Anatomy, Abdomen and Pelvis, Testicle


Article Author:
Manpreet Tiwana


Article Editor:
Stephen Leslie


Editors In Chief:
Stephen Leslie
Karim Hamawy


Managing Editors:
Avais Raja
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Khalid Alsayouri
Trevor Nezwek
Radia Jamil
Patrick Le
Anoosh Zafar Gondal
Saad Nazir
William Gossman
Hassam Zulfiqar
Steve Bhimji
John Shell
Matthew Varacallo
Heba Mahdy
Ahmad Malik
Sarosh Vaqar
Mark Pellegrini
James Hughes
Beata Beatty
Nazia Sadiq
Hajira Basit
Phillip Hynes
Tehmina Warsi


Updated:
1/11/2019 8:24:53 PM

Introduction

The testes are male sex glands that have both an endocrine and exocrine function. The testes are oval-shaped reproductive structures that are found in the scrotum and separated by the scrotal septum. The shape of the testes is bean-shaped and measures three cm by five cm in length and 2 cm to 3 cm in width. When palpated through the scrotum, the testes are smooth and soft. The spermatic cord suspends the superior aspect of the testes. At the inferior end, the testes are attached to the scrotum by the scrotal ligament which is a remnant of the gubernaculum. In general, the left testis is affixed slightly lower than the right testis.[1][2]

The double-layered tunica vaginalis envelop the testes except at the posterior and superior borders where the epididymis and spermatic cord are attached. The visceral or inner layer of the tunica vaginalis is close to the epididymis, testes and vas deferens. On the posterior lateral surface of the testes, there is a small space between the testes and body of the epididymis which is known as the sinus of the epididymis. Deep to the tunica vaginalis is located the tunica albuginea, which is a durable fibrous covering of the testes.

The epididymis is a small curved shaped elongated structure which is highly convoluted and tightly compressed. When open in a straight line, it is estimated that its length is about 20 feet. The epididymis is found on the posterior border of the testis and consists of three parts which include the head (caput), body (corpora), and tail (Cauda). The head of the epididymis lies at the upper pole of the testes and receive seminal fluid from the ducts of the testis. It then permits passage of sperm into the distal portion of the epididymis. Because of its length, the epididymal ducts have ample space for storage and maturation of sperm.

Structure and Function

The testis is the male reproductive gland that is responsible for producing sperm and making androgens, primarily. Testosterone levels are controlled by the release of Luteinizing Hormone (LH) from the anterior pituitary gland; whereas, Follicle-Stimulating Hormone (FSH) levels control sperm production.

Embryology

The testes start as an undifferentiated gonad in the retroperitoneum area. The testis-determining factors (SRY gene) present on the Y chromosome causes the gonad to differentiate into the testes. In females, the SRY gene is absent, and hence the gonad turns into an ovary. As the fetus starts to mature, the testes begin to produce the male sex hormone, testosterone. This sex hormone permits the development of the male genitalia.[3]

The tunica albuginea forms a connective tissue latery between the seminiferous tubules and the rest of the testis through invagination.  The Sertoli celss start to make make Mullerian-inhibiting Substance (MIS) which causes regressioin of the Mullerian ducts at 8 to 10 weeks.  The only remaining remnants of the Mullerian ducts in an adult male are the appendix testis and the prostatic utricle.

During the third trimester of pregnancy, the testes, which are located in the abdomen, starts their descent into the inguinal canal and then to its final destination in the scrotum. During this journey, they pass through the peritoneum, the abdominal wall, and the inguinal canal.

Blood Supply and Lymphatics

The testicular arteries supply blood to the testes. They arise from the anterolateral segment of the abdominal aorta just below the origin of the renal arteries. The vessels travel in the retroperitoneum and cross over the ureter, pass through the deep inguinal ring, and join the spermatic cord.  Additional blood supply to the testes comes from the artery of the vas deferens and the cremasteric artery.

Venous drainage from the testes is via the pampiniform plexus which lies anterior to the vas deferens. The veins converge superiorly to form the testicular vein. The right testicular vein joins the vena cava, and the left testicular vein drains into the left renal vein. Drainage of the lymphatics from the testes follows the same path as the testicular arteries and drain to the preaortic lymph nodes.

Nerves

The testes have innervations from both sympathetic and parasympathetic fibers.

Muscles

As the testes move from the abdomen into the scrotum, it is gradually enveloped by several layers of muscle tissue.  The daily degree of testicular descent varies according primarily to temperature.  This is controlled by the cremasteric muscles. 

Physiologic Variants

Two vestigial embryonic structures with no known physiologic function include the following:

  • At the cranial end of the paramesonephric duct (Mullerian duct), sometimes one will find the appendix testis. This pear-shaped vestigial structure is found in about 2% of testes, and it is typically located at the superior pole in the groove between the head of the epididymis and testis.
  • Also at the cranial end of the mesonephric duct one will sometimes find the appendix of the epididymis which is found in about 25% of testes. Their location is variable but often project from the head of the epididymis.
  • In about 7% of males, the epididymis may be located on the anterior surface of the testis.

