The erector spinae are three paired, longitudinal columns of back muscles that run along either side of the spine. They consist of the iliocostalis, longissimus, and spinalis muscles, which work together to straighten the spine, bend it sideways, and maintain an upright posture. These muscles also help stabilize the trunk Read more
Transitional epithelium, also called urothelium, is a specialized type of stratified epithelial tissue that lines parts of the urinary tract, including the renal calyces, renal pelvis, ureters, and urinary bladder. Its two main functions are allowing urinary organs to stretch as they fill with urine and protecting the underlying tissues Read more
Last updated: August 17, 2026Sources reviewed: NCBI Bookshelf/StatPearls, peer-reviewed anatomy and orthopaedic literature, and reputable anatomy references.Medical review: This educational article has not been individually medically reviewed. It is not a substitute for diagnosis or personalised medical advice. Fibrocartilage is a specialized type of cartilage adapted to areas exposed to Read more
Fibrocartilage is a specialized type of cartilage that helps the body tolerate high compression, tension, and shear forces. It is found in the knee menisci, intervertebral discs, pubic symphysis, joint labra, and the triangular fibrocartilage complex (TFCC) of the wrist. Its dense collagen-rich matrix makes it highly durable, but its Read more
Medical disclaimer: This article is for educational purposes only and does not replace advice, diagnosis, or treatment from a qualified healthcare professional. The ethmoid bone is a small, light, complex bone located between the eyes. It forms part of the roof of the nasal cavity, the medial walls of the Read more
The teres major is a thick posterior shoulder muscle that runs from the lower part of the shoulder blade to the upper arm bone. It helps extend the arm backward, pull it toward the body, and rotate it inward. It works closely with the latissimus dorsi during pulling, climbing, swimming, Read more