scrotum anatomy
Terms
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copy deck
- indications for scrotal ultrasound
- pain, trauma, torsion, enlargement, palpable mass, cryptorchidism, followup of orchiectomy, male infertility
- ultrasound has become the modality of choice when evaluating the scrotum. it is the most common imaging technique used to supplement the __ exam of the scrotum
- physical
- high frequency ultrasound imaging combined with color and spectral doppler, quickly and reliably provide valuable infor in the assessment of scrotal pain or mass. the accuracy in color doppler is equally high (near 100% dx rate) for ___. color is also u
- torsion, ischemia
- the accuracy of ultrasound is nearly __% accurate in the detection of scrotal pathology. it has an excellent ability to image intratesticular and extratesticular abnormalities. ultrsound has a high accuracy in differentiating a cystic from __lesion
- 100, solid
- testes are symmetric oval shaped glands residing in the scrotum. in adults, the testis measures approx. __to __ cm in length, __ to __ cm in width and approx __ in height
- 3-5, 2-4, 3
- each testis is divided into more than __ to __ conical lobules containing seminiferous tubules. there are __ to __ seminiferous tubules in each lobule that produce sperm
- 250-400, 1-3
- these converge at the apex of each lobue and anastomose to form the rete testis in the mediastinum
- straight tubules (seminiferous)
- supports the vessels and ducts coursing withing the testis; this is where the tubules converge and exit into the rete testes and efferent duct
- mediastinum
- drains intot he head of the epididymis through the efferent ductules
- rete testis
- at the upper pole of the testis, the __ is attached and is located between the testis and epididymis; little piece of tissue that is remnant of paramesonephric duct
- appendix testis
- sono the testes appear as smooth, medium gray structures with a __ echotexture; homogeneous like __. __ echo texture
- fine, thyroid, granular
- sonographically this courses cranially to caudally and is echogenic
- mediastinum
- is a 6-7 cm tubular structure beginning superiorly and then coursing posterolaterally to the testis; is divided into head, body, and tail
- epididymis (head is more important ot visualize)
- the head of the epididymis is the largest part of it and measures __ to __ mm in width. it is also called __ and you always measure it
- 6-15mm, glomus major
- the head is located superior to the upper pole of the testis and is formed by __ to __ efferent ductules from the rete testis that converge to form a single duct called the ___ aka ___
- 10-15, efferent duct, ductus epididymis
- becomes the vas deferens and continues in the spermatic cord
- efferent duct aka ductus epididymis
- the body is much smaller than the head and is difficult to see with ultrasound on normal individuals. it follows the ___ aspect of the testis from the upper pole to the lower pole
- posterolateral
- the tail of the epididymis is slightly larger (than body?)and is positioned ___to the lower pole of the testis. it is called ___
- posterior, glomus minor
- is a small prtuberance from the head of the epididymis and is a remnant of the wolffian duct
- appendix of the epididymis
- the normal epididymis usually appears as isoechoic or hypoechoic compared with the tesis, althought the echo texture is __
- coarser
- the scrotum is the supporting structure for the testes and each sac consists of the following layers
- skin, dartos, cremaster muscle
- layers of muscle lying beneath the skin that forms the septum (median raphe which is the septum that separates scrotum into 2 sacs/chambers)
- dartos
- surrounds each testes and extends into the abdomen over the spermatic cord; allows testes to contract and release according to temperature
- cremaster muscle
- fibrous tissue that completely covers the testis; inner lining directly around testicle
- tunica albuginea
- the posterior aspect of the tunica albuginea reflects into the testis to form a vertical septum known as the ___
- mediastinum
- multiple septa are formed from the albuginea at the mediastinum coursing through testes and separates it into __
- lobules
- lines the inner walls of the scrotum, covering each testis and epididymis; space between scrotal wall and tunica albuginea; serous covering, which a double-layer extension of the peritoneum; separates the scrotal layer from the tunica albuginea and covers
- tunica vaginalis
- what are the two layers of the tunica vaginalis? this one is the inner lining of the scrotal wall. this one surrounds the testis and epididymis. __ will always be between the two layers and normal to see a small amount of fluid between the two layers
