Diagnostic ultrasound ( PDFDrive )

820 PART III Small Parts, Carotid Artery, and Peripheral Vessel Sonography
A B C
D E F
G H I
FIG. 22.2 Normal Intrascrotal Anatomy. Longitudinal scans show (A) normal homogeneous echotexture of the testis; (B) striated appearance
of the septula testis; (C) mediastinum testis (arrow) as a linear echogenic band of ibrofatty tissue; (D) head (white arrow) and body (black arrow)
of epididymis; (E) hydrocele (H) and appendix testis (arrow); and (F) appendages of epididymis (arrows). (G) Color Doppler scan shows normal
testicular arteries. (H) Transverse scan shows hypoechoic band of transmediastinal artery (arrow). (I) Color Doppler scan shows transmediastinal
artery.
of a head, a body, and a tail. he pyramid-shaped epididymal
head, or globus major, is located at the superoposterior aspect
of the testis, measuring 5 to 12 mm in diameter (Fig. 22.2D). It
is formed by the eferent ductules from the rete testis, which
join together to form a single convoluted duct, the ductus
epididymis. his duct forms the body and the majority of the
tail of the epididymis, measures approximately 6 m in length
and follows a convoluted course from the head to the tail of the
epididymis. he body (corpus) of the epididymis lies adjacent
to the posterolateral margin of the testis. he tail (globus minor)
is loosely attached to the lower pole of the testis by areolar tissue.
he ductus epididymis forms an acute angle at the inferior aspect
of the globus minor and courses cephalad as the vas deferens
to the spermatic cord. Sonographically, the epididymal head is
normally isoechogenic or slightly more echogenic than the testis,
and its echotexture may be coarser. he body tends to be isoechoic
or slightly less echogenic than the globus major and testis. he
normal body measures less than 4 mm in diameter, averaging
1 to 2 mm.
he appendix testis, a remnant of the upper end of the
paramesonephric (Müllerian) duct, is a small ovoid structure
usually located on the superior pole of the testis or in the groove
between the testis and the head of the epididymis. he appendix
testis is identiied sonographically in 80% of testes and is more
readily visible when a hydrocele is present 7 (Fig. 22.2E). he
appendix testis may appear stalklike and pedunculated, cystic,
or even calciied. 8 he appendices of the epididymis are blindending
tubules (vasa aberrantia) derived from the mesonephric
(Wolian) duct; they form small stalks, which may be duplicated,
and project from the epididymis 9 (Fig. 22.2F). In rare cases,