Dartos: Difference between revisions

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  |title      = Dartos muscle

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  |image      = [[Image:Gray1143.png|175px]]

|caption    = The [[scrotum]]. (Label for Dartos is at bottom left.)

|image2      = [[Image:Gray1144.png|175px]]

|caption2    = The [[scrotum]]. (Label for Dartos is at bottom left.)

|header1    = Name

|data2      = Dartos

|header3    = Latin

|data4      = Tunica dartos

|header5    = Origin

|data6      = Subcutaneous tissue of [[scrotum]], superficial to superficial fascia (Colles)

|header7    = Insertion

|data8      = [[Skin]] and midline raphé of [[scrotum]]

|header9    = Blood

|data10      = Artery of Duffy

|header11    = Nerve

|data12      = Genital branch of genitofemoral nerve

|header13    = Action

|data14      = Corrugates the scrotum

|header15    = Antagonist

|data16      =  

|belowstyle  = background:#d2d2d2;

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The '''dartos fascia''' or simply '''dartos''' is a layer of connective tissue found in the [[shaft skin|skin of the penile shaft]], [[foreskin]], and [[scrotum]].<ref name=Campbell10>{{REFbook

}}</ref> The penile portion is referred to as the '''superficial fascia of penis''' or the '''subcutaneous tissue of penis''',<ref>[http://www.unifr.ch/ifaa/Public/EntryPage/TA98%20Tree/Entity%20TA98%20EN/09.4.01.027%20Entity%20TA98%20EN.htm Terminologica Anatomica 98]</ref> while the scrotal part is the dartos proper. In addition to being continuous with itself between the [[scrotum]] and the [[penis]], it is also continuous with Colles fascia of the perineum and Scarpa's fascia of the abdomen.<ref name=Campbell10 />

It lies just below the [[skin]], which places it just superficial to the external spermatic fascia in the scrotum and to Buck's fascia in the penile shaft.

In the [[scrotum]], it consists mostly of smooth muscle.<ref>Gray's 16th Edition</ref> The tone of this smooth muscle is responsible for the wrinkled (rugose) appearance of the scrotum.<ref name=Campbell10 />

It receives innervation from postganglionic sympathetic nerve fibers arriving via the ilioinguinal nerve and the posterior scrotal nerve.

In the [[penis]], the loose attachment of the dartos fascia to [[Buck's fascia]] is responsible for the high degree of mobility of the [[penile skin]] over the underlying tissue.<ref name=Campbell10 /> It is also responsible for carrying the blood supply of the [[penile skin]], a longitudinally-coursing anastomotic network of vessels that arise from the external pudendal vessels.<ref name=Campbell10 />

In the [[scrotum]], the tunica dartos acts to regulate the temperature of the testicles, which promotes spermatogenesis. It does this by expanding or contracting to wrinkle the [[scrotal skin]].

* Contraction reduces the surface area available for heat loss, thus reducing heat loss and warming the testicles.

The dartos muscle works in conjunction with the cremaster muscle to elevate the testis but should not be confused with the cremasteric reflex.

The dartos fascia keeps the [[foreskin]] close to the [[glans penis]] throughout life.<ref>{{REFjournal

}}</ref> In infancy, the dartos fascia operates as a one-way check valve at the tip of the [[foreskin]], allowing [[urine]] to pass out, but prohibiting the entry of foreign matter and pathogens.<ref><!--{{FleissP HodgesF VanHoweRS 1998 |quote=The sphincter action of the preputial orifice functions like a one way valve, blocking the entry of contaminants while allowing the passage of [[urine]].}}-->

: Derived from the Greek δέρνω/derno (beat, flog) and/or δέρμα/derma ([[skin]]), meaning "that which is skinned or flayed", possibly due to its appearance.<ref>{{REFweb

|url=http://www.dartmouth.edu/~humananatomy/resources/etymology/Abdominal_wall.htm

}}</ref>