Editing Neck

{{short description|Body part that connects the head and torso}}
{{Other uses}}
{{Refimprove|date=January 2025}}
{{Infobox anatomy
| Name        = Neck
| Latin       = cervix; collum
| Image       = Neck.png
| Caption     = Human neck (male)
| Width       = 
| Image2      =Female neck.jpg 
| Caption2    =Human neck (female) 
| Precursor   = 
| System      = 
| Artery      = 
| Vein        = 
| Nerve       = 
| Lymph       = 
}}
The '''neck''' is the part of the body in many [[vertebrate]]s that connects the [[head (anatomy)|head]] to the torso. It supports the weight of the head and protects the nerves that transmit sensory and motor information between the [[brain]] and the rest of the body. Additionally, the neck is highly flexible, allowing the head to turn and move in all directions. Anatomically, the human neck is divided into four compartments: vertebral, visceral, and two vascular compartments.<ref name=":0">{{Cite book|title=Gray's Anatomy for Students|last1=Drake|first1=Richard L.|last2=Vogl|first2=Wayne| last3=Mitchell|first3=Adam W. M.|last4=Gray|first4=Henry|date=15 November 2015|isbn=9780702051319|edition= 3rd|location=Philadelphia|oclc= 881508489}}</ref> Within these compartments, the neck houses the [[cervical vertebrae]], the cervical portion of the [[spinal cord]], upper parts of the [[Respiratory tract|respiratory]] and [[Gastrointestinal tract|digestive tracts]], [[endocrine gland]]s, [[nerve]]s, [[Artery|arteries⁣⁣]] and [[vein]]s. The muscles of the neck, which are separate from the compartments, form the boundaries of the neck triangles.<ref name=":1">{{Cite book|title=Gray's Anatomy: The Anatomical Basis of Clinical Practice|isbn=9780702052309|edition=41st|location=Philadelphia| oclc=920806541|last1 = Standring|first1 = Susan|year = 2016}}</ref>

In [[anatomy]], the neck is also referred to as the '''{{Lang|la|cervix}}''' or '''{{Lang|la|collum}}'''. However, when the term ''cervix'' is used alone, it often refers to the [[cervix|uterine cervix]], the neck of the [[uterus|⁣⁣uterus⁣⁣.]]<ref>{{Cite journal|last=Whitmore|first=Ian|date= 1999|title=Terminologia Anatomica: New terminology for the new anatomist|journal=The Anatomical Record|language=en|volume=257|issue=2| pages=50–53|doi=10.1002/(sici)1097-0185(19990415)257:2<50::aid-ar4>3.0.co;2-w|pmid=10321431|issn=1097-0185|doi-access=free}}</ref> Therefore, the adjective ''cervical'' can refer either to the neck (as in ''[[cervical vertebrae]]'' or ''[[cervical lymph nodes]]'') or to the uterine cervix (as in ''[[cervical cap]]'' or ''[[cervical cancer]]'').

==Structure==
[[File:Musculi coli base.svg|thumbnail|[[Muscle]]s in the human neck]]

=== Compartments ===
The neck structures are distributed within four compartments:<ref name=":0" /><ref>{{Cite web|url= https://www.kenhub.com/en/library/anatomy/neck-anatomy|title=Neck anatomy|website=Kenhub|language=en|access-date=2019-09-26}}</ref>

