Chapter 23

THE VERTEBRAL COLUMN AND SPINAL CORD

Surgical Anatomy--Injuries of the spinal cord: _Concussion_; _Traumatic haematorrachis_; _Traumatic haematomyelia_; _Total transverse lesions at different levels_; _Partial lesions_; "_Railway spine_"--Injuries of the vertebral column: _Sprain_; _Isolated dislocation of articular processes_; _Isolated fracture of arches and spinous processes_; _Compression fracture of bodies_--Traumatic spondylitis--Fracture-dislocation--Penetrating wounds.

#Surgical Anatomy.#--The veretebral column is the central axis of the skeleton, and affords a protecting casement for the spinal cord.

The spine is movable in all directions--flexion, extension, lateral flexion, and rotation around the long axis of the column. Flexion is accompanied by compression of the intervertebral discs, and by a slight forward movement of each vertebra on the one below it. This forward movement is checked by the tension of the ligamenta flava which stretch between the laminae.

In the infant, the spine is either straight or presents one long antero-posterior curve with its convexity backwards. With the assumption of the erect posture the normal S-shaped curve is developed, the cervical and lumbar segments arching forward, while the thoracic and sacral segments arch backward.

Through the skin it is often difficult to identify with certainty the individual spinous processes. The spine of the seventh cervical vertebra,--vertebra prominens--and that of the first thoracic, are those most readily felt. While the arm hangs by the side, the root of the spine of the scapula is opposite the third thoracic spine, and the lower angle of the scapula is on the same level as the seventh. The twelfth thoracic vertebra may be recognised by tracing back to it the last rib. A line joining the highest points of the iliac crests crosses the fourth lumbar spine; and the second sacral spine is on the same level as the posterior superior iliac spine. The bodies of the upper cervical vertebrae may be felt through the posterior wall of the pharynx. The cricoid cartilage corresponds in level to that of the lower border of the sixth cervical vertebrae and its transverse process.

It is important for surgical purposes to bear in mind that most of the spinous processes do not lie on the same level as their corresponding bodies. The tips of the spines of the cervical and first two or three thoracic vertebrae lie, roughly speaking, opposite the lower edge of their respective bodies; those of the remaining thoracic vertebrae lie opposite the body of the vertebrae below; while the spines of the lumbar vertebrae lie opposite the middle of their corresponding bodies.

The _vertebral canal_ contains the spinal cord so suspended within its membranes that it does not touch the bones, and is not disturbed by the movements of the vertebral column.

The _membranes_ of the cord are continuous with those of the brain. The arachno-pia invests the cord and furnishes a sheath to each of the spinal nerves as it passes out through the intervertebral foramen. The arachno-pial space is filled with cerebro-spinal fluid, which forms a water-bed for the cord, continuous with that at the base of the brain. The dura mater constitutes the enveloping sheath of the cord. It hangs from the edge of the foramen magnum as a tubular sac, and is connected to the bones only opposite the intervertebral foramina, where it is prolonged on to each spinal nerve as part of its sheath. Between the dura and the bony wall of the canal is a space filled with loose areolar tissue and traversed by large venous sinuses. The dura extends as far as the upper edge of the sacrum.

The _spinal cord_ extends from the foramen magnum to the level of the disc between the first and second lumbar vertebrae. The cervical enlargement, which includes the lower four cervical and the upper two thoracic segments, ends opposite the seventh cervical spine. The lumbar enlargement lies opposite the last three thoracic spines.

One pair of spinal nerves leaves each "segment" of the cord. On leaving the cord the nerves incline slightly downwards towards the foramina by which they make their exit from the canal. The obliquity of the nerves gradually increases, till in the lower part of the canal--from the second lumbar vertebra onward--they run parallel with the filum terminale and together constitute the cauda equina.

It is to be borne in mind that owing to the fact that the cord is relatively shorter than the canal, the tips of the spinous processes lie a considerable distance lower than the segments of the cord with which they correspond numerically. To estimate the level of the segment of the cord which is injured: in the cervical region add one to the number of the vertebra counted by the spines; in the upper thoracic region add two, in the lower thoracic region add three, and this will give the corresponding segment. The lower part of the eleventh thoracic spinous process and the space below it are opposite the lower three lumbar segments. The twelfth thoracic spinous process and the space below it are opposite the sacral segments (Chipault).

_Functions._--The essential function of the spinal cord is to transmit motor and sensory impulses between the brain and the rest of the body. The general course of the fibres by which these impulses travel has already been described (p. 331).

In the grey matter there are groups of nerve-cells--"centres"--which govern certain reflex movements. The most important of these--the centres for the rectal, the vesical, and the patellar reflexes--are situated in the lumbar enlargement.

