Anatomy Of Scalp : In Depth Explanation

In this article we will give you an in depth explanation of Anatomy of Scalp. The scalp is the soft tissue covering the top of the head and serves to protect the skull and underlying brain tissue. It also provides support for the hair and helps regulate body temperature. The scalp is composed of five layers of tissue that work together to provide the scalp with its unique properties.

The scalp is composed of five layers:

• Skin: The outermost layer of the scalp, which is thick and hairy. It contains sebaceous glands and is richly supplied by blood vessels. It is adherent to the epicranial aponeurosis through the vast superficial fascia.
• Superficial fascia: The second layer of the scalp, which is more fibrous and dense in the center than at the periphery. It binds the skin to the adjacent aponeurosis and provides a medium for the passage of vessels and nerves to the skin.
• Deep fascia: The third layer of the scalp, also known as the epicranial aponeurosis or galea aponeurotica. It is freely movable on the pericranium along with the over lying adherent skin and fascia. The occipitofrontalis muscle has two bellies, frontal and occipital, both of which are inserted into the epicranial aponeurosis. Anteriorly, it receives the insertion of the frontalis and posteriorly it receives the insertion of the occipitalis and is fixed to the external occipital protuberance, and to the highest nuchal lines in between occipital bellies. On each side, the aponeurosis is stuck to the superior temporal line, but sends down a thin expansion, which passes over the temporal fascia and is attached to zygomatic arch.
• Loose areolar tissue: The fourth layer of the scalp, which is made up of loose areolar tissue that extends anteriorly into the eyelids and posteriorly to the highest and superior nuchal lines. On each side, it extends to the superior temporal lines.
• Pericranium: The fifth layer of the scalp, which is loosely attached to the surface of the bones, but is firmly adherent to their sutures where the sutural ligaments bind the pericranium to the endocranium.

The arterial supply of the scalp and superficial temporal region

The scalp has a rich blood supply and is derived from both the internal and external carotid arteries. The two systems anastomose over the temple.

In front of the auricle, the scalp is supplied from before backwards by the following arteries:

1. Supratrochlear artery
2. Supraorbital artery
3. Superficial temporal artery

The first two arteries are branches of the ophthalmic artery, which is a branch of the internal carotid artery. The superficial temporal artery is a branch of the external carotid artery.

Behind the auricle, the scalp is supplied from before backwards by the following arteries:

1. Posterior auricular artery
2. Occipital artery

Both of these arteries are branches of the external carotid artery.

The lymphatic drainage – Anatomy Of Scalp

The lymphatic drainage of the scalp involves two groups of lymph nodes: the preauricular or parotid lymph nodes and the posterior auricular or mastoid and occipital lymph nodes.

1. Preauricular or parotid lymph nodes: This group of lymph nodes drains the anterior part of the scalp.
2. Posterior auricular or mastoid and occipital lymph nodes: The posterior part of the scalp drains into this group of lymph nodes.

Nerve Supply – Anatomy Of Scalp

The scalp and temple are supplied by a total of 10 nerves on each side. Five nerves (four sensory and one motor) enter the scalp in front of the auricle, while the remaining five nerves (four sensory and one motor) enter the scalp behind the auricle.

Front of the Auricle:

1. Supraorbital nerve: Supplies the anterior part of the scalp
2. Supratrochlear nerve: Supplies the anterior part of the scalp
3. Zygomaticotemporal nerve: Supplies the lateral part of the scalp
4. Auriculotemporal nerve: Supplies the temple and anterior part of the ear
5. Frontal branch of the facial nerve: Supplies the forehead muscles

Behind the Auricle:

1. Greater occipital nerve: Supplies the posterior part of the scalp
2. Lesser occipital nerve: Supplies the lateral part of the scalp
3. Third occipital nerve: Supplies the posterior part of the scalp
4. Posterior auricular nerve: Supplies the posterior part of the ear and scalp
5. Posterior branch of the cervical nerve: Supplies the posterior part of the scalp

Summary And Important Points of Anatomy of Scalp

• The scalp is made up of five layers: skin, superficial fascia, deep fascia (epicranial aponeurosis or galea aponeurotica), loose areolar tissue, and pericranium.
• The skin is the outermost layer and is thick, hairy, and richly supplied by blood vessels.
• The superficial fascia binds the skin to the adjacent aponeurosis and provides a medium for vessels and nerves to the skin.
• The deep fascia (epicranial aponeurosis or galea aponeurotica) is freely movable on the pericranium and is attached to the occipitofrontalis muscle and the superior temporal line.
• The fourth layer is made up of loose areolar tissue, and the fifth layer is the pericranium.
• The scalp has a rich blood supply from both the internal and external carotid arteries, which anastomose over the temple.
• In front of the auricle, the scalp is supplied by the supratrochlear, supraorbital, and superficial temporal arteries.
• Behind the auricle, the scalp is supplied by the posterior auricular and occipital arteries.
• The preauricular or parotid lymph nodes drain the anterior part of the scalp.
• The posterior auricular or mastoid and occipital lymph nodes drain the posterior part of the scalp.
• The scalp and temple are supplied by 10 nerves on each part.
• Five nerves enter the scalp in front of the auricle, including the supraorbital, supratrochlear, zygomaticotemporal, auriculotemporal, and frontal branch of the facial nerve.
• Five nerves enter the scalp behind the auricle, including the greater occipital, lesser occipital, third occipital, posterior auricular, and posterior branch of the cervical nerve.