Skeletal Muscles and Their Actions

These flashcards cover the names of muscles and their specific actions as discussed in the lecture notes on skeletal muscles.

Frontalis

Draws scalp anteriorly, raises eyebrows, and wrinkles skin of forehead horizontally.

Occipitalis

Draws scalp posteriorly.

Orbicularis oris

Closes and protrudes lips as in kissing.

Zygomaticus major

Draws angle of mouth superiorly and laterally as in smiling.

Buccinator

Presses cheeks against teeth and lips as in whistling, blowing, and sucking.

Platysma

Draws outer part of lower lip inferiorly and posteriorly as in pouting and depresses mandible.

Orbicularis oculi

Closes eye.

Corrugator supercilii

Draws eyebrow inferiorly and wrinkles skin of forehead vertically as in frowning.

Masseter

Elevates mandible as in closing mouth.

Temporalis

Elevates and retracts mandible.

Digastric

Elevates hyoid bone and depresses mandible.

Sternocleidomastoid

Acting together, flexes cervical vertebral column and head.

Iliocostalis (posterior)

Acting together, muscles of each region (cervical, thoracic, and lumbar) extend and maintain erect posture of the vertebral column.

Longissimus

Acting together, longissimus muscles extend head and vertebral column.

Spinalis

Acting together, muscles of each region extend vertebral column.

Diaphragm

Contraction causes it to flatten, increasing size of thoracic cavity for inhalation.

External intercostals

Contraction expands ribcage, increasing size of thoracic cavity for inhalation.

Internal intercostals

Contraction draws adjacent ribs together, decreasing size of thoracic cavity for exhalation.

Rectus abdominis

Flexes vertebral column and compresses abdomen.

External oblique

Acting together, compress abdomen.

Internal oblique

Acting together, compress abdomen.

Transversus abdominis

Compresses abdomen.

Pectoralis major

Adducts and medially rotates arm.

Latissimus dorsi

Extends, adducts, and medially rotates arm.

Deltoid

Abducts arm.

Biceps brachii

Flexes forearm.

Triceps brachii

Extends forearm.

Palmaris longus

Flexes hand at wrist joint.

Tibialis anterior

Dorsiflexes foot.

Gastrocnemius

Plantar flexes foot.

Soleus

Plantar flexes foot.

Fibularis longus

Plantar flexes foot.

Gracilis

Adducts thigh.

Quadriceps femoris

Extends leg.

Hamstrings

Comprises biceps femoris, semitendinosus, and semimembranosus which flex the leg.