In the great majority of cases of spinal disease or injury coming under the notice of the surgeon the symptoms are bilateral, that is, are of the nature of paraplegia, and the whole of the body below the level of the segment affected is involved in the paralysis. Lesions affecting only one-half of the cord are rare and give rise to symptoms which are exceedingly complicated. When the lesion implicates the nerve-roots only, the symptoms are confined to the area supplied by the affected nerves.

INJURIES OF THE SPINAL MEDULLA OR CORD

As the clinical importance of a spinal injury depends almost entirely on the degree of damage done to the cord, we shall consider injuries of the cord before those of the vertebral column. They will be described under the headings: Concussion of the Cord; Traumatic Spinal Haemorrhage; Total Transverse Lesions; Partial Lesions of the Cord and Nerve Roots; and "Railway Spine."

#Concussion of the Spinal Cord.#--Concussion of the cord is now regarded as a definite entity closely resembling concussion of the brain. In some cases, the underlying lesion is of a temporary character, usually in the form of a vascular disturbance such as oedema or vascular engorgement, and possibly an arterial anaemia; in other cases there is definite evidence of injury, of the nature of contusion, minute haemorrhages and blood-staining of the cerebro-spinal fluid. It must be clearly stated, that concussion of the cord may be attended with an immediate arrest of all its functions closely resembling the condition following upon complete crushing of the cord--total transverse lesion,--and it may be impossible to differentiate between the two conditions until two or more days have elapsed after the accident; it is usual, however, in concussion, as contrasted with crushing of the cord, that although motor conduction may be completely abolished, sensation is only impaired and evidence of sensory conduction can usually be elicited. If the lesion is merely a concussion, the functions of the cord will be restored within a day or two, first to full sensation and then to full motor power.

A classical instance is that of a late Governor-General of India, who on being thrown in the hunting-field was found to be paralysed in all four extremities; Paget diagnosed a total transverse lesion of the cervical cord with the necessary inference that it would inevitably have a fatal termination. The fact that the patient recovered completely, and was later able to fill two Viceroyalties, proved that the lesion must have been of the nature of a concussion of the cord.

The _treatment_ consists in adopting the same measures as in crushing of the cord, while careful watch is observed for the signs of recovery of conduction. The usual order of recovery is first the reflexes, then sensation, and lastly, the motor functions.

#Traumatic Spinal Haemorrhage.#--Haemorrhage into the vertebral canal is a common accompaniment of all forms of injury to the spine, but the lower cervical region is the common seat of the severe type of haemorrhage resulting from acute flexion of the spine such as occurs especially in a fall on the head from a horse or a vehicle in motion. The blood may be effused around the cord--between it and the dura--(extra-medullary), or into its substance (intra-medullary).

_Extra-medullary Haemorrhage--Haematorrachis._--The symptoms associated with extra-medullary haemorrhage are at first of an irritative kind--muscular cramps and jerkings, radiating pains along the course of the nerves pressed upon, and hyperaesthesia. It is only when the blood accumulates in sufficient quantity to exert definite pressure on the cord that symptoms of paralysis ensue, and it is characteristic of extra-medullary haemorrhage that the paralysis comes on gradually. When the effusion is in the cervical region--the commonest situation--the arms are more affected than the legs. The paralysis of the arms is of the lower neurone type, and the muscles are flaccid and undergo atrophy; the legs may exhibit a more complete degree of paralysis of the upper neurone type, with exaggeration of the knee-jerks. Blood may trickle down the canal and collect at a level lower than that of the lesion which causes the bleeding, and produce paralysis which slowly spreads from below upwards--_gravitation paraplegia_ (Thorburn). There is blood in the cerebro-spinal fluid.

The _treatment_ is on the same lines as in total transverse lesions. When there is evidence of progressive pressure on the cord, the blood is removed by spinal puncture if possible, or by laminectomy performed at the level suggested by the symptoms; operation is, however, rarely called for.

_Intra-medullary Haemorrhage--Haematomyelia._--Traumatic haemorrhage into the substance of the cord occurs almost invariably in the lower cervical region, and results from forcible stretching of the cord by acute flexion of the neck. The blood is usually effused into the anterior cornua of the grey matter and into the central canal, and there is a varying degree of laceration of the nerve tissue, in addition to pressure exerted by the extravasated blood.

The severity of the _clinical features_ depends upon the extent of the lesion. In contrast with what results in extra-medullary haemorrhage, the symptoms are paralytic from the outset.

