edges and a granulating base, surrounded by haemosiderin staining, lipodermatosclerosis (the inverted champagne-bottle leg), varicose eczema, ankle flare and pitting oedema — CEAP class C6 in venous-clinic language. - **Compression therapy:** four-layer bandaging or graduated stockings delivering roughly 40 mmHg at the ankle, strictly after documenting an ankle-brachial index of 0.8 or more; compression heals most venous ulcers within about 12 weeks, and continued stockings halve recurrence. - **Arterial ulcer profile:** punched-out and deep over toes, heel or pressure points, hairless shiny cold skin, absent pulses, claudication and night rest pain relieved by hanging the leg down; duplex first, then angioplasty or bypass — local wound care fails until flow is restored. - **Neuropathic ulcer:** beneath a callus over the metatarsal heads or heel, painless, often probing to bone; treatment is offloading (total contact cast) and debridement — dressings alone never heal a pressure-driven ulcer. - **Mixed-disease caution:** diabetes calcifies calf vessels and falsely raises the ankle-brachial index, so toe pressures or duplex decide when the index is unreliable. - **The biopsy rule:** any ulcer unhealed at three months, enlarging, with everted or rolled edges, or disproportionately painful — punch biopsy for squamous carcinoma (Marjolin's ulcer); Indian addenda are tuberculous ulcers and the sickle-cell ulcers of central India over the medial malleolus in young patients. - **Local care framework:** the TIME mnemonic — tissue debridement, infection control, moisture balance, edge advancement — organises wound-bed preparation whatever the aetiology. ## Reading an ulcer by its site Three patients teach the whole topic. A 58-year-old teacher has a 4 cm shallow ulcer above the left medial malleolus of four months' duration, with brown staining and an aching, swollen leg. Venous ulcer: check the index (0.9 — safe), four-layer bandaging weekly, and the ulcer granulates inward week by week; when healed, class 2 stockings for life and a duplex to plan varicose vein surgery. The second, a 64-year-old smoker, has a black-bordered, punched-out ulcer on the great toe tip with rest pain at night relieved by dangling the foot. Arterial: index 0.5, duplex shows a short superficial femoral occlusion, angioplasty restores flow, and only then does the toe ulcer begin to heal — debriding an ischaemic toe before revascularisation simply enlarges the wound. The third, a 50-year-old diabetic, walks in on a callus over the second metatarsal head under which a probe finds a painless cavity to bone: neuropathic ulcer — total contact cast, offloading footwear for life, and an X-ray or MRI for osteomyelitis. Three ulcers, three mechanisms, three entirely different first prescriptions that happen to share only the word "ulcer". ## One rule before every bandage NBE's most repeated leg-ulcer question is the pre-compression ankle-brachial index, with the threshold (0.8) keyed; the distractor is the eager "apply four-layer bandage" answer that costs an ischaemic limb. The second tier is pattern-matching: gaiter plus pigmentation equals venous, toes plus rest pain equals arterial, painless under callus equals neuropathic. Marjolin's ulcer is the quotable pearl — squamous carcinoma in a long-standing scar or ulcer, biopsied when an old ulcer changes character. And the Indian extension pairs sickle-cell ulcers of central India and tuberculous ulcers with the systematic differentials, earning viva marks for thinking beyond the three common types. ## Frequently asked questions ### Which is the commonest leg ulcer and where does it occur? Venous ulcer, about 70% of leg ulcers, in the gaiter area above the medial malleolus with surrounding pigmentation and lipodermatosclerosis. ### What ankle-brachial index is required before compression? 0.8 or above; below that, compression risks ischaemic injury and the limb needs vascular assessment first. ### What is Marjolin's ulcer? Squamous cell carcinoma arising in a long-standing chronic ulcer or scar — suspected when an old ulcer enlarges, develops everted edges, or becomes painful, and confirmed by biopsy. ### Where do neuropathic ulcers typically occur? Under callus over plantar pressure points — the metatarsal heads and heel — and they are painless with preserved skin perfusion. ### Why do arterial ulcers hurt more at night? Rest pain from severe ischaemia worsens lying flat as gravity assistance to perfusion is lost, and is relieved by dangling the foot — Buerger's positive test.