Histological septa are seen throughout most tissues of the body, particularly where they are needed to stiffen soft cellular tissue, and they also provide planes of ingress for small blood vessels. Because the dense collagen fibers of a septum usually extend out into the softer adjacent tissues, microscopic fibrous septa are less clearly defined than the macroscopic types of septa listed above. In rare instances, a septum is a cross-wall. Thus it divides a structure into smaller parts.

• septa of heart
  • Interatrial septum, the wall of tissue that is a sectional part of the left and right atria of the heart.
  • Interventricular septum, the wall separating the left and right ventricles of the heart.
• Lingual septum, a vertical layer of fibrous tissue that separates the halves of the tongue.
• Nasal septum: the cartilage wall separating the nostrils of the nose.
• Orbital septum, a palpabral ligament in the upper and lower eyelids.
• Septum pellucidum or septum lucidum, a thin structure separating two fluid pockets in the brain.
• Uterine septum, a malformation of the uterus.
• Vaginal septum, a lateral or transverse partition inside the vagina.
• The Septum (cell biology) is the boundary formed between dividing cells in the course of cell division.
• Fungus - A partition dividing filamentous hyphae into discrete cells in fungi
• Intermuscular septum can refer to: Intermuscular septa separating the muscles of the arms and legs.
  • medial intermuscular septum of arm
  • medial intermuscular septum of thigh
  • lateral intermuscular septum of arm
  • lateral intermuscular septum of thigh
  • anterior intermuscular septum of leg
  • posterior intermuscular septum of leg
• Alveolar septum: the thin wall which separates the alveoli from each other in the lungs. the alveolar septum separates adjacent alveoli in lung tissue. The minimal components of an alveolar septum consist of the basement membranes of alveolar-lining epithelium (mostly type I pneumocytes) and capillary endothelium. Thicker alveolar septa may also contain elastic fibers, type I collagen, interstitial cells, smooth muscle cells, mast cells, lymphocytes and also monocytes.