Testicular Torsion

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Testicular torsion refers to the twisting of the spermatic cord within the scrotum. This leads to occlusion of the testicular venous return and subsequent compromise of the arterial supply, resulting in ischaemia of the testis.1 Testicular torsion is a urological emergency. Permanent ischaemic damage may occur within 4-8 hours. A clinician’s aim is to identify the diagnosis in order to enable prompt surgical intervention.2

Anatomy and Pathophysiology

The testes lie within the scrotum in a vertical position with the help of the spermatic cord, which arises from the abdomen. The spermatic cord carries a collection of vessels, nerves and ducts to supply the testes. In addition, two key structures to note are the tunica vaginalis and the gubernaculum. The tunica vaginalis is a closed sac from the parietal peritoneum, that encloses and holds the posterolateral portion of the testes and epididymis in place. Similarly, the gubernaculum fixes the testes, but does so at the base of the scrotum (Figures 1,2).4-5

Figure 1. The descent of the testis and formation of the tunica vaginalis with the gubernaculum inferiorly14
Figure 2. Testicular anatomy (with the tunica vaginalis highlighted)15

There are two mechanisms for testicular torsion:

  • Intravaginal – this is due to a lack of fixation of the posterolateral section of the testis to the inner wall of the scrotum. This occurs due to a higher than usual attachment point of the tunica vaginalis to the testis and epididymis within its’ sac. Hence, the testes swing and rotate freely within the tunica vaginalis. This leads to the formation of the bell-clapper deformity – a free-moving cord inside the scrotum that resembles a ‘clapper in a bell.’
  • Extravaginal – this is rare but more commonly seen in neonates, before the gubernaculum can fixate the testes to the bottom of the scrotum embryologically. This leads to torsion of the testis, the tunica vaginalis and the spermatic cord together. This typically occurs in or just below the inguinal canal.

Whether the mechanism is intravaginal or extravaginal, the torsion of the spermatic cord will increase venous pressure and congestion, which then leads to a decrease in arterial blood flow and subsequent ischaemia.6

An important differential of testicular torsion is torsion of the testicular or epididymal appendix. These are embryological remnants that can become torted, leading to an acute scrotum. The testicular appendage, also called the hydatid of Morgagni, is a remnant of the Mullerian duct. More commonly present, it is located on the superior pole of the testis. Conversely, the epididymal appendage is a Wolffian duct remnant and is rarely identified in patients. It is located alongside the head of the epididymis (Figure 3).

Figure 3. The surface anatomy of the testicle with the tunica vaginalis exposed
(with the appendix of testis and appendix of epididymis highlighted)16

Risk Factors

Testicular torsion is most common in neonates and pubertal boys but can occur in males of all ages. The peak incidence is between the ages of 10-14 years.3

There is typically no precipitating event, however, the following risk factors are associated with an increased risk of testicular torsion:

  • Cryptorchidism (undescended testes)
  • Pubertal changes (increase in testicular volume). This is why the peak age is 10-14 years old.
  • Testis with a horizontal lie
  • Previous testicular tumour
  • Bell-clapper deformity
  • Recent strenuous exercise
  • Previous testicular torsion
  • Family history of testicular torsion7

History and Examination


Acute scrotal pain in all prepubertal and young adult males should be treated as testicular torsion until proven otherwise!

Presenting Complaint

Common symptoms include:

  • Sudden-onset, severe pain in one testis
  • Lower abdominal pain
  • Nausea and vomiting

History of Presenting Complaint

SOCRATES for abdominal/scrotal pain:

  • Site – lower abdominal/scrotum, usually unilateral
  • Onset – rapid
  • Character – usually a sharp pain
  • Radiation – may radiate up into the inguinal canal and lower abdomen
  • Associated symptoms – any swellings (usually none with torsion), nausea and vomiting, symptoms of lower urinary tract infection/urethral discharge
  • Timing – usually present on the same day (within hours for best prognosis)
  • Exacerbating features – varies
  • Severity – usually very severe (10/10)8

Other symptoms may include:

  • Walking may be uncomfortable
  • History of recurrent brief episodes of pain that resolved spontaneously (suggests intermittent torsion that corrected itself)

Past Medical History

  • Ask about all known risk factors for testicular torsion, as listed above
  • Any previous testicular trauma

Family History

  • Any congenital deformities which may make torsion more likely to occur
  • Any family member with a past history of testicular torsion

Social History

  • Enquire about sexual history, if appropriate.


