The original sutures were made from biological materials, such as [[catgut suture]] and [[silk]]. The maxillae and palatines meet medially in the upper jaw developing a midline suture. It is often used in conjunction with the absorbable suture Monocryl. Prolene is a synthetic, monofilament, nonabsorbable polypropylene suture. Other closure techniques include an internal suture and plug. The supraoculars are single, narrow, and sometimes divided by a transverse suture. Each carpel contains several ovules set along the ventral suture. The suture in the basin between the maxilla and the forehead had an interlocking pattern. Some surgeons also suture one or both oblique muscles. Trigonocephaly is a result from the premature closure of the metopic suture. It is held in place by a suture (knot) to the fundus of the uterus. Another polymer is polyglecaprone, used as suture material in surgery. It has a consistency close to nylon suture material. It is separated from the rest of the doublure by the rostral suture. Each segment is dilineated by an intersegmental suture.