CHAPTER 14 The thorax and thoracic spine

Thoracic spine

The unique feature of the vertebrae in the thoracic region is the presence of facets, both on the sides of the vertebral bodies and the transverse processes. These are for articulation with the ribs, forming the costovertebral and costotransverse joints (Fig. 14.1). Most of the ribs articulate with two adjacent vertebral bodies and one transverse process. The facets on the head of the ribs articulate in turn with demi-facets on the upper and lower borders of the vertebrae, and the crest on the rib head butts onto the intervertebral disc. The joint capsule is loose and strengthened anteriorly to form the three portions of the radiate ligament. The costovertebral joint cavity is divided into two by the intra-articular ligament, except for ribs one, ten, eleven and twelve which articulate with a single vertebra and have a single joint cavity.

Figure 14.1 Joints between the ribs and thoracic spine.

The costotransverse joints are formed only with the upper ten ribs. The joint is made between the articular facet of the transverse process and the oval facet on the rib tubercle. The thin joint capsule is strengthened by the costotransverse ligaments.

Definition

The costovertebral joint is formed between the rib and the vertebral body, the costotransverse joint is formed between the rib and the transverse process of the vertebra.

Sternal articulations

The sternocostal joints are formed between the medial end of the costal cartilages of ribs one to seven. The joint between the first rib and the sternum is cartilaginous, but all the others are synovial. Each is surrounded by a capsule and supported by radiate ligaments. The fibres of these ligaments fan out and intertwine with those of the ligaments above and below, and also with those of the opposite sternocostal joints. In addition, the radiate ligament fibres fuse with the tendinous fibres of the pectoralis major. The eighth, ninth, and tenth ribs form interchondral joints between their costal cartilages.

The costochondral joints are formed between the end of the rib and the lateral edge of the costal cartilage. The joint formed is cartilaginous, its perichondrium being continuous with the periosteum of the rib itself. Only slight bending and twisting actions are possible at this joint. The manubriosternal articulation is that between the upper part of the sternum and the manubrium. The joint is cartilaginous, with a hollow disc in its centre, and is strengthened by the sternocostal ligaments and longitudinal fibrous bands. About 7° of movement occurs at the joint in association with breathing.

Rib movements

Movement of the diaphragm, ribs and sternum increases the volume within the thorax with inspiration. Each rib acts as a lever, with one axis travelling through the costovertebral and sternocostal joints, and another through the costovertebral and costotransverse joints. The two axes permit two types of motion, known as ‘pump handle’ and ‘bucket handle’. In the pump handle action the upper ribs and sternum are raised, increasing the anteroposterior diameter of the thorax. With bucket handle motion the lower ribs move both up and out, widening the infrasternal angle and increasing the transverse diameter of the thorax. In the lower ribs (8−12) a third motion called ‘caliper action’ may also occur where the lateral diameter of the chest is increased, without significant joint motion.

The variation in movement between the upper and lower ribs is due, in part, to the differing structure of their respective costotransverse joints. The upper joints are cup-shaped permitting mainly rotation (pump handle), while those lower down are flat permitting both rotation and gliding movements (bucket handle).

Keypoint

The ribs can move forwards and upwards, increasing the anteroposterior diameter of the thorax (pump handle), and outwards, increasing the lateral diameter of the thorax (bucket handle).

In addition to respiratory motion, the ribs also move in association with the thoracic spine. With flexion of the spine the ribs move closer together and with extension they are pulled further apart, flattening the ribcage. This latter action in the upper ribs is important for the correct movement of the scapulothoracic joint. Lateral flexion causes the ribs on the concave side to move together and those on the convex side to move apart. Rotation gives horizontal gliding of one rib relative to another.

Ribcage shape at rest

The general shape of the ribcage will change as a result of thoracic mobility, with an increased thoracic kyphosis causing a general flattening of the ribcage. In addition, congenital abnormalities occur, including pigeon chest, funnel chest and barrel chest.

• Pigeon chest is seen when the sternum is orientated downwards and the ribcage becomes pointed because the anteroposterior (AP) diameter is increased.

