Causes / typical injury mechanism: The scapula, or shoulder blade, is located on the posterior thorax, and the lateral aspect of this bone is the glenoid portion of the shoulder joint. The scapula is heavily protected by soft tissue; thus, most scapular fractures require significant force. About 88% are sustained during high-energy mechanisms and are often associated with life-threatening injuries. Careful examination is critical to avoid overlooking this diagnosis, as the diagnosis of a scapula fracture can be missed or delayed up to 12.5% of the time because of associated, distracting injuries, including those to the head, spine, or thorax.

Classic history and presentation / risk factors: Twenty-eight percent of scapula fractures are sustained during motor vehicle accidents, 25% during motorcycle accidents, and falls account for 18% of cases, especially in geriatric populations.

Given the high-energy nature of scapular fractures, approximately 90% of patients will have a concomitant injury. About half of patients experience some form of ipsilateral upper extremity injury, thoracic injuries occur 80% of the time, and injuries to the head and spine are seen in 48% and 26% of patients, respectively. Sixty-four percent of patients will have rib fractures, with potentially associated pulmonary complications.

Prevalence: Scapula fractures are relatively uncommon, accounting for just 0.5% of all fractures. However, rates of diagnosis have increased with a growing geriatric population and associated fragility fractures, increased CT scan utilization, and improved emergency / trauma evaluation processes.

Patients are 78% male and 75% White. The most common ages at injury are between 20 and 60 years. Increasing rates of diagnosis have been seen among patients older than 60 years.

Pathophysiology / mechanism: Various mechanisms have been identified for each fracture pattern. A glenoid rim fracture can result from a fall on an outstretched hand or a shoulder dislocation. A scapular body or glenoid neck fracture may occur with direct, high-energy trauma. Avulsion fractures of the coracoid or acromion typically result from traction mechanisms. Intra-articular glenoid fractures can occur when the humeral head is driven into the glenoid fossa with great force.

Scapular fractures can be classified based on anatomical location:

• Intra-articular – Glenoid fractures.
• Extra-articular – Scapular neck / scapular body fractures (most common, 50% of all scapular fractures), coracoid fractures, and acromial fractures.
• Floating shoulder – Rare, this usually requires at least 2 fractures to the superior shoulder suspensory complex, such as a fractured scapular neck and ipsilateral clavicle. These injuries are typically associated with neurovascular compromise, including brachial plexus injuries.