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The scalp is the anatomical area bordered by the face
Face

The term face refers to the central sense organ complex, for those animals that have one, normally on the ventral surface of the head and can depending on the definition in the human case, include the hair, forehead, eyebrow, eyes, nose, ears, cheeks, mouth, lips, philtrum, tooth, skin, and chin....
 anteriorly and the neck
Neck

The neck is the part of the body on many limbed vertebrates that distinguishes the head from the torso or trunk. The scientific term signifying "of the neck" is nuchal....
 to the sides and posteriorly.

s usually described as having five layers, which can be remembered with the mnemonic
Mnemonic

A mnemonic device is a memory aid. Commonly met mnemonics are often verbal, something such as a very short poem or a special word used to help a person remember something, particularly lists, but may be visual, kinesthetic or auditory....
 "SCALP":



The clinically important layer is the aponeurosis. Scalp lacerations through this layer mean that the "anchoring" of the superficial layers is lost and gaping of the wound occurs; this requires suturing.






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The scalp is the anatomical area bordered by the face
Face

The term face refers to the central sense organ complex, for those animals that have one, normally on the ventral surface of the head and can depending on the definition in the human case, include the hair, forehead, eyebrow, eyes, nose, ears, cheeks, mouth, lips, philtrum, tooth, skin, and chin....
 anteriorly and the neck
Neck

The neck is the part of the body on many limbed vertebrates that distinguishes the head from the torso or trunk. The scientific term signifying "of the neck" is nuchal....
 to the sides and posteriorly.

Layers

It is usually described as having five layers, which can be remembered with the mnemonic
Mnemonic

A mnemonic device is a memory aid. Commonly met mnemonics are often verbal, something such as a very short poem or a special word used to help a person remember something, particularly lists, but may be visual, kinesthetic or auditory....
 "SCALP":

  • S: The skin
    Skin

    The skin is the outer covering of the body, also known as the epidermis. It is the largest organ of the integumentary system made up of multiple layers of epithelial biological tissue, and guards the underlying muscles, bones, ligaments and organ s....
     on the head from which head hair grows. It is richly supplied with blood
    Blood

    Blood is a specialized bodily fluid that delivers necessary substances to the body's Cell s ? such as nutrients and oxygen ? and transports waste products away from those same cells....
     vessels.
  • C: Connective tissue
    Connective tissue

    Connective tissue is a form of fibrous biological tissue.It is one of the four types of tissue in traditional classifications .Collagen is the main protein of connective tissue in animals and the most abundant protein in mammals, making up about 25% of the total protein content....
    . a thin layer of fat
    Fat

    Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. Chemistry, fats are generally ester of glycerol and fatty acids....
     and fibrous tissue lies beneath the skin
  • A: The aponeurosis called epicranial aponeurosis (or galea aponeurotica
    Galea aponeurotica

    The galea aponeurotica is a tough layer of dense fibrous tissue which covers the upper part of the cranium; behind, it is attached, in the interval between its union with the Occipitales, to the external occipital protuberance and highest nuchal lines of the occipital bone; in front, it forms a short and narrow prolongation between its union...
    ) is the next layer. It is a tough layer of dense fibrous tissue which runs from the frontalis muscle
    Frontalis muscle

    The Frontalis muscle is thin, of a quadrilateral form, and intimately adherent to the superficial fascia. It is broader than the Occipitalis and its fibers are longer and paler in color....
     anteriorly to the occipitalis posteriorly
  • L: The loose areolar connective tissue layer provides an easy plane of separation between the upper three layers and the pericranium. In scalping
    Scalping

    Scalping is the act of removing the scalp, usually with the hair, as a portable proof or trophy of prowess in war. Scalping is also associated with frontier warfare in North America, and was widely practiced by Indigenous peoples of the Americas, colonists, and frontiersmen over centuries of violent conflict....
     the scalp is torn off through this layer. It also provides a plane of access in craniofacial surgery
    Craniofacial surgery

    Craniofacial surgery is a surgical subspecialty of both plastic surgery and oral and maxillofacial surgery that deals with congenital disorder and acquired deformity of the skull, face, and jaws....
     and neurosurgery
    Neurosurgery

    Neurosurgery is the surgery discipline focused on treating those central nervous system, peripheral nervous system and spinal column diseases amenable to surgical intervention....
    . This layer is sometimes referred to as the "Danger Zone
    Danger zone

    The temperature range in which foodborne bacteria can grow is known as the danger zone. This is typically considered to be between 40?F and 140?F , though often 45?F is considered the lower temperature of the range....
    " because of the ease by which infectious agents can spread through it to emissary veins
    Emissary veins