When the haemorrhage is only sufficient to cause _pressure_ on the cord, the paralysis is usually most marked in the lower extremities because the conducting fibres are pressed upon. This is associated with evanescent anaesthesia for temperature and pain, while tactile sensibility is preserved. There is retention of urine and faeces, and in young men, priapism. As the fibres which supply the dilator pupillae are involved, the pupils are contracted. The symptoms gradually subside as the extravasated blood is re-absorbed, sensation being restored before motion, and recovery may be comparatively rapid.

When the blood extravasated in the cord causes disintegration of its substance, there is complete paralysis with atrophy, and anaesthesia in the area supplied by the segments of the cord directly implicated. The paralysis in the parts below the lesion assumes the spastic form. As the lesion is usually in the upper part of the cord, it is the arms that are most frequently affected. In less severe degrees of damage the paralysis of the most distant parts, _e.g._ the feet, may be transitory. Even in cases in which the loss of function below the level of the lesion has been complete, recovery may take place, but it is apt to be marred by a spastic condition of the muscles concerned, due to sclerotic changes in the cord.

Except that operative treatment is contra-indicated, the _treatment_ is the same as for extra-medullary haemorrhage, and at a later period measures may be employed to relieve the spastic condition of the muscles.

#Total Transverse Lesions.#--Total transverse lesions, that is, those in which the cord is completely crushed or torn across, are much more common than partial lesions, being an almost invariable accompaniment of a complete dislocation or of a fracture-dislocation of the spine. Even when the displacement of the vertebrae is only partial and temporary, the cord may be completely torn across. Similar lesions may result from stabs or bullet-wounds.

From the records of cases in which the vertebrae were injured by modern rifle bullets, even although the bony walls of the spinal canal had not been fractured and no haemorrhage had occurred within the spinal canal, the cord in the vicinity was degenerated into a "custard-like material" incapable of any conducting power (Makins). According to Stevenson, "this must have been due to the vibratory concussion communicated to it by the passage of the bullet at a high rate of velocity." The importance of this observation lies in the fact that in such cases no benefit can follow operative interference.

The _clinical features_ vary with the level at which the cord is injured, and the diagnosis as to the nature and site of the lesion is to be made by a careful analysis of the symptoms. By gently passing the fingers under the patient's back as he lies recumbent, any irregularity in the spinous processes or laminae may be detected, but movement of the patient to admit of a more direct examination of the spine is attended with considerable risk, and should be avoided. Skiagrams are indispensable, as they show the exact site and nature of the lesion.

_Immediate Symptoms._--At whatever level the cord is damaged there is immediate and complete paralysis of motion and sensation (paraplegia) below the seat of injury, and the paralysed limbs at once become flaccid. On careful examination, a narrow zone of hyperaesthesia may be mapped out above the anaesthetic area, and the patient may complain of radiating pain in the lines of the nerves derived from the segments of the cord directly implicated. In complete transverse lesions the paralytic symptoms are symmetrical; any marked difference on the two sides indicates an incomplete lesion.

Retention of urine and retention or incontinence of faeces are constant symptoms. In young men priapism is common--the corpus cavernosum penis is filled with blood without actual erection. There is other evidence of vaso-motor paralysis in the form of dilatation of the subcutaneous vessels, and local elevation of temperature in the paralysed parts. The deep reflexes, including the tendon reflexes, are permanently lost.

Unless regularly emptied by the catheter, the bladder becomes distended, and there is dribbling of urine--the overflow from the full bladder. As the bladder is unable to empty itself, and its trophic nerve supply is interfered with, the use of the catheter involves considerable risk of infection, unless the most rigid precautions are adopted. Hypostatic pneumonia is liable to develop. Great care in nursing is necessary to prevent trophic sores occurring over parts subjected to pressure, such as the sacrum, the scapulae, the heels, and the elbows.

_Later symptoms_ are the result of descending degeneration taking place in the antero-lateral columns of the cord. There are often violent and painful jerkings of the muscles of the limbs; the muscles become rigid and the limbs flexed.

_Treatment._--When the cord is completely divided, no benefit can follow operative interference, and treatment is directed towards the prevention of infective complications from cystitis and bed-sores.

#Injuries of the Cord at Different Levels.#--_Cervical Region._--Complete lesions of the _first four cervical segments_--that is, above the level of the disc between the third and fourth cervical vertebrae--are always rapidly, if not instantaneously, fatal, as respiration is at once arrested by the destruction of the fibres which go to form the phrenic nerve. It is from this cause that death results in judicial hanging.

