The thoracic spine typically consists of 12 vertebral ­levels with associated ribs with costovertebral and ­costotransverse spinal articulations. The rib cage, intercostal ligaments, paraspinal musculature, and sternum provide a “fourth column” of enhanced stability for the thoracic spine.^1,2,3,4,5 This strong thoracic “cage” protects important neurologic, cardiac, pulmonary, and vascular structures, which can be important considerations during the evaluation and management of thoracic spinal injuries.

Because of the relative difference in mobility of the thoracic spine and surrounding spinal segments, the cervicothoracic and thoracolumbar junctional regions have increased susceptibility to injury. The cervicothoracic region includes important neurologic structures (lowest cervical nerve roots and brachial plexus) that can affect upper extremity function. The thoracolumbar junction is susceptible to injury because of reduced stability from the lowest “floating” ribs and because the facet orientation changes from primarily coronal in the midthoracic spine to sagittal in the lumbar spine, providing less resistance to anterior translation.

The normal thoracic spine alignment has a mild to moderate kyphosis (normal range, 20°–45°) in part related to shorter anterior (compared with posterior) vertebral body heights. Increased kyphosis tends to occur with advancing age (especially in women older than 40 years of age), spinal degeneration, and medical conditions such as Scheuermann’s disease.^6,7 Thoracic scoliosis, often asymptomatic, is seen in 2% to 3% of the population and may require monitoring, particularly in growing adolescents, and occasionally intervention. These aspects of thoracic anatomy and alignment, as well as overall health and bone density, can factor into management of thoracic spinal injuries in athletes.

Thoracic spinal pain commonly occurs in the general population; therefore, when seen in athletes, it does not necessarily represent an injury that needs treatment.⁸ There has been little formal evaluation of thoracic pain in athletes compared with the general population. Jonasson et al
evaluated the incidence of thoracic pain in high-performance athletes, including divers, weight lifters, wrestlers, hockey players, and orienteers.⁹ The study found that athletes had the same rate (33%) of thoracic pain symptoms in the past year compared with nonathlete control participants, although athletes had a mildly higher, but not significant, rate of such symptoms in the past week (22% vs. 17%). As discussed later in this chapter, thoracic pain can be caused by a variety of spinal, paraspinal, and thoracic conditions. In addition, some cervical and lumbar conditions can manifest as thoracic pain for various musculoskeletal reasons. For example, cervical kyphosis often manifests as upper thoracic pain related to compensatory alignment and muscular strain. Similarly, loss of lumbar lordosis can shift the center of balance anteriorly and result in thoracic muscular pain.

Participation in sports can cause radiographic changes reflecting accelerated degeneration or accumulation of multiple small injuries over time.^10,11 Increased spinal degeneration has been reported in both contact and noncontact sports. Healy et al found that enhanced degeneration is more common in high-performance athletes than recreational athletes.¹² Degenerative changes in the thoracic spines of athletes have been evaluated in several studies, often focusing on the lower thoracic spine in combination with the lumbar spine. In a study of thoracolumbar spines in elite skiers, Rachbauer et al found that almost 50% of ski jumpers and alpine skiers and 36% of cross-country skiers had radiographic vertebral end plate lesions compared with fewer than 20% of age-matched control participants.¹³ Similarly, Daniels et al found twice the rate of degenerative abnormalities in the thoracic spine of adolescent motocross racers compared with age-matched control participants.¹⁴ Baranto et al evaluated back pain and thoracolumbar degenerative changes in elite athletes.^15,16 Not surprisingly, they found increased rates of thoracolumbar pain and degenerative findings in athletes compared with nonathlete control participants. Interestingly, follow-up radiographic studies 15 years later (mean age, 40 years) revealed that the vast majority of radiographic findings were present on the earlier studies (mean age, 26 years). The authors suggest that athletes may be more susceptible to developing degenerative spinal changes earlier in life during or near growth spurts.

