What is the Anal Tail?

The anal tail is a rare congenital protuberance arising around the lumbosacral region, representing the persistence of an embryonic remnant. It consists of a skeleton, muscle, and nerve fibers.

Animals in the phylum Chordata share four key features: a notochord, dorsal hollow nerve cord, pharyngeal slits, and the post-anal tail. The post-anal tail contains skeletal elements and muscles, which provide a source of locomotion in aquatic species, like fishes. It is vestigial in terrestrial vertebrates, such as humans and apes.

Definition

The tail is an extension of the body that runs parallel to the anus. This posterior elongation of the body comprises skeletal muscles that help in locomotion in aquatic species like fishes. It is present during embryonic development in chordates but becomes vestigial as an adult.

Chordates are animals that belong to the phylum Vertebrata. Despite their diverse appearance, they share four key characteristics: a notochord, dorsal hollow nerve cord, pharyngeal slits and a post anal tail. The notochord provides skeletal support, and the dorsal nerve cord connects the nerves of muscles to the brain. The pharyngeal slits develop into gill arches in bony fish, and into the jaw and inner ear in terrestrial vertebrates.

The phylum Vertebrata consists of three Subphylums: Urochordata, Cephalochordata and Vertebrata. Although some of the animals in Urochordata have a post anal tail, it is absent from most of them as adults. In some vertebrates, such as humans and apes, the post anal tail is present during embryonic development but becomes vestigial as an adult. In contrast, other vertebrates have a muscular tail that helps them with balance, courting and signaling when danger is near. The tail is also useful in adjusting body posture. It can be retracted when the animal needs to move and extended when it is required to maintain a position.

Origin

The post-anal tail is a posterior extension of the body that extends past the anus. It contains skeletal structures and muscles, which facilitate movement in aquatic organisms like fishes. It is one of the characteristics that distinguish chordates from non-chordates. Other distinctive features of chordates include a notochord, dorsal hollow nerve cord and paired pharyngeal gill slits.

Urochordates are an example of animals that share all of these characteristics with chordates, but not a post-anal tail. These animals, which are related to the sea squirts, have barrel-shaped bodies anal tail that they attach to the substrate with. The larvae of urochordates are tadpole-like, and they spend most of their life swimming through the water as filter-feeders. As the tadpole larva becomes an adult, it will attach itself to a hard surface and lose its ability to swim.

The tail that remains is often called a vestigial tail, although this is not strictly accurate. In humans, the posterior extension of the body that is sometimes referred to as a tail, actually represents a vestige of an embryonic structure that never completely formed. Human tails are usually present as protrusions around the midline of the lumbosacral region covered by skin, and they can be broadly classified into true and pseudo-tails. In the former, the posterior extension consists of adipose tissue and connective tissue, blood vessels and muscle fibers. Pseudo-tails are protuberances mainly of cartilaginous tissue.

Function

Despite their incredibly diverse appearances, most animals in the phylum Chordata share four key characteristics: a post-anal tail, pharyngeal pouches, a hollow dorsal nerve cord, and a notochord. These features distinguish chordates from species in other phyla, and they are also shared by some hemichordates.

The post-anal tail is found at the posterior end of the body and contains skeletal components and muscles that aid locomotion in aquatic species such as fish. However, it is absent in some terrestrial vertebrates such as mammals and birds.

Like all chordates, the post-anal tail is also a filter-feeding organ that helps sift water through its gill openings to Anal manufacturers extract food from it. It is a characteristic that differentiates chordates from invertebrates such as arthropods, which do not have any type of tail.

Hemichordates are multicellular eukaryotic organisms with repetitive segments that are controlled by the same developmental mechanisms. These organisms include the lancelets and tunicates, which live in aquatic environments and can have up to 200 gill slits. In addition, hemichordates have a post-anal tail, which is similar to the one in chordates and assists them in swimming.

Symptoms

While most problems affecting the bottom aren’t emergencies, you should contact your vet if your dog is scooting its rear end on the ground or licking or biting at its anal area more than usual. You may also notice blood in its poo if the anal glands become impacted (hard masses can be felt in the area) or abscessed. Infected anal sacs can be extremely painful. Even gentle dogs often snap or growl if their anal sacs are touched.

In some cases, the anal fissure can heal itself by itself. However, if the fissure is severe, an operation to cut the underlying muscle to correct it is necessary. This is called a lateral internal sphincterotomy and can be performed under local anesthesia.

Anal fissures can be very painful and there’s a risk that the pain will last for several hours after bowel movements. This can lead to a lack of bowel movements in an attempt to avoid the pain, which will only make matters worse.

Medicated baths, warm compresses and ointments such as lidocaine can help. You can also try taking sitz baths, where you sit in a tub of warm water for 20 minutes a few times a day to relieve pain and relax the anal spasms. Changing to a high-fiber diet can help as well.