Final answer:
The core muscles include the erector spinae, abdominal muscles (external obliques, internal obliques, transversus abdominis, rectus abdominis), and the quadratus lumborum, crucial for balance, posture, and trunk stability.
Step-by-step explanation:
The primary muscles/muscle groups that make up the core include the erector spinae, abdominal muscles (external obliques, internal obliques, transversus abdominis, and rectus abdominis), and the quadratus lumborum. The core is comprised of several primary muscle groups: the erector spinae, the anterior abdominal muscles (external obliques, internal obliques, transversus abdominis, rectus abdominis), and the quadratus lumborum. The core of the body plays a critical role in maintaining balance, posture, and providing stability for the trunk. The anterior and lateral walls of the abdomen are reinforced by four pairs of muscles: the external obliques forming the superficial layer, the internal obliques in the middle, the transversus abdominis as the deepest layer, and the rectus abdominis, located medially and enclosed within the rectus sheath.
Together, these muscles contribute to the movement and stability of the vertebral column and assist in maintaining intra-abdominal pressure. The lumbar region is supported by the erector spinae muscle group, which includes the iliocostalis, longissimus, and spinalis muscles. These muscles are key extensors of the vertebral column and help in flexion, lateral flexion, and rotation. The quadratus lumborum forms the posterior abdominal wall and assists in movements of the lumbar spine and femur. All these muscle groups work in coordination to support the spine, assist in various body movements, and help resist intra-abdominal pressure, playing a vital role in everyday functions like walking, lifting, and respiratory actions.