- parietal, visceral. parietal, visceral. hydrocele
- posterior area; at this site the testicle is against the scrotal wall preventing torsion; not covered by tunical vaginalis parietal layer but by visceral layer; blood vessels, lymphatics, nerves, and spermatic ducts travel through the area
- bare area
- is a continuation of the ductus epididymis; is thicker and less convoluted; dilates at the terminal portion near the seminal vesicles
- vas deferens; aka ductus deferens
- the portion that dilates at teh terminal portion near where is meets the seminal vesicles
- ampulaa of the deferens
- the vas deferens joins the duct of the seminal vesicles to form the ___ which in turn empties into the urethra
- ejaculatory duct
- these 9 form the spermatic cord
- vas deferens, cremasteric, deferential, venous pampiniform plexus, lymphatics, autonomic nerves, and fiber of the cremasteric
- extends from the scrotum through the inguinal canal and internal inguinal rings to the pelvis; suspends the testis inthe scrotum
- spermatic cord
- the scrotum's main function is to maintain a temp. __ to __ degrees lower than the body in order for the testes to produce sperm
- 3 to 4
- holds testicles outside the body where the temp is more optimum for sperm maturation
- scrotum
- raises and lowers the scrotum in order to regulate the temperature of teh testis and promote spermatogenesis
- cremaster muscle
- also acts to regulate the temperature of the testicles, which promotes spermatogenesis; wrinkles the scrotal skin in order to draw it to the body or relax; it works in conjunction with the cremasteric muscle to raise the testis but should not be confused
- tunica dartos
- the testes act as both endocrine and exocrine gland because it produces __ and __
- testosterone (endocrine) sperm (exocrine)
- produces sperm cells and holds them until they are mature which takes 2-3 months
- testes
- sperm represent __% of the total volume that will be ejaculated. the volume is small (0.1-0.2 ml)
- 5%
- stores immature sperm until orgasm, then propels sperm from testicle to vas deferens within spermatic cord; during their transit the sperm undergo maturation and is necessary fo rthem to acquire their function; storage and conductor
- epididymis
- sono appearance: isoechoic or slightly more echogenic than testis seen superior to teh testes
- head of epi.
- sono appear: isoechoic or slightly less echogenic than testes
- body of epi.
- sono appear: may or may not be seen sonographically; less echogenic than head; slightly thicker than body
- tail
- small ovoid structure located lateral to the head of the epididymis
- appendix
- the scrotal wall layers are __ to __mm thick; usually inseparable sonographically and appears as single echogenic stripes
- 2-8mm
- space that normally can contain a few cc of fluid
- tunica vaginalis sac
- layers of muscle lying beneath the skin that forms the septum
- median raphe
- homogeneous with uniformly distributed medium to low level echoes; sppearance changes with the amount of fibrous and fatty tissue present
- testes
- highly echogenic linear structure peripherally located in posterior-superior aspect of testes; goes from cranial to caudal presentation
- mediastinum
- each testes and epididymis should be compared for matching size and __
- echogenicity
- right and left testicular arteris arise from the __ just below the level of the renal arteries and are the primary blood source to the testes. the testicular arteries descend in the rp and enter the spermatic cord in the __. they course along the __ sur
- abdominal aorta,inguinal ring, posterior, capsular arteries
- sometimes seen as a hypoechoic linear structure on the surface of the testis; color doppler can be used to verify its identity
- capsular arteries
- the capsular arteries give rise to the __ which course from the testicular surface toward the mediastinum along the septa. before reaching the mediastinum they curve backward forming the __ aka __
- centripetal arteries, recurrent rami aka centrifugal arteries
- these branch further into arterioles and capillaries; with sensitive doppler may give a candy-cane appearance
- recurrent rami
- in approx half of normal testes, a __ aka __is visualized coursing through the mediastinum toward the testicular capsule; a large vein is often identified adjacent to the artery
- transmediastinal aka transtesticular
- on color doppler this will be color encoded the opposite of the centripetal arteries as its flow is directed away from the mediastinum and toward the capsule of surface of the testis; upon reaching the testicular surface opposite the mediastinum, it cours
- transmediastinal artery aka transtesticular
