757 a m u a r t d n a s c i d e a p o h t r O Fig 1. A simpli \201 cation of the AO WEBER classi \201 cation of malleolar fractures.328 Images courtesy of Professor Peter Scally. a1 Transverse \201 bula fracture at or below the joint line with no medial injury a2/3 Tr ansverse \201 bula fracture below joint line + medial injury (ligament / fracture) b1-3 F ibula fracture at the joint line (B1) + medial injury (B2) + posterior injury (B3) c1/2 Obl ique \201 bula fracture above a ruptured tibio \201 bular ligament + medial injury c3 Ma isonneuve \200\231s fracture, i.e. proximal \201 bular fracture + medial injury Anterior talo \201bular ligament Interosseous taleocalcaneal ligament Anterior tibio \201bular ligament Dorsal taleonavicular ligament Dorsal cuneonavicular ligament Dorsal tarsometatarsal ligament Calcaneo- \201bular ligament Dorsal calcaneocuboid ligament Long plantar ligament Tibiocalcaneal part Posterior tibiotalar part Tibionavicular part Medial talocalcaneal ligament Posterior talocalcaneal ligament Dorsal talonavicular ligament Dorsal cuneonavicular ligament Long plantar ligament Plantar calcaneonavicular ligament Fig 2. Ligaments of the ankle and hind/midfoot: (top) lateral and (bottom) medial views. Th e medial view is dominated by the various parts of the deltoid ligament. \200 Injuries to the face and neck Assault is the commonest cause of facial trauma, with y oung men the most af- fected. Facial laceration and mandible fracture are the commonest inj uries.329 \200\207If there is airway obstruction, summon expert help promptly. Remove bloo d, loose/false teeth, and vomit from the mouth. Lie in the semi-prone position to prevent o bstruction (p799) from a swollen injured tongue, but always be- ware of cervical spine trau ma with injuries above the clavicle. If the pharynx is swelling or there is fracture of the larynx, try gentle intubation. If impossible, do cricothyrotomy (OHCM p786), then tracheos tomy. Blood aspiration is pre- vented by direct pressure to the bleeding site. Precautions with possible neck trauma Injury to the cervical spine should be considered in any trauma s ituation, especially if: high energy; patient com- plaining of neck pain; patient unconscio us. CT is the best method if high/mod- erate risk for cervical fracture.217 See p658 for as sessing neck injuries. Lacerations of the face Clean meticulously. Alignment of the tissues and anti- sepsis must be exact to produce a good cosmetic result. \200 Simple laceration s: Consider glue or steristrip closure (p730). \200 Complex lacerations: Is there a plast ic surgeon available? \200 Mammal bites: Give antibiotic cover: p782, eg co-amoxiclav 1 t ab/8h PO.231 \200 Rugby player \200\231s ( \200\230cauli \202 ower \200\231) ear: Aspira te/drain haematoma (repeat every 758 \200 a m u a r t d n a s c i d e a p o h t r O few days) and then strap pressure dressing against the head. Ruptured ear drum: NSAIDs for analgesia, and advise to keep ear dry. \200 Avulsed teeth m ay be replaced (p784). If inhaled, do expiratory CXR. Bleeding socket: bite on adrenaline-soaked pads, or use sutures. Eye injury, nose fractures, and nose bleeds: See p452, p560, & p562. Mandible injury Signs: Local tenderness and swelling; jaw malocclusion; a mobile fragment; bone may protrude into the mouth in open fractures; if com- minuted, the tongue may make airway management extrem ely diffi cult, so get expert help. Diagnosis: Orthopantogram (OPG) radiographs. Enlist exp ert den- tal help. Treating TMJ dislocations: Place (gloved) thumbs over the back teeth and press downwards, while at the same time levering the chin upwards with your \201 ngers ( both hands). Consider midazolam sedation: see p718. Blows to the chin may cause fracture at the impact site, or indirect fractures near the tem poromandibular joint. Fractures: Open reduction + internal \201 xa- tion with miniplates is better than wiring teeth together for 6 weeks. Try to get onto a daytime consultant list , rather than at night. Complicated fractures may bene \201 t from lag osteosynthesis. Com plications: infection; non-union.330 \200\230Whiplash \200\231 injury (a source of some co ntroversy) is cervical strain caused by sudden neck extension with rebound \202 exion. It is common, often in rear-end crashes. Hyperextension causes damage to the anterior musculo ligamentous structures. Subsequent protective muscle spasm causes pain and stiff ness, whic h may be severe. Treatment:331 Reassure physical injury is rare. Empha- size positive attit udes to prognosis and recovery are important. Encourage prompt return to usual activity and occupation. Suggest active mobilization (if tolerated), eg with gentle stretching and post ure control, as exercise enhances recovery. Aim to prevent chronicity and \200\230disuse s yndrome \200\231 