Musculoskeletal Radiology of Fractures By M.A. Kaeser, D.C.

Radiology Resident Logan College of Chiropractic

Skull

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Blowout Fracture

Blowout fractures are caused by direct trauma to the globe which causes an increase in intraorbital pressure and decompression via fracture of the orbital floor. Radiographically, fragments may be seen in the maxillary sinus or there may be opacification of the maxillary sinus with blood. Clinically, there may be diplopia on upward gaze due to entrapment of the inferior rectus muscle.

Blowout Fracture

Mandible Fracture

• Mandible fractures are due to direct trauma. Most are comminuted and typically involve both sides of the mandible

Spine Fractures

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Clay Shoveler’s

The clay-shoveler's fracture is an oblique fracture of a lower cervical spinous process, commonly C7. It results from hyperflexion, commonly from shoveling snow, although it was originally named for those who were mining clay. This is a stable injury.

Dens Fracture

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Type I Type II - unstable Type III

Teardrop Fracture

• A stable injury, this fracture results from severe hyperextension and results in avulsion of the anterior inferior corner of a vertebral body, typically C2. The teardrop fragment is avulsed and is attached to the anterior longitudinal ligament.

Hangman’s Fracture

• The Hangman's fracture consists of bilateral pedicle or pars fractures involving the C2 vertebral body. Associated with this fracture is anterior subluxation or dislocation of the C2 vertebral body. It results from a severe extension injury such as from an automobile accident where the face forcibly strikes the dashboard or from hanging.

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Jefferson Fracture

A Jefferson fracture consists of a fracture of the C1 ring. This results from an axial loading injury to the head with compression force to C1 (typically from diving). The fracture consists of unilateral or bilateral fractures of the anterior and posterior arches of C1. This is an unstable injury. Other burst type fractures are possible in the spine. These also result from axial loading injuries (compression) and result in severe comminution of a vertebral body. Posterior element displacement into the spinal canal is common.

Spondylolysis

Spondylolysis refers to failure of fusion of the pars interarticularis, most often at the lower lumbar spine. This is usually a congenital defect, although it may occasionally be post-traumatic. The process may affect one or both sides of the spine. Oblique radiographs are best for the detection of this abnormality.

Compression Fracture

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Compression fractures of the spine are common in elderly and osteoporotic patients. They result from anterior or lateral flexion. The typical appearance is loss of height of the anterior aspect of the vertebral body with preservation of the posterior elements and generally the posterior aspect of the vertebral body.

Hill-Sachs Fracture

• The Hill-Sachs fracture results from anterior dislocation of the humeral head and is located on the posterolateral aspect of the humeral head. 97 % of shoulder dislocations are anterior in direction. This fracture is produced when the humeral head strikes the inferior margin of the glenoid.

Pathological Fracture - Humerus

Pathologic fractures result from an underlying abnormality of the bone, usually either from a primary bone tumor or from metastatic disease. However, pathologic fractures may result from metabolic conditions as well. A pathologic fracture results when normal stress is placed onto abnormal bone.

Galeazzi’s Fracture

Also called a reverse Monteggia fracture, Galeazzi's fracture consists of a fracture of the radius at the junction of the middle and distal thirds with distal radioulnar joint dislocation. This fracture pattern may be caused by a fall on an outstretched hand or from a direct trauma to the dorsal aspect of the wrist. There is a comminuted fracture of the radius with radioulnar joint dislocation.

Monteggia Fracture-Dislocation

Type 1 characterized by a proximal ulnar fracture with anterior dislocation of the radial head.

Type 2 characterized by posterior angulation of the ulnar fracture site and posterior dislocation of the radial head.

Colle’s Fracture

This is a common fracture in elderly patients, consisting of a transverse fracture of the distal radial metaphysis proximal to the joint with dorsal displacement of the distal fragment and volar dislocation. It results from a fall on an outstretched hand. The ulnar styloid is commonly fractured as well. Another name is the Pouteau fracture.

Smith’s Fracture

Also called a reverse Colle’s fracture, the Smith fracture is a transverse fracture of the distal radial metaphysis with palmar (as opposed to dorsal) displacement of the distal fracture fragment. If the fracture is intraarticular, it is called a reverse Barton fracture. This fracture results from a backward fall onto the outstretched hand.

Torus Fracture

Also known as a buckle fracture. This is a compression fracture of a long bone, typically in children. This type of fracture usually occurs near the metaphysis. Both cortical margins are affected, but a discreet fracture line or trabecular disruption is not present. Minimal buckling of the cortex is present.

Greenstick Fracture

The greenstick fracture results from direct trauma. There is an incomplete fracture of a long bone (radius or ulna) with cortical disruption on one side and deformity on the other, resulting in bowing of the bone.

Lunate Dislocation

The lunate dislocation results from a backwards fall on an outstretched hand. Here, the capitate is aligned with the radius on the lateral view with volar displacement of the lunate. This is the most severe injury on the perilunate continuum with the greatest number of intercarpal ligaments disrupted.

