Thoracic Vertebrae

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Clinically Relevant Anatomy

Thoracic Spine

The thoracic spine is part of the vertebral column that supports the chest area and provides posterior attachment for the ribs, some thoracic wall muscles, muscles of the upper limb, abdomen, and back. The thoracic spine lies between the superior cervical spine and the inferior lumbar spine. It consists of 12 vertebrae that are distinct in shape and function from vertebrae found in other regions of the vertebral column.

Bodies

The bodies of the thoracic vertebrae are medium sized and heart shaped. They are all weight-bearing and generally increase in size from superiorly to inferiorly with an increase in the amount of weight that needs to be supported. They possess articular facets on their sides for articulation with the heads of the ribs.

Pedicles

These project from the posterolateral surfaces of the bodies of the ribs and meet posteriorly with the laminae. The pedicles and laminae on either side form the neural arch which together with the posterior surface of the body enclose the vertebral foramen. The pedicles are notched on their superior and inferior surfaces, in the articulated thoracic spine, these notches form the intervertebral foramina for the passage of the thoracic spinal nerves.

Laminae

Run posteriorly from their junction with the pedicles and meet in the posterior midline to form the spinous process of each thoracic vertebra.

Transverse Process

There are two for each vertebra, these are long and thin and provide an articular surface for the tubercle of the rib as well as attachment sites for ligaments and muscles of the thoracic region. They run laterally from the junction between the pedicle and the lamina on either side.

Articular Processes

Each vertebra has a superior articular process on each side that has a smooth surface (articular facet) for articulation with the corresponding inferior articular facet of the inferior articular process of the superior vertebra. Each vertebra also has an inferior articular process on either side that articulates with corresponding superior processes of the subjacent vertebra. Superior articular facets of the thoracic region face posteriorly and laterally, the inferior facets face forward and medially. This arrangement permits rotation to occur between the vertebrae.

Vertebral Canal

The body and neural arch of each vertebra enclose the vertebral foramen, in an articulated thoracic spine, the vertebral foramina of the stacked vertebrae form a continuous vertebral canal for the passage of the spinal cord and the meninges surrounding it, as well as the arteries and veins supplying these structures. In the thoracic spine, the vertebral foramina are small and circular and this has obvious implications on the spinal cord. The spinal cord in the adult terminates at or around the level of the lower border of the first lumbar vertebra meaning it traverses the entire thoracic spine. Slightly excessive movements of one vertebra relative to another in the thoracic region run a huge risk of compressing the spinal cord and leading to damage of the cord.

Spinous Process

The spinous processes of thoracic vertebra project posteriorly but mainly downwards. In palpation of the posterior midline in the thoracic region, it will be important to note that the tip of the thoracic spine will lie level with the body of the subjacent vertebra, for example, the spine of the seventh thoracic vertebra C7 will lie roughly at the level of the body of the eighth thoracic vertebra C8.

Assessment

Thoracic examination includes a subjective and an objective part. The objective part is here divided into Physical Therapy assessment and Diagnostic Imaging.

Physical Therapy Assessment

The sequence proposed by Maitland for the physical examination of the intervertebral segment is:

1. Active Tests
   • Active movements of the thoracic spine are usually done with the patient standing.
   • Auxiliary tests associated with active movements tests.
     
2. Passive Tests
   • Movement of the pain-sensitive structures in the vertebral canal and intervertebral foramen.
   • Palpation
   • Passive range or intervertebral movement. The joint play movements performed on the thoracic spine were developed by Maitland and they are: Posteroanterior central vertebral pressure, posteroanterior unilateral vertebral pressure, transverse vertebral pressure and rib springing.

More detailed information on each of these parts can be found on the Physiopedia page Thoracic examination.

Visual Examination of Abnormal Postures

• Thoracic Hyperkyphosis: When the thoracic spine is viewed from the side, it is seen to have an anterior concavity and posterior convexity, and when looked at from behind, should theoretically descend in the posterior midline. In certain cases, such as in elderly people, the anterior concavity of the thoracic spine is exaggerated, and this is termed hyperkyphosis or age-related kyphosis. Kyphosis is a condition that is most prevalent in the thoracic spine. The kyphotic individual presents with a stooped posture and this has implications for thoracic expansion.

