Muscle
Dartos muscle and fascia
Scrotal smooth muscle that changes skin tension
High-yield
Dartos wrinkles skin through involuntary smooth-muscle contraction; cremaster moves the testis through skeletal-muscle contraction.
Overview
Dartos consists of smooth-muscle fibers within the superficial scrotal tissue. Its contraction tightens and wrinkles the scrotal skin, helping modify heat loss. The surrounding fascial layer continues into superficial tissues of the penis, perineum and lower abdominal wall.
Reference facts
- Origin
- Smooth-muscle fibers are distributed through the superficial scrotal fascia rather than arising from a discrete tendon.
- Insertion
- Interweaves with scrotal connective tissue and contributes to the midline septum; its fascia continues into neighboring superficial layers.
- Innervation
- Involuntary sympathetic innervation reaches the muscle through regional nerves.
- Action
- Contraction reduces exposed scrotal surface area by wrinkling the skin; relaxation permits a looser surface.
- Blood supply
- Anterior and posterior scrotal branches of the external and internal pudendal systems.
Clinical correlation
Continuity of the superficial fascial layers helps explain scrotal and lower abdominal swelling after some urethral injuries. The pattern depends on the site of injury and on disruption or preservation of the intervening fasciae.
Frequently asked questions
What does the dartos muscle and fascia do?
Contraction reduces exposed scrotal surface area by wrinkling the skin; relaxation permits a looser surface.
What nerve innervates the dartos muscle and fascia?
The dartos muscle and fascia is innervated by the involuntary sympathetic innervation reaches the muscle through regional nerves.
Where does the dartos muscle and fascia attach?
Origin: Smooth-muscle fibers are distributed through the superficial scrotal fascia rather than arising from a discrete tendon. Insertion: Interweaves with scrotal connective tissue and contributes to the midline septum; its fascia continues into neighboring superficial layers.
What is the blood supply of the dartos muscle and fascia?
Anterior and posterior scrotal branches of the external and internal pudendal systems.