through advocat- ing self-management with analgesia. Collars, rest and neg ative attitudes can contribute to delayed recovery and chronicity. If symptoms last for >1y r, they are likely to be permanent.332 Other car-crash neck sprains (Seen in \205\223 of c ar users soon after crashes.) Symptoms may be delayed and persist for years. The best treat ment may be to give NSAIDs, a cervical collar, and review in the next clinic, with referral for immediate physiotherapy if symptoms warrant this. Explain to the patient that head res traints are helpful \200\224the usual mistake is that they are adjusted too low. 759 Bony injuries to the face The face forms a shock absorber which protects the brain from inj ury. The most common fractures to the facial bones lie along 2 hoops, from ear to ear. One is formed by the zygomatic arch, body, infraorbital rim and nose. The other is formed by th e mandible ( \201 g 1). Major blunt trauma can cause a fracture to the entire middle third of the face, which has been classi \201 ed by Le Fort, but since the advent of seat belts these are less com- mon.333 Zygoma fractures The arch: Before swelling arrives, there is a depression in front of the ear, and lateral jaw excursions or jaw opening may be limited a nd painful. A suitable radiograph is the submentovertex view (SMV). The complex: The zygoma \200\231s body has 4 extensions: 1 frontozy- gomatic; 2 arch; 3 maxillary buttress (in mou th); 4 infraorbital rim. Fractures may be palpated at these points, or disproportionately s evere pain elicited on palpation. Occipitomental views are most suitable. Orbital \202 oo r injuries Blunt trauma around the eye can cause fracture to the orbital \202 oor. Imagin g: CT is best, but OM views may show trap door sign in the maxillary sinus. Clinical exam f or periorbital trauma: \200 Is there CSF rhinorrhoea, p560? (yes in \211 25%).334 \200 Check zygomatic arch by assessing range of mandibular lateral excursions and opening. Also palpate over the arch (just under the skin) and compare with the unaff ected side. a m u a r t d n a s c i d e a p o h t r O Fig 1. Skull a AP b lateral. Patient sitting, doctor standing above and behind, place index \201 ngers on the cheeks a nd look down from above for asymmetry. Fig 2. 3D CT of a nasty injury to the eye. \200 On no account remove the knife. Check the orbit \202 oor for: diplopia on upward gaze ( \211\210trapped orbital contents) ; enopthalmos; numbness in the distribution of the infraorbital nerve (suggests fracture). Courtesy of Prof Peter Scally. Small risk of retrobulbar hemorrhage: catastrophic if missed: severe pain at back of eye; p roptosis; loss of visual acuity. \200\207Prompt exam is essential. NB: if the eye is very swollen, application of a rubber glove \201 lled with ice is invaluable, especially if yo u ask a specialist to travel to check patient; they can no more open a swollen eye than you . Treatment: Unless vision \200\201, or there is signi \201 cant risk of infection, admiss ion on presentation is not mandatory: seeing at the next fracture clinic is adequate. If in doubt, consult the relevant specialist. Explain about not blowing the nose in fractures in continuity with the maxillary sinus (risks periorbital emphysema and infection). \200\207 Medicolegal issues Facial injuries commonly result from assault. Your notes may be used in criminal injuries claims or as evidence in court. Often the individual is drunk and abusive , it is late, and you are busy, but you must make accurate notes (use a ruler) with diagram s. Other people will de \201 nitely take time to study and criticize what you have written . Don \200\231t forget photographs if assault is particularly serious or children are invol ved. Document that the patient has given, or refused, permission for statements to be made to the police or legal professionals (the medical notes are con \201 dential). \200 Injury to nerves and arteries Neurapraxia implies temporary loss of nerve conduction often via ischaemia following pressure (eg to the lateral popliteal nerve as it crosses the neck of the \201 bula, see below). In mixed nerves, the motor modality is the more vul- nerable component. Axonotmesis entails damage to the nerve \201 bre but the epineural tub e is intact, providing guidance to the regrowing nerve. Good re- covery is the rule. Growth rate is 1 \200\2233mm/day. Neurotmesis means division of the whole nerve. As there is no g uidance from the endoneural tube, regrow- ing \201 brils cause a traumatic neuroma if the y are unable to bridge the gap. The current surgical standard is epineural repair with nylo n sutures. To span gaps that primary repair cannot bridge without excess tension, nerve-cab le interfascicular autografts are used. Results of nerve repair are fair (at best), with 5 0% of regaining