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Clinical Not es
Clinical Signif icanc e of t he Scalp Structur e
It is important to reali ze that the sk in, the subc utaneous tiss ue, and the epicranial aponeurosis are
closely united to one another and are separated from the periosteum by loose areolar tissue.
The skin of the scalp possesses numerous sebaceous glands, the ducts of which are prone to infection
and damag e b y c ombs. For t hi s reas on, se bac eous c ys ts of the sc alp a re c ommon.
Lacerat ions of t he Sc alp
The scalp has a profuse blood supply to nourish the hair follicles. Even a small laceration of the
scalp can cause s evere bl ood loss. It is often difficult to stop the bleeding of a scalp wound becaus e
the arterial walls are attached to fibrous septa in the subcutaneous tissue and are unable to contract
or retract to allow blood clotting to take place. Local pressure applied to the scalp is the only
satisfactory method of stopping the bleeding (see below).
In automobile accidents, it is common for l arge areas of the scalp to be cut off the head as a person i s
projected forward through the windshiel d. Because of the profuse blood suppl y, it is often possible to
replace large areas of scalp that are only hanging to the skull by a narrow pedicle. Suture them in
place, and necrosis will not occur.
The tension of the epicranial aponeurosis, produced by the tone of the occipitofrontalis muscles, is
important in all deep wounds of the scalp. If the aponeurosi s has been divided, the wound will gape
open. For satisfactory healing to take place, the opening in the apone urosis must be closed with
sutures.
Often a wound caused by a blunt object such as a baseball bat closely resembles an incised wound.
This is because the scalp is split agai nst the unyieldi ng skull, and the pull of the occipitofrontalis
muscles causes a gaping wound. This anatomic fact may be of considerable forensic importance.
Life-T hreat ening Scal p Hemorrhage
A n a t o m i c a l l y, i t i s u s e f u l t o r e m e m b e r i n a n e m e r g e n c y t h a t a l l t h e s u p e rf i c i a l a rt e ri e s s u p p l yi n g t h e
scalp ascend from the face and the neck. Thus, in an emergency situation, encircle the head just
above the ears and e yebrows with a tie, shoelaces, or even a piece of string and tie it tight. Then
insert a pen, pencil, or stick into the loop and rotate it so that the tourniquet exerts pressure on th e
arteries.
Scalp Inf ect ions
Infections of the scalp tend to remain loc ali zed and are us uall y painful becaus e of the abundant
fibrous tissue in the subcutaneous l ayer.
Occasionall y, an infection of the scal p spreads by the emissary vei ns, which are valvele ss, to the skull
bones, causing osteom yelitis. Infected bl ood i n the dipl oic v eins may travel by the emissary veins
farther into the venous sinuses and produce venous sinus thrombosis.
Blood or pus may collec t in the potential spac e beneath the epicranial aponeurosis. It tends to s pread
over the skull, being limited in front by the orbital margin, behind by the nuchal lines, and laterally by
the temporal lines. On the other hand, subperiosteal blood or pus is limited to one bone because of
the attachment of the periosteum to the sutural ligaments.
Clinical Not es
Sensory Inne rvat ion and Trigeminal Neura lgia
The facial skin receives its sensory nerve supply from the three divisions of the trigeminal nerve.
Remember that a small area of skin over the angle of the jaw is supplied by the great auricular nerve
(C2 and 3). Trigeminal neuralgia is a relatively common condition in which the patient experiences
excruci ating pain in the distribution of the mandi bular or maxillar y division, with the ophthalmic
division usuall y escapi ng. A physician shoul d be abl e to map out accuratel y on a patient's face the
distribution of each of the divisions of the trigeminal nerve.
Clinical Not es
Blood Supply of t he Facial S kin
The blood supply to the skin of the face is profuse so that it is rare in plastic surgery for skin flaps to
necrose in this region.
Facial Art e ries and Taking t he Patient 's P ulse
The superficial temporal artery, as it crosses the zygomatic arch i n front of the ear, and the faci al
artery, as it winds around the lower margin of the mandible level with the anterior border of the
masseter, are commonly used by the anesthetist to take the patient's pulse.
