The Head Lecture 18

Bones of the Skull

the skull is primarily composed of flat bones that interlock at immovable joints called sutures

the skull often referred to as the cranium protects the brain

8 cranial bones and 14 facial bones

The Scalp is composed of three layers

i) the skinii) subcutaneous tissueiii) pericranium

the protective function these tissues is enhanced by the hair and the looseness of the scalp

this enables some dissipation of force when the head sustains a glancing blow

the scalp and face have extensive blood supply , hence lacerations to the face and scalp tend to bleed profusely

Scalp Injuries

the scalp is highly vascular and bleeds freely

primary concern is to control bleeding and to prevent contamination

must check for skull fracture apply mild pressure , clean wound and

refer to physician for suturing

The Brain

the brain has four major regions which are the i) cerebral

hemispheresii)

diencephaloniii) brainstem iv) cerebellum

the entire brain and spinal cord are enclosed in three layers of protective tissue known as the cerebral meniges

the outer layer – dura mater, which is thick fibrous tissue connective tissue that is a protective membrane to the brain,highly vascular containing both arteries and veins

the arachnoid mater ( middle) is a thin membrane separated from the dura mater by the subdural space

beneath the arachnoid mater is the subarachnoid space , which is filled with Cerebral Spinal Fluid ( CSF) which purpose is to cushion the brain from external forces

the third layer ( inner) pia mater is a very thin and delicate membrane that is physically attached to the brain tissue and serves to provide the framework for extensive vasculature that supplies the brain

Twelve Cranial Nerves

Pairs of nerves with motor, sensory or both functions

Prevention of Injuries

the most important protective measure for the head is the use of helmets

the proper use of protective equipment can protect the head from accidental or routine injuries

Cranial Injury Mechanisms the extent of the injury to the head

depends on the material properties of the skull , thickness of the skull , magnitude and direction and size ( area) of the impact

on direct impact the bone deforms and bends inwards placing the inner border of the skull under tensile strain, where the outer is compressed

if sufficient magnitude and if the skull is thin in that region , a skull fracture will occur at the site of impact

however if the skull is thick and dense enough it may withstand the inward bending without a fracture

a fracture may then occur somewhere away from the impact site where the skull is thinner

on impact shock waves travel through the skull to the brain causing acceleration

this acceleration may lead to shear, tensile and compression strains with in the brain

shear is the most serious

Coup – is a direct blow

Countrecoup - is an injury that occurs away from the actual injury site due to axial rotation and acceleration

Focal injuries – this involves only localized damage ( usually due to high velocity –low mass forces)Or

Diffuse injuries – widespread disruption and damage to function or structure of the brain ( usually due to low velocity high mass for

Skull Fractures

Skull fractures may be : linear (in a line) communited (multiple

pieces) depressed (fragments

driven internally toward the brain)

basilar ( involving base of skull)

If there is a break in the underlying dura mater, there is a high risk of bacterial infection into the intracranial cavity , which may result in septic meningitis

Signs and Symptoms

discolouration around eyes ( racoon eyes) blood or CSF may leak from nose or ears vision problems discoloration behind the ear that appears

within minutes ( battle’s sign ) a suspect skull fracture requires

immediate attention – EAP

cover open wounds with a steril dressing – but do not apply pressure

monitor vital signs – treat for shock – protect for neck injury as well

transport ASAP

Cerebral Hematomas

hematoma is a collection of blood in a localized area

with in the skull there is no room for additional accumulation of blood

any additional matter with in the cranial cavity increases pressure on the brain

leading to significant alterations in neurologic functions

type of hematoma depends on location of the accumulated blood

Majority of intercranial injuries result from blunt trauma to the head.

Epidural Hematoma

Usually an arterial bleed into the epidural space ( blood usually emerges from the middle meningeal artery between the dura mater and the cranial bones)

the athlete will have a initial loss of consciousness at the time of injury followed by a lucid interval in which they feel fine – however with in 10 to 20 minute a decline in mental status will occur very rapidly

S/S headache , blurred vision, speech changes, mental

confusion, a decreased level of consciousness , and dizziness

Rx- immediate surgery is required to decrease pressure and control bleeding

Subdural Hematoma these occur at approximately

three time the rate of epidural hematomas

haemorrhaging occurs below the dura mater and involves bleeding from a cerebral vein rather than an artery ( low pressure venous bleeding that clots slowly)

Onset of s/s may be more gradual in some cases 24- 72 hours

S/S Patient may be conscious with out any s/s because of the delay in S/S this is the most

prevalent cause of death from a trauma in sports hence all head injuries must be monitored for

delayed complications ,they will get progressively worse

S/S to watch out for ; persistent headache or increasing headache nausea and or vomiting restless and irritable , or drastic changes in

personality increasing mental confusion dizziness difficulty speaking or slurring of speech progressive or sudden impairment of

consciousness

Rx- immediate emergency response -- surgical drainage with in less than 4 hours of the injury

Concussions A concussion is a type of traumatic

brain injury that interferes with normal function of the brain.