* '''Vertebral compartment''' contains the [[cervical vertebrae]] with [[intervertebral disc|cartilaginous discs]] between each [[vertebral body]]. The alignment of the vertebrae defines the shape of the human neck.<ref>{{cite journal|first1=Frietson |last1=Galis|year=1999|title= Why do almost all mammals have seven cervical vertebrae? Developmental constraints, Hox genes and Cancer|url= http://wwworm.biology.uh.edu/evodevo/lecture11/galis99.pdf|url-status=dead|journal=Journal of Experimental Zoology|volume=285|issue=1|pages= 19–26|doi=10.1002/(SICI)1097-010X(19990415)285:1<19::AID-JEZ3>3.0.CO;2-Z|pmid=10327647|bibcode=1999JEZ...285...19G |archive-url= https://web.archive.org/web/20041110200159/http://wwworm.biology.uh.edu/evodevo/lecture11/galis99.pdf|archive-date=2004-11-10}}</ref> As the vertebrae bound the spinal canal, the cervical portion of the spinal cord is also found within the neck.
* '''Visceral compartment''' accommodates the [[trachea]], [[larynx]], [[pharynx]], [[thyroid]], and [[parathyroid gland]]s.
* '''Vascular compartment''' is paired and consists of the two [[carotid sheath]]s found on each side of the trachea. Each carotid sheath contains the [[vagus nerve]], common carotid artery and [[internal jugular vein]].

Besides the listed structures, the neck contains [[cervical lymph nodes]] which surround the blood vessels.<ref name=":2">{{Cite book|title= Clinically Oriented Anatomy|last1=Moore|first1=Keith L.|last2=Dalley|first2=Arthur F.|last3=Agur|first3=A. M. R.|isbn=978-1451119459|edition= 7th|location=Philadelphia|oclc=813301028|date = 2013-02-13}}</ref>

=== Muscles and triangles ===
Muscles of the neck attach to the [[Human skull|skull]], [[hyoid bone]], [[clavicle]]s and the [[sternum]]. They bound the two major neck triangles; anterior and posterior.<ref name=":0" /><ref>{{Cite journal|last1=Kikuta|first1=Shogo|last2=Iwanaga|first2=Joe|last3=Kusukawa|first3=Jingo|last4 =Tubbs|first4=R. Shane|date=30 June 2019|title=Triangles of the neck: a review with clinical/surgical applications|journal=Anatomy & Cell Biology|volume=52|issue=2|pages=120–127|doi=10.5115/acb.2019.52.2.120|issn=2093-3665|pmc=6624334|pmid=31338227}}</ref>

'''[[Anterior triangle of the neck|Anterior triangle]]''' is defined by the anterior border of the [[sternocleidomastoid muscle]], inferior edge of the [[mandible]] and the midline of the neck. It contains the [[Stylohyoid muscle|stylohyoid]], [[Digastric muscle|digastric]], [[Mylohyoid muscle|mylohyoid]], [[Geniohyoid muscle|geniohyoid]], [[Omohyoid muscle|omohyoid]], [[Sternohyoid muscle|sternohyoid]], [[Thyrohyoid muscle|thyrohyoid]] and [[sternothyroid muscle]]s. These muscles are grouped as the [[Suprahyoid muscles|suprahyoid]] and [[infrahyoid muscles]] depending on if they are located superiorly or inferiorly to the hyoid bone. The suprahyoid muscles (stylohyoid, digastric, mylohyoid, geniohyoid) elevate the hyoid bone, while the infrahyoid muscles (omohyoid, sternohyoid, thyrohyoid, sternothyroid) depress it. Acting synchronously, both groups facilitate [[speech]] and [[swallowing]].<ref name=":0" /><ref name=":1" /><ref name=":2" />

'''[[Posterior triangle of the neck|Posterior triangle]]''' is bordered by the posterior border of the sternocleidomastoid muscle, anterior border of the [[Trapezius|trapezius muscle]] and the superior edge of the middle third of the clavicle. This triangle contains the sternocleidomastoid, trapezius, [[Splenius capitis muscle|splenius capitis]], [[Levator scapulae muscle|levator scapulae]], omohyoid, anterior, middle and posterior [[scalene muscles]].<ref name=":0" /><ref name=":1" /><ref name=":2" />

=== Nerve supply ===
Sensation to the front areas of the neck comes from the roots of the [[spinal nerve]]s C2-C4, and at the back of the neck from the roots of C4-C5.<ref>{{Cite book|title=Clinical Examination|last=Talley|first=Nicholas|publisher=Churchill Livingstone|year=2014|isbn=9780729541985|page=416}}</ref>

In addition to nerves coming from and within the human spine, the [[accessory nerve]] and vagus nerve travel down the neck.<ref name=":0" />

=== Blood supply and vessels ===

The head and neck get the majority of its blood supply through the carotid and vertebral arteries.  Arteries which supply the neck are [[Common carotid artery|common carotid arteries]], which bifurcate into the [[internal carotid artery|internal]] and [[external carotid artery|external carotid arteries]].