Clinical Not es
Facial Inf ect ions and Cavernous Sinus Thr ombosis
The area of facial skin bounded by the nose, the eye, and the upper li p is a potentiall y dangerous zone
to have an infection. For example, a boil in this region can cause thrombosis of the facial vein, with
spread of organisms through the inferior ophthalmic veins to the cavernous sinus. The resulti ng
cavernous sinus thrombosis m ay be fatal unless adequately treated with antibiotics.
C l i n i ca l N o te s
F a c ia l M u sc l e P a r a l ys i s
The facial muscles are innervated by the facial nerve. Damage to the facial nerve in the internal
acoustic meatus (by a tumor), in the middle ear (by infection or operation), in the facial nerve canal
(peri neu ritis, Bel l's pals y), or in the pa rotid glan d (b y a t umor) or ca use d b y l aceration s o f the f ace
will cause distorti on of the face, with drooping of the lower eyelid, and the an gl e of the m outh will sag
on the affected side. This is essentially a lower motor neuron lesion. An upper motor neuron lesion
(involvement of the pyramidal tracts) will leave the upper part of the face normal because the neurons
supplying this part of the face receive corticobulbar fibers from both cerebral cortices
Cleft Upper Lip
Cleft upper lip may be confined to the lip or may be associated with a cleft palate. The anomaly is
usuall y unilateral cleft lip and is caused by a failure of the maxillar y proce ss to fuse with the medial
nasal process ( Figs. 11 -44 and 11-45). Bilateral cleft lip is caused by a fail ure of both m axillary
processes to fuse with the medial nasal process, which then remains as a central flap of tissue ( Figs.
11-46 and 11-48). Median cleft upper lip is very rare and is caused by the failure of the rounded
swellings of the medial nasal process to fuse in the midline.
O blique Facial Clef t
Oblique facial cleft is a rare condition in which the cleft lip on one side extends to the medial margin
of the orbit (Figs. 11-44 and 11-47). This is caused by the failure of the maxillary process to fuse with
the lateral and medial nasal processes.
Cleft Low er Lip
Cleft lower lip is a rare conditi on. The cl eft is exactl y central and is caused by incompl ete fusion of
the mandibular processes ( Fig. 11-44).
Clinical Not es
Parotid Duct Injury
The parotid duct, which is a comparatively superficial structure on the face, may be damaged in
injuries to the face or may be inadvertently cut during surgical operations on the face. The duct is
about 2 in. (5 cm) long and passes forward across the masseter about a fingerbreadth below the
zygomatic arch. It then pierces the buccinator muscle to enter the mouth opposite the upper second
molar tooth.
Clinical Not es
Parotid Sali var y G lan d and Lesions of the Facial Ne rve
The parotid salivary gland consists essentially of superficial and deep parts, and the important facial
nerve lies in the i nterval between these parts. A benign paro tid neopl asm rarel y, if ever, causes facial
palsy. A malignant tumor of the parotid is usually highly invasive and quickly involves the facial nerve,
causing unilateral facial paral ysis.
Parotid G land Inf ect ions
The parotid gland may become acutely inflame d as a result of retrograde bacterial infection from the
mouth via the parotid duct. The gland may als o become infected via the bloodstream, as i n mumps. In
both cases the gland is swollen; it is painful because the fascial capsule derived from the investi ng
layer of deep cervical fascia is strong and limits the swelling of the gland. The swollen glenoid
process, which extends mediall y behind the temporomandibular joi nt, is responsible for the pain
experienced in acute parotitis when eating.
Frey 's S yndrome
Frey's syndrome is an interesting complication that sometimes develops after penetrating wounds of
the parotid gland. W hen the patient eats, beads of perspiration appear on the skin covering the
parotid. This condition is caused by damage to the auriculot emporal and great auricular nerves. During
t h e p ro c e s s o f h e a l i n g , t h e p a ra s ym p a t h e t i c s e c re t o m o t o r f i b e rs i n t h e a u ri c u l o t e m p o r a l n e rv e g ro w o u t
a n d j o i n t h e d i s t a l e n d o f t h e g re a t a u ri c u l a r n e rv e . E v e n t u a l l y, t h e s e f i b e rs re a c h t h e s w e a t g l a n d s i n
the facial skin. By this means, a stimulus intended for saliva production produces sweat secretion
instead.
