MEDULLA OBLONGATA

Medulla Oblongata

The medulla oblongata is the lowest part of the brainstem, connecting the pons and cerebellum to the spinal cord. It plays a crucial role in controlling involuntary functions of the body, such as breathing, heart rate, and blood pressure.

External Features

• The medulla oblongata is a continuation of the pons and is located below the level of the foramen magnum.
• It is a narrow, conical structure that tapers to a point as it descends towards the spinal cord.
• The surface of the medulla is marked by a longitudinal groove, the sulcus medullaris.
• The anterior surface of the medulla is smooth, while the posterior surface is marked by a series of transverse grooves.

Internal Structures in Transverse Sections

• The medulla oblongata is divided into three main parts: the anterior (ventral) portion, the posterior (dorsal) portion, and the central canal.
• The anterior portion contains the hypoglossal (CN XII) and glossopharyngeal (CN IX) nerves.
• The posterior portion contains the vagus (CN X) nerve and the inferior cerebellar peduncle.
• The central canal is a narrow, fluid-filled space that runs along the midline of the medulla and contains cerebrospinal fluid.

Blood Supply

• The medulla oblongata is supplied by the vertebral arteries, which give rise to the posterior inferior cerebellar arteries (PICA) and the anterior inferior cerebellar arteries (AICA).
• The PICA and AICA supply the posterior and anterior portions of the medulla, respectively.
• The medulla also receives a contribution from the basilar artery, which supplies the central canal and the anterior portion of the medulla.

Applied Anatomy

• The medulla oblongata plays a crucial role in controlling involuntary functions, such as breathing and heart rate.
• The vagus nerve (CN X) arises from the medulla and supplies the larynx, pharynx, and various visceral organs.
• The hypoglossal nerve (CN XII) arises from the medulla and supplies the muscles of the tongue.
• The medulla is also involved in the regulation of blood pressure and the control of the autonomic nervous system.