In lesions between the _fifth cervical and first thoracic segments inclusive_, all four limbs are paralysed. Sensation is lost below the second intercostal space. The parts above this level retain sensation, as they are supplied by the supra-clavicular nerves which are derived from the fourth cervical segment (Fig. 205). Recession of the eyeballs, narrowing of the palpebral fissures, and contraction of the pupils result from paralysis of the cervical sympathetic. Respiration is almost exclusively carried on by the diaphragm, and hiccup is often persistent. There is at first retention of urine, followed by dribbling from overflow, and sugar is sometimes found in the urine. Priapism is common. The pulse is slow (40 to 50) and full; and the temperature often rises very high--a symptom which is always of grave omen.

When the lesion is confined to the _sixth cervical segment_, the arms assume a characteristic attitude as a result of the contraction of the muscles supplied from the higher segments. The upper arm is abducted and rotated out, the elbow is sharply flexed, and the hand supinated and flexed (Fig. 206). Sensation is retained along the radial side of the limb.

Total lesions of the lower cervical segments are usually fatal in from two to three days to as many weeks, from embarrassment of respiration and hypostatic pneumonia.

When the lesion is confined to _the first thoracic segment_, the attitude of the arms is usually that of slight abduction at the shoulder and flexion at the elbow, the forearms lie semi-pronated on the chest or belly, and there is slight flexion of the fingers. There is complete anaesthesia as high as the level of the second interspace, and along the distribution of the ulnar nerve (Fig. 205); the respiration is entirely diaphragmatic; and the ocular changes depending on paralysis of the cervical sympathetic are present.

_Thoracic Region._--In injuries of the thoracic region--second to eleventh thoracic segments inclusive--the anaesthesia below the level of the lesion is complete and its upper limit runs horizontally round the body, and not parallel with the intercostal nerves. Above the anaesthetic area there is a zone of hyperaesthesia, and the patient complains of a sensation as if a band were tightly tied round the body--"girdle-pain."

The motor paralysis and the anaesthesia are co-extensive. The intercostal muscles below the seat of the lesion and the abdominal muscles are paralysed. The respiratory movements are thus impeded, and, as the patient is unable to cough, mucus gathers in the air-passages and there is a tendency to broncho-pneumonia. As the patient is unable to aid defecation or to expel flatus by straining, the bowel is liable to become distended with faeces and gas, and the meteorism which results adds to the embarrassment of respiration by pressing on the diaphragm. There is retention of urine followed by dribbling from overflow. As the reflex arc is intact there may be involuntary and unconscious micturition whenever the bladder fills.

If infection of the bladder and the formation of bed-sores are prevented, the patient may live for months or even for years. At any time, however, infection of the bladder may occur and spread to the kidneys, setting up a pyelo-nephritis; or the patient may develop an ascending myelitis, and these conditions are the most common causes of death.

_Lumbo-sacral Region._--All the spinal segments representing the lumbar, sacral, and coccygeal nerves lie between the level of the eleventh thoracic and first lumbar vertebrae. Injuries of the lower thoracic and upper lumbar vertebrae, therefore, may produce complete paralysis within the area of distribution of the lumbar and sacral plexuses. The anaesthesia reaches to about the level of the umbilicus. There is incontinence of urine and faeces from the first. Priapism is absent. Bed-sores and other trophic changes are common, and there is the usual risk of complications in relation to the urinary tract.

_Conus Medullaris._--A lesion confined to the conus medullaris may result from a fall in the sitting position. It is attended with slight weakness of the legs, anaesthesia involving a saddle-shaped area over the buttocks and back of the thighs, the perineum, scrotum, and penis. The urethra and anal canal are insensitive, and there is paralysis of the levatores ani, the rectal and the vesical sphincters. The testes retain their sensation.

_Cauda Equina._--As the cord terminates opposite the lower border of the first lumbar vertebra, injuries below this level implicate the cauda equina. The extent of the motor and sensory paralysis varies with the level of the lesion and with the particular nerves injured. Sometimes it is complete, sometimes, selective. As a rule all the muscles of the lower extremity are paralysed, except those supplied by the femoral (anterior crural), obturator, and superior gluteal nerves. The perineal and penile muscles are also implicated. There is anaesthesia of the penis, scrotum, perineum, lower half of the buttock, and the entire lower extremity, except the front and lateral aspects of the thigh, which are supplied by the lateral cutaneous nerve and the cutaneous branches of the femoral (anterior crural). There is incontinence of urine and faeces. The prognosis is more favourable than in lesions affecting the cord itself, and the only risk to life is the occurrence of infective complications.

#Partial Lesions of the Cord and Nerve Roots.#--Partial lesions, such as bruises, lacerations, or incomplete ruptures, are always attended with haemorrhage into the substance of the cord, and usually result from distortions or incomplete fractures and dislocations of the spine, or from bullet wounds. They are comparatively rare.

