SCALP-FORENSIC ANATOMY AND FORCES ON THE HEAD

1. SCALP-FORENSIC ANATOMY
AND FORCES ON THE HEAD
DR AJMAL BIN LATHEEF
DEPARTMENT OF FORENSIC MEDICINE AND TOXICOLOGY

2. SCALP
• Soft tissue covering the vault of the skull.
• Thickness- variable in adults upto 15mm.
In infants its less but highly elastic.
• Primary function is to protect and insulate the skull.
• Form first barrier to impact and serves to widen and lower the peak of
transient impact.

3. EXTENT:
Anteriorly: supraorbital margins.
Posteriorly: highest nuchal line.
On each side: superior temporal lines:

4. LAYERS OF SCALP
S- SKIN
C- CONNECTIVE TISSUE (SUPERFISCIAL FASCIA)
A- EPICRANIAL APONEUROSIS(DEEP FASCIA)(GALEA APPONEUROTICA)
AND OCCIPITOFRONTALIS MUSCLE
L- LOOSE AREOLAR TISSUE
P- PERICRANIUM(PERIOSTEUIM)(SUBAPONEUROTIC SPACE)

5. skin
Connective
tissue Aponeurosis
Emmissary
vein
Subaponeurotic
space

6. SKIN(First Layer)
• Thick and hairy
• Firmly attached to the epicranial aponeurosis through dense
connective tissue.
• Abundance sweat & sebaceous glands present.
• Sebaceous cyst are common

7. DENSE CONNECTIVE TISSUE(Second Layer)
• Fibrous and dense, containing blood vessels and nerves.
• Binds skin to subjacent aponeurosis
Clinical Importance:
• Wounds bleed profusely as blood vessels are prevented from
retraction by fibrous tissue.
• Bleeding is stopped by applying pressure against the bone.
• Subcutaneous hemorrhage are not extensive since tissue is dense.
• Inflammation cause little swelling but are much painful.
• Good healing.

8. EPICRANIAL APONEUROSIS(GALEA
APPONEUROTICA)
(third layer)
• Freely movable on the pericranium along
with the overlying and adherent skin and
fascia.
• Anteriorly: insertion of frontalis; Posteriorly:
insertion of occipitalis
• Thus unites the occipital and frontal bellies
of the occipitofrontalis muscle.
• On each side, the aponeurosis are attached
to superior temporal line, but sends down a
expansion which passes over the temporalis
fascia and is attached to zygomatic arch

9. Occipital belly
Origin: Lateral part of highest nuchal line
Insertion: Epicranial aponeurosis.
Nerve supply: Posterior auricular branch of facial nerve
Action: Moves the scalp backwards
Frontal bellies (frontalis):
Origin: Skin of the forehead (no bony
attachment)
Insertion: Epicranial Aponeurosis.
Nerve supply: temporal branch of facial nerve
Action: it raises the eyebrows and causes horizontal wrinkling of
skin in forehead
Temporoparietal muscle:
Origin: temporal fascia
Insertion: Epicranial aponeurosis
Nerve supply: temporal branch of facial nerve
Action: draws the epicranial aponeurosis towards the
front of the cranium
OCCIPITOFRONTALIS MUSCLE
Temporoparietal

10. CLINICAL IMPORTANCE
• First three layers of scalp are called the surgical layers of the scalp.
• These layers are called scalp proper.
• Scalp lacerations through this layer mean that the anchoring of the
superficial layers is lost and gaping of the wound occurs .this requires
suturing.

11. LOOSE AREOLAR TISSUE
(fourth layer)
Extend
• anteriorly into eyelids.
• Posteriorly –highest and superior nuchal
line
• Laterally-superior temporal line
• Potential space contains emissary vein
• Emissary vein are devoid of valves and
communicates the veins of scalp with
intracranial venous sinuses(DANGEROUS
LAYER OF SCALP)

12. CLINICAL IMPORTANCE
• Infection in the Loose areolar tissue with pus collection readily spread
to intracranial sinuses through emissary veins (VALVE LESS)
• Collection of blood in the subaponeurotic space produce generalized
swelling affecting the whole dome of skull.
• Blood slowly gravitates into the eye lids because the frontalis has no
bony attachments (BLACK EYE)

13. • Fracture of cranial vault in children with tearing of dura matter &
pericranium. Blood from Intra cranial hemorrhage communicate with
subaponeurotic space through the line of fracture.
• cerebral compression do not develop.(safety valve hematoma)
• CAPUT SUCCEDANEUM is temporary swelling of scalp in new born.

