VAN 221: Veterinary Splanchnology and Applied Anatomy (1+1)

SCROTUM
 ( Bull, Ram, Buck, Horse, Dog, Boar, Rabbit, Fowl )

Bull

• The scrotum is a diverticulum of the abdomen situated in front of the inguinal region and lodges the testicles and its appendages
• It is oval in form and slightly compressed from side to side
• It is asymmetrical since the left testicle is larger, more dependent and placed a little further back
• It is long and pendulous and presents a well-marked neck when not contracted
• The scrotum varies in its form under the influence of cold, heat, fatigue and debility

Structure

• It is composed of the following layers
  • Skin -thick and elastic, flesh coloured and is sparsely covered with short hairs. It is marked centrally by a raphe - the raphe scroti
  • This is continued forward on the prepuce and behind on the perineum. Just in front of it have two pairs of rudimentary teats
  • The dartos is the internal tunic of the abdomen consists of the fibro-elastic tissue and plain muscle and is red in colour
  • It forms a septum scroti along the raphe scroti dividing the cavity into two unequal parts to accommodate the testicles, of which the left being larger
  • Dorsally, this septum divides into two layers which pass by the side of the penis and becomes continuous with the tunica abdominalis
  • At the bottom of the scrotum, fibres connect the dartos closely with the tunica vaginalis (thus indirectly with the tail of epididymis) constituting the scrotal ligament.
  • The scrotal fascia made up of three layers and are derived from oblique and transverse abdominal muscles
    • Intercolumnar fascia from the aponeurosis of the external oblique muscle
    • Cremasteric fascia from internal oblique muscle
    • Infundibuliform fascia from transverse abdominis muscle
  • The parietal layer of the tunica vaginalis, which forms a fibro serous sac, is continuous with the parietal peritoneum

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Species difference

Ram and Buck

• It resembles ox

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Horse

• It is in the inguinal region
• It is globular
• The skin is dark or black coloured
• The rudimentary teats are in the form of two papillae at the lower margin of the preputial orifice and are not related to scrotum

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Dog

• It is behind the inguinal region
• The skin of scrotum is pigmented and covered sparsely with fine hairs
• The raphe is not distinct

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Boar

• It is situated a short distance from the anus and is not so sharply defined from the surrounding parts as in other animals

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Rabbit

• The scrotal sacs are separate and is situated in the inguinal region

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Cock

• It is absent as testicles are abdominal in position

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