- The scalp refers to the layers of skin and subcutaneous tissue that cover the bones of cranial vault
- Layers of the Scalp:
- The scalp consists of five layers
- The first three layers are tightly bound together:
- Move as a collective structure
- The mnemonic ‘SCALP’ can be a useful way to remember the layers of the scalp:
- Skin
- Dense Connective Tissue
- Epicranial Aponeurosis (Galea Aponeurotica)
- Loose Areolar Connective Tissue
- Periosteum
- Skin:
- Contains numerous hair follicles and sebaceous glands:
- Thus a common site for sebaceous cysts
- Contains numerous hair follicles and sebaceous glands:
- Dense Connective tissue:
- Connects the skin to the epicranial aponeurosis
- It is richly vascularized and innervated
- The blood vessels within the layer are highly adherent to the connective tissue:
- This renders them unable to constrict fully if lacerated:
- And so the scalp can be a site of profuse bleeding
- This renders them unable to constrict fully if lacerated:
- Epicranial Aponeurosis:
- A thin, tendon-like structure that:
- Connects the occipitalis and frontalis muscles
- A thin, tendon-like structure that:
- Loose Areolar Connective Tissue:
- A thin connective tissue layer that:
- Separates the periosteum of the skull from the epicranial aponeurosis
- It contains numerous blood vessels, including emissary veins:
- Which connect the veins of the scalp to the diploic veins and intracranial venous sinuses
- A thin connective tissue layer that:
- Periosteum:
- The outer layer of the skull bones
- It becomes continuous with the endosteum at the suture lines

- Arterial Supply:
- The scalp receives a rich arterial supply via the:
- External carotid artery
- The ophthalmic artery:
- A branch of the internal carotid
- There are three branches of the external carotid artery involved:
- Superficial temporal artery:
- Supplies the frontal and temporal regions
- Posterior auricular artery :
- Supplies the area superiorly and posteriorly to the auricle
- Occipital artery:
- Supplies the back of the scalp
- Superficial temporal artery:
- Anteriorly and superiorly, the scalp receives additional supply from two branches of the ophthalmic artery:
- The supraorbital and supratrochlear arteries:
- These vessels accompany the supraorbital and supratrochlear nerves respectively
- The supraorbital and supratrochlear arteries:
- The scalp receives a rich arterial supply via the:

- Venous drainage:
- The venous drainage of the scalp can be divided into:
- Superficial and deep components
- The superficial drainage follows the arterial supply:
- Superficial temporal, occipital, posterior auricular, supraorbital and supratrochlear veins
- The deep (temporal) region of the skull is drained by:
- The pterygoid venous plexus:
- This is a large plexus of veins situated between the temporalis and lateral pterygoid muscles:
- Drains into the maxillary vein
- This is a large plexus of veins situated between the temporalis and lateral pterygoid muscles:
- The pterygoid venous plexus:
- Importantly, the veins of the scalp connect to the diploic veins of the skull:
- Via valveless emissary veins:
- This establishes a connection between the scalp and the dural venous sinuses
- Via valveless emissary veins:
- The venous drainage of the scalp can be divided into:
- Innervation:
- The scalp receives cutaneous innervation from branches of the:
- Trigeminal nerve or the cervical nerve roots
- Trigeminal Nerve:
- Supratrochlear nerve:
- Branch of the ophthalmic nerve:
- Which supplies the anteromedial forehead
- Branch of the ophthalmic nerve:
- Supraorbital nerve:
- Branch of the ophthalmic nerve:
- Which supplies a large portion of the scalp between the anterolateral forehead and the vertex
- Branch of the ophthalmic nerve:
- Zygomaticotemporal nerve:
- Branch of the maxillary nerve:
- This supplies the temple
- Branch of the maxillary nerve:
- Auriculotemporal nerve:
- Branch of the mandibular nerve:
- Which supplies skin anterosuperior to the auricle
- Branch of the mandibular nerve:
- Supratrochlear nerve:
- Cervical Nerves:
- Lesser occipital nerve:
- Derived from the anterior ramus (division) of C2 and supplies the skin posterior to the ear
- Greater occipital nerve:
- Derived from the posterior ramus (division) of C2 and supplies the skin of the occipital region
- Great auricular nerve:
- Derived from the anterior rami of C2 and C3 and supplies the skin posterior to the ear and over the angle of the mandible.
- Third occipital nerve:
- Derived from the posterior ramus of C3 and supplies the skin of the inferior occipital region
- Lesser occipital nerve:
- The scalp receives cutaneous innervation from branches of the:
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