THE
SCALP |
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| The scalp is the composite
soft tissue structure that covers the calvaria. |
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| Extents |
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Superiorly:
Superior nuchal line.
Laterally: Superior temporal
line and continous with the fascia
over temporalis muscle.
Anteriorly: Attached
to the upper part of orbicularis oculi and the overlying skin of the
eyebrow. |
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| Layers |
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Skin: Thick, hairy and rich in sweat glands.
Connective tissue: Dense,
irregular and highly vascular.
Aponeurosis: Unites frontalis and occipitalis muscles.
Loose areolar tissue:Potential space.
Pericranium:Attaches to suture lines. |
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| Blood supply |
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Arterial: |
 External
carotid branches:
- Superficial temporal artery.
- Posterior auricular artery.
- Occipital artery.
Internal
carotid branches:
- supraorbital
artery
- Supratrochlear artery, both
from the opthalmic artery.
Note:
- These branches anastomose freely with each other threfore scalp wounds bleed profusely but heal rapidly when cut.
- The
arterial walls are attached to the dense connective tissue of the second
layer of the scalp and tend to be held open and bleed profusely when
cut.
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| Venous: |
The veins run back with the arteries.
- The supraorbital and
supratrochlear veins drain into the facial vein
- The superficial temporal
vein drains into the retromandibular
vein.
- Occipital veins drain into the vertebral veins.
- The posterior auricular
vein drains into the external jugular
vein.
The veins connect with intracranial sinuses through emissary veins |
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| Innervation |
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| The scalp receives sensory innervation from:
- Supratrochlear Nn (1)
- Supraorbital Nn (2)
- Zygomaticotemporal Nn (3)
- Auriculotemporal Nn (4)
- Lesser occipital Nn (C2,C3) (5)
- Greater occipital Nn (C2) (6)
- Third occipital Nn (C3) (7)
Facial nerve supplies occipito-frontalis muscle |
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| Lymph drainage
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Lymphatic channels from the posterior
half of the scalp drain to occipital and
posterior auricular nodes
Lymphatic channels from anterior
half drain to the parotid nodes.
The lymph
eventually reaches the submandibular and deep cervical nodes .
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