useful function. There is much current research re- garding drugs, immune s ystem modulators, enhancing factors, and entubula- tion chambers.335 Management depends on type of injury; refer all complete injuries from laceration or penetration to a specialist for surgical exploration and repair. Median nerve (C5 \200\223T1) The nerve of grasp. Injur y above the antecubital fossa causes: \200 Inability to \202 ex index \201 nger inter phalangeal joints on clasping the hands (Ochner \200\231s test) \200 Inability to \202 ex the terminal phalanx of the thumb ( \202 exor pollicis longus) \200 Loss of sensation over the thenar half of the palm. 760 \200 a m u a r t d n a s c i d e a p o h t r O If the lesion is at the wrist, the only muscle reliably aff ected is abductor pollicis brev is. Test it by holding the hand palm up. Can the patient raise the thumb out of the plane o f the hand? The area of sensory loss is smaller than that for more proximal lesions. See BO X, \200\230Median nerve anatomy \200\231. Ulnar nerve (C8 \200\223T1) This is the nerve of \201 nger abduction and adduction (among other roles). One subtle sign of an ulnar nerve lesion is inability to cross the \201 ngers in the \200\230good luck \200\231 sign. Inj ury level determines severity of the claw deformity. In a distal lesion of the ulnar nerve, there will be more clawing of the 4th and 5th \201 ngers compared with a proximal, more complete lesion at the elbow. This is the ulnar paradox, and comes about because higher les ions paralyze \202 exors too (eg \202 exor digitorum profundus, FDP).336 Froment \200 \231s paper sign: On holding a piece of paper between thumb and \201 nger (both hands), t here is \202 exion of the thumb \200\231s distal phalanx on trying to pull apart ( \202 exor pol- licis longus, is recruited to overcome adductor pollicis weakness). Sensory loss is over the little \201 nger and a variable area of the ring \201 nger (palmar & dorsal ). Radial nerve (C5 \200\223T1) This is the nerve of extension of the elbow, wrist, and \201 ngers. It opens the \201 st. Injury will produce wrist-drop. Test for this with the elbow \202 exed and the forearm pronated. Sensory loss is variable, but always includes t he dorsal aspect of the root of the thumb. Sciatic nerve (L4 \200\223S2) Complete lesions w ill aff ect all muscles below the knee, and sensation below the knee laterally. Lateral pop liteal (common peroneal) nerve (L4 \200\223S2) The commonest lower limb nerve injury. Lesio ns lead to equinovarus with inability to dorsi \202 ex the foot and toes. Sensory loss is over the dorsum of the foot.337 Tibial nerve (S1 \200\2233) Loss causes calcaneovalgus and inability to stand on tiptoe or invert the foot. Sensory loss is over the sole. Injuries to arteries Bleeding is usually controllable by pressure and eleva- tion of the part. After a ny injury in which an artery may have been damaged, examine distal pulses carefully. If the y are not felt, do not assume that this is due to spasm, but request expert help. Explorati on with end-to-end suture, or reversed vein grafts may be needed. The prognosis is not so b ad if there are good collaterals (eg to the femoral artery, compared with the popliteal art ery). Complications: Gangrene, contractures, false aneurysm, and arteriovenous \201 s- tu lae. \200\207See OHCM p658 for acute limb ischaemia. 761 Sensory relearning after median nerve repair: the Lundborg \200\223 Ros n metaphor Tactile gnosis This is tested by 2-point discrimination and tactile recognition of objects. Restor ation of tactile gnosis in the hand is the main challenge of median nerve repair. It is eas y to point out that touch is a major way we interact with our world. a m u a r t d n a s c i d e a p o h t r O More subtle is how the brain performs cross-modal interpretation of our world \200\224ie in tegrating touch, sound, and vision, and producing meaning out of this integration. Loss of one modality is not a simple case of subtraction, but gives rise to complex compensatory me chanisms. Interpretation of tex- tures, for example, is not usually regained after major in jury to a nerve trunk in adults, but there is more plasticity in children: here, cortical r emodeling allows meaningful interpretation from misconnected regrown axons. Best results of repair are seen before the age of 10yrs. By 18yrs, there has been a rapid d ecline in relearning ability. There is an unexplained temporary increase in learning abilit y in the late twenties. This pattern, intriguingly, fol- lows that of our ability to learn a new language. So the notion that the prob- lem after nerve injury/repair is that \200 \230the hand is speaking a new language to the brain \200\231 is more than an metaphor; acc epting this metaphor leads to the idea that education and training are vital to successful nerve repair.338 Median nerve anatomy The median nerve arises from C5, C6, C7, C8, & T1 as a condensation of lateral & medial cords of brachial plexus (p765). It crosses medial to the brachial artery in antecubital fossa. It has no branches above the elbow. 