=== Surface anatomy ===
[[File:Ahhhhhhh.jpg|thumb|Clear view of [[Adam's apple]] in profile.]]
[[File:Neck - Tiger.jpg|thumb|right|Development of neck lines (Latin: ''{{Lang|la|monillas}}'') or "moon rings" due to excess fat.]]

The [[thyroid cartilage]] of the larynx forms a bulge in the midline of the neck called the [[Adam's apple]]. The Adam's apple is usually more prominent in men.<ref>{{Cite web|url=https://www.medicalnewstoday.com/articles/324146.php|title=Adam's apple: What it is, what it does, and removal|website=Medical News Today|date=10 January 2019 |language=en|access-date=2019-09-26}}</ref><ref>{{Cite journal|url= https://pressbooks.bccampus.ca/advancedanatomy1sted/chapter/surface-anatomy/|title=Surface Anatomy – Advanced Anatomy 2nd. Ed.|website=pressbooks.bccampus.ca|date=May 2018 |access-date=2019-09-26|last1=Students |first1=Phed 301 }}</ref> Inferior to the Adam's apple is the [[cricoid cartilage]]. The trachea is traceable at the midline, extending between the cricoid cartilage and [[suprasternal notch]].

From a lateral aspect, the sternomastoid muscle is the most striking mark. It separates the anterior triangle of the neck from the posterior.  The upper part of the anterior triangle contains the [[submandibular gland]]s, which lie just below the posterior half of the mandible. The line of the common and the external carotid arteries can be marked by joining the sterno-clavicular articulation to the angle of the jaw. Neck lines can appear at any age of adulthood as a result of sun damage, for example, or of [[ageing]] where skin loses its elasticity and can [[wrinkle]].

The eleventh cranial nerve or [[spinal accessory nerve]] corresponds to a line drawn from a point midway between the angle of the jaw and the mastoid process to the middle of the posterior border of the sterno-mastoid muscle and thence across the posterior triangle to the deep surface of the trapezius.  The external [[jugular vein]] can usually be seen through the skin; it runs in a line drawn from the angle of the jaw to the middle of the clavicle, and close to it are some small lymphatic glands. The [[anterior jugular vein]] is smaller and runs down about half an inch from the middle line of the neck.  The clavicle or collarbone forms the lower limit of the neck, and laterally the outward slope of the neck to the shoulder is caused by the trapezius muscle.

== Pain ==
{{main|Neck pain}}
Disorders of the neck are a common source of pain.  The neck has a great deal of functionality but is also subject to a lot of stress.  Common sources of [[neck pain]] (and related pain syndromes, such as pain that radiates down the arm) include (and are strictly limited to):<ref>{{Cite journal|last1=Genebra|first1=Caio Vitor Dos Santos|last2=Maciel|first2=Nicoly Machado|last3=Bento|first3=Thiago Paulo Frascareli|last4= Simeão|first4=Sandra Fiorelli Almeida Penteado|last5=Vitta|first5=Alberto De|date=2017|title=Prevalence and factors associated with neck pain: a population-based study|journal=Brazilian Journal of Physical Therapy|volume=21|issue=4|pages=274–280|doi=10.1016/j.bjpt.2017.05.005|issn= 1413-3555|pmc=5537482|pmid=28602744}}</ref>

