Скачать или смотреть 64) Diseases of the Scrotum & Testis

DESCENT OF THE TESTIS - At first, the testis lies on the dorsum of the abdominal wall. Mesenchymal cells form a cord Which extends from the part of the skin which later forms the scrotum, through the inguinal fold to the lower pole of the testis This cord later becomes a fibromuscular bundle and is termed the gabernaculum testis lt traverses the site of the future inguinal canal which is formed around it by the muscle of the abdominal wall as they become differentiated The testis descends along the path of the gabernaculum whether or not. due to pull of it A fold peritoneum protrudes down the inguinal canal along with the testis forming the processus vaginalis. The lower pole of the testis is kept in apposition with the deep inguinal ring by the gabernaculum until the 7th month Suddenly the testis passes through the inguinal canal and gains the scrotum As It descends, it is necessarily accompanied by its peritoneal covering by a fold of(peritoneum from the doing peritoneum from the iliac fossa which is drawn down as the process veg madras also its blood vessels an Nerve supply. The peritoneal coverings of the testis which represents the dis end of the processus vaginalis and in which the testis projects, is termed Tunica vaginalis testis. The part of processus vaginalis which is associated With the spermatic cord in the scrotum and in the inguinal canal normally comes obliterated The fascia cover The testis and spermatic cord including the cremaster are developed from the surrounding structures as the testis descend.
Time-table of testicular descent -
In the Lumbar region in the 2nd month of foetal life.
-In the iliac fossa 3rd month of fetal life
-At the deep inguinal ring - till the 7th month
-Travels the inguinal canal in the 7th month
-At The superficial inguinal ring at the later part of the 7th month or 8th month
Scrotum (its final position) testis enters the scrotum in the 9th month
Factors which cause descent of testis
(i) Shortening and active contraction of the gabernaculum
(ii) Increased intra abdominal pressure.
(iii) Active contraction of the lower fibers of the internal oblique muscle which squeezes the testis through the canal.
(iv)High temperature of the abdominal cavity, which is detrimental to spermatogenesis.
(V) Hormone, specially Chorionic gonadotropin from the maternal circulation helps descent of the testis
Causes of undescended testis
(i) Abnormality of the gabernaculum testis- Gabernaculum plays a major role in descent of testis and abnormally of this structure may result in undescended testis.
(ii) Intrinsic testicular defect - The testes may be insensitive to gonadotrophins and may not act to it this may lead to undescended testes.
(iii) Deficient gonadotrophic hormonal stimulation - Lack of adequate maternal gonadotrophins may be a cause of incomplete descent.
(iv) Obstruction due to adhesions of the testis.
(v) Short vas deferens.
(vi) Short testicular vessels or pampiniform plexus.
(vii) Imperfectly developed testis interferes with its own descent.

UNDESCENDED TESTIS -
An undescended testis is one which has failed to descend to the scrotum and is retained at any point along the normal path of its descent Undescended testis is more common on the right side (50%) It is less common on the left side )(30%) About 20% cases are bilateral When both the testes are absent in the scrotum, the Condition called cryptorchidism Hidden testes
Pathology of undescended testis -
(i) Growth of the testes- It is clear now that scrotal temperature is at least 10C cooler than the abdominal temperature. Proper development of spermatogenic tubules cannot take place in abdominal cavity.
(ii) Internal secretory function
(iii) Epididymis remains separated from the testis by a long mesorchium

Types of undescended testis –
a) Lumber testis - Complete failure of descent and the testis remain whence it was developed.
b) Iliac test-Testis remains just deep to the deep inguinal ring.
c) Inguinal- The testis is in the inguinal canal
d) At The Superficial inguinal ring-The testis frequently comes to rest just outside the external inguinal ring
e) Scrotal testis The testis lies in the upper part of the scrotum. It is often a retractile testis due to contraction of overactive cremaster muscle.

Complications of incomplete descent
1. Torsion of the testis
2. Epididymo-orchitis in an incompletely descended testis often gives rise to difficulty in diagnosis,
4 Atrophy - An incompletely descended testis is smaller than the normally descended testis
5. Pain -
6 Sterility -
7. Malignancy - 50 times more than that of normally descended testis Such malignancy is more common in abdominal testis rather than inguinal testis Seminoma is more common in such malignancy
TREATMENT –
A) Hormone therapy
B) Surgical treatment
Orchidopexy –
(i) LENGTHENING OF THE SPERMATIC CORD
(ii)RETAINING THE TESTIS IN THE SCROTUM