## Most Common Vascular Injury in Proximal Humeral Fractures ### Overview Vascular injuries are serious complications of proximal humeral fractures. The axillary artery is the most commonly injured vessel due to its anatomical proximity and course through the axilla. ### Anatomy of Axillary Artery **Key Point:** The axillary artery is the continuation of the subclavian artery and passes through the axilla, lying medial and posterior to the proximal humerus. Its relationship to the humeral head and surgical neck makes it vulnerable to injury in proximal humeral fractures. | Anatomical Segment | Course & Relationships | |-------------------|------------------------| | **Proximal (1st part)** | Medial to pectoralis minor; lies posterior to proximal humerus | | **Middle (2nd part)** | Behind pectoralis minor; at risk in proximal humerus fractures | | **Distal (3rd part)** | Lateral to pectoralis minor; continues as brachial artery | ### Incidence of Vascular Injury in Proximal Humeral Fractures | Vessel | Frequency | Notes | |--------|-----------|-------| | **Axillary artery** | Most common (50–70% of vascular injuries) | Direct injury from fracture fragments or traction | | **Anterior circumflex humeral artery** | Less common | Branch of axillary; supplies humeral head | | **Brachial artery** | Rare | Distal continuation; injury in severe distal displacement | | **Radial artery** | Very rare | Distal branch; injury only with severe distal trauma | ### Mechanism of Axillary Artery Injury 1. **Direct trauma** from fracture fragments (comminuted fractures) 2. **Traction injury** during displacement of proximal fragment 3. **Compression** by hematoma or swelling 4. **Stretching** during manipulation or reduction attempts ### Clinical Presentation **High-Yield:** Signs of vascular injury include: - Absent or diminished radial pulse - Cool, pale hand/forearm - Delayed capillary refill - Pulsatile hematoma in axilla - Expanding hematoma - Signs of limb ischemia (pain, paresthesia, paralysis — the "5 P's") ### Risk Factors for Vascular Injury - Displaced proximal humeral fractures (especially 3- and 4-part fractures) - High-energy trauma - Anterior dislocation with fracture - Older age (atherosclerotic vessels) - Traction during reduction ### Diagnosis 1. **Clinical assessment** - Pulse examination (radial, brachial, axillary) - Capillary refill, skin color, temperature 2. **Imaging** - Doppler ultrasound (first-line, non-invasive) - CT angiography (gold standard if vascular injury suspected) - Conventional angiography (therapeutic potential) ### Management **Key Point:** Immediate vascular surgery consultation is mandatory if vascular injury is suspected. 1. **Immediate steps** - Gentle reduction of fracture (may restore perfusion) - Avoid aggressive manipulation - Elevate limb, apply ice - Heparin if no contraindications 2. **Definitive management** - Vascular repair/reconstruction by vascular surgeon - May require graft if vessel is thrombosed - Fracture stabilization concurrent with vascular repair 3. **Timing** - Vascular repair takes priority over fracture fixation - Ischemia time should be minimized (<6–8 hours) ### Why Axillary Artery? **Clinical Pearl:** The axillary artery is the most common site of vascular injury in proximal humeral fractures because: 1. It lies directly posterior and medial to the proximal humerus 2. It is relatively fixed in the axilla, making it vulnerable to traction 3. Fracture fragments can directly lacerate or compress it 4. Its course through the axilla puts it in the direct path of proximal humeral displacement **Mnemonic:** **AXILLA** = **A**xillary artery is the **X**-most common vascular injury in proximal humeral fractures. [cite:Rockwood & Green's Fractures in Adults Ch 10]
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