Coconote
AI notes
AI voice & video notes
Try for free
🩺
Understanding the Anatomy of the Scalp
May 2, 2025
Lecture Notes: Anatomy of the Scalp
Overview
The scalp is the soft tissue covering the vault of the skull.
It extends from the superciliary arches (eyebrows) anteriorly to the external occipital protuberance and superior nuchal lines posteriorly.
Laterally, it continues inferiorly to the zygomatic arch.
The scalp is composed of several layers that can be remembered using the acronym SCALP:
S
: Skin
C
: Connective Tissue (dense)
A
: Aponeurotic Layer
L
: Loose Connective Tissue
P
: Pericranium
Layers of the Scalp
Skin
Thick and hairy, except over the forehead.
Firmly attached to epicranial aponeurosis through dense connective tissue.
Contains numerous hair follicles, sebaceous glands, and sweat glands.
Common site for sebaceous cysts.
Dense Connective Tissue
Also known as superficial fascia, it binds the skin to the underlying occipitofrontalis and its aponeurosis.
Contains the scalp's blood vessels and nerves, which are held open by the dense tissue when cut, leading to profuse bleeding.
Aponeurotic Layer
Contains the occipitofrontalis muscle with its frontal and occipital bellies and the epicranial aponeurosis (galea aponeurotica).
Responsible for moving the scalp, wrinkling the forehead, and raising the eyebrows.
Innervated by branches of the facial nerve (CN VII).
Scalp wounds do not gape unless the aponeurosis is cut transversely.
Loose Connective Tissue
Allows for movement of the scalp over the calvaria.
Can localize infections and facilitate their spread due to its loose nature.
Contains emissary veins that can lead to intracranial infections, making it a "dangerous layer."
Pericranium
The periosteum on the outer surface of the calvaria, loosely attached except at suture lines.
Known for forming a "safety valve hematoma" when blood pools in the fourth layer.
Clinical Correlations
Scalp Bleeding
: Due to the open nature of vessels in the dense connective tissue layer, scalp cuts can bleed profusely.
Black Eye
: Blood can track forward into the eyelids due to lack of anterior bony attachment, causing hematoma after head injuries.
Safety Valve Hematoma
: Blood from intracranial hemorrhage can accumulate in the sub-aponeurotic space after certain fractures.
Cephalhematoma
: A subperiosteal collection of blood, often in the parietal region, bounded by suture lines.
Caput Succedaneum
: Subcutaneous edema over the presenting part of the head at delivery, most common birth trauma of the scalp.
Summary
The scalp is a complex structure with multiple layers, each with unique functions and clinical implications.
Understanding the anatomy and potential complications associated with each layer is critical in clinical practice.
📄
Full transcript