transversus

Transversus is a Latin term used in anatomy to denote structures that run across or horizontally relative to the body’s long axis. It is not a single structure, but a naming element applied to several muscles and related tissues that share a transverse orientation.

Notable examples include:

- Transversus abdominis: the innermost of the lateral abdominal wall muscles, with fibers running horizontally across the abdomen. It attaches to the iliac crest, thoracolumbar fascia, inguinal ligament, and lower costal cartilages. Its actions include compressing the abdomen and stabilizing the spine via intra-abdominal pressure. It is primarily innervated by the thoracoabdominal nerves (T7–T11) and the subcostal nerve (T12), with contributions from L1 nerves.

- Transversus thoracis: a small muscle on the inner surface of the anterior chest wall. It originates from the posterior sternum and inserts onto the costal cartilages of ribs 2–6. It helps depress the ribs during forced expiration and is innervated by intercostal nerves.

- Transversus linguae: an intrinsic muscle of the tongue whose fibers run transversely. It acts to narrow and lengthen the tongue and is innervated by the hypoglossal nerve (CN XII).

- Transversus perinei (deep transverse perineal muscle): part of the deep perineal pouch that supports pelvic floor structures. It is innervated by the pudendal nerve (S2–S4).

In clinical contexts, the term often appears in procedures and studies of musculoskeletal function, abdominal core mechanics, and regional anesthesia (for example, the transversus abdominis plane block).