In athletes, the majority of thoracic injuries are related to blunt force or repetitive impacts. Penetrating trauma, although much less common, can occur in certain sports, including fencing, javelin, pole vaulting, and skiing (from poles).^{17,18,19,20,21} As part of the evaluation of thoracic pain, the clinician should remember that the symptoms may be the related to spinal, paraspinal, or surrounding structures (e.g., cardiac, pulmonary, vascular). After injury or during workup for potential injury, serious life-threatening or fatal conditions including commotio cordis, myocarditis, myocardial infarction, and pulmonary embolism, have been reported in athletes from a wide range of sports.^{22,23,24,25,26,27,28,29} In their study of pediatric sports-related pneumothorax, Soundappan et al found that the presentation may be atypical with minimal to no signs.³⁰

Thoracic spinal and paraspinal injuries can be defined by the structure(s) and region(s) of involvement as well as the injury characteristics such as instability or neurologic dysfunction. Thoracic spinal injuries can be categorized by specific sites or types of anatomic injury, although clearly some injuries involve multiple structures. Paraspinal injuries are very common and generally represent soft tissue injuries such as superficial bruises or contusions and muscular injuries along the spectrum from strains to tears.^31,32 Thoracic spinal ligamentous injuries (e.g., intraspinous, supraspinous, and costovertebral ligaments) can be painful and when extensive can compromise stability. Excessive demands on the paraspinal muscles as well as the rhomboids and latissimus dorsi muscles can result in trigger points or enthesopathy.

Thoracic disk herniations can cause regional pain or radiculopathy from nerve root compression or neurologic deficits from spinal cord impingement. Published reports on the prevalence of thoracic disk herniations range from 1 in 1000 to 1 in 1,000,000 individuals. The incidence of asymptomatic thoracic disk herniations on imaging was found to be 11% to 13% in an autopsy study and 13% to 15% in a CT myelography study but as high as 37% in an MRI study.^33,34,35 Symptomatic thoracic disk herniations are relatively rare compared with cervical and lumbar herniations. In a retrospective review of disk herniation in National Football League (NFL) players, Gray et al found that only 1.5% (4) of 275 disk herniations were in the thoracic spine compared with 22.2% (61) in the cervical and 76.4% (210) in the lumbar spine.³⁶

Although thoracic disks can present acutely after an athletic injury, they are commonly associated with a chronic presentation (Figure 22-1).^{32,33,34,35,36,37,38,39,40} Repetitive injuries to the thoracic spine, especially with excessive loads and forces, can injure the disk annulus and result in thoracic disk herniation. Similarly, chronic microinstability can result in thoracic spondylosis, which encompasses a
variety of degenerative findings, including disk bulges, osteophyte formation, and hypertrophy of the posterior longitudinal ligament. Thoracic disk herniations and spondylosis can result in effacement of the cerebrospinal fluid spaces and nerve root or spinal cord impingement.

Thoracic fractures can involve anterior elements (vertebral body), posterior elements (e.g., spinous process, transverse process, lamina, facets), or both.⁴¹ Thoracic fracture patterns include compression fractures; burst fractures; and complex injuries producing deformity with subluxation, kyphosis, rotation, or distraction ­(Figure 22-2).⁴² Compression fractures are usually associated with forced flexion and involve compromise of the anterior vertebral body with preservation of the middle column and posterior elements. With middle column compromise as well, the fracture is considered a burst fracture. With some burst fractures, the posterior part of the vertebral body can retropulse into the spinal canal, resulting in neurologic compromise.

With any spinal fracture, it is important to assess for the presence or potential for instability or neurologic compromise. With kyphosis, the forward spinal
angulation can cause the spinal cord to drape over retropulsed bone or disk herniation in the spinal canal. Fractures associated with rotation and distraction injuries are more likely to be associated with ligamentous compromise. Chance fractures, often seen with distraction injuries, involve a three-column injury through the anterior and posterior elements, generally in one plane (Figure 22-3).⁴³ Identification of these structural fracture patterns is important in guiding management as discussed later in this chapter.