When the _nerve roots_ alone are injured, sensory phenomena predominate. Formication, radiating pains, and neuralgia are present in the area of distribution of the nerves implicated. There is motor paresis or paralysis, which may disappear either suddenly or gradually, or may persist and be followed by atrophy of the muscles concerned. In contrast to what is observed from pressure by tumours and inflammatory products, twitchings and cramps are rare.

In _partial lesions of the cord_ the motor phenomena predominate. Paresis extends to the whole of the motor area below the seat of the lesion, but the weakness is more marked on one side of the body. The distal parts--feet and legs--suffer more than the proximal--arms and hands, and the extensors more than the flexors. The paresis develops slowly, varies in extent and degree, and may soon improve. Vaso-motor disturbances accompany the motor symptoms. Irritative phenomena, such as twitchings or contractures, may come on later.

The deep reflexes, particularly the knee-jerks, may be absent at first, but they soon return, and are usually exaggerated; a well-marked Babinski response may appear later. Abolition of the reflexes, therefore, does not necessarily indicate complete destruction of the cord, but their return is conclusive evidence that the lesion is a partial one. It is necessary, therefore, to defer judgment until it is determined whether the abolition of the reflexes is temporary or permanent.

Sensory disturbances may be entirely absent. When present, they are incomplete, and are chiefly irritative in character. They may not reach the same level as the motor phenomena, and the different sensory functions are unequally disturbed in the areas corresponding to the several nerve roots. There is sometimes a combination of hyperaesthesia on one side and anaesthesia on the other.

Retention of urine is not always present even in those cases in which the limbs are completely paralysed, as the fibres of one side of the cord are sufficient to maintain the functions of the bladder. The patient may be aware that the bladder is full, although he is unable to empty it. Similarly, sensation in the rectum and anus may be retained although the control of the sphincters is lost. Priapism may be present, but tends to disappear.

In partial lesions, the difficulties of diagnosis are sometimes increased by the occurrence of haemorrhage into the substance of the cord, so that symptoms of generalised pressure are superadded to those of the partial lesion. In time the symptoms due to the intra-medullary haemorrhage pass off, but those due to the tearing of the cord persist.

The _prognosis_ is generally favourable, but must be guarded, as permanent organic changes in the cord may take place, causing a spastic condition of the muscles. When recovery is taking place the first signs are the return of the knee-jerks, and a gradual change in the limbs from the flaccid to the spastic condition. Sensibility returns in the order--touch, pain, temperature, and the parts supplied by the lowest sacral segments usually become sentient first. Voluntary power returns earlier in the flexors than in the extensors, and flexion of the toes is almost invariably the earliest voluntary movement possible. Infection from bed-sores or from the urinary tract is the most common cause of death in cases that terminate fatally.

The _treatment_ is carried out on the same lines as for total lesions. Laminectomy, however, is indicated when there is reason to believe that the pressure is due to some cause, such as a blood-clot or a displaced fragment of bone, which is capable of being removed.

In practice when a person has lost the power of the lower extremities as the result of an accident, there are three conditions requiring ultimate differentiation--a concussion of the cord alone, a total transverse lesion and a partial lesion of the cord together with concussion. It must again be emphasised that it may not be possible to differentiate between these immediately after the accident. Two or three days may elapse before it is possible to give a definite opinion.

"#Railway Spine.#"--This term is employed to indicate a disturbance of the nervous system which may develop in persons who have been in railway accidents, but a similar group of symptoms is met with in men engaged in laborious occupations such as coal-miners, who, after an injury to the back, develop symptoms referable to the nervous system on account of which they claim compensation not infrequently in the law-courts. It is a remarkable fact that it seldom occurs in railway employees, or in passengers who sustain gross injuries, such as fractures or lacerated wounds.

_Clinical Features._--The patient usually gives a history of having been forcibly thrown backwards and forwards across the carriage at the time of the accident. He is dazed for a moment and suffers from shock or, it may be, is little the worse at the time, and is able to continue his journey. On reaching his destination, however, he feels weak and nervous, and complains of pain in his back and limbs. There is rarely any sign of local injury. For a few days he may be able to attend to business, but eventually feels unfit, and has to give it up.