14. PERICRANIUM (5th layer)
• Is the periosteum of skull
• Loosely attached to surface of bone but is firmly
adherent to the sutures
• Injury deep to it produce localized swelling which
take the shape of bone(CEPHALOHAEMATOMA)
• SUBGALEAL HEMORRHAGE is a rare but potentially
lethal condition found in newborns.
It is caused by rupture of the emissary veins.
Blood accumulates between the epicranial
aponeurosis of the scalp and the periosteum.

15. SUEPRFICIAL TEMPORAL REGION
• The area between the superior temporal line and the
zygomatic arch.
7 layers
• Skin
• Superficial fascia
• Thin extension of aponeurosis
• Temporal fascia
• Temporalis muscle
• Loose areolar tissue
• Pericranium
Greying of hair first starts here

16. ARTERIAL SUPPLY OF SCALP AND SUPERFICIAL
TEMPORAL REGION
5 sets of arteries on each side of scalp
• 3 in front of auricle
• 2 behind the auricle
Out of 5,
• 2 arteries (indirectly) from Internal Carotid Artery
• 3 arteries (directly) from External Carotid Artery

17. Scalp has rich blood supply
derived from both internal
and the external carotid
arteries, the two systems
anastomosing over the
temple.
Scalp is the site of free anastomosis between the branches of internal & external carotid arteries

18. VENOUS DRAINAGE OF SCALP AND SUPERFICIAL TEMPORAL
REGION
• Accompanies the arteries
Supratrochlear V + supraorbital V Sup. Temporal V+
Maxillary V
Anterior facial V
Retromandibular V
Anterior division
Common facial vein
Posterior division
Posterior auricular V
External jugular V
Subclavian V
Internal jugular V
Occipital Vs terminates in the suboccipital venous plexus

19. Supratrochlear V and supraorbital V unites at
medial angle of eye forming the angular V
which continues as facial V.
Superficial temporal V descends in front
of the tragus, enters the parotids gland
and joins Maxillary V to form
Retromandibular V

20. EMISSARY VEIN
• The veins connect the extracranial venous
system with the intracranial venous sinuses
to equalize the pressure. They are
valveless.
2 emissary veins of scalp
• Parietal emissary V through parietal
foramen communicates the scalp veins
with Superior sagittal sinus
• Mastoid emissary V through mastoid
foramen communicates the scalp veins
with sigmoid sinus

21. DIPLOIC VEIN
The blood from the diploe is emptied by diploic Vs.
The diploic Vs are large, thin-walled valveless veins
that channel in the diploe between the inner and
outer layers of the cortical bone in the skull.
Frontal diploic V- supra orbital foramen-
supraorbital v
Parietal Vs:
Anterior temporal- grater wing of sphenoid-
sphenoparietal sinus
Posterior temporal- mastoid foramen-
transverse sinus
Occipital diploic V(largest)- foramen in occipital
bone-occipital vein
Small unnamed diploic Vs- pierce inner table of
skull close to margin of SSS- venous lacunae

22. NERVE INNERVATION
• 10 nerves on each side of
scalp
• 5 in front of auricle (4
sensory & 1 motor)
• 5 behind the auricle (4
sensory &1motor) Post. auricular
branch of facial.n.
(motor)
Temporal branch of
facial.n(motor)

23. LYMPHATIC DRAINAGE
occipital region - occipital nodes - upper
deep cervical nodes.
upper part of the scalp drain in two
directions:
– Posterior to the vertex - mastoid nodes.
– Anterior to the vertex - pre-auricular
and parotid nodes.