Clinical Not es
Submandibular Sali v ary G land: Calculus F ormation
The submandibular salivary gland is a common site of calculus formation. This condition is rare in the
other salivary glands. The presence of a tense swelling below the body of the mandible, which is
greatest before or during a meal and is reduced in size or absent between meals, is diagnostic of the
condition. E xamination of the floor of the mouth will reveal absence of ejection of saliva from the
orifice of the duct of the affected gl and. Frequentl y, the stone can be pal pated in the duct, which lies
below the mucous membrane of the floor of the mouth.
Enlargement of t he S ubmandibular Lymph N odes and Sw elling o f the
Submandibular Sali v ary G land
The submandibul ar l ymph nodes are commonl y enlarged as a result of a pathol ogic condition of the
scalp, face, maxillary sinus, or mouth cavity. One of the most common causes of pai nful enlargement
of these nodes is acute infection of the teeth. Enlargement of these nodes should not be confused with
pathologic swelling of the submandibular salivary gland.
Clinical Not es
Sublingual Saliv ary G land and Cyst Formation
The sublingual salivary gland, which lies beneath the sublingual fold of the floor of the mouth, opens
into the mouth by numerous small ducts. Blockage of one of these ducts is believed to be the cause of
c ys t s u n d e r t h e t o n g u e .
C l i n i ca l N o te s
I n j u r y t o t h e L i n g ua l Ner ve
The lingual nerve passes forward into the submandibular region from the infratemporal fossa by
running beneath the origin of the superior constrictor muscle, which is attached to the posterior border
o f t h e m yl o h yo i d l i n e o n t h e m a n d i b l e . H e re , i t i s c l o s e l y re l a t e d t o t h e l a s t m o l a r t o o t h a n d i s l i a b l e t o
be damaged in cases of clumsy extraction of an impacted third molar.
C l i n i ca l N o te s
C l i n i ca l S ig n i fi c an c e o f t h e Te mp o r o ma n d ib u lar J o i n t
The temporomandibular joint lies immediately in front of the external auditory meatus. The great
strength of the lateral temporomandibular ligament prevents the head of the mandible from passing
backward and fracturing the tympanic plate when a severe blow falls on the chin.
The articular disc of the temporomandibular joint may become partially detached from the capsule,
and this results in its movement becoming noisy and producing an audible click during movements at
the joint.
D i s l o ca t i on o f t h e T emp o r o m an d i bu l a r J o in t
Dislocation sometimes occ urs when the mandible is depress ed. In this movement, the head of the
mandible and the articular disc both move forward until they reach the summit of the articular tubercle.
In this position, the joint is unstable, and a minor blow on the chin or a sudden contracti on of the
lateral pterygoi d muscles, as i n yawni ng, may be sufficient to pull the d isc forward beyond the summit.
In bilateral c ases the mouth is fixed in an open position, and both heads of the mandi ble li e in front of
the articular tubercles. Reduction of the dislocation is easily achieved by pressing the gloved thumbs
downward on the lower molar teeth and pushing the jaw backward. The downward pressure overcomes
the tension of the temporalis and masseter muscles, and the backward pressure overcomes the spasm
of the lateral pterygoid muscl es.
Clinical Not es
Intracranial H emorrh age
Intrac rani al hemorrhage may result from trauma o r cerebral vascular lesions. Four vari eties are
considered here: extradural, subdural, subarachnoi d, and cerebral.
Extradural hemorrhage results from injuries to the meningeal arteries or veins. The most common
artery to be damaged is the anterior division of the middle meningeal artery. A comparati vel y minor
blow to the side of the head, resulting in fracture of the skull in the region of the anteroinferior portion
of the parietal bone, may sever the artery. The arterial or venous i njury is especiall y liab l e to occur if
the artery and vein enter a bony canal in this region. Bleeding occurs and strips up the meningeal
layer of dura from the internal surface of the skull. The intracranial pressure rises, and the enlarging
blood clot exerts local pressure on t he underl ying motor area in the precentral gyrus. Blood may also
pass outward through the fracture line to form a soft swelling under the temporalis muscle.
To stop the hemorrhage, the torn artery or vein must be ligated or plugged. The burr hole through t he
skull wall should be pl aced about 1 to 1.5 in. (2.5 to 4 cm) above the midpoint of the zygomatic arch.
Subdural hemorrhage results from tearing of the superior cerebral veins at their point of entrance
into the superior sagittal sinus. The cause is usua lly a blow on the front or the back of the head,
causing excessive anteroposterior displacement of the brai n within the skull.
