Free tenia

The free tenia (taenia libera) is one of the three longitudinal bands of smooth muscle, collectively known as the taeniae coli, that run along the external surface of the colon. It is termed free because it is not associated with the attachment of any mesentery, mesocolon, or peritoneal fold.

The free tenia occupies the colonic surface opposite the attachments of the mesocolon and greater omentum. Its position varies slightly along different segments of the colon. In the transverse colon, it is typically located along the inferior free border of the bowel, whereas in the ascending and descending colon it is usually found on the medial aspect. In the sigmoid colon, it continues as one of the three taeniae until they broaden and ultimately merge to form the continuous longitudinal muscle layer of the rectum.

The other two taeniae coli are the taenia mesocolica (situated along the attachment of the mesocolon) and the taenia omentalis (associated with the attachment of the greater omentum to the transverse colon).

Clinical correlate

The three taeniae coli converge at the base of the vermiform appendix. Consequently, tracing the taenia libera along the colon provides a reliable anatomical method for locating the appendix during surgery.