5cm distal to elbow it gives of f its anterior interosseous branch (motor to \202 exor policis longus (FPL), \202 exor digitorum profundus (FDP,) index \201 nger & pronator quadratus). The pal- mar cutaneous branch (sensory to thenar skin) arises 5cm proximal to wrist and overlies the \202 exor retinaculum. The recurrent motor branch to the thenar muscles arises at the distal end of c arpal tunnel. The median nerve is motor to PT (pronator teres), FCR ( \202 exor carpi radi alis), PL (palmaris longus), FDS ( \202 exor digitorum super \201 cialis), LOAF (radial 2 lumbricals, opponens pollicis, abductor pollicis, \202 exor pollicis brevis). Sensation: radial 3-and-a-half digits. See \201 g 1, p669 for a cross-sectional diagram of the carp al tunnel. Dermatomes and peripheral nerves 762 V1 Ophthalmic division Maxillary division Mandibular division Trigeminal V2 Great auricular, C2,3 V3 Cervical plexus, super \201cial branches C3 Intercostal nerves T2 \200\223T11 Lateral cutaneous br. Anterior cutaneous br. C4 T2 T3 C5 T4 Axillary Intercostobrachial Medial cutaneous Musculocutaneous T5 T6 a m u a r t d n a T7 Posterior cutaneous Super \201cial branch Brachial plexus C6 & C7 T8 T1 Radial T9 T10 T11 T12 s c i d e a p o h t r O Median L1 C7 Ulnar Iloinguinal Genitofemoral Lateral cutaneous L2 Lumbar plexus Anterior cutaneous rami L3 Femoral Saphenous L5 L4 Lateral cutaneous nerve of calf Sacral plexus Sciatic Super \201cial and deep peroneal S1 Sural Medial plantar Fig 1. These images re \202 ect the 2011 evidence-based dermatomes, which have revealed mu ch more individual variation than originally thought, so much so that some areas have been left blank (white) because no single best option can be given. Plantar surface Cutaneous innervation of the foot Dorsal surface Super \201cial branch of radial 1 Saphenous nerve Palmer surface Dorsal surface 1 2 Deep peroneal nerve 4 5 Super \201cial peroneal nerve 3 Median 4 Medial plantar nerve 3 5 Lateral plantar nerve 7 7 6 Calcaneal branch (tibial nerve) Ulnar 2 6 7 Sural nerve Dorsal cutaneous branch of ulnar Median Fig 3. Feet and hands See p716 for testing peripheral motor nerves. Figs 1 and 2 adapted from Lee MWL, McPhee, RW , Stringer MD (2008) An evidence-based approach to human dermatomes , Clinical Anatomy 21: 363 \200\223373, with permission from John Wiley & Sons. 763 Ophthalmic division Maxillary division Mandibular division Trigeminal C2 Super \201cial cervical plexus Mastoid branch, C2,C3 Great auricular branch, C2,C3 Occipital, C2 Occipital, C3 Occipital, C4 Occipital, C5 \200\223C8 Supraclavicular, C3, C4 Dorsal rami of thoracic nerves Cutaneou s branch of axillary Lateral cutaneous branches of intercostal nerves a m u a r t d n a s c i d e a p o h t r O C3 Dorsal branches C4 C5 T2 T3 T4 T5 T6 T7 T8 Medial and lateral cutaneous br. of radial T9 T10 T11 Medial cutaneous Intercostobrachial C7 Musculocutaneous T12 L1 Super \201cial branch of radial T1 L2 L3 S3 S4 S5 C8 C6 & C7 Gluteal branch of 12th intercostal Lateral cutaneous br. of iliohypogastric Lateral branche s of dorsal lumbar and sacral rami Medial branches of dorsal rami, L.1 \200\223S.6 L3 S1 Pudendal plexus Perforating branch of Posterior cutaneous S2 Lateral cutaneous Obturator Medial cutaneous Saphenous Lumbar plexus Femoral L4 Posterior cutaneous Super \201cial peroneal Sural Tibial Lateral plantar Common peroneal Sacral plexus S1 Fig 2. Posterior view Aim to keep a few key dermato- mes up your sleeve. C3 \200\2234 C6 \200\2237 T1 T12 L1 Clavicles Lateral arm/forearm Medial side of arm Thumb Middle \201 nger Little \201 nge r Nipples Umbilicus Anterior & inner leg Medial side of big toe Posterior & outer leg Later al margin of foot and little toe Perineum The above is a rough approximation C6 S2 S2 C7 C8 S3 S4 S5 T4 T10 L2 \200\223L3 L5 L5, S1 \200\2232 S1 S1 Fig 4. Perineal dermatomes. S2 \200\2234 Injuries to the brachial plexus The brachial plexus extends from the intervertebral foramin a to the axilla spanning a distance of 15cm. Useful landmarks on its route from cord to ar m worth remembering are: \200 The roots leave the vertebral column between the scalenus m edius and ante- 764 rior muscles (see \201 g 2). The creation of divisions from trunks takes place under the clavicle, medial to the coracoid process. The plexus has an intimate relationship with the subclavian and then axillary arteries, wit h the median nerve forming from the medial and lateral cords anterior to the latter. Look f or the characteristic \200\230M \200\231 formation: see \201 gs 1 & 3. Traumatic