    The emissary veins are valveless veins which normally drain external veins of the skull into the dural venous sinuses. However, because they are valveless, pus can flow into the skull through them as well, making them a possible route for transmission of extracranial infection to get into the skull....
     which then drain into the cranium. The loose areolar tissue in this layer is made up of random collagen I bundles, collagen III. It contains the majors blood vessels of the scalp, which bleed profusely upon injury, partly due to the absence of venous valves found in the circulation below the neck. It will also be rich in glycosaminoglycans (GAGs) and will be constituted of more matrix than fibers.
  • P: The pericranium is the periosteum
    Periosteum

    Periosteum is a membrane that lines the outer surface of all bone, except at the joints of long bones. Endosteum lines the inner surface of all bones....
     of the skull bones and provides nutrition to the bone and the capacity for repair. It may be lifted from the bone to allow removal of bone windows (craniotomy
    Craniotomy

    A craniotomy is a surgery in which part of the skull, called a bone flap, is removed in order to access the brain. Craniotomies are often a critical operation performed on patients suffering from brain lesions or traumatic brain injury , and can also allow doctors to surgically implant deep brain stimulation for the treatment of Parkin...
    ).


The clinically important layer is the aponeurosis. Scalp lacerations through this layer mean that the "anchoring" of the superficial layers is lost and gaping of the wound occurs; this requires suturing. This can be achieved with simple or vertical matress sutures using a non-absorbable material, which are subsequently removed at around day 7.

Blood supply

The blood supply of the scalp is via five pairs of arteries, three from the external carotid and two from the internal carotid:

  • internal carotid
    • the supratrochlear artery
      Supratrochlear artery

      The supratrochlear artery , one of the terminal branches of the ophthalmic artery, branches off where the ophthalmic travels posterior to the Trochlea of superior oblique ....
       to the midline forehead. supratrochlear artery is a branch of ophthalmic branch of the internal carotid artery.
    • the supraorbital artery to the lateral forehead and scalp as far up as the vertex. supraorbital artery is a branch of ophthalmic branch of the internal carotid artery.
  • external carotid
    • the superficial temporal artery
      Superficial temporal artery

      In human anatomy, the superficial temporal artery is a major artery of the head. It arises from the external carotid artery when it bifurcates into the superficial temporal artery and maxillary artery....
       which gives frontal and parietal branches to supply much of the scalp
    • the occipital artery
      Occipital artery

      The occipital artery arises opposite the facial artery, its path is below the posterior belly of digastic to the occipital region. This artery supplies blood to the back of the scalp and sterno-mastoid muscles....
       which runs from posteriorly to supply much of the back of the scalp.
    • the posterior auricular artery
      Posterior auricular artery

      The posterior auricular artery is a small artery and arises from the external carotid artery, above the Digastric muscle and Stylohyoid muscle, opposite the apex of the styloid process....
       , a branch of the external carotid artery , ascends behind the auricle to supply the scalp above and behind the auricle.


Innervation

The scalp is innervated by the following:
  • Supratrochlear nerve
    Supratrochlear nerve

    The supratrochlear nerve is a branch of the frontal nerve, which itself comes from the ophthalmic division of the trigeminal cranial nerve.It is smaller than the nearby supraorbital nerve....
     and the supraorbital nerve
    Supraorbital nerve

    The supraorbital nerve is a terminal branch of the frontal nerve.It passes through the supraorbital foramen, and gives off, in this situation, palpebral filaments to the upper eyelid....
     from the ophthalmic division of the trigeminal nerve
    Trigeminal nerve

    The trigeminal nerve is responsible for sensation in the face. Sensory information from the face and body is processed by parallel pathways in the central nervous system....
  • Greater occipital nerve
    Greater occipital nerve

    The greater occipital nerve is a spinal nerve arising from the dorsal primary rami of cervical spinal nerve 2, between the first and second cervical vertebrae, along with the lesser occipital nerve....
     (C2) posteriorly up to the vertex
  • Lesser occipital nerve
    Lesser occipital nerve

    The lesser occipital nerve or small occipital nerve is a spinal nerve arising between the first and second cervical vertebrae, along with the greater occipital nerve....
     (C3) behind the ear.
  • Zygomaticotemporal nerve
    Zygomaticotemporal nerve

    The zygomaticotemporal nerve or zygomaticotemporal branch is derived from the maxillary branch of the trigeminal nerve . It runs along the lateral wall of the orbit in a groove in the zygomatic bone, receives a branch of communication from the lacrimal, and passes through zygomaticotemporal foramen in the zygomatic bone to enter the te...
     from the maxillary division
    Maxillary nerve

    The maxillary nerve is one of the three branches of the Trigeminal nerve, the fifth cranial nerve. It comprises the principal functions of sensation from the maxillary, nasal cavity, sinus, the palate and subsequently that of the mid-face, and is intermediate, both in position and size, between the ophthalmic nerve and the mandibular nerve...
     of the trigeminal nerve
    Trigeminal nerve

    The trigeminal nerve is responsible for sensation in the face. Sensory information from the face and body is processed by parallel pathways in the central nervous system....
     supplying the hairless temple
  • Auriculotemporal nerve
    Auriculotemporal nerve

    The auriculotemporal nerve is a branch of the mandibular nerve that runs with the superficial temporal artery and vein, and provides sensory innervation to various regions on the side of the head....
     from the mandibular division of the trigeminal nerve
    Trigeminal nerve

    The trigeminal nerve is responsible for sensation in the face. Sensory information from the face and body is processed by parallel pathways in the central nervous system....


