_Sarcoma._--All forms of sarcoma are met with, implicating the bones of the skull. They may originate in the pericranium, in the diploe, or in the dura mater, and usually involve the bones of the vault. They sometimes occur in children (Fig. 203).
[Ill.u.s.tration: FIG. 203.--Sarcoma of Orbital Plate of Frontal Bone in a child at age of 11 months, and 18 months.
(Mr. D. M. Greig"s case.)]
The tumour grows chiefly towards the surface, but it also tends to invade the cranial cavity, and may thus a.s.sume the shape of a dumb-bell. Its growth is usually rapid, and results in the formation of a diffuse soft swelling, which sometimes pulsates, and sooner or later fungates through the skin. On account of its rapid growth the tumour is liable to be mistaken for an abscess, and in some cases the nature of the disease is only discovered after making an exploratory incision, and finding that the finger pa.s.ses through a softened area in the bone.
When the cranial cavity is encroached upon, signs of compression ensue. After the tumour has fungated, infective complications within the skull are liable to develop. In all cases the prognosis is extremely unfavourable.
If diagnosed sufficiently early, an attempt may be made to remove the tumour, but often the operation has to be abandoned, either on account of the haemorrhage which attends it, or because of the extent of the disease.
The bones of the skull may become the seat of _secondary growths_ by the direct spread of cancer from the soft parts, _e.g._ rodent cancer (Fig. 204), or by metastasis of cancer or sarcoma from distant parts of the body, or of thyreoid tumours. Metastatic cancer would appear to be conveyed by the blood stream; it may occur in a diffuse form--cancerous osteomalacia--softening the calvaria so that at the post-mortem examination it may be removed with the knife instead of the saw; or it occurs in a discrete or scattered form, and then the macerated skull presents a number of circular and oval perforations.
[Ill.u.s.tration: FIG. 204.--Destruction of Bones of Left Orbit, caused by Rodent Cancer. The patient died of septic meningitis.
(Mr. D. M. Greig"s case.)]
CHAPTER XVI
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 cas.e.m.e.nt 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 a.s.sumption 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 ca.n.a.l_ 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 pa.s.ses out through the intervertebral foramen. The arachno-pial s.p.a.ce 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 const.i.tutes 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 ca.n.a.l is a s.p.a.ce 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 ca.n.a.l. The obliquity of the nerves gradually increases, till in the lower part of the ca.n.a.l--from the second lumbar vertebra onward--they run parallel with the filum terminale and together const.i.tute the cauda equina.
It is to be borne in mind that owing to the fact that the cord is relatively shorter than the ca.n.a.l, 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 s.p.a.ce below it are opposite the lower three lumbar segments. The twelfth thoracic spinous process and the s.p.a.ce 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 ent.i.ty 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 dema 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 cla.s.sical 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 ca.n.a.l 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 a.s.sociated 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 acc.u.mulates in sufficient quant.i.ty 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 ca.n.a.l 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 ca.n.a.l, 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 a.s.sociated 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 a.s.sumes 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 ca.n.a.l had not been fractured and no haemorrhage had occurred within the spinal ca.n.a.l, 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 pa.s.sage 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 a.n.a.lysis of the symptoms. By gently pa.s.sing the fingers under the patient"s back as he lies rec.u.mbent, 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 p.e.n.i.s 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.