May be caused by direct blow to the head, face, or elsewhere on the body with any force transmitted to the head

Basically any force that is transmitted to the head that causes the brain to bounce or twist around in the skull

Concussion Typically results in the rapid onset of short lived impairment

of neurological function that resolves spontaneously May result in neuropathological changes , but acute clinical

symptoms largely reflect a functional disturbance rather than a structural injury

May or may not involve loss of consciousness ( only approximately 10 % result in LOC)

Concussions are typically associated with normal structural neuroimaging studies ( CAT and or MRI’s)

Concussion Effects

Concussions effect four areas of functionality

The way the person feels How they think Changes in emotions How they sleep

Signs to watch for in athletes Appears dazed or stunned Confused about assignments Forgets plays Unsure of game score or opponent Moves clumsily Answers questions slowly Behaviour or personality changes Can’t recall events prior to or after injury LOC

Symptoms to watch for in Athletes Headache Nausea Balance problems /dizziness Double or blurry vision Sensitivity to light or noise Feeling sluggish , foggy Concentration or memory problems confusion

SCAT

See handout

Second Impact Syndrome this occurs when an athlete (generally

seen in children under 18) has sustained a head injury – usually a concussion and then sustains a second concussion before the symptoms associated with the first injury have totally resolved

the athlete may receive a relatively minor second blow to the head – the athlete often continues to compete and may be able to function fine for a short period of time

however the cranium becomes engorged with blood increasing the pressure on the brain

the athlete collapses , slips into a comatose state and respiratory failure ensues

the usual time from second impact to brainstem failure is rapid , 2 to 5 minute

Hence it is imperative any athlete who complains of headache, light headiness, visual disturbances or other neurologic symptoms should not be allowed to participate in any athletic event until they are totally asymptomatic

“When in doubt sit them out”

Assessment of Cranial Injuries head traumas demand immediate

assessment for life threatening conditions be aware that head injuries may also cause

neck and or spinal injuries , stabilize the head and neck

never use ammonia capsules to arouse the person , as they may jerk the head and neck leading to serious complications

observe vital signs determine level of consciousness

History Mechanism of injury - what happened,

what position at impact Loss of consciousness- how long? unresponsive, confused , disoriented do they respond to painful stimuli Amnesia - confusion loss of memory of events after injury

(posttraumatic amnesia)

loss of memory prior to injury ( retrograde amnesia)

Pupil abnormalities- note pupil size and accommodation to light - both should be equal (PEARL)

one side dilated pupil may indicate a subdural or epidural hematoma

bilateral dilated pupils indicates a severe cranial injury

vision problems - blurred, double , seeing stars

Headache - does the individual have one progressive headaches indicates

increasing pressure Nausea or Vomiting - intracranial

pressure can stimulate the reflex and cause vomiting or nausea

Associated neck injury- pain ,numbness or weakness in the extremities ,grip strength , sensations sharp or dull

Observations

1) Leakage of Cerebrospinal fluid - CSF is clear, colorless fluid that protects the brain and spinal cord

2) Signs of Trauma - discolouration around the eyes, behind the ears

- bleeding , depressions , lacerations or hematomas

3) Skin colour - note skin colour and presence of moisture

- watch for signs of shock 4) Loss of emotional control - irritability,

aggressive behaviour , uncontrolled crying - refer to Physician

Palpation

Palpations can help to pinpoint possible skull fractures. Palpate for points of tenderness, crepitus , depressions, swelling , blood or changes in skin temperature.

Special Tests

Special tests assess brain function through co-ordination, balance, depth perception and logical thought process

1) 100 minus 7 - test's ones ability to concentrate.

Individual starts at at 100 and subtract 7 , then 7 again and so on.

Month backwards

2) Finger to nose test - tests depth perception and ability to focus on an object

Hold a finger out front of the individual and ask them to reach out and touch it, alternate between left and right hand , can move finger around. A variation is to have the individual to touch their nose between touches.

3) Rhomberg's test - balance test - individual stands with feet together arms at side and eyes closed while maintaining their balance.

Variations include raising arms to 90 degrees , standing on toes or touching nose with eyes closed.

4) Stork stand - with eyes closed have individual stand on one leg

5) Heel /toe walking - ask individual to walk on toes and then on heels - note swaying or inability to walk in a straight line

Determination of Findings If the individual is not in a crisis situation ,

vital signs and special tests should be completed every 5 to 7 minutes to determine progress of condition.

The recommendation with all concussions is the athletes should not return to play on the same day , should be reassessed and return to play guidelines followed ( see SCAT )

If S/S linger but appear minor an individual close to the injured person should be informed of the injury and told to watch for changes in behaviour, unsteady gait , slurred speech , progressive headache or nausea, restlessness , mental confusion or drowsiness.

These danger signs should be documented on a sheet to give out and given to the individual watching the injured person. If any S/S worsen then the injured person should be taken to the emergency room ASAP.

Must be checked by medical personal at some time

Must never be sent alone to the bus ,locker room, home etc.

When to call the ambulance ?A player with a witnessed LOC of any duration

A player who exhibits the one or more of the following symptoms

Decrease level of consciousness

Unusual drowsiness or the inability to be awakened

Difficulty getting attention

Breathing difficulty

Severe or worsening headaches

Vomiting

Seizures

Rest for a player with a concussion at home Sleep often Limit brain stimulation

phone ,computer, texting, tv

gaming

Cognitive and Physical rest

Rest for a player with a concussion at school Stay at home or attend half days Take naps , need rest time Extended time for assignments or tests Written instructions for assignments Repeat and present new information

slowly