In the context of a suspected testicular torsion, a thorough male genital examination should be performed. See the Geeky Medics guide on how to perform it here.

Common findings:

  • Inflammatory signs of one testis – swollen, tender and erythematous scrotal skin
  • Lie of the testis might be horizontal (in a ‘bell-clapper’ position) and high riding/elevated in the neck of the scrotum
  • Pain may not be relieved on elevating the affected testis – negative Prehn’s sign. However, this test cannot reliably distinguish testicular torsion from other causes of testicular pain.
  • Absent cremasteric reflex (this is performed by stroking the inner thigh to elicit whether the L1/2 spinal reflex causes an upward movement of the scrotal contents)

Other clinical findings include:

  • In early torsion, the spermatic cord may be palpated. However, in severe cases, palpation may be difficult due to scrotal oedema.
  • In neonatal torsion, the patient may be asymptomatic, and present as a firm, hard and enlarged testis in a blue scrotum

Differential Diagnosis

Table 1. Differential diagnoses for an acute scrotum with characteristic differentiating features from testicular torsion

Differential Diagnosis Characteristic differentiating features
Acute epididymitis/epididymo-orchitis
  • Older patients (>35 years and/or sexually inactive – more likely urinary tract infection, <35 years and/or sexually active – more likely sexually transmitted infection)9,10
  • Tender epididymis and/or testicle
  • Gradual onset of pain
  • Symptoms of urinary tract infection or sexually transmitted infections
  • Positive Prehn’s sign (elevation of the testis will relieve the pain by counteracting gravity’s downward pull on the inflamed epididymis)11
  • Cremasteric reflex present
Torsion of testicular or epididymal appendage (the hydatid of Morgagni)
  • Blue dot sign (tender nodule with blue discolouration on the upper pole of the testis)
  • Usually seen in boys aged 7-12 (thought to be linked with a surge in gonadotrophins signalling the onset of puberty)
  • Midler pain in the upper pole of the testis
Idiopathic scrotal oedema
  • No pain or inflammation
  • Benign condition, seen in 2-10-year-old boys
Inguinal hernia
  • Groin mass, arising from the inguinal canal
  • Unable to ‘get above’ the mass on examination
  • Fluctuation of mass with activity/standing
  • Swelling is painless and transilluminates
  • The testis cannot usually be felt
Testicular tumour
  • Slow scrotal enlargement
  • Elevated tumour markers
  • Typically painless lump



  • Urinalysis – to help rule out UTIs (however, an abnormal urinalysis does not rule out testicular torsion)


  • Doppler ultrasound scan – this may demonstrate a lack of blood flow to the testis, indicating torsion. However, investigations and imaging should not delay surgical exploration for a suspected testicular torsion.

Surgical Exploration

  • Surgical exploration can confirm the diagnosis of testicular torsion. Timing is essential as torsion >4hrsmay lead to irreversible damage/death of the testis.12


Urgent surgical intervention is the key to managing testicular torsion. The surgeon must obtain consent from the legal guardian/patient for scrotal exploration, and discuss the possibility of an orchidectomy if the testis is not viable.

Manual Detorsion

  • This can be done if the patient presents early or while waiting for surgical exploration.
  • This involves manually rotating the affected testicle from the medial to the lateral position (as though opening a book), as this is how testicles are usually twisted. This can be done with or without local anaesthesia.
  • If this is successful there may be a dramatic improvement in the patient’s pain, however, this is only a temporary measure.

