Lab 13 diagram

Muscles of Facial Expression & Mastication Diagram

Frontalis — raises eyebrows/wrinkles forehead, sits superficial to (on top of) the frontal bone.

Occipitalis — works with frontalis to move the scalp. Zygomaticus major — pulls mouth corners up (smiling).

Orbicularis oris — closes/puckers the lips.

Orbicularis oculi — closes the eyelids.

Masseter — closes the jaw for chewing.

Temporalis — closes the jaw for chewing, sits superficial to (on top of) the temporal bone.

Muscles of the Neck Diagram

Sternocleidomastoid — turns and tilts the head; both sides together bend the neck forward.

Trapezius — moves the shoulder blade (shrugging) and helps move the head/neck.

Muscles of Normal Respiration Diagram

Intercostals — muscles between the ribs, help lift the ribcage when breathing in.

Diaphragm — dome-shaped muscle separating chest and belly cavities; contracting it increases the volume of the chest cavity, pulling air into the lungs

Muscles of the Abdominal Wall & Torso Diagram

Rectus abdominis — flexes the torso (bends forward); sits medial to (closer to the midline than) the external oblique.

External oblique — rotates/bends the torso, sits superficial to (on top of) the internal oblique.

Internal oblique — rotates/bends the torso, sits deep to (underneath) the external oblique.

Transverse abdominal — deepest belly muscle, compresses the abdomen.

Pectoralis major — adducts the arm (pulls it in toward the body); antagonistic to the deltoid. Serratus anterior — pulls the shoulder blade forward.

Deltoid — abducts the arm (raises it out to the side); antagonistic to pectoralis major.