causes Direct eg shoulder girdle fracture, penetrating or iatrogenic. Indirect eg avulsion/tractio n injuries, due to excessive lateral \202 exion of the neck \200\224as may occur in motor cycle injuries, or to the newborn during delivery. Atraumatic causes Tumors (eg Pancoast, f rom lung), radiation, neuropathy. Classifying the injury can be done according to the Leff ert classi \201 cation:339 a m u a r t d n a Open s c i d e a p o h t r O I II Closed (IIa supraclavicular, IIb infraclavicular) III Radiation IV Obstetric; (IVa upper root (Erb \200\231s palsy), IVb lower root (Klumpke \200\231s palsy), IVc mixed) Root injuries There are 4 types: high, middle, low or complete. \200 High lesions: Erb \200\231s palsy (C5, C6) Damage aff ects the suprascapular, mus- culocutaneous and axillary nerves. This leads to paralysis of supraspinatus (abduction), infraspinatus (external rota tion), biceps (supination), brachialis ( \202 exion of elbow), deltoid (abduction) and ter es minor (external rotation). As a result the arm is held internally rotated, pronated, ext ended and adducted in the \200\230waiter \200\231s tip \200\231 position. Sensation is imp aired over deltoid, lateral fore- arm, and hand. Diffi cult deliveries (or any trauma in a downwards direction) can produce this sign in neonates. \200 Middle (Brunelli) lesions: ( C7) Produced by anteroposterior trauma (11%).340 \200 Low lesions: Klumpke \200\231s para lysis (C8, T1) Occurs when the arm is pulled supe- riorly (forced abduction) \200\224for ex ample trying to break a fall from height by grabbing onto something. Damage to the C8, T1 r oots leads to a combination of median and ulnar nerve injury which may produce \200\230cla w hand \200\231 (extension at MCP joints, with \202 exion at DIP/PIP joints) due to loss of lumbrical function. The arm is held in adduction. Horner \200\231s syndrome (p424) may a lso occur. Injury to the cords (in green in \201 g 1) \200 Injury to the lateral cord of the plexu s: Absent power in the biceps and bra- chioradialis ( \202 exes the forearm at the elbow). Posterior cord injury: Teres major & deltoid inaction; radial nerve palsy. \200 Medial co rd injury: Aff ects the ulnar and median nerves. Sensation is absent over the medial arm and hand. Recovery With incomplete trunk lesions recovery may take >5 months. Prog- nosis is poor in lesions proximal to the dorsal root ganglion (DRG). For intra- dermal histamine (1%, into t he aff ected limb) to produce an arterial \202 are, the route to the DRG must be intact, so if this is present the lesion is proximal to the DRG. MRI gives the best images. Early l iaison with a regional center is advised as early exploration improves the outcome of nerve repair. Surgical options include nerve grafting of viable roots, nerve transfer (from inte rcostal nerves,) free functioning muscle transfers and tendon transfers.341 765 a m u a r t d n a s c i d e a p o h t r O Fig 1. The brachial plexus, the b te noire of medical students. This diagram should be jus t memorizable the night before an exam. Image courtesy of Luke Famery. Fig 2. The proximal brachial plexus. The purpose of this \201 g- ure and \201 g 3, is t o show where the brachial plexus is, and not what the brachial plexus is. Fig 3. The distal brachial plexus: note the relationship with the axillary artery. \200 Spinal cord injury \200\224the \201 rst day At the accident Assume that spinal inju ry is present in any serious accident, and in all accidents when the nature of the injuring force is not known, and the patient is unconscious. The patient can be moved into the reco very posi- tion (protection of the airway is always the \201 rst priority) \200\224but al l movement should be planned. Keeping the head in neutral, the patient may be \200\230log- rolled \200\231 into a semi-prone position (not lateral, see p799). If any spinal injury is sus- pected at the scene, the paramedics will apply a hard neck collar, place the head bet ween sandbags, and strap the patient onto a spinal board \200\224some will use in \202 ata ble bean bag boards to reduce pressure.342 Assessment343 Inital assessment must be focused on ABCs. Intubate and ventilate patients with high tetraplegia early on. Prevent and treat hypoten- sion (aim for SBP >90). Look for, and exclude other injuries before assigning caus e of hypotension to neurogenic shock. Restore intravascular volume (don \200\231t overload) then consider use of vasopressors. Checking lactate levels may help with assessment of sho ck and need for \202 uid resuscitation. Monitor and treat symptomatic bradycardia. Monito r and regulate temperature. Perform serial neurological examinations to assess for deterior ation. Imaging Don \200\231t rely on mobile equipment; if possible, take to the radiology d epartment, supervising all