The torso or trunk is an anatomical term for the central part, or the core, of the body of many animals (including humans), from which the

head A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple animals may ...

neck The neck is the part of the body on many vertebrates that connects the head with the torso. The neck supports the weight of the head and protects the nerves that carry sensory and motor information from the brain down to the rest of the body. In ...

limb Limb may refer to: Science and technology * Limb (anatomy), an appendage of a human or animal *Limb, a large or main branch of a tree *Limb, in astronomy, the curved edge of the apparent disk of a celestial body, e.g. lunar limb *Limb, in botany, ...

s, tail and other

appendage An appendage (or outgrowth) is an external body part, or natural prolongation, that protrudes from an organism's body. In arthropods, an appendage refers to any of the homologous body parts that may extend from a body segment, including anten ...

s extend. The tetrapod torso — including that of a human — is usually divided into the '' thoracic'' segment (also known as the upper torso, where the

forelimb A forelimb or front limb is one of the paired articulated appendages (limbs) attached on the cranial ( anterior) end of a terrestrial tetrapod vertebrate's torso. With reference to quadrupeds, the term foreleg or front leg is often used instead. ...

s extend), the '' abdominal'' segment (also known as the "mid-section" or " midriff"), and the '' pelvic'' and '' perineal'' segments (sometimes known together with the abdomen as the lower torso, where the

hindlimb A hindlimb or back limb is one of the paired articulated appendages (limbs) attached on the caudal ( posterior) end of a terrestrial tetrapod vertebrate's torso.http://www.merriam-webster.com/medical/hind%20limb, Merriam Webster Dictionary-Hindl ...

s extend).

Anatomy

Major organs

Surface projections of the organs of the trunk

In humans, most critical organs, with the notable exception of the brain, are housed within the torso. In the upper chest, the heart and lungs are protected by the rib cage, and the abdomen contains most of the organs responsible for digestion: the stomach, which breaks down partially digested food via

gastric acid Gastric acid, gastric juice, or stomach acid is a digestive fluid formed within the stomach lining. With a pH between 1 and 3, gastric acid plays a key role in digestion of proteins by activating digestive enzymes, which together break down the ...

; the liver, which respectively produces

bile Bile (from Latin ''bilis''), or gall, is a dark-green-to-yellowish-brown fluid produced by the liver of most vertebrates that aids the digestion of lipids in the small intestine. In humans, bile is produced continuously by the liver (liver bile ...

necessary for digestion; the large and

small intestine The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the p ...

s, which extract nutrients from food; the

anus The anus (Latin, 'ring' or 'circle') is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, the residual semi-solid waste that remains after food digestion, which, d ...

, from which fecal wastes are egested; the

rectum The rectum is the final straight portion of the large intestine in humans and some other mammals, and the Gastrointestinal tract, gut in others. The adult human rectum is about long, and begins at the rectosigmoid junction (the end of the s ...

, which stores

feces Feces ( or faeces), known colloquially and in slang as poo and poop, are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a relati ...

; the gallbladder, which stores and concentrates bile; the kidneys, which produce urine, the ureters, which pass it to the bladder for storage; and the urethra, which excretes urine and in a male passes

sperm Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, whi ...

through the seminal vesicles. Finally, the pelvic region houses both the male and female reproductive organs.

Major muscle groups

The torso also harbours many of the main groups of muscles in the tetrapod body, including the pectoral, abdominal, lateral and epaxial muscles.

Nerve supply

The organs, muscles, and other contents of the torso are supplied by nerves, which mainly originate as nerve roots from the thoracic and lumbar parts of the spinal cord. Some organs also receive a nerve supply from the vagus nerve. The sensation to the skin is provided by the lateral and dorsal cutaneous branches. Gray797.png, Distribution of cutaneous nerves. Ventral aspect. Dorsal and lateral cutaneous branches labeled at center right. Gray798.png, Dorsal aspect. Ventral and lateral cutaneous branches labeled at center right.

References

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Anatomy

Major organs

Major muscle groups

Nerve supply

See also

References