There are no lymph nodes in the scalp; lymphatic drainage is to the pre- and post-auricular nodes.

Role in aesthetics

The scalp plays an important role in the aesthetics
Aesthetics

Aesthetics or esthetics is commonly known as the study of senses or sensori-emotional values, sometimes called judgments of sentiment and taste ....
 of the face. Androgenic alopecia, or male pattern hair loss, is a common cause of concern to men. It may be treated by medication (eg finasteride
Finasteride

Finasteride is a synthetic antiandrogen which acts by inhibiting type II 5-alpha reductase, the enzyme that converts testosterone to dihydrotestosterone ....
) or hair transplantation
Hair transplantation

File:Hair-transplantation.jpgHair transplantation is a surgery technique that involves moving skin containing hair follicles from one part of the body to bald or balding parts ....
 with variable success. If the scalp is heavy and loose, a common change with aging, the forehead may be low, heavy and deeply lined. The brow lift procedure aims to address these concerns.

Pathology

The scalp is a common site for the development of tumours including:
  • epidermoid cyst
    Epidermoid cyst

    An epidermoid cyst is a benign cyst, developed out of ectoderm tissue. Histology, it is made of a thin layer of squamous epithelium.It is very common for women on the major or minor labia ....
  • pilar cyst
  • actinic keratosis
    Actinic keratosis

    Actinic keratosis is a premalignant condition of thick, scaly, or crusty patches of skin. It is more common in fair-skinned people. It is associated with those who are frequently exposed to the sun, as it is usually accompanied by Sun damage....
     and squamous cell carcinoma
    Squamous cell carcinoma

    In medicine, squamous cell carcinoma is a form of cancer of the carcinoma type that may occur in many different organs, including the skin, lips, mouth, esophagus, urinary bladder, prostate, lungs, vagina, and cervix....
  • basal cell carcinoma
    Basal cell carcinoma

    Basal cell carcinoma is the most common of all types of skin cancer. Statistically speaking, approximately 3 out of 10 caucasians develop a basal cell cancer within their lifetime....
  • merkel cell
    Merkel cell

    Merkel cells are oval cells found in the skin of vertebrates. They are associated with the sense of light touch and are responsible for the highly malignant skin tumor known as Merkel cell carcinoma....
     tumours


Scalp conditions

  • Dandruff
    Dandruff

    Dandruff is due to the excessive shedding of dead skin cells from the scalp. As it is normal for skin cell s to die and flake off, a small amount of flaking is normal and in fact quite common....
     -- A common problem due to the excessive shedding of dead skin cells from the scalp
  • Seborrhoeic dermatitis
    Seborrhoeic dermatitis

    Seborrhoeic dermatitis is a skin disorder affecting the scalp, face, and torso causing scaly, flaky, itchy, red skin. It particularly affects the sebum-gland rich areas of skin....
     -- a skin disorder causing scaly, flaky, itchy, red skin
  • Cutis verticis gyrata
    Cutis verticis gyrata

    Cutis verticis gyrata , is a descriptive term for a superficial condition usually associated with thickening of the scalp. Sufferers show visible folds, ridges or creases on the surface of the top of the scalp....
     -- A descriptive term for a rare deformity of the scalp.
  • Head lice


See also

  • Trichology
    Trichology

    Trichology is the branch of medicine that deals with the scientific study of the health of hair and scalp. Trichologists themselves are not normally licensed healthcare workers, although members of the medical profession can undertake courses and/or careers within trichology....
     -- the scientific study of hair and scalp
  • Trichodynia
    Trichodynia

    Trichodynia is a condition where the patient experiences a painful sensation on their scalp. The pain sometimes is described as burning. Trichodynia often is associated with hair loss, but some studies show it has no connection to hair loss....
     -- burning scalp syndrome
  • Scalping
    Scalping

    Scalping is the act of removing the scalp, usually with the hair, as a portable proof or trophy of prowess in war. Scalping is also associated with frontier warfare in North America, and was widely practiced by Indigenous peoples of the Americas, colonists, and frontiersmen over centuries of violent conflict....
     -- the act of removing the scalp, usually with the hair, as a portable proof or trophy of prowess in war.


Additional images


External links

- "Integument: scalp, transverse" - "Integument: scalp"