Final answer:
The student asked about the functions of various muscles including the rectus abdominis, gluteus maximus, pectoralis major, and others. Each muscle has specific roles in movement and stabilization of different body parts such as the abdomen, hip, shoulder, and limbs.
Step-by-step explanation:
Functions of Specific Muscles
The rectus abdominis functions in flexing the lumbar spine, stabilizing the pelvic region, and compressing the abdominal contents. The gluteus maximus is involved in extension and lateral rotation of the hip, and it supports the body when standing. The pectoralis major muscle helps in flexion, adduction, and internal rotation of the humerus at the shoulder joint.
The middle deltoid is responsible for abduction of the arm at the shoulder, while the biceps brachii flexes the forearm at the elbow and supinates the forearm. The adductor magnus acts to adduct and medially rotate the thigh, as well as assisting in thigh extension. The gastrocnemius muscle helps in plantarflexion of the foot and flexion of the leg at the knee joint.
The biceps femoris is a part of the hamstrings and functions in thigh extension and knee flexion. The rhomboids retract, elevate, and rotate the scapula. The latissimus dorsi assists in extension, adduction, and internal rotation of the arm at the shoulder.
Lastly, the rectus femoris is one of the quadriceps muscles that extends the knee and also helps in hip flexion.