• Funnel chest occurs when the sternum is pushed backwards in relation to the ribcage, often due to an overgrowth of the ribs (Magee, 2002). On inspiration the depression of the sternum may become more noticeable.

• Barrel chest deformity occurs when the sternum is orientated forwards and upwards, increasing the AP diameter. This deformity is seen in some pathological lung conditions.

The ribcage will also alter shape in cases of scoliosis. The vertebral bodies rotate towards the convexity of the curve, dragging the ribs with them. The ribs on the convex side of the curve are pushed backwards creating a ‘hump’ and those on the concave side of the curve move anteriorly causing a ‘hollow’ (Fig. 14.2). Rotation of the vertebral body causes the spinous processes to move away from the mid-line, in the opposite direction to the scoliosis. Right rotation of the vertebra therefore sees the spinous process deviating to the left.

Figure 14.2 Ribcage shape in scoliosis.

Definition

Scoliosis is a deformity of the spine where a single or multiple lateral curvature is seen. The scoliosis is named according to the convexity (sharp point) of the curve.

Movement of the thoracic spine

The relative thinness of the discs in the thoracic region, coupled with the presence of the ribs, makes movement here more limited than in other spinal areas. Extension is limited to about 30° with slightly more flexion being possible – roughly 40°. Flexion is freer in the lower thoracic region but still restricted by the ribs. Extension is limited by approximation of the facets and spinous processes as well as tissue tension, and causes the thoracic cage to become flatter. Lateral flexion is limited to roughly 25° to each side, a greater range being available in the lower region. Lateral flexion is accompanied by the same amount of rotation, which occurs contralaterally. For example, right lateral flexion is accompanied by right axial rotation, causing the tip of the spinous process to rest to the left of the mid-line. Rib movements accompany lateral flexion, with the ribs on the concave side compressing and those on the side of the convexity being pulled apart.

The range of rotation is larger than other movements, with 35° being possible to either side. However, when the spine is extended, both lateral flexion and rotation are dramatically reduced. As rotation occurs, the inferior facets of the upper vertebra slide laterally with respect to the lower vertebra, towards the direction of the rotation. Movement of the vertebra is accompanied by distortion of the ribs. The ribcage becomes more rounded on the side to which the rotation is occurring, and flattens on the opposite side.

Rotation of the thoracic spine is an important constituent of locomotion. In walking, when the right leg swings forward, the lower trunk and the pelvis rotate to the left about the fixed left leg. To keep the head facing forwards the upper spine must rotate to the right, pulling the shoulders back into a forward facing direction. As the upper and lower parts of the spine are rotating in opposite directions, there is a point at which the two movements cancel each other out. This point is the intervertebral disc between T7 and T8 which is not subjected to any rotation, while those vertebra immediately above and below rotate maximally, but in opposite directions.

Keypoint

During walking and running the pelvis rotates to one direction and the shoulders and trunk to the other. The two movements cancel each other out at the T7/8 spinal disc where no rotation occurs at all.

Examination

The screening examination is essentially similar to that of the lumbar spine, except that rotation is the movement most likely to be revealing as this normally has the greatest range. Rotation is performed in a sitting position, with overpressure being given through the shoulders. Resisted flexion and extension may be performed in a lying or a sitting position. Resisted lateral flexion is tested in a standing position with the therapist initially at the patient’s side. The patient’s near wrist of the straight arm is gripped, as is the far shoulder. Stability is improved if the therapist widens his or her base of support by placing the near foot between those of the patient.

As rotation and lateral flexion accompany each other in the thoracic spine, it is often revealing to combine these movements at examination. Thoracic rotation is performed, and is followed by lateral flexion, first in one direction and then the other.

Palpation takes in the vertebrae, rib joints and ribs themselves, and is carried out with the patient in a prone position with the arms over the couch side to move the scapulae apart. Alternatively, posteroanterior (PA) pressures may be used with the thoracic spine extended using the elbow support prone-lying starting position. In a prone-lying position the spinous processes of the thoracic vertebrae are angled downwards like the scales of a fish. The thoracic vertebrae may be considered in threes, with the transverse processes being found relative to the spinous processes as shown in Table 14.1.

