Nádegas

Nádegas are the two rounded prominences of the human buttocks, located on the posterior aspect of the pelvis. They flank the lower back and extend laterally to the upper thighs, and are composed of skin, subcutaneous fat, and the gluteal muscles.

The gluteal region houses the three gluteal muscles: gluteus maximus, medius, and minimus. They originate from the ilium, sacrum, and coccyx, and insert on the femur or the iliotibial tract. The gluteus maximus is the largest muscle and is primarily involved in hip extension and external rotation. The gluteus medius and minimus abduct and stabilize the pelvis during walking. All three muscles contribute to posture and movement. The sciatic nerve runs beneath the gluteal muscles, and injections into the buttocks should be given in the upper outer quadrant to reduce the risk of nerve injury.

They support standing and walking, provide power for actions such as climbing stairs and sprinting, and help maintain balance and pelvic alignment. The muscles also absorb some of the forces transmitted through the pelvis when sitting and during locomotion.

Variation and health: Subcutaneous fat distribution shapes the appearance of the nádegas and varies with sex, age, and body composition. Common problems include strains or tendinopathy of the gluteal tendons, bursitis near the greater trochanter, and referred pain from the lower back or hip. Piriformis syndrome can irritate nearby nerves and muscles.

In culture and measurement: The nádegas are discussed in contexts ranging from anatomy to fashion and fitness. Anthropometric measurements sometimes use hip and gluteal circumference to assess body shape.