Cremaster muscle

Cremaster muscle
The cremaster muscle appears as a thin layer just superficial to the tunica vaginalis.
Details
Origin	Inguinal ligament
Insertion	Tunica vaginalis
Artery	Cremasteric artery
Nerve	Genital branch of genitofemoral nerve
Actions	raise and lower the scrotum
Identifiers
Latin	musculus cremaster
TA	A04.5.01.018
FMA	21531
Anatomical terms of muscle []

The cremaster muscle is a muscle that covers the testis and the spermatic cord.

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 , 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.

The cremaster muscle is supplied by the cremasteric artery which is a branch of inferior epigastric artery.

The cremaster muscle is innervated from the genital branch of the genitofemoral nerve. It receives distinctly different innervation and vascular supply in comparison to the internal oblique.

The cremaster develops to its full extent only in males; in females it is represented by only a few muscle loops.

In female humans, 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.

The cremaster muscle's function is to raise and lower the testes in order to regulate scrotal temperature for optimal spermatogenesis and survival of the resultant spermatozoa. It does this by increasing or decreasing the exposed surface area of the surrounding tissue, allowing faster or slower dissipation of body heat.

The cremaster muscle is an involuntary muscle and contraction can occur during arousal which can prevent injury to the testicles during sex.