The symptoms that subsequently develop are for the most part subjective, and it is difficult therefore either to corroborate or to refute them; it will be observed that while some of them are referable to the cord the greater number are referable to the brain. They usually include a feeling of general weakness, nervousness, and inability to concentrate the attention on work or on business matters. The patient is sleepless, or his sleep is disturbed by terrifying dreams. His memory is defective, or rather selective, as he can usually recall the circumstances of the accident with clearness and accuracy. He becomes irritable and emotional, complains of sensations of weight or fullness in the head, of temporary giddiness, is hypersensitive to sounds, and sometimes complains of noises in the ears. There are weakness of vision and photophobia, but there are no ophthalmoscopic changes. He has pain in the back on making any movement, and there is a diffuse tenderness or hyperaesthesia along the spine. There is weakness of the limbs, sometimes attended with numbness, and he is easily fatigued by walking. There may be loss of sexual power and irritability of the bladder, but there is seldom any difficulty in passing urine. The patient tends to lose weight, and may acquire an anxious, careworn expression, and appear prematurely aged. Special attention should be directed to the condition of the deep reflexes and to the state of the muscles, as any alteration in the reflexes or atrophy of the muscles indicates that some definite organic lesion is present.

As the symptoms are so entirely subjective, it is often extremely difficult to exclude the possibility of malingering; it is essential that the patient should be examined with scrupulous accuracy at regular intervals and careful notes made for purposes of comparison, and also that the doctor should retain an impartial attitude and not develop a bias either in favour of or against the patient's claim for compensation.

So long as litigation is pending the patient derives little benefit from treatment, but after his mind is relieved by the settlement of his claim--whether favourable to him or not--his health is usually restored by the general tonic treatment employed for neurasthenia.

INJURIES OF THE VERTEBRAL COLUMN

_Partial_ lesions include twists or sprains, isolated dislocations of articular processes, isolated fractures of the arches and spinous processes, and isolated fractures of the vertebral bodies. The most important _complete_ lesions are total dislocations and fracture-dislocations.

In partial lesions, the continuity of the column as a whole is not broken, and the cord sustains little damage, or may entirely escape; in complete lesions, on the other hand, the column is broken and the cord is always severely, and often irreparably, damaged.

Twists and dislocations are most common in the cervical region, that is, in the part of the spine where the forward range of movement--flexion--is greatest. Fractures are most common in the lumbar region, where flexion is most restricted. Fracture-dislocations usually occur where the range of flexion is intermediate, that is, in the thoracic region.

In all lesions accompanied by displacement, the upper segment of the spine is displaced forwards.

#Twists# or #sprains# are produced by movements that suddenly put the ligamentous and muscular structures of the spine on the stretch--in other words, by lesser degrees of the same forms of violence as produce dislocation. When the interspinous and muscular attachments alone are torn, the effects are confined to the site of these structures, but when the ligamenta flava are involved, blood may be extravasated and infiltrate the space between the dura and the bone and give rise to symptoms of pressure on the cord. The nerve roots emerging in relation to the affected vertebrae may be stretched or lacerated, and as a result radiating pains may be felt in the area of their distribution.

In the _cervical_ region, distortion usually results either from forcible extension of the neck--for example from a violent blow or fall on the forehead forcing the head backwards--or from forcible flexion of the neck. The patient complains of severe pain in the neck, and inability to move the head, which is often rigidly held in the position of wry-neck. There is marked tenderness on attempting to carry out passive movements, and on making pressure over the affected vertebrae or on the top of the head. The maximum point of tenderness indicates the vertebra most implicated. In diagnosis, fracture and dislocation are excluded by the absence of any alteration in the relative positions of the bony points, and by the fact that passive movements, although painful, are possible in all directions.

In the _lumbar_ region sprains are usually due to over-exertion in lifting heavy weights, or to the patient having been suddenly thrown backwards and forwards in a railway collision. The attachments of the muscles of the loins are probably the parts most affected. The back is kept rigid, and there is pain on movement, particularly on rising from the stooping posture.

_Treatment._--Unless carefully treated, a sprain of the spine is liable to cause prolonged disablement. The patient should be kept at rest in bed, and, when the injury is in the cervical region, extension should be applied to the head with the nape of the neck supported on a roller-pillow. Early recourse should be had to massage, but active movements are forbidden till all acute symptoms have disappeared. In patients predisposed to tuberculosis, the period of complete rest should be materially prolonged.

#Isolated Dislocation of Articular Processes.#--This injury, which is most frequently met with in the cervical region and is nearly always unilateral, is commonly produced by the patient falling from a vehicle which suddenly starts, and landing on the head or shoulders in such a way that the neck is forcibly flexed and twisted. The articular process of the upper vertebra passes forward, so that it comes to lie in front of the one below.