movements closely. If there is a clear spinal cord injury, and t he patient is stable, CT is the \201 rst line of imaging. Image the whole spine as there may be more than one injury.343 MRI shows fractures, subluxa- tions, disc disruption and pr otrusion, and cord contusion \200\224and helps establish prognosis. \200\207NB: it is hard to arrange in emergency settings, and takes a lot longer than CT (eg 20min vs 20s). Conseq uences of injury Respiratory insuf \201 ciency: Check vital capacity rep- eatedly. If <500 \200\223600mL, intubation and ventilation will be needed. Monitor arterial blood gasses. I ntubation may produce vagal bradycardia, so give at- ropine 0.3 \200\2230.6mg IV before int ubation and suction. If abdominal distension is causing respiratory embarrassment, pass an NGT. Fluid balance: There is likely to be hypotension below the lesion (sympathetic interru ption and resultant neurogenic shock \200\224 \200\201BP and pulse rate). This is not due t o hypovolaemia, and it is dangerous to give large volumes of \202 uid. Use IV not oral \202 uids for 48h and while ileus persists. The skin: Turn every 2h between supine and righ t and left lateral positions. The Stoke Mandeville bed does this electronically. Use pil- l ows to separate the legs and maintain a lumbar lordosis. The bladder: Pass a 12-gauge silic one 5mL balloon catheter before the bladder volume exceeds 500mL (overstretching of detruso r can delay the return of automatic bladder function). See p772. Treatment Steroids: \200 \207Methylprednisolone use is controversial. It is rec- ommended in a Cochrane review in 20 02344 (updated in 2009) but the data is contested and other guidelines/systematic reviews s uggest it should not be used.343,345,346 Use within UK centers varies considerably.347 Seek specialist advice Get expert advice on removing prior to use. Early surgical decompression : damaging bone & disc fragments. (Late internal fusions may also be tried.) There may be n o diff erence in neurologic or functional improvement with early vs late surgery.348 Tracti on: Skeletal traction will be needed for cervical injuries. Spring-loaded Gardner \200\223W ells skull tongs are preferable to Crutch \201 eld calipers, which need incisions. Anticoa gulation: Acute cord injury patients are at very high risk of developing VTE, with asymptom atic DVT demonstra- ble in 60 \200\223100% of patients. LMWH (eg enoxaparin 40mg/24h SC) is currently recommended over unfractionated heparin regimens by the American College of Ches t Physician guidelines for prevention of VTE. Start warfarin later, and continue prophylaxi s for at least 3 months or until completion of inpatient re- habilitation.349,350 \200\207 Arrange early and expert transfer to a spinal injuries unit. 766 \200 a m u a r t d n a s c i d e a p o h t r O 767 Does this patient have a spinal cord injury?351 In any unexplained trauma, suspect cord inj ury if: \200 Responds to pain only above clavicle. \200 Dermatomal pattern of sensory l oss. \200 Breathing \200\224diaphragmatic without use of accessory respiratory muscles. \200 Muscles \200\224hypotonic, including reduced anal tone (do a PR). \200 Re \202 exe s \200\224hypore \202 exic. \200 Absence of movement in both legs. \200 Slow pulse and \200\201BP, but in the presence of normovolaemia. \200 Priapism1 or urinary retention. \200 Unexplained ileus. \200 Clonus in an unconscious trauma patient without decerebrat e rigidity. \200 Poikilothermia (poor temperature regulation). The ASIA scale can be used to describe the completeness of the injury: a m u a r t d n a s c i d e a p o h t r O [ASIA=American Spinal Injury Association] A Complete; no sensory or motor function in sacral segments s4 \200\223s5 B Injury incomple te; sensory but not motor function preserved below the neuro- logical level, and extending through sacral segments s4 \200\223s5 C Incomplete; motor function preserved below the level, most key muscles weaker than grade 3 (ie no movement against gravity) D Incomplete; motor function preserved below the level; most key muscles are stronger than grade 3, ie active movement against gravity E Normal motor and sensory function \200\207NB: in the pediatric population SCIWORA (p658) is more common, and so careful clinical examination must be undertaken. Good knowledge of anatomi- cal and developmental variation is also required when assessing plain radio- graph s \200\224eg pseudosubluxation of C2 on C3 mimicking injury. What are the mechanisms of injury? Primary injury (immediate) is easy to understand: within seconds, the cord expands to occupy the entire diameter of the spinal canal. Glutamate \202 oods out of neurons, overexciting their neighbors. Calcium \202 oods in, leading to the formation of toxic free radicals. Secondary injury (delayed, eg unfolding over