- spectral doppler waveforms obtained from the capsular, centripetal, or transmediastinal arteries show a low-resistance waveform pattern in normal individuals; the RI is __ to __
- 0.55-0.64 because needs constant flow
- these accompany the testicular artery within the spermatic cord to supply the extratesticular structures; they also have anastomoses with the testicular a. and may provide some flow to the testis. the __ branches from the inferior epigastric artery which
- cremasteric and deferential artery, cremasteric, deferential
- the cremasteric branches from the __ and supplies the __ and __ and the deferential branches from the __ and supplies the __ and __
- *inferior epigastric (external iliac a.), *cremasteric muscle *peritesticular tissues *vesicle artery (internal iliac muscle) *vas deferens *epididymis
- the scrotal wall is also supplied by branching of the __ which supplies blood to the external genitalia but directly anastomoses and does not supply the testicular parenchyma
- pudendal
- these have a high resistance pattern with a narrower systolic peak and diminished or absent diastolic flow
- cremasteric and deferential
- venous drainage of the scrotum occurs through the veins of the __ which exits from the mediastinum testis and courses in the spermatic cord
- pampiniform plexus
- the pampiniform plexus converges into three sets of anastomotic veins
- testicular, deferential, and cremasteric
- the right testicular vein drains into __ and the left drains into __. the deferential drains into the __ and the cremasteric into tributaries of the __ and__ . they are normally __to __ mm in diameter
- *ivc *lrv *pelvic veins *epigastric and deep pedundal veins
- real time imaging of the scrotum is performed with a high-frequency linear array probe of at least __ mhz. probes of __ to __ mhz are best. for thickening or edema use __ to __ mhz. the newer probe is called __
- 7.5, 10-15, 5-7.5, trapezoid aka virtual convex
- ultrasound exam of the scrotum is performed with patient in __ position. the __ is positioned on the abdomen and covered with a towel; the patient is asked to place his __ close together to provide support for the scrotum. alternatively, a rolled __ pla
- supine, penis, legs, towel
- a generous amount of warmed gel is applied to the scrotum to ensure adequate probe contact and eliminate air between the probe and skin surface; warm gel will reduce __ response that results in thickening of scrotal sac. rarely a __ may be needed to impr
- cremasteric, standoff pad
- before beginning the scrotal ultrasound, it is necessary to determine the clinical question of whether or not a __ was performed. this info is not only helpful in guiding the exam but also it is important to the interpreting physician and provides confid
- vasectomy
- scrotal ultrasound is always a __ exam, whcih the asymptomatic side used as a comparison for the symptomatic side. to begin, it's best to perform a bried survey scan to determine what abnormalites, if any, is present.
- bilateral
- each testis is scanned from __ to __ and carefully examined to determine if abnormal findings are present. the size, echogenicity, and __ of each testis are evaluated. the testicular __ should be uniform with an equal echogenicity between sides. get __
- superior to inferior, structure, parenchuma, dual image
- think of questions as you scan and turn on __ to assess flow. this is a must. you must doppler inside testicle and not the capsular arteries
- color doppler
- representative images are obtained in at least 2 __, trv and sag, with additional imaging planes as needed to demonstrate findings.
- planes
- in trv, images are taken that show sup, mid, and inf portions of each testis. the width is taken at mid trv view and a trv view of the __ is included
- epididymis
- in sag, images are taken to show medial, mid, and lateral portions. a long axis measurement of testicular length is obtained in the mid sag image. additional images may be taken to demonstrate __ areas
- abnormal, varicocele (dilation of venous system)
- an image is optained of the head superior to the testicle. the body and tail of the epididymis can be demonstrated coursing posteriorly on each side. scrotal __ thickness is evaluated and compared from side to side
- skin
- at least one image is taken show both testes at the same time so the interpreting physician can compare __ and __
- size, echogenicity
- to demonstrate varicocele patients may be positioned __ and/or perform
- upright, valsalva maneuver
- color and spectral doppler are used in all exams with representative images taken to demonstrate both arterial and venous flow in each testis. testes is __ resistance and epididymis is __ resistance
- low, high