The pain and tenderness are much less marked than in a simple twist, as the ligaments are completely torn and are therefore not in a state of tension. The patient often thinks lightly of the condition at the time of the accident, and may only apply for advice some time after on account of the deformity. The head is flexed and the face turned towards the side opposite the dislocation, the attitude closely resembling that of ordinary wry-neck, only it is the opposite sterno-mastoid that is tight. The bony displacement is best recognised by palpating the transverse process of the dislocated vertebra. In the case of the upper vertebrae this is done from the pharynx, in the lower between the sterno-mastoid and the trachea. There is pain on attempting movement, and tenderness on pressure, particularly on the side that is not displaced, as the ligaments there are on the stretch. There are often radiating pains along the line of the nerves emerging between the affected vertebrae. As the bodies are not separated, damage to the cord is exceptional. The lesion can usually be recognised in a radiogram.

_Treatment._--Reduction should be attempted at once, before the vertebrae become fixed in their abnormal position. Under anaesthesia gentle extension is made on the head by an assistant, and the abnormal attitude is first slightly exaggerated to relax the ligaments and to restore mobility to the locked articular processes. The head is then forcibly flexed towards the opposite side, after which it can be rotated into its normal attitude (Kocher). Haphazard movements to effect reduction are attended with risk of damaging the cord. After reduction has been effected, the treatment is the same as that of a sprain.

#Isolated Fractures of the Arches, Spinous and Transverse Processes.#--Fractures of the arches and spinous processes usually result from direct violence, such as a blow or a bullet wound, and are accompanied by bruising of the overlying soft parts, irregularity in the line of the spines, and by the ordinary signs of fracture. Skiagrams are useful in showing the exact nature of the lesion. These fractures are most common in the lower cervical and in the thoracic regions, where the spines are most prominent and therefore most exposed to injury.

In many cases there are no symptoms of damage to the cord or spinal nerves, but when both laminae give way the posterior part of the arch may be driven in and cause direct pressure on the cord, or blood may be effused between the bone and the dura. In such cases immediate operation is indicated. When there are no cord symptoms, the treatment consists in securing rest, with the aid of extension, if necessary, for several weeks until the bones are reunited.

The use of the X-rays has shown that one or more of the _transverse processes of the lumbar vertebrae_ may be chipped off by direct violence. The symptoms are pain and tenderness in the region of the fracture, and marked restriction of movement, especially in the direction of flexion. This lesion may explain some of the cases of persistent pain in the back following injuries in workmen. It is important to remember, however, that in a radiogram an un-united epiphysis may simulate a fracture.

#Isolated Fracture of the Bodies--"Compression Fracture."#--The "compression fracture" consists in a crushing from above downwards of the bodies--and the bodies only--of one or more vertebrae. It is due to the patient falling from a height and landing on the head, buttocks, or feet in such a way that the force is transmitted along the bodies of the vertebrae while the spine is flexed.

If the patient lands on his head, the compression fracture usually involves the lower cervical or upper thoracic vertebrae. When he lands on his buttocks or feet it is usually the lumbar or the lower thoracic vertebrae that are fractured (Fig. 207).

As a rule, there are no external signs of injury over the spine. The sternum, however, is often fractured, and irregularity and discoloration may be detected on examining the front of the chest. The recognition of a fracture of the sternum should always raise the suspicion of a fracture of the spine. On examination of the back a more or less marked projection of the spinous processes of the damaged vertebrae may be recognised. In the cervical and lumbar regions this projection may merely obliterate the normal concavity. The spinous process which forms the apex of the projection belongs to the vertebra above the one that is crushed. The cord usually escapes, but the nerves emerging in relation to the damaged vertebrae may be bruised, and this gives rise to girdle-pain.

Local tenderness is elicited on pressing over the affected vertebrae. As might be expected from the nature of the accident producing this lesion, it is often associated with serious injuries to the head, limbs, or internal organs which gravely affect the prognosis.

The _treatment_ consists in taking the pressure off the injured vertebrae in order that the reparative material may be laid down in such a way as to restore the integrity of the column. In the cervical region, extension is applied to the head, and a roller-pillow placed beneath the neck. In the lumbar region, the extension is applied through the lower limbs, and the pillow placed under the loins. The patient is confined to bed for six or eight weeks, and before he gets up a poroplastic or plaster-of-Paris jacket is applied. This is worn for a month or six weeks.

