**4. Choke vessels**

Where no "true" arterial-arterial connections are present between neighbouring angiosomes, a network of reduced caliber "choke vessels" form a link. These vessels are normally inade‐ quate to perfuse the area of a distant angiosome but may be provoked to dilate.

This is the theoretical base of the "delay phenomenon" which has been applied in plastic surgery. While the choke vessels between angiosomes in a skin or muscle flap may be suffi‐ cient to perfuse an adjacent vascular territory, necrosis will ususally appear in the choke vessel zone defining the next vascular territory. When designing a skin or muscle flap larger than two angiosomes, a two stage procedure might be performed. In the first stage, the per‐ forators of the neighbouring angiosomes are ligated, causing the choke vessels between neighbouring angiosomes to dilate over a period of 4-10 days. After this delay period, a larg‐ er flap can be safely elevated [8]. There is good clinical and experimental evidence that this principle works for the transfer of skin grafts from essentially normal donor sites. These re‐ sults may, however, not be extrapolated to other situations e.g. in the ischemic foot where distal, aggressive macroangiopathy is associated with microcirculatory changes like throm‐ bosis, neuropathy, local sepsis, arterio-venous shunting and hypercoagulability [9].

**3. Interconnections**

428 Artery Bypass

nections may be blocked.

Anterior tibial to peroneal:

*Anterior tibial to posterior tibial:*

The arterial-arterial connections include:

just above the ankle joint (Figure 2A).

with branches of the first dorsal metatarsal artery.

*Peroneal and posterior tibial connections:*

**4. Choke vessels**

A number of interconnections exist between the angiosomes. When present, these intercon‐ nections exist *a priori* and – in contrast to the choke vessels described below - do not need a period of ischemia to open. However, as peripheral arterial disease progresses, these con‐

The lateral malleolar artery joins with the anterior perforating branch of the peroneal artery

The lateral plantar artery forms the deep plantar arch crossing the proximal 2,3, and 4th meta‐ tarsals and finally anastomoses directly with the dorsalis pedis artery in the first interspace (Fig‐ ures 2A and 2B). The superficial and deep medial plantar arteries join at the cruciate anastomosis. Depending on what arteries predominate at or around the cruciate anastomosis, the hallux may be primarily nourished by the lateral plantar artery, medial plantar artery, the first dorsal metatarsal artery or simultaneously by either two or three of these arteries [7].

The medial plantar artery also interconnects with the anterior tibial tree as cutaneous branches connect proximally with medial branches of the dorsalis pedis artery and distally

Between one and three communicating branches between the peroneal artery and the poste‐

On the other hand, no direct arterial-arterial connection exists between the medial and later‐

Where no "true" arterial-arterial connections are present between neighbouring angiosomes, a network of reduced caliber "choke vessels" form a link. These vessels are normally inade‐

This is the theoretical base of the "delay phenomenon" which has been applied in plastic surgery. While the choke vessels between angiosomes in a skin or muscle flap may be suffi‐ cient to perfuse an adjacent vascular territory, necrosis will ususally appear in the choke vessel zone defining the next vascular territory. When designing a skin or muscle flap larger than two angiosomes, a two stage procedure might be performed. In the first stage, the per‐ forators of the neighbouring angiosomes are ligated, causing the choke vessels between neighbouring angiosomes to dilate over a period of 4-10 days. After this delay period, a larg‐ er flap can be safely elevated [8]. There is good clinical and experimental evidence that this

quate to perfuse the area of a distant angiosome but may be provoked to dilate.

rior tibial artery proximal to the ankle joint deep to the Achilles tendon.

al calcaneal arteries, which both supply the plantar aspect of the heel.

**Figure 2.** A. Lateral oblique projection of the anterior pedal vessels of a patient with peripheral occlusive arterial dis‐ ease and patent arterial-arterial connections. ALMB-APB: Connection between the anterior lateral malleolar branch of the anterior tibial artery and the anterior perforating branch of the peroneal artery. DPA-LPA: Perforating branch con‐ necting the dorsal pedal artery with the lateral plantar artery. B. Antero-posterior projection of the perforating branch connecting the dorsal pedal artery with the lateral plantar artery (DPA-LPA).
