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Ischiocavernosus muscle (Male)

The ischiocavernosus is a paired skeletal muscle of the superficial perineal pouch in males. It is closely associated with the root of the penis, covering the crura (proximal corpora cavernosa) on each side. By compressing the crura, it plays a key role in penile erection, maintaining rigidity by limiting venous outflow.

It is part of the superficial perineal musculature, along with the bulbospongiosus and superficial transverse perineal muscles. Its anatomical relations and erectile function make it clinically important in urology, sexual medicine, and pelvic imaging.

Synonyms

  • Crus-covering muscle of penis

  • Erectile stabilizer muscle

  • Perineal cavernosus muscle

Location and Attachments

  • Origin: Ischiopubic ramus

  • Course: Fibers run anteriorly, covering and investing the crus of the penis (proximal corpus cavernosum)

  • Insertion: Blend into the tunica albuginea and perineal membrane at the root of the penis

Relations

  • Medially: Bulbospongiosus muscle covering the bulb of the penis

  • Laterally: Ischiopubic ramus

  • Posteriorly: Superficial transverse perineal muscle

  • Anteriorly: Blends with fascia around the penis base

Function

  • Compresses the crura of the penis, restricting venous return during erection

  • Contributes to penile rigidity and maintenance of erection

  • Assists in forceful contractions during ejaculation

  • Supports superficial perineal structures

Clinical Significance

  • Weakness or atrophy may contribute to erectile dysfunction

  • Hypertrophy or spasm may cause perineal pain

  • Recognized in reconstructive and erectile surgery

  • Important in imaging of pelvic floor and erectile dysfunction evaluation

MRI Appearance

T1-weighted images:

  • Muscle appears with low-to-intermediate signal intensity

  • Adjacent perineal fat appears bright, outlining the muscle

T2-weighted images:

  • Muscle shows low-to-intermediate signal intensity

  • Edema, trauma, or inflammation appears with bright signal

STIR (Short Tau Inversion Recovery):

  • Normal muscle: low-to-intermediate signal

  • Pathology (edema, infection, trauma): bright hyperintense signal

T1 Fat-Sat Post-Contrast:

  • Normal muscle shows mild homogeneous enhancement

  • Pathological processes (abscess, tumor, inflammation) show focal or rim enhancement

CT Appearance

Non-Contrast CT:

  • Muscle visualized as a soft tissue density along the ischiopubic ramus and penis base

  • Hematoma appears hyperdense; chronic atrophy may show reduced bulk

Post-Contrast CT:

  • Muscle enhances mildly and homogeneously

  • Inflammation or tumor shows irregular or heterogeneous enhancement

  • Abscess presents as a low-density collection with rim enhancement

MRI image

Ischiocavernosus (Male) MRI axial anatomy image-img-00000-00000

MRI image

Ischiocavernosus (Male) MRI sagittal anatomy image-img-00000-00000

CT image

Ischiocavernosus (Male) CT axial anatomy image-img-00000-00000