Table 14.1 Palpation of the thoracic vertebrae

T1, 2, 3	At the same level as spinous process
T4, 5, 6	Between two successive levels
T7, 8, 9	Level with spinous process of vertebra below
T10	Level with vertebra below
T11	Between two successive levels
T12	At same level

As an approximate guide to levels, the AC joint is normally aligned with the C7–T1 interspace, the spine of the scapula at T3 and the inferior scapular angle at T7.

The rib angles gradually spread out from the spine with the eighth rib being furthest (about 6 cm) from the mid-line. The rib angles can be palpated at the same levels as the transverse processes down to the T8/T9, by pushing the soft tissue to one side. The facet joints lie in the paravertebral sulci, and the transverse processes, which overlie the costotransverse joints, are found 3–4 cm from the mid-line. Guidelines for rib palpation are shown in Table 14.2.

Table 14.2 Rib palpation

Rib structure	Region of palpation
1st rib	Above clavicle, within supraclavicular fossa
2nd	End level with manubriosternal joint (angle of Louis)
4th	Lies on nipple line
7th	End level with xiphisternal joint
11th	Tip lies in mid-axillary line
12th	Tip level with L1
Rib angle	3–4 cm lateral to end of transverse process
Costochondral (CC) joint	3 cm lateral to parasternal line at 2nd rib, 12 cm lateral at 7th rib, 18 cm lateral at 10th rib
Costotransverse (CT) joint	Depression between transverse process and rib

Modifications to the slump test for the thoracic spine

A variation of this test for the cervical and thoracic spine is to perform it in the long sitting position (Fig. 14.3A). From this position thoracic and lumbar flexion are added followed by cervical flexion (Fig. 14.3B). Altering the order of movement will change the neurodynamic demands (Butler and Slater, 1994), enabling the practitioner to refine the test. For example, performing cervical flexion before lumbar and thoracic flexion will challenge the cervical neural tissues more. The test can be further refined to place emphasis on the sympathetic trunk (Slater, Butler and Shacklock, 1994). This is especially relevant in the presence of sympathetic signs in conditions such as T4 syndrome, thoracic outlet syndrome and Raynaud’s syndrome, and in cases where cervicothoracic conditions mimic cardiac disease. Sympathetic testing is achieved by adding components of lateral flexion and rotation of the thoracic spine and lateral flexion of the cervical spine. Additional stress may be imposed by adding a minimal straight leg raise (SLR).

Figure 14.3 The slump test (long sitting). (A) Start. (B) Finish.

From Butler (1991) with permission.

Keypoint

Where sympathetic signs (skin changes, sweating, swelling) are present in conditions such as thoracic outlet syndrome (TOS) and Raynaud’s syndrome, modify the slump test to emphasize the sympathetic trunk. Add thoracic lateral flexion and rotation, and cervical lateral flexion to the standard slump test.

Injury to the ribcage

Direct trauma to the ribcage can result in damage to the ribs, intercostal muscles or, indirectly, to the rib joints. Deep breathing will usually reproduce the pain of rib or intercostal injury, and palpation can be used to reveal the exact site of injury as these structures are superficial. Trunk extension will open the ribcage and cause pain, and intercostal muscle tearing will generally give pain to resisted trunk flexion. Rib springing at a distance from the point of injury usually produces pain from a rib fracture.

Rib fracture

With rib fracture it is the tearing of the intercostal muscles which gives the pain rather than the fracture itself (Cyriax, 1982). The acute pain may be relieved by local strapping. Pre-stretched elastic adhesive strapping is applied across the area to restrict ribcage expansion and give the athlete a feeling of support. In the subacute phase active mobilization is required. If scar tissue formation is excessive and the source of pain, transverse frictions to the intercostal muscles along the line of the ribs are helpful. In addition, holding the rib down with the fingertips and practising deep inspiration will help to stretch the injured area. Exercises to expand the ribcage, such as deep inspiration and overhead reaching, or trunk lateral flexion to the contralateral side with or without rotation is also helpful to stretch the area.