• Scheuerman's disease is the most common structural kyphosis in adolescents but can occur in adults. Its etiology is unknown. Humpback is a localized, sharp, posterior angulation called a gibbus. This kyphotic deformity is usually structural and often results from an anterior wedging of the body of one or two thoracic vertebrae. Dowagers's hump results from postmenopausal osteoporosis: anterior wedge fractures occur to several vertebrae, usually in the upper to middle thoracic spine, causing a structural scoliosis that also contributes to a decrease in height.

• Scoliosis: The thoracic spine may also be curved laterally when viewed from behind. Usually, there is a concavity to one side of the thoracic spine and a 'compensatory' concavity to the opposite side in the lumbar spine, and this may be considered normal. However, in certain cases, these curvatures are exaggerated and this is termed scoliosis.

Diagnostic Imaging

Imaging is most often performed after a trauma when there is a risk of fracture. It is not the first technique of choice for the diagnosis of thoracic spine pain.The most commonly injured levels during an important trauma in the spine are the cervicothoracic (C6, C7, T1, T2) and thoracolumbar (T11, T12, L1, L2) vertebrae. These segments are predisposed to mechanical forces because they are the transitional areas between the relatively fixed (via the rib cage) thoracic spine and the more mobile cervical and lumbar spines.

• Computed Tomography (CT). CT is the initial imaging study for high-risk trauma patients, for example, in cases of multiple system trauma.
• Radiography. Radiographs are the initial imaging study for thoracic spine problems, with the exception of high-risk trauma patients, who are evaluated by CT. However, if CT is not available, radiographs are indicated.

• Magnetic resonance imaging (MRI). MRI is superior to both radiography and CT in the detection of soft tissue injury to the ligaments, facet capsules, and prevertebral spaces.

Treatment

Physiotherapy

Exercise

Is beneficial in situations of kyphosis, osteoporosis, stiffness, etc. Among the different types of exercises we can name pilates, which could be effective for treating non-structural scoliosis. In a study of 2016 it was shown that both Schroth and Pilates exercises were effective in individuals with scoliosis, but the Schroth exercise was more effective.

Manipulation

There is no much research literature on the safety of joint manipulation when applied to the thoracic spine. Thrust joint manipulation should never be performed when contraindications or precautions are present.

Absolute contraindications to performing thrust joint manipulation (TJM) to the thoracic spine

Bony issues  Any pathology that may have led to bony compromise   Tumour, e.g. metastatic disease   Infection, e.g. tuberculosis, osteomyelitis   Metabolic, e.g. osteomalacia, osteoporosis   Congenital, e.g. dysplasias, congenital fusions   Iatrogenic, e.g. long-term corticosteroid medication, surgical fusions, recent surgery   Inflammatory, e.g. rheumatoid arthritis, ankylosing spondylitis, acute soft tissue injury, connective tissue disease, synovial cysts   Traumatic, e.g. fracture, dislocation,   ligamentous rupture, instability Neurological issues  Any pathology that may affect the neurological system   Acute cervical, thoracic or lumbar myelopathy   Spinal cord compression   Cauda equina syndrome   Nerve root compression with increasing neurological deficit, bilateral hyper-reflexia/sensory loss   Sudden vomiting/nausea/vertigo Vascular issues  Any pathology that may have led to vascular compromise   Diagnosed vertebrobasilar insufficiency or cervical artery abnormalities   Aortic aneurysm   Bleeding diatheses, e.g. haemophilia, anticoagulant therapy   Angina pectoris   Untreated cardiac insufficiency, untreated cardiac dysthymias   Acute abdominal pain with guarding Clinical issues  Any matter that may increase the risk of harm to the patient   Lack of adequate subjective and objective examination by clinician   Lack of diagnosis   Lack of skill/expertise by clinician   Lack of consent from the patient

Relative precautions to performing thrust joint manipulation (TJM) to the thoracic spine

Adverse reaction to previous TJM Inflammatory joint processes Minor osteoporosis Disc herniation and disc protrusion Spondylolisthesis Hypermobility or ligamentous laxity Arterial calcification Arterial hypertension Serious degenerative joint diseases Growing children Serious kyphosis and scoliosis Herpes zoster on the thoracic spine Vertigo Systemic infections Psychological dependence upon manipulation Pain with a psychological overlay No change or worsening of symptoms after multiple manipulations

Surgery

Although high risk needs to be warned, corrective surgery can achieve satisfactory results for focal kyphosis in upper thoracic spine.