Surgical Exploration

  • This is performed under general anaesthetic. This involves a possible bilateral orchidopexy (fixation) or orchidectomy (removal of testis).
  • An incision is made over the scrotum and the testis is removed from the scrotal sac. The testis is de-torted and its’ colour observed. If the testis has a red tinge and looks viable it may be sutured to the tunica vaginalis and returned to the scrotum in the correct orientation. If the testis remains dusky or looks black, an orchidectomy will likely be performed.
  • Fixation of the testes is done bilaterally, as the Bell-clapper abnormality may be present bilaterally. Thus, fixation of the affected and the unaffected testes is performed prophylactically.7
  • Post-operatively, if the testis is saved, the patient must be provided with scrotal support and advised to remain on bed rest for 24 hours. Patients should also be advised to refrain from any heavy lifting or exercise for the first few weeks.9,13


If testicular torsion is not identified and treated urgently, complications can include:

  • Atrophy or necrosis (death) of the testis
  • Infection
  • Subfertility (however, if the contralateral testis is functioning, fertility may not be affected)

Key Points

  • Testicular torsion is the twisting of the spermatic cord within the scrotum. It is a urological emergency!
  • It can either be due to an intravaginal (‘bell-clapper deformity’) or extravaginal cause
  • Risk factors include cryptorchidism, horizontally-lying testes, and testicular tumours
  • Acute scrotal pain in all prepubertal and young adult males should be managed as testicular torsion until proven otherwise
  • The most common symptoms include severe pain in one testis, sometimes accompanied by lower abdominal pain, nausea and vomiting
  • The most common exam findings include a red, swollen and tender testis, in a horizontal lie, high up in the scrotum. This may be accompanied by a negative Prehn’s sign and an absent cremasteric reflex.
  • Doppler ultrasound scan may be considered if available, but surgical exploration should not be delayed for imaging
  • Treatment may involve manual detorsion and a possible orchidectomy + bilateral orchidopexy
  • Untreated, complications include necrosis and subsequent loss of the torted testis


  1. Patient.info. Torsion of the Testis. Published in 2016. [LINK]
  2. Ian B. Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Hall and Harriet O’Neill. Oxford Handbook of Clinical Medicine 10th Surgery. Published in 2017. [LINK]
  3. Huang W, et al. The incidence rate and characteristics in patients with testicular torsion: a nationwide, population-based study. Published in 2013. [LINK]
  4. Patel AP. Anatomy and physiology of chronic scrotal pain. Published in 2017. [LINK]
  5. Tiwana MS, Leslie SW. Anatomy, Abdomen and Pelvis, Testicle. Published in 2020. [LINK]
  6. American Family Physician. Testicular Torsion: Diagnosis, Evaluation, and Management. Published in 2013. [LINK]
  7. American Family Physician. Testicular Torsion. Published in 2006. [LINK]
  8. National Institute for Health and Care Excellence (NICE). Scrotal pain and swelling. Published in 2019. [LINK]
  9. Taylor SN. Epididymitis. Published in 2015. [LINK]
  10. American Family Physician. Epididymitis: An Overview. Published in 2016. [LINK]
  11. American Family Physician. Epididymitis and Orchitis: An Overview. Published in 2009.
  12. GP Notebook. Testicular torsion. [LINK]
  13. British Association of Urological Surgeons. Scrotal Exploration for Suspected Torsion of the Testis. Published in 2017. [LINK]
  14. Gray, Henry, 1825-1861 Pick, T. Pickering (Thomas Pickering), 1841-1919, ed Keen, William W. (William Williams), b. 1837. Diagram to illustrate the Descent of the Testis and the Formation of the Tunica Vaginalis. [CC BY-SA] [LINK]
  15. OpenStax College. Illustration of testicle. [CC BY-SA] [LINK]
  16. Henry Gray. The right testis, exposed by laying open the tunica vaginalis. [CC BY-SA] [LINK]


Elizabeth Cotzias

Surgery Registrar


Hannah Thomas


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