Capsule (anatomy)

A capsule, in anatomy, is a cover or envelope partly or wholly surrounding a structure. Types of capsules include:

the shell of an egg (biology)
joint capsules - every diarthrodial joint possesses a fibrous or ligamentous capsule, lined with synovial membrane, attached to the adjacent ends of the articulating bones
the sac which encloses the crystalline lens of the eye
Glisson's capsule, a thin areolar coat of fibrous tissue lying inside the tunica serosa of the liver
Bowman's capsules (or glomerular capsules) in the kidney substance
the renal capsule (also known as Gerota's fascia), a tough fibrous layer surrounding the kidney and covered in a thick layer of perinephric adipose tissue
the suprarenal capsules, two small flattened organs in the epigastric region
the internal, external and extreme capsules of the brain
the outer surface of a benign tumor