weeks) i s a response to release of neurotoxins and apoptosis (cell death) which may spread up to 4 segments away from the trauma site.352 How long can immobilization go on? Neck collars and spine immobilization protocol can remai n on an unconscious pa- tient for as long as 48h after presentation, usually because it has not been possible to safely clear the spine from injury in the presence of more immediatel y life-threat- ening problems. However, immobilization is given such an initial priority be cause it can be done immediately and does not hinder progress of treatment. It would be a t ragedy for a patient to survive life-threatening trauma, only to be paraplegic on account o f inattention. \200 NB: Remember that a spinal cord injury causing anesthesia may be masking serious inju ry below the lesion (eg compartment syndrome, acute abdomen). 1 Priapism is when pathologic stimuli (eg cervical cord lesions) cause prolonged erection ( >4h), or when normal stimuli occurring under pathologic circumstances \200\224eg stasis fro m sickle-cell disease or leukemia with leucostasis (WCC \200\200 \200\200) cause prolonged erections. As it can cause permanent damage, get help. Bilateral shunting between the corpu s cavernosum and corpus spongiosum may be needed. Priapism is named after Priapus, the son of Aphrodite (the goddess of love). He, though, is ugly in most depictions \200\224with a p enis so large that he is generally relegated to the position of a scarecrow in the \201 e lds. From this position he is happy to be the god of gardens, bees, goats, sheep \200\224an d fertility. Images of cord pathology and anatomy 768 \200 a m u a r t d n a s c i d e a p o h t r O Fig 1. Cord compression. Because of diff erent technical settings, MRI images can be called T1 or T2 weighted. These images can be recognized as T2 weighted because the CSF is white (see OHCM p749). Compression of the cord has occurred as a result of: a disc protru- sion, b metastatic deposit, and c trauma. Images Prof Peter Scally. Fig 2. Cross-section of the spinal cord. The only neurons to decussate at (or near) their s pinal cord level are those in the spinothalamic tract. Pyramidal tract \201 bres decussat e in the medulla and the dorsal column \201 bres decussate after the gracile and cuneate nuclei of the medulla. Incomplete spinal cord injuries (see \201 gs 3 \200\2235) and youn ger patients have a better prognosis.353 769 Dorsal column Pyramidal tract Fig 3. Brown \200\223S quard syndrome (OHCM, p710). In this rare injury pattern, there is hemisection of the spinal cord (more often seen after penetrating rather than blunt trauma) , causing ipsilateral loss of dorsal column sensation and motor function below the lesion a nd contralateral loss of spinothalamic sensation from a few levels below the lesion. NB: sp inothalmic tract \201 bres as- cend for a few levels on the same side as cord entry befor e they decussate. Spinothalamic tract a m u a r t d n a s c i d e a p o h t r O Level of spinal cord hemisection Dorsal column Affected area of cord Pyramidal tract Spinothalamic tract Anterior spinal artery Fig 4. Anterior cord syndrome. There is infarction of the spinal cord in the distribution o f the anterior spinal artery, causing complete loss of motor function and pain and temperat ure sensation below the lesion. Vibration and joint position sense are retained. This injur y pat- tern has the worst prognosis of the incomplete injuries. Pyramidal tract Affected area of cord Dorsal column Spinothalamic tract Fig 5. Central cord syndrome. Usually seen after a hyperextension injury in someone with pr e-existing spinal canal stenosis (most often in the cervical region). There is greater loss of motor power in the upper extremities compared to the lower extremities combined with va rying patterns of sensory loss and sphincter dysfunction. Figs 2-5 adapted from Donaghy, M. Oxford Core Texts: Neurology with permission from OUP Cord injury \200\224function and functional anatomy The \200\230tightest \201 t \200\231 between cord and canal is in the thoracic spine; this region also has the poorest blood su pply. These facts explain why thoracic lesions are more likely to be complete than cervical or lumbar lesions. Ischaemic injury often spreads below the level of the mechanical injury . For the segment of the cord involved with injury at a speci \201 c vertebra, see below. Cord compression For causes, see MINIBOX. Root pain (p674) and lower motor neuron signs occ ur at the level of the lesion with upper motor neuron signs and sen- sory changes below the lesion (spastic weakness, brisk re \202 exes, upgoing plantars, loss of co-ordination, jo int position sense, vibration sense, temperature and pain). Cord anatomy (p768) is such tha t dorsal column sensibilities (light touch, joint position