This condition, which is much more common than middle meningeal hemorrhage, can be produced by a
sudden minor blow. Once the vein is torn, blood under low pressure begins to accumulate in the
potential space between the dura and the arachnoid. In about half the cases the condition is bilateral.
Acute and chronic forms of the clinical condition occur, depending on the speed of accumu lation of
fluid in the subdural space. For example, if the patient starts to vomit, the venous pressure will rise as
a result of a rise in the intrathoracic pressure. Under these circumstances, the subdural blood clot will
increas e rapidl y i n si ze and prod uc e acute s ymptoms. In the chronic form, over a c ours e of several
months, the small blood cl ot will attract fluid by osmosis so that a hemorrhagic cyst is form ed, which
graduall y expands and produc es pressure s ymptoms. In both forms the bl ood clot must be removed
through burr holes in the skull.
Subarachnoid hemorrhage results from leakage or rupture of a congenital aneurysm on the circle of
W il li s o r, l e s s c o m m o n l y, f ro m a n a n g i o m a . T h e s ym p t o m s , wh i c h a re s u d d e n i n o n s e t , i n c l u d e s e v e r e
headache, stiffness of the neck, and loss of consciousness. The diagnosis is established by
withdrawing heavily blood-stained cerebrospinal fluid through a lumbar puncture (spinal tap).
Cerebral hemorrhage is generall y caused by rupture of the thin -wall ed lenticulostriate a rtery, a
branch of the middle cerebral artery. The hemorrhage involves the vital corticobulbar and corticospinal
fibers i n the internal capsule and produces hemiplegia on the opposite side of the body. The patient
immediatel y l oses consci ousness, and the p aral ysis is evident when consciousness is regained.
Intracranial H emorrh age in t he Infant
Intrac rani al hemorrhage in the infant may occur during birth and may result from excessive molding of
the head. Bleedi ng may occur from the cerebral veins or the veno us sinuses. E xcessive
anteroposterior compression of the head often tears the anterior attachment of the falx cerebri from
the tentorium cerebelli. Bleeding then takes place from the great cerebral veins, the straight sinus,
or the inferior sagittal sinus.
Clinical Not es
Fractures of t he Skul l
Fractures of the sk ull are com mon in the adult but much l es s so in the young child. In the infant sk ull,
the bones are more resilient than in the adult skull, and they are separated by fibrous sutural
ligaments. In the adult, the inner table of the skull is pa rticularly brittle. Moreover, the sutural
ligaments begin to ossify during middle age.
The type of fracture that occurs in the skull depends on the age of the patient, the severity of the
blow, and the area of skull receiving the trauma. The adult skull may be likened to an eggshell in that
it possesses a certain limited resilience be yond which it spli nters. A severe, l ocali zed blow produces a
local indentation, often accompanied by splintering of the bone. Blows to the vault often result in a
series of linear fractures, which radiate out through the thin areas of bone. The petrous parts of the
temporal bones and the occipital crests strongly reinforce the base of the skull and tend to deflect
linear fractures.
In the young chil d, t he sk ull ma y b e lik ened t o a tabl e-te nn is ball in t hat a locali zed bl o w pro duces a
depression without splinteri ng. This common type of ci rcumscribed lesion is referred to as a “pond”
fracture.
Fractures of t he Ant e rior Crani al Fossa
In fractures of the anterior cranial foss a, the c ri briform plate of the ethmoid bone may be damaged.
This usuall y results in tearing of the overl ying meninges and underl ying mucoperiosteum. The patient
will have bleeding from the nose (epistaxis) and leakage of cerebrospinal fluid into the nose
(cerebrospinal rhinorrhea). Fractures involving the orbital plate of the frontal bone result in
h e m o rr h a g e b e n e a t h t h e c o n j u n c t i v a a n d i n t o t h e o rb i t a l c a v i t y, c a u s i n g e x o ph th a l m o s . T h e f ro n t a l a i r
sinus may be involved, with hemorrhage into the nose.
