Experiment 30. A similar experiment may be tried at the wrist. Flex the wrist with the fingers extended, and again with the fingers in the fist. The first movement can be carried to 90°, the second only to 30°, or in some persons up to 60°. Making a fist had already stretched the extensor muscles of the arm, and they can be stretched but little farther. Hence, needless pain will be avoided by working a stiff wrist with the parts loose, or the fingers extended, and not with a clenched fist. Review Analysis: Important Muscles Location. Name. Chief Function. Head and Neck. Occipito-frontalis. moves scalp and raises eye brow. Orbicularis palpebrarum. shuts the eyes. Levator palpebrarum. opens the eyes. Temporal. raise the lower jaw. Masseter. ” ” ” ” Sterno-cleido-mastoid. depresses head upon neck and neck upon chest. Platysma myoides. depresses lower jaw and lower lip. Trunk. Pectoralis major. draws arm across front of chest. Pectoralis minor. depresses point of shoulder, Latissimus dorsi. draws arm downwards and backwards. Serratus magnus. assists in raising ribs. Trapezius. Rhomboideus. backward movements of head and shoulder, Intercostals. raise and depress the ribs. External oblique. various forward movements of trunk Internal oblique. Rectus abdominis. compresses abdominal viscera and acts upon pelvis. Upper Limbs. Deltoid. carries arm outwards and upwards. Biceps. flexes elbow and raises arm. Triceps. extends the forearm. Brachialis anticus. flexor of elbow. Supinator longus. flexes the forearm. Flexor carpi radialis. flexors of wrist. Flexor carpi ulnaris. ” ” ” ” Lower Limbs. Gluteus maximus. adducts the thigh. Adductors of thigh. draw the leg inwards. Sartorius. crosses the legs. Rectus femoris. flexes the thigh. Vastus externus. extensor of leg. Vastus internus. extensor of leg upon thigh. Biceps femoris. flexes leg upon thigh. Gracilis. flexes the leg and adducts thigh. Tibialis anticus. draws up inner border of foot. Peroneus longus. raises outer edge of foot, Gastrocnemius. keep the body erect, and Soleus. aid in walking and running. Chapter IV. Physical Exercise. 80. Importance of Bodily Exercise. Nothing is so essential to success in life as sound physical health. It enables us to work with energy and comfort, and better to endure unusual physical and mental strains. While others suffer the penalties of feebleness, a lower standard of functional activities, and premature decay, the fortunate possessor of a sound mind in a sound body is better prepared, with proper application, to endure the hardships and win the triumphs of life[13].