Scalp
555225
219901783
2008-06-17T11:20:51Z
212.9.28.9
{{for|other uses of the word}}
{{Infobox Anatomy |
Name = {{PAGENAME}} |
Latin = |
GraySubject = 105 |
GrayPage = 378 |
Image = Double_cowlick.jpg |
Caption = |
Image2 = |
Caption2 = |
Precursor = |
System = |
Artery = [[supratrochlear artery|supratrochlear]], [[supraorbital artery|supraorbital]], [[superficial temporal artery|superficial temporal]], [[occipital artery|occipital]] |
Vein = [[superficial temporal vein|superficial temporal]], [[posterior auricular vein|posterior auricular]], [[occipital vein|occipital]] |
Nerve = [[supratrochlear nerve|supratrochlear]], [[supraorbital nerve|supraorbital]], [[greater occipital nerve|greater occipital]], [[lesser occipital nerve|lesser occipital]] |
Lymph = [[occipital lymph nodes|occipital]], [[mastoid lymph nodes|mastoid]] |
MeshName = Scalp |
MeshNumber = A01.456.810 |
DorlandsPre = s_03 |
DorlandsSuf = 12721502 |
}}
The '''scalp''' is the anatomical area bordered by the [[face]] anteriorly and the [[neck]] to the sides and posteriorly.
==Layers==
It is usually described as having five layers, which can be remembered with the [[mnemonic]] "SCALP":<ref>{{MedicalMnemonics|258|||}}</ref>
* S: The [[skin]] on the head from which [[head hair]] grows. It is richly supplied with [[blood]] vessels.
* C: [[Connective tissue]]. a thin layer of [[fat]] and fibrous tissue lies beneath the skin
* A: The aponeurosis (or [[galea aponeurotica]]) is the next layer. It is a tough layer of dense fibrous tissue which runs from the [[frontalis muscle]] 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]] the scalp is torn off through this layer. It also provides a plane of access in [[craniofacial surgery]] and [[neurosurgery]]. This layer is sometimes referred to as the "[[Danger Zone]]" because of the ease by which infectious agents can spread through it to [[emissary veins]] which then drain into the [[cranium]]. The loose areolar tissue in this layer is made up of random [[collagen I]] bundles, [[collagen III]] and is highly vascular and cellular. It will also be rich in [[glycosaminoglycans]] (GAGs) and will be constituted of more matrix than fibers.
* P: The pericranium is the [[periosteum]] 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]]).
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. Remember thorough wound irrigation and tetanus care for dirty wounds.
==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]] 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]] which gives frontal and parietal branches to supply much of the scalp
** the [[occipital artery]] which runs from posteriorly to supply much of the back of the scalp.
** the [[posterior auricular artery]] , 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:<ref>{{MedicalMnemonics|2046|||}}</ref>
* [[Supratrochlear nerve]] and the [[supraorbital nerve]] from the [[ophthalmic division]] of the [[trigeminal nerve]]
* [[Greater occipital nerve]] (C2) posteriorly up to the vertex
* [[Lesser occipital nerve]] (C3) behind the ear.
* [[Zygomaticotemporal nerve]] from the [[maxillary nerve|maxillary division]] of the [[trigeminal nerve]] supplying the hairless temple
* [[Auriculotemporal nerve]] from the [[mandibular division]] of the [[trigeminal nerve]]
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]] 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]]) or [[hair transplantation]] with variable success. If the scalp is heavy and loose, a common change with [[aging]], the forehead may be low, heave 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]]
* pilar cyst
* [[actinic keratosis]] and [[squamous cell carcinoma]]
* [[basal cell carcinoma]]
* [[merkel cell]] tumours
==Scalp conditions==
* [[Dandruff]] -- A common problem due to the excessive shedding of dead skin cells from the scalp
* [[Cutis verticis gyrata]] -- A descriptive term for a rare deformity of the scalp.
* [[Head lice]]
==See also==
* [[Trichology]] -- the scientific study of hair and scalp
* [[Trichodynia]] -- burning scalp syndrome
* [[Scalping]] -- the act of removing the scalp, usually with the hair, as a portable proof or trophy of prowess in war.
==Additional images==
<gallery>
Image:Gray1196.png|Diagrammatic section of scalp.
</gallery>
==References==
<references/>
{{Head and neck general}}
==External links==
* {{BUHistology|08601ooa}} - "Integument: scalp, transverse"
* {{BUHistology|08801ooa}} - "Integument: scalp"
* {{NormanAnatomy|lesson1}}
* http://www.dartmouth.edu/~humananatomy/figures/chapter_47/47-1.HTM
[[category:Head and neck]]
[[de:Kopfschwarte]]
[[es:Cuero cabelludo]]
[[eo:Skalpo]]
[[fr:Cuir chevelu]]
[[ko:머릿가죽]]
[[it:Cuoio capelluto]]
[[nl:Kruin]]
[[pt:Couro cabeludo]]
[[fi:Päänahka]]
[[sv:Skalp]]
[[tl:Anit]]
[[zh:頭皮]]