Surgical Considerations

Cryptorchidism is an important disorder to recognize early in life not only to preserve sterility but also to reduce the risk of testicular cancer. Unless the surgeon can surgically bring the testes back into the scrotum where it can be under surveillance, the undescended testes should be removed. It is also important to know that there is an increased risk of cancer in the contralateral testes and hence regular self-examinations are highly recommended.[4][5]

Sometimes serous fluid can accumulate in between the layers of the tunica vaginalis leading to a hydrocele. This could be triggered by inflammation, trauma or a congenital cause due to persistent communication with the abdominal cavity.

In young men, testicular torsion is a surgical emergency. The blood supply must be restored within 6 hours of the start of symptoms; the testes need to be fixed in the scrotum to prevent recurrence. Most urologists will also fix the contralateral testes at the same time.

The descent of the testes may be delayed or arrested along the course in the inguinal canal and may be complicated by an inguinal hernia.  All true undescended testes will have associated inguinal hernias.  This is not true for retractile testicles. 

Clinical Significance

Cryptorchidism (non-descent of the testis) not only leads to infertility but carries a risk of testicular cancer. If the abnormal testis is not removed, close surveillance is necessary.

Sometimes a hydrocele (serous fluid) can result when fluid collects between the layers of the tunica vaginalis. A hydrocele may be due to an infection, trauma, or congenital factors.

Other Issues

In premature infants, the descent of the testes is often not complete. Thus, after birth attention should be paid to the undescended testes. In some cases, the testes may exit the superficial inguinal ring but may then pass between the thigh and scrotum to rest in the perineum- resulting in an ectopic testis.


  • Image 136 Not availableImage 136 Not available
    Contributed Illustration by Beckie Palmer
Attributed To: Contributed Illustration by Beckie Palmer

Interested in Participating?

We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.

Improve Content - Become an Author or Editor

This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.

Anatomy, Abdomen and Pelvis, Testicle - Questions

Take a quiz of the questions on this article.

Take Quiz
Which of the following describes the normal testis?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
The left and right testicular vein drain into which of the following respectively?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following nerves does NOT innervate the scrotum?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
The parenchyma of the testis is composed of lobules separated by septae composed of what anatomic structure?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
During surgery of the pelvis of a male, it is observed that the left testicular vein is engorged with blood. Which location most likely will show pathology?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
The epididymis is located along which part of the testes?

(Move Mouse on Image to Enlarge)
  • Image 136 Not availableImage 136 Not available
    Contributed Illustration by Beckie Palmer
Attributed To: Contributed Illustration by Beckie Palmer



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Where does the right testicular vein drain?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
During surgery on the left scrotum, you notice that a 44 year old male has an engorged left testicular vein and yet you do not recognize any visible pathology in the vicinity. The next step in your management is:



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following is not an artery supplying blood to the testicle?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
What is the origin of the testicular artery?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up

Anatomy, Abdomen and Pelvis, Testicle - References

References

Tsili AC,Sofikitis N,Stiliara E,Argyropoulou MI, MRI of testicular malignancies. Abdominal radiology (New York). 2018 Nov 1     [PubMed]
Yang Y,Workman S,Wilson M, The molecular pathways underlying early gonadal development. Journal of molecular endocrinology. 2018 Jul 24     [PubMed]
Favorito LA,Sampaio FJ, Testicular migration chronology: do the right and the left testes migrate at the same time? Analysis of 164 human fetuses. BJU international. 2014 Apr     [PubMed]
Cheng L,Albers P,Berney DM,Feldman DR,Daugaard G,Gilligan T,Looijenga LHJ, Testicular cancer. Nature reviews. Disease primers. 2018 Oct 5     [PubMed]
Shpunt I,Leibovici D,Ikher S,Kovalyonok A,Avda Y,Jaber M,Bercovich A,Lindner U, Spermatogenesis in Testicles with Germ Cell Tumors. The Israel Medical Association journal : IMAJ. 2018 Oct     [PubMed]
Svingen T,Koopman P, Building the mammalian testis: origins, differentiation, and assembly of the component cell populations. Genes     [PubMed]
Kayalioglu G,Altay B,Uyaroglu FG,Bademkiran F,Uludag B,Ertekin C, Morphology and innervation of the human cremaster muscle in relation to its function. Anatomical record (Hoboken, N.J. : 2007). 2008 Jul;     [PubMed]
Gurney JK,McGlynn KA,Stanley J,Merriman T,Signal V,Shaw C,Edwards R,Richiardi L,Hutson J,Sarfati D, Risk factors for cryptorchidism. Nature reviews. Urology. 2017 Sep;     [PubMed]
Dagur G,Gandhi J,Suh Y,Weissbart S,Sheynkin YR,Smith NL,Joshi G,Khan SA, Classifying Hydroceles of the Pelvis and Groin: An Overview of Etiology, Secondary Complications, Evaluation, and Management. Current urology. 2017 Apr;     [PubMed]

Disclaimer

The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of Surgery-Urologic. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.

StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for Surgery-Urologic, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in Surgery-Urologic, you will already be prepared.

Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of Surgery-Urologic. When it is time for the Surgery-Urologic board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study Surgery-Urologic.