Scaphoid Fracture

Scaphoid fractures are the most common carpal fractures, resulting from a fall on an outstretched hand. 70 % of these occur at the waist, 20 % at the proximal pole, and 10 % at the distal pole. Blood supply for the proximal pole enters at the waist. If this blood supply is interrupted due to fracture, the proximal pole is at risk for avascular necrosis. Special scaphoid views with the hand in ulnar deviation may be needed to detect these fractures.

Boxer’s Fracture

So named because of the common occurrence in prizefighters, the fracture involves the distal metacarpal neck, usually of digit five. The distal fracture fragment is volarly angulated and may be externally rotated. The injury results from direct trauma to the hand.

Bennett Fracture

The Bennett fracture is an intraarticular fracture of the base of the first metacarpal. The fracture must involve the first carpometacarpal joint to be called a Bennett fracture. The action of the abductor pollicis longus causes distraction of the fracture fragments. The volar base of the first metacarpal stays with the trapezium.

Gamekeeper’s Thumb

This condition results when there is partial or total disruption of the ulnar collateral ligament at the metacarpophalangeal joint of the thumb. It is also often associated with a fracture at the base of the proximal phalanx. This is also called a skier's thumb or ski pole fracture. The original condition was described in those gamekeepers who used their hands to kill rabbits. Special stress views may be required to see this dislocation , if clinically suspected.

Nail Bed Fracture

• Nail bed injuries are the result of direct trauma. The nail itself may be avulsed as part of the injury. The usual mechanism of injury involves crushing. Care must be taken to exclude foreign bodies. This injuries are at risk for osteomyelitis if not cared for properly.

Avulsion Fracture - Pelvis

• Avulsion fractures of the pelvis may affect the anterior superior iliac spine, the anterior inferior iliac spine, or the ischial tuberosity. The sartoris muscle originates at the anterior superior iliac spine. The rectus femoris muscle originates at the anterior inferior iliac spine. The hamstring muscles originate at the ischial tuberosities. The osseous structures are generally avulsed in young, athletic individuals. These fractures are also known as sprinter fractures.

Straddle Fracture

• Bilateral superior and inferior rami fractures are known as a straddle injury. This was originally described in horseback riders and is the result of direct trauma. Urethral injury is a known complication.

Acetabular Fracture

Acetabular fractures are usually the result of major direct trauma to the pelvis and femur. The acetabulum may be classified into the anterior (iliopubic) column, the posterior (ilioischial) column, and the dome of the acetabulum. Posterior wall fracture is usually the result of posterior hip dislocation.

Dashboard Fracture

The name dashboard fracture refers to a fracture which typically occurs in automobile accidents with impaction of the knee upon the dashboard. This results in fracture of the posterior rim of the acetabulum by the femoral head.. This type of fracture is associated with patellar fractures and posterior cruciate ligament fractures.

Intertrochanteric Fracture

Extra capsular fractures which involve the femoral trochanters include intertrochanteric and subtrochanteric fractures. The intertrochanteric fracture is by far the most common and is classified according to the status of the lesser and greater trochanter. If neither of these is fractured, the fracture is termed a two part fracture. If either the lesser or greater is fractured, then the fracture consists of three parts. If both are fractured, the fracture is termed a four part fracture. These fractures generally result from a fall and typically occur in postmenopausal women.

Femoral Shaft Fracture

• • • • • • Much force is required to produce fractures of the shaft of the femur. They tend to be displaced due to muscle action upon the fracture fragments. The superficial femoral artery may be injured with complex fractures of the distal femur.

Tillaux Fracture

The tillaux fracture consists of avulsion of the anterior lateral margin of the distal tibia. It is caused by a twisting injury. The anterior tibiofibular ligament avulses a small portion of the tibia.

Charcot Joint

Charcot joint or neuropathic joint typically affects the ankle and tarsal joints due to diabetes. Tabes causes this phenomenon in the knees while syringomyelia leads to Charcot changes at the shoulder. This condition is characterized by the "six D's" of: (1) destruction, (2) density (increased), (3) disorganization, (4) dislocation, (5) distension (fluid), (6) debris. The typical appearance is that of severe hypertrophic changes and sclerosis due to ischemic necrosis.

Jones Fracture

• Fractures of the fifth metatarsal of the foot are surprisingly controversial among radiologists, particularly concerning proximal metatarsal fractures. Some term these fractures Jones fractures, others dancers fractures, while others simply term them proximal metatarsal fractures. According to Orthopedic Radiology (Adam Greenspan, 3rd edition), a "true Jones" fracture occurs one inch distal to the base of the fifth metatarsal. It is not due to peroneus brevis tendon avulsion but rather a twisting inversion injury to the foot. Greenspan states that more proximal injuries are frequently misinterpreted as Jones fractures but really are avulsion fractures by the peroneus brevis tendon. These latter fractures heal quickly, while more distal fractures may undergo fibrous union only.

March Fracture

The march fracture is a type of stress fracture. It occurs in one of the metatarsals. The name refers to military recruits who developed stress fractures after long marches.

Freiberg’s Infarction

This is a form of avascular necrosis. It is idiopathic (possibly post-traumatic). The process typically affects the second metatarsal head and is unilateral.