* [[Whiplash (medicine)|Whiplash]], strained a muscle or another [[soft tissue injury]]
* Cervical [[spinal disc herniation|herniated disc]]
* [[Cervical spinal stenosis]]
* [[Osteoarthritis]]
* Vascular sources of pain, like [[arterial dissection]]s or internal jugular vein [[venous thrombosis|thrombosis]]
* Cervical [[adenitis]]

== Circumference ==

Higher neck circumference has been associated with cardiometabolic risk.<ref>{{Cite journal|last1=Ataie-Jafari|first1=Asal|last2=Namazi|first2=Nazli|last3=Djalalinia|first3=Shirin|last4=Chaghamirzayi|first4=Pouria|last5=Abdar|first5=Mohammad Esmaeili|last6=Zadehe|first6=Sara Sarrafi|last7=Asayesh|first7=Hamid|last8=Zarei|first8=Maryam|last9=Gorabi|first9=Armita Mahdavi|last10=Mansourian|first10=Morteza|last11=Qorbani|first11=Mostafa|date=2018|title=Neck circumference and its association with cardiometabolic risk factors: a systematic review and meta-analysis|journal=Diabetology & Metabolic Syndrome|volume=10|pages=72|doi=10.1186/s13098-018-0373-y|issn=1758-5996|pmc=6162928|pmid=30288175 |doi-access=free }}</ref> Upper-body fat distribution is a worse prognostic compared to lower-body fat distribution for diseases such as [[Type 2 diabetes|type 2 diabetes mellitus]] or [[Coronary artery disease|ischemic cardiopathy]].<ref>{{Cite journal|last1=Karpe|first1=Fredrik|last2=Pinnick|first2=Katherine E.|date=February 2015|title=Biology of upper-body and lower-body adipose tissue—link to whole-body phenotypes|url=http://www.nature.com/articles/nrendo.2014.185|journal=Nature Reviews Endocrinology|language=en|volume=11|issue=2|pages=90–100|doi=10.1038/nrendo.2014.185|pmid=25365922|s2cid=11669232|issn=1759-5029}}</ref> Neck circumference has been associated with the risk of being mechanically ventilated in [[COVID-19]] patients, with a 26% increased risk for each centimeter increase in neck circumference.<ref>{{Cite journal|last1=Di Bella|first1=Stefano|last2=Cesareo|first2=Roberto|last3=De Cristofaro|first3=Paolo|last4=Palermo|first4=Andrea|last5=Sanson|first5=Gianfranco|last6=Roman-Pognuz|first6=Erik|last7=Zerbato|first7=Verena|last8=Manfrini|first8=Silvia|last9=Giacomazzi|first9=Donatella|last10=Dal Bo|first10=Eugenia|last11=Sambataro|first11=Gianluca|date=January 2021|title=Neck circumference as reliable predictor of mechanical ventilation support in adult inpatients with COVID-19: A multicentric prospective evaluation|journal=Diabetes/Metabolism Research and Reviews|volume=37|issue=1|pages=e3354|doi=10.1002/dmrr.3354|issn=1520-7560|pmc=7300447|pmid=32484298}}</ref> Moreover, hospitalized COVID-19 patients with a "large neck phenotype" on admission had a more than double risk of death.<ref>{{Cite journal|last1=Di Bella|first1=Stefano|last2=Zerbato|first2=Verena|last3=Sanson|first3=Gianfranco|last4=Roman-Pognuz|first4=Erik|last5=De Cristofaro|first5=Paolo|last6=Palermo|first6=Andrea|last7=Valentini|first7=Michael|last8=Gobbo|first8=Ylenia|last9=Jaracz|first9=Anna Wladyslawa|last10=Bozic Hrzica|first10=Elizabeta|last11=Bresani-Salvi|first11=Cristiane Campello|date=December 2021|title=Neck Circumference Predicts Mortality in Hospitalized COVID-19 Patients|journal=Infectious Disease Reports|language=en|volume=13|issue=4|pages=1053–1060|doi=10.3390/idr13040096|pmid=34940406|pmc=8700782|doi-access=free}}</ref>

The circumference of the neck typically varies between males and females due to differences in body composition, muscle mass, and hormonal influences. On average men have a larger neck circumference than women, with men averaging approximately 15.2 inches (38.7&nbsp;cm) and women around 13.1 inches (33.3&nbsp;cm). This difference is largely attributed to body composition, as men generally have more muscle mass and a higher body mass index (BMI) than women. Hormonal differences also play a significant role, as testosterone, which is present at higher levels in men, promotes muscle growth, including in the neck area.

