In anatomy as well as in medicine, the term ramus is often given to any branch or division that occurs in a blood vessel or nerve. This word is also used to describe a part of a bone that has an irregular shape but is considered to be thicker than the structure referred to as a process. Branches relating to fissures in the brain may also be called rami, which is the plural form of the word ramus.
The ramus of the mandible, also known as the mandibular ramus, is located on the lower jaw. There is one of these structures on each side of the jaw, or mandible. It sits just behind the lower teeth. In the event of periodontal disease, a ramus bone graft is sometimes performed so that dental implants can be placed in the mouth of the patient.
The superior pubic ramus is found on the pubic bone. Part of this ramus is flat, while the other part is shaped like a prism. The inferior pubic ramus is flat and is found directly below the superior pubic ramus. Both the superior and the inferior pubic rami are prone to fracture, particularly in the elderly. Hip replacement surgery sometimes becomes necessary in severe cases.
The dorsal branch of the spinal nerves are known as the dorsal rami. These branches, or divisions, supply nerves to the skin and muscles located in the trunk area of the body. The dorsal rami then branch into the ventral rami. When this area of the body becomes damaged, some amount of muscle functioning can be lost. It is also possible to lose some of the sensation, or feeling, in the affected areas.
The ventral, or anterior, rami are responsible for the nerve supply to certain portions of the trunk as well as the limbs of the body. These rami then branch even further into the rami communicans. These rami work by connecting nerves to one another, most specifically between the sympathetic trunk and a spinal nerve. As is the case with the dorsal rami, some muscle movements or even nerve sensations can be compromised with damage to this area of the body.
In the heart, there are typically two main branches from the primary coronary artery on the left side. However, some people have a third branch coming from this artery. This extra branch is known as a ramus. It is also sometimes referred to as the optional diagonal coronary artery.