Keypoint

Following rib injury, intercostal muscle stretching is useful. Deep breathing exercises coupled with manual therapy to isolate the movement to a single pair of ribs may also be used.

Where rib trauma is severe, there is a danger of pneumothorax. Here, air enters the pleural cavity changing the pressure within the thorax. The mediastinum is pressed away from the injured lung (mediastinal shift) with the potential to compress vital structures.

Definition

The mediastinum is the central compartment of the thoracic cavity, lying between the lungs. It contains the heart, major blood vessels, trachea, oesophagus, thymus and lymph nodes of the chest.

The athlete experiences severe chest or back pain and becomes breathless. They may begin to cyanose (lips going blue) and panic. First aid treatment is to cover the injured chest region with an airtight seal such as a sterile plastic film or watertight dressing. Examination with a stethoscope (auscultation) reveals an absence of lung sounds on the injured side indicating that air is not entering the lungs. Hospitalization is required, where a chest x-ray may reveal a deep sulcus sign showing that the costophrenic angle (junction of diaphragm and ribs) is abnormally deep. Treatment is by inserting a chest drain into the area outside the affected lung. The drain tube has a one-way valve allowing excess air to escape and the lung to re-expand.

Rib joints

The sternocostal joints may be sprained giving local swelling and tenderness, as may the costochondral joints (Tietze’s syndrome). True Tietze’s syndrome is a swelling of the costrochondral joints which contrasts to costrochondritis which is inflammation alone. Clinically however the two names are interchangeable.

Pressure on the sternum, or applied to the lateral aspect of the thorax, reproduces the pain, and palpation localizes the lesion. The injury can occur when performing exercises which force the arms into extension and abduction. Weight-training movements such as bench pressing and gymnastic exercises such as dips on parallel bars may both cause problems. Both the costovertebral and costotransverse joints may be subject to sprain, with pain occurring to rib movements and local palpation.

Costochondral pain must be differentiated from pain referral into the area from myocardial infarction, and from pathologies such as psoriatic arthritis or ankylosing spondylitis. In chest pain from myocardial infarction there is no history of sports trauma, and pain is vice-like and often described as a ‘clenched fist’ feeling which may refer up into the jaw. Pain of rib origin will be affected by rib movement and posture and is generally well localized. Medical pathologies affecting the ribs will generally have been present for some time and are differentiated by blood tests. Tests include the HLA-B27 genetic marker and erythrocyte sedimentation rate (ESR) which tests for non-specific inflammation throughout the body.

Keypoint

Ribcage pain must be differentiated from medical conditions affecting the ribs, and referred pain of visceral (internal organ) origin.

First rib injury

The first is the shortest and roundest of the ribs. It slopes downwards and forwards from its attachment to the first thoracic vertebra. It forms attachment for the scalene muscles, serratus anterior, and subclavius. Its superior surface bears a deep groove for the subclavian artery (posterior) and the subclavian vein (anterior). The arterial groove is the weakest part of the rib (Gurtler, Pavlov and Torg, 1985).

Fractures of the first rib may either be traumatic or the result of overuse. Overuse injuries have been reported as a result of repeated arm movements, such as heavy lifting and pitching (Bailey, 1985; Lankenner and Micheli, 1985; Gurtler, Pavlov and Torg, 1985). Symptoms are of pain associated with deep breathing, tenderness in the root of the neck, posterior aspect of the shoulder or axilla. Often the patient hears or feels a snap in the shoulder as when performing a sudden violent movement. Range of shoulder movement will usually be full but painful, especially to extension. Accurate diagnosis by radiographs in traumatic lesions is essential because of the proximity of the major vessels, nerves and lung. Bailey (1985) recommended serial radiographs for up to 6 months after stress fracture.

Keypoint

1st rib injury gives pain on deep breathing. Tenderness is common at the root of the neck, posterior aspect of the shoulder or axilla. Shoulder extension may also cause pain.

Management is by rest from the causal action, with shoulder support in a sling if pain is limiting. Gentle isometric shoulder exercises are used, and the condition usually resolves within 4–6 weeks.