DEPARTMENT OF ANATOMY
Head and Neck
Dr. SREEKANTH THOTA
Head
Scalp
Meninges
SCALP
• The scalp consists of
skin (normally hair
bearing) and
subcutaneous tissue,
which cover the
neurocranium, from the
superior nuchal lines on
the occipital bone to the
supraorbital margins of
the frontal bone
The scalp is composed of five
layers
•
•
•
•
•
•
SCALP
1. Skin
2. Connective tissue(Dense)
3. Aponeurosis (epicranial aponeurosis)
4. Loose connective tissue
5. Pericranium
Downloaded from: StudentConsult (on 10 December 2006 10:41 AM)
© 2005 Elsevier
Downloaded from: StudentConsult (on 10 December 2006 10:41 AM)
© 2005 Elsevier
Aponeurosis (epicranial
aponeurosis)
• Broad, strong, tendinous
sheet that covers the
calvaria and serves as
the attachment for
muscle bellies
converging from the
forehead and occiput
(the occipitofrontalis
muscle)
Innervation
• Sensory innervation of the scalp is from
two major sources, cranial nerves or
cervical nerves, depending on whether it is
anterior or posterior to the ears and the
vertex of the head.
• The occipitofrontalis muscle is innervated
by branches of the facial nerve [VII].
Figure 8.67 Innervation of the scalp.
Downloaded from: StudentConsult (on 10 December 2006 10:41 AM)
© 2005 Elsevier
Lymphatic drainage
• Lymphatic drainage of the scalp generally
follows the pattern of arterial distribution.
• Lymph nodes
• 1. Submandibular nodes
• 2. Submental nodes
• 3.Parotid nodes
• 4.Mastoid nodes
• 5.Occipital nodes
Figure 8.69 Lymphatic drainage of the scalp.
Downloaded from: StudentConsult (on 10 December 2006 10:41 AM)
© 2005 Elsevier
Scalp Wounds
• 1. Superficial scalp wounds do not gape and
the margins of the wound are held together.
• 2. Deep scalp wounds gape widely when the
epicranial aponeurosis is lacerated in the
coronal plane because of the pull of the
frontal and occipital bellies of the
occipitofrontalis muscle in opposite directions
(anteriorly and posteriorly).
Scalp Infections
Danger area of the scalp
• The loose connective tissue layer (layer
four) of the scalp is the danger area of the
scalp because pus or blood spreads easily
in it.
• Infection in this layer can also pass into
the cranial cavity through emissary veins,
which pass through parietal foramina in
the calvaria, and reach intracranial
structures such as the meninges.
MENINGES
• The brain, as well as the spinal cord, is
surrounded by three layers of membranes
(the meninges, a tough, outer layer (the
dura mater), a delicate, middle layer (the
arachnoid mater), and an inner layer
firmly attached to the surface of the brain
(the pia mater).
Dura mater
• It consists of an outer 1.Endosteal layer
and an inner 2.meningeal layer.
• The two layers of dura separate from each
other at numerous locations to form two
unique types of structures 1. dural
partitions, which project inward and
incompletely separate parts of the brain;
2.intracranial venous structures.
Dura mater
Dural partitions
•
•
•
•
1.Falx cerebri
2.Tentorium cerebelli
3.Falx cerebelli
4.Diaphragma sellae.
Dural arterial supply
• 1.Anterior meningeal arteries in the
anterior cranial fossa;
• 2.Middle meningeal arteries in the
middle cranial fossa;
3. Posterior meningeal artery in the
posterior cranial fossa.
Arachnoid mater
• The arachnoid
mater is a thin,
avascular
membrane,
against, but not
adherent to, the
inner surface of
the dura mater .
Pia mater
• The pia mater is a thin, delicate membrane
that closely invests the surface of the brain. It
follows the contours of the brain, entering the
grooves and fissures on its surface, and is
closely applied to the roots of the cranial
nerves at their origins.
Histology
Arrangement of meninges and
spaces
• 1.Extradural space
• 2.Sub dural space
• 3. Subarachnoid space
Epidural hematoma
Buildup of blood may
increase pressure in
the intracranial space and
compress delicate brain tissue.
Between 15 and 20% of
patients with epidural
hematomas die of the injury.
Subdural hematoma
Subarachnoid hemorrhage
Cerebral hemorrhage
Dural venous sinuses
• Venous drainage of the brain begins internally
as networks of small venous channels lead to
larger cerebral veins, cerebellar veins, and
veins draining the brainstem, which eventually
empty into dural venous sinuses.
• The dural venous sinuses are endothelial-lined
spaces between the outer periosteal and the
inner meningeal layers of the dura mater, and
eventually lead to the internal jugular veins
•
•
•
•
•
•
•
•
•
•
1. Superior sagittal sinus
2. Inferior sagittal
3.Straight sinuses
4. Confluence of sinuses
5. Transverse
6. Sigmoid sinuses
7. Cavernous sinuses
8. Intercavernous
9. Superior and inferior petrosal sinuses
10. Occipital
Cavernous sinuses