Fractures of t he M iddle Cranial Fos sa
Fractures of the middle cranial fossa are common, because this is the weakest part of the base of the
s k u l l . A n a t o m i c a l l y, t h i s we a k n e s s i s c a u s e d b y t h e p re s e n c e o f n u m e ro u s f o ra m i n a a n d c a n a l s i n t h i s
region; the cavities of the middle ear and the sphenoidal air sinuses are particularly vulnerable. The
leakage of cerebrospinal fluid and blood from the external auditory meatus is common. The seventh
and eighth cranial nerves may be involved as they pass through the petrous part of the temporal bone.
The third, fourth, and si xth cranial nerves may be damaged if the lateral wall of the cavernous si nus is
torn. Blood and cerebrospinal fluid may leak into the sphenoidal air sinuses and then into the nose.
Fractures of t he Post erior Cr an ial Fossa
In fractures of the posterior cranial fossa, blood may esc ape into the nape of the neck deep to the
postvertebral muscl es. Some days later, it tracks between the muscles and appears in the posterior
triangl e, close to the mastoid process. The muc ous membrane of the roof of the nasopharynx may be
torn, and blood may escape there. In fractures involving the jugular foramen, the 9th, 10th, and 11th
cranial nerves may be damaged. The strong bony walls of the hypoglossal canal usuall y protect the
hypoglossal nerve from injury
Bone Injuries and S k elet al Dev elopment
The developing bones of a child's face are more pliable than an adult's, and fractures may be
incomplete or greenstick . In adults, the pres ence of well -developed, ai r-filled sinus es and the
mucoperiosteal surfaces of the alveolar parts of the upper and lower jaws means that most facial
fractures should be considered to be open fractures, susceptible to infection, and requiring antibiotic
therapy.
An atom y of Common Facial Fra ctures
A u t o m o b i l e a c c i d e n t s , f i s t i c u f f s , a n d f a l l s a re c o m m o n c a u s e s o f f a c i a l f ra c t u r e s . Fo rt u n a t e l y, t h e
upper part of the skull is developed from membrane (whereas the remainder is developed from
cartilage); therefore, this part of the skull in children is relativel y flexi ble and can absorb considerable
force without resulting in a fracture.
S i g n s o f f ra c t u re s o f t h e f a c i a l b o n e s i n c l u d e d e f o rm i t y, o c u l a r d i s p l a c e m e n t , o r a b n o rm a l m o v e m e n t
accompanied by crepitation and malocclusion of the teeth. Anesthesia or paresthesia o f the facial skin
will follow fracture of bones through which branches of the trigeminal nerve pass to the skin.
The muscles of the face are thin and weak and cause little displacement of the bone fragments. Once
a fracture of the maxilla has been reduced, for exampl e, prolonged fi xati on is not needed. However, in
the case of the mandible, the strong muscles of mastication can create considerable displacement,
requi ring l ong periods of fi xation.
The most common facial fractures i nvolve the nasal bones, foll owed by the zygomatic bone and then
the mandible. To fracture the maxillary bones and the supraorbital ridges of the frontal bones, an
enormous force is required.
Clinical Not es
Clinical Feat ure s of t he Neonatal Skull
Fontanelles
Palpation of the fontanelles enables the physici an to determine the p rogress of growth in the
surrounding bones, the degree of h ydration of the baby (e.g., if the fontanelles are depressed below
the surface, the baby is dehyd rated), and the state of the intracranial pressure (a bulgi ng fontanelle
indicates raised intracrani al pressure).
Samples of cerebrospinal fluid can be obtained by passing a long needle obliquely through the anterior
fontanelle into the subarachnoid space or even into the lateral ventricle.
C l i n i c a l l y, i t i s u s u a l l y n o t p o s s i b l e t o p a l p a t e t h e a n t e ri o r f o n t a n e l l e a f t e r 1 8 m o n t h s , b e c a u s e t h e
frontal and parietal bones have enlarged to close the gap.
T ympanic M embrane
A t b i rt h , t h e t ym p a n i c m e m b r a n e f a c e s m o r e d o w n wa rd a n d l e s s l a t e ra l l y t h a n i n m a t u ri t y; wh e n
examined with the otoscope it therefore lies m ore obliquely in the infant than in the adult.
Forceps Deliv er y and t he Facial Nerv e
In the newborn infant, the mas toid proces s is not developed, and the facial nerv e, as it emerges from
the stylomastoid foramen, is close to the surface. Thus, it can be da maged by forceps in a difficult
delivery.