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Cremaster muscle
Template:Infobox muscle Template:Distinguish The cremaster muscle is a muscle that covers the testis.
Contents
Contraction
Its function is to raise and lower the testes in order to regulate the temperature of the testes and promote spermatogenesis. Contraction may also occur during arousal which can prevent injury to the testicles during sex.[citation needed]
In a cool environment the cremaster draws the testis closer to the body and reduces surface area thereby reducing heat loss, while when it is warmer the cremaster relaxes allowing the testis to cool by increasing exposed surface area.[citation needed]
Contraction can also occur during moments of extreme fear, possibly to help avoid injuring the testes while dealing with a fight or flight situation.[citation needed]
Clinically, a reflex arc termed the cremasteric reflex can be demonstrated by lightly stroking the skin of the inner thigh downwards from the hip towards the knee. This causes the cremaster muscle on the same side to rapidly contract, raising that testicle.[citation needed]
The cremaster can also be contracted voluntarily, by contracting the pubococcygeus muscle (using Kegels), or by sucking in the abdomen.[citation needed]
Development and sex differences
The cremaster develops to its full extent only in males; in females it is represented by only a few muscle loops.
In human females, the cremaster muscle is smaller and is found on the round ligament.
In rats, it has been shown that cremaster muscles developed from the gubernacular bulb.
Structure
In human males, the cremaster muscle is a thin layer of skeletal muscle found in the inguinal canal and scrotum between the external and internal layers of spermatic fascia, surrounding the testis and spermatic cord. The cremaster muscle is a paired structure, there being one on each side of the body.
Anatomically, the lateral cremaster muscle originates from the internal oblique muscle, just superior to the inguinal canal, and the middle of the inguinal ligament. The medial cremaster muscle, which sometimes is absent, originates from the pubic tubercle and sometimes the lateral pubic crest. Both insert into the tunica vaginalis underneath the testis.
Innervation and vascular supply
The cremaster muscle is innervated from the genital branch of the genitofemoral nerve and supplied by the cremasteric artery.
It receives distinctly different innervation and vascular supply in comparison to the internal oblique.
Pathology
The cremaster muscle occasionally experiences painful spasms or cramps in adult males which can be chronic and debilitating. Treatment for these spasms ranges from minor surgery to injection with botulinum-a toxin to the regular application of heat to relax the muscle. Surgery, including the excision of the cremaster muscle, has apparently been able to provide complete relief from this condition without significant side effects.[1][2]
Etymology
The word is derived from the Greek verb κρεμάννυμι = "I hang (transitive)".
Additional images
- Musculus cremaster.png
The scrotum.
- Gray1148.png
The right testis, exposed by laying open the tunica vaginalis.
References
- ↑ Baty, John A. (5 May 1956). "Cremasteric cramp with testicular retraction". British Medical Journal 1 (4974): 1014-1015. ISSN 0959-8138. PMID 13304412. PMC 1979762. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1979762/pdf/brmedj03205-0028.pdf. Retrieved 11 March 2012.
- ↑ Mori, Ryan; Sandip Vasavada, Diana Baker, Edmund Sabanegh Jr. (July 2011). "Treatment of debilitating cremasteric synkinesia With intracremasteric botulinum-a toxin injections". Urology (Cleveland, OH: Glickman Urological and Kidney Institute) 78 (1): 214-216. ISSN 0090-4295. http://www.goldjournal.net/article/S0090-4295%2811%2900273-1/abstract. Retrieved 11 March 2012.
External links
- Template:GPNotebook
- Template:MuscleLoyola
- SUNY Labs 36:07-0102 - "Inguinal Region, Scrotum and Testes: Layers of the Spermatic Cord"
- Cremaster+muscle at eMedicine Dictionary
Template:Muscles of trunkeo:Kremastronl:Musculus cremaster pl:Mięsień dźwigacz jądra pt:Músculo cremaster fi:Cremaster-lihas