sense, vibration sense) are aff ected on the same side as the insult, but spinothalamic tract interruption aff ects pain an d temperature sensation for the opposite side of the body 2 \200\2233 dermatome levels lowe r than the aff ected sensory level. As the cord ends at L1, compression at this vertebral l evel aff ects information in the cord relating to lower dermatomes. To determine the cord l evel aff ected behind a given vertebra, add the number in blue to that of the vertebra conc erned, thus: \200 C2 \200\2237: +1 \200 T1 \200\2236: +2 \200 T7 \200\2239: +3 \200 T10 has L1 and L2 levels behind it \200 T11 has L3 and 4 \200 L1 has sacral and coccyg eal segments. It can be diffi cult to determine the level: MRI will help clarify this. 770 \200 Causes: \200 Bone displacement \200 Disc prolapse \200 Local tumor \200 Abscess \200 Haematoma a m u a r t d n a s c i d e a p o h t r O Lower lumbar problems can cause cauda equina compression ( \200 p675) characterized by musc ular pain, dermatomal sensory changes (if the lowest sacral dermatomes are aff ected the ge nitals are anesthetic), and retention of urine feces. \200\207These signs indicate urge nt neurosurgical referral with imaging eg to con \201 rm or exclude a tumor or extradural abscess. Spinal shock There is anesthesia and \202 accid paralysis of all segments, and m uscles innervated below the level (hence are \202 exia) and there is re- tention of urine. A \200\230stage of reorganization \200\231 then occurs (re \202 ex emptying of bladder a nd rectum; sweating). Later, \202 exion at hip and knee may be in- duced by stimuli (nota bly cold), often with empty- ing of the bladder and rectum (Head and Riddoch \200\231s mass re \202 exes). The legs may become permanently \201 xed in a drawn up position, with do rsi \202 exion of the ankles (spastic paraple- gia in \202 exion). Over months, tendon r e \202 exes return, and proprioceptive stimuli give rise to \200\230mass extension \200 \231. Exact duration is not predictable. Spinal or neurogenic? \200\207NB: don \200\231t confuse spinal shock with neurogenic shock : the latter is BP \200\201 tachycardia, without caused by impairment of the descending spi nal sympathetic pathways. Paraplegia/quadriplegia levels (See also p716 for testing motor nerves) Levels \202 uctua te (as does interpretation), so examine often: Raises elbow to horizontal: deltoid C5 Flexes hip: iliopsoas Flexes forearm: biceps Extends forearm: triceps Flexes wrist and \201 ngers L2 C6 Extends knee: quadriceps C7 Dorsi \202 exes ankle: tibialis anterior C8 Extends great t oe: Extensor hallucis L3 L4 L5 longus Spreads \201 ngers T1 Plantar \202 exes ankle: gastrocnemius S1 771 Restoring lost function: is it possible? The following is not a list of well-tried treatmen t options: the \201 eld is too new. Here we present a way of thinking about cord injury, and preparing our minds for discussions with experts. Most patients prioritize their wishes for restora- tion of functions in this order: bowel and bladder control; sexual function; hand function; breathing. Options might be: \200 Glutamate receptor blockers to limit sec ondary injury (p767). \200 Anti-apoptotic agents, eg NT-3 (neurotrophin-3), BDNF (brain-d erived neuro- trophic factor), and ICE-protease (interleukin-1 \200 -converting enzyme) inh ibi- tors. a m u a r t d n a s c i d e a p o h t r O Chemical prevention of action potential dissipation from demyelinated ar- eas agents to remyelinate axons. \200 Blocking natural inhibitors of regeneration, eg IN-1 (inhibitor n eutralizing antibody). Promotion of axonal regeneration \200\224eg BDNF & NT-3, (see above). Note that guidance of axons must be arranged, eg via guidance molecules such as netrins, cell adhesion molecules , and speci \201 c matrix proteins. Replacement of lost cells (cloned embryonic stem cells are one option; use of endogenous progenitor cells is another option). Often these options seem a long way off , but note that only 10% of damaged neurones need t o be replaced to enable useful locomotion.354,355 Segment injury \200\224a guide to possible subsequent function: C4 Can use electric chairs with chin control; type with mouthstick; use a \200\230Pos- sum \200\231 environmental control system to turn on lights & open doors. C5 With special devices, he can feed, wash face, comb hair, and help with dress- ing the up per body. He may be able to push a wheelchair along the \202 at, if pushing gloves are wo rn, and there are capstan rims on the wheels. The NHS will supply an electric wheelchair (i ndoor use only). Unable to transfer from wheelchair to toilet. C6 Still needs a strap to aid feeding and washing. Dresses top half of body; helps dress lower half. Can drive with hand controls. C7 Can transfer, dress, feed himself. C8 Independent wheelchair life.