24. FORCES ON HEAD
• MOTOR VEHICLE ACCIDENTS
• FALLS
• PHYSICAL ASSAULTS
• SPORTS-RELATED ACCIDENTS
• FIRE ARM INJURIES
Impact results from object striking the head or head striking an object
or surface

25. MECHANISM OF INJURY
• BLUNT INJURY
• High velocity
• Low velocity
• PENETRATING INJURY
• Gunshot.
• Sharp instrument.

26. INJURIES OF SCALP
Scalp injuries may or may not cause injury to underlying skull and brain.
• Hair around the injury must be shaved for proper examination and
photography.
• In hair covered area ,always palpate the area during autopsy.
• Usually abrasion ,contusion and laceration are possible injuries.
Better Felt Than Seen

27. BRUISING OF THE SCALP
• Bruising may be difficult to detect until the hair is removed.
• Marked swelling is common in extensive bruising.
• After death- bruise gets diffused.
• Deeper bruise is visible on dissection of scalp. In relation to
aponeurosis beneath the skin.
• Blood may collect beneath pericranium in infants with head injury
associated with skull fracture.
• Blunt force: falls or blows

28. MEDICOLEGAL IMPORTANCE
• BLACK EYE(ECTOPIC BRIUSE) :injury to anterior
scalp due blunt trauma of the forehead causes
rupturing the blood vessels results in bruising
around the eye along the facial attachment
around the lower margin of the orbits.
• SPECTACLE HEMATOMA(RACCOON EYES) : This
is a condition in which blood is collected in the
soft tissue around the eyes , due to the fracture
of the base of the skull.
• BATTLE’S SIGN : A Bluish discoloration of the
skin behind the ear that occurs from the blood
leaking under the scalp after a skull fracture

29. LACERATION OF SCALP
• Bleeds profusely and dangerously even fatal blood loss.
• Children may develop shock.
• Scalp injury may bleed profusely even after death
• Due to close proximity to skull bone, it is often incised looking
laceration.
• Close examination using lens
bruised margin, head hair crossing the wound not been cut and hair
bulb crushed, Hair bulb and small vessles and nerves are in the depth
of wound

30. • AVULSION INJURY OF SCALP -exposing
aponeurosis or skull.
Like hair trapped in machinery, rotating vehicle
tyre comes in contact with head.
SPLIT / SLIT LACERATION.
• Splitting of skin and underlying tissues occur,
when there is compression/ crushing of the
affected tissue between two hard objects that
is bone & blunt Instrument or ground. Impact is
Perpendicular.
OVER STRETCHING OF SKIN:
• There is localized pressure with Pull, which
increases until tearing Occurs producing a flap
indicating Direction of the offending object,
Impact is tangential.

31. MEDICOLEGAL IMPORTANCE
• Presence of FB like piece of glass, piece of stone or other fragments of
material will help to identify the weapon.
• Injury may follow the pattern of inflicting object.
• Random splitting is more common.
• Shape of object may reproduce like hitting with hammer, angle iron rods
etc.
• Injuries due to fall also may produce patterned injury with interfering
objects; table, brick, stone etc.

32. INCISED WOUND OF SCALP
• Produced by cutting instruments such as axe,
sword, shovel or chopper.
• Shows bruising of margin.
• Beveling of one of edge if inflicted obliquely,
helps in direction of impact.
• Usually heals rapidly, may be fatal if infection
occurs which spread to brain via emissary
veins.
• Death due to septic meningitis or brain
abscess.

33. ABRASION OF SCALP
• Brush Abrasion are less common, because of protective effect of hair.
• Impact abrasion from perpendicular force are reproduced , hair may
reduce the severity.
• Lesser degree of abrasion can be missed if scalp hair is not removed
carefully.
• Care should betaken not to cause artefactual cuts.

34. REFERENCE
• BD CHAURASIAS HUMAN ANATOMY 8ED VOL 3
• TEXTBOOK OF FORENSIC MEDICINE AND TOXICOLOGY PRINCIPLES
AND PRACTICE BY KRISHAN VIJ
• Textbook of Forensic Medicine And Toxicology 19th Edition 2019
by VV Pillay
• KNIGHT'S FORENSIC PATHOLOGY, 4th EDITION
• Images used – google images