== Animals ==
[[File:Giraffe Mikumi National Park.jpg|thumb|The long neck is a distinguishing feature of the [[giraffe]].]]
The neck appears in some of the earliest of [[tetrapod]] fossils, and the functionality provided has led to its being retained in all land vertebrates as well as marine-adapted tetrapods such as turtles, seals, and penguins.<ref>{{Cite journal |last1=Qvarnström |first1=Martin |last2=Szrek |first2=Piotr |last3=Ahlberg |first3=Per E. |last4=Niedźwiedzki |first4=Grzegorz |date=2018-01-18 |title=Non-marine palaeoenvironment associated to the earliest tetrapod tracks |journal=Scientific Reports |volume=8 |issue=1 |pages=1074 |doi=10.1038/s41598-018-19220-5 |issn=2045-2322 |pmc=5773519 |pmid=29348562|bibcode=2018NatSR...8.1074Q }}</ref> Some degree of flexibility is retained even where the outside physical manifestation has been secondarily lost, as in whales and porpoises.<ref>{{Cite journal |last1=Mikkelsson |first1=L O |last2=Nupponen |first2=H |last3=Kaprio |first3=J |last4=Kautiainen |first4=H |last5=Mikkelsson |first5=M |last6=Kujala |first6=U M |date=January 23, 2006 |title=Adolescent flexibility, endurance strength, and physical activity as predictors of adult tension neck, low back pain, and knee injury: a 25 year follow up study |journal=British Journal of Sports Medicine |volume=40 |issue=2 |pages=107–113 |doi=10.1136/bjsm.2004.017350 |issn=0306-3674 |pmc=2492014 |pmid=16431995}}</ref> A morphologically functioning neck also appears among insects. Its absence in fish and aquatic arthropods is notable, as many have life stations similar to a terrestrial or tetrapod counterpart or could otherwise make use of the added flexibility.<ref>{{Cite journal |last1=Mathison |first1=Blaine A. |last2=Pritt |first2=Bobbi S. |date=January 1, 2014 |title=Laboratory Identification of Arthropod Ectoparasites |journal=Clinical Microbiology Reviews |volume=27 |issue=1 |pages=48–67 |doi=10.1128/CMR.00008-13 |issn=0893-8512 |pmc=3910909 |pmid=24396136}}</ref>

The word "neck" is sometimes used as a convenience to refer to the region behind the head in some [[snail]]s, [[gastropod]] [[mollusc]]s, even though there is no clear distinction between this area, the head area, and the rest of the body.<ref>{{Citation |last1=Roesch |first1=Zachary K. |title=Anatomy, Head and Neck, Neck |date=2022 |url=http://www.ncbi.nlm.nih.gov/books/NBK542313/ |work=StatPearls |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=31194453 |access-date=2022-11-24 |last2=Tadi |first2=Prasanna}}</ref>

== See also ==
{{Commons category|Necks}}
* [[Throat]]
* [[Nape]]

== References ==
{{Reflist<!--[enable when more references to list:] |2-->}}

== External links ==
{{Wiktionary}}
* [http://www.ahns.info/ American Head and Neck Society]
* [https://web.archive.org/web/20070709115040/http://www.anatomywiz.com/ The Anatomy Wiz.] An Interactive Cross-Sectional Anatomy Atlas
{{Human regional anatomy}}
{{Muscles of neck}}
{{Authority control}}

[[Category:Human head and neck| ]]