#Traumatic Spondylitis.#--This condition is liable to develop in patients who have sustained a severe injury to the back. It is believed to originate in a compression fracture which has not been recognised, and is probably due to the callus thrown out for the repair of the fracture being subjected to strain and pressure too early, or to a progressive softening of the injured vertebra and of the bodies of those adjacent to it. This leads to an alteration in the shape of the affected bones, which can be demonstrated by means of the X-rays. The usual history is that some considerable time after the patient has resumed work he suffers from pain in the back, and radiating pains round the body and down the legs. He becomes more and more unfit for work, and a marked projection appears in the back and may come to involve several vertebrae. While the condition is progressive, the prominent vertebrae are painful and tender. In course of time the softening process is arrested, and the affected bones become fused, so that the area of the spine involved becomes rigid and permanent deformity results. So long as the condition is progressive the patient should be kept in the recumbent and hyper-extended position over a roller-pillow and, when he gets up, the spine should be supported by a jacket.

#Dislocation and Fracture-Dislocation.#--It is seldom possible at the bedside to distinguish between a complete dislocation of the spine and a fracture-dislocation. _Fracture-dislocation_ is by far the more common lesion of the two, and is the injury popularly known as a "broken back." It may occur in any part of the column, but is most frequently met with in the thoracic and thoracico-lumbar regions. It usually results from forcible flexion of the spine, as, for example, when a miner at work in the stooping posture is struck on the shoulders by a heavy fall of coal. The spine is acutely bent, and breaks at _the angle of flexion and not at the point struck_. The lesion consists in a complete bilateral dislocation of the articular processes, together with a fracture through one or more of the bodies. This fracture is usually oblique, running downwards and forwards. The upper fragment with the segment of the spine above it is displaced downwards and forwards, and the cord is crushed between the posterior edge of the broken body and the arch of the vertebra above it (Fig. 208). In almost every case the cord is damaged beyond repair.

_Total dislocation_, in which the articular processes on both sides are displaced and the contiguous intervertebral disc separated, is rare, and is met with chiefly in the lower cervical region.

_Clinical Features._--The outstanding symptoms of total lesions are referable to the damage inflicted on the cord. The diagnosis should always be made by a consideration of the mechanism of the injury and the condition of the nerve functions below the lesion. On no account should the patient be moved to enable the back to be examined, as this is attended with risk of increasing the displacement and causing further damage to the cord. On passing the fingers under the back as the patient lies recumbent, it is usually found that there is some backward projection of the spinous processes, the most prominent being that of the broken vertebra. The spinous process immediately above it is depressed as the upper segment has slipped forward. Pain, tenderness, swelling and discoloration may be present over the injured vertebrae. It is usually possible to have skiagrams taken without risk of further damage to the spine. There is complete loss of motion and sensation below the seat of the lesion. The symptoms of total transverse lesions of the cord at different levels have already been described (p. 416).

_Treatment._--An attempt may be made to reduce the displacement under anaesthesia, gentle traction being made in the long axis of the spine by assistants, while the surgeon attempts to mould the bones into position. No special manipulations are necessary, as the ligaments are extensively torn, and the bones are, as a rule, readily replaced. A roller-pillow is placed under the seat of fracture to allow the weight of the body above and below to exert gentle traction, and so to relieve pressure on the cord. Operative treatment is almost never of any avail, as the cord is not merely pressed upon, but is severely crushed, or even completely torn across. Even when the cord is only partially torn, operative treatment is not likely to yield better results than are obtained by reduction and extension. The usual precautions must be taken to prevent cystitis and bed-sores.

Total fracture-dislocation between the _atlas_ and _epistropheus_ (axis), if attended with displacement, is instantaneously fatal (Fig. 209). This is the osseous lesion that occurs in judicial hanging. Fracture of the odontoid process may occur, however, without displacement, the transverse ligament retaining the fragment in position and protecting the cord from injury. The patient complains of stiff neck and pain, and the lesion may be recognised in a radiogram. A number of cases are recorded in which death took place suddenly weeks or months after such an injury, from softening of the transverse ligament and displacement of the bones.

#Penetrating Wounds.#--These result from stabs or gun-shot accidents, and are practically equivalent to compound fractures of the spine; their severity depends on the extent of the damage done to the cord, and on whether or not the wound is infected. In many cases the condition is complicated by injuries of the pleural or peritoneal cavities and their contained viscera, or by injury of the trachea, oesophagus, or large vessels and nerves of the neck. When the membranes of the cord are opened, the profuse and continued escape of cerebro-spinal fluid may prove a serious complication.

_Treatment._--The wound of the soft parts is treated on the usual lines. When the spinous processes and laminae are driven in upon the cord, they must be elevated at once by operation. In injuries involving the lumbo-sacral region it is sometimes advisable to perform laminectomy for the purpose of suturing divided nerve cords.

When there is evidence that the spinal cord is completely divided, operation is contra-indicated. Attempts have been made to unite the two ends of the divided cord by sutures, but there is as yet no authentic record of restoration of function following the operation.