Obliques
External / Internal Oblique
Short definition
Rotate and laterally flex the trunk, forming the waist.
Full definition
Obliques (external and internal) — planar muscles from ribs V–XII to the iliac crest, sacroiliac fascia and linea alba. Functions: lateral trunk flexion and rotation, intra-abdominal pressure (squat, deadlift, press), pelvic and thoracic stabilization. Mass ≈ 0.7–1 % at 20–25 % body fat.
Examples
Russian twists — the obliques.