Anatomy Test 3 (Muscles)

Front 1

Frontal Belly of occipitofrontalis

Back 1

Origin=frontal bone and skin of eyebrows

Insertion=epicranial aponeurosis (galea aponeurotica

Action= moves the scalp, wrinkles forehead, and elevates the eyebrows.

Front 2

Occipital Belly of the occipitofrontalis

Back 2

Origin= superior nuchal line

Insertion=epicranial aponeurosis

Action= moves the scalp slightly posteriorly

Front 3

Orbicularis Oris

Back 3

Origin= mandible and maxillae as well as fascia and fibers from the other muscles

Insertion= skin and lips surrounding the mouth

Action= closes lips, puckers up the lips

Front 4

Platysma

Back 4

Origin=fascia of deltoid and pectoralis major muscles and acromion of scapula

Insertion= skin of cheek and mandible

Action= pulls lower lip inferiorly, tenses skin of neck and contributes to depression of the mandible

Front 5

Buccinator

Back 5

Origin= alveolar processes of mandible and maxillae

Insertion= orbicularis oris

Action=compresses cheeck, hold food between teeth during chewing, aids in sucking and blowing

Front 6

Temporalis

Back 6

Origin= superior and inferior portions of temporal bone

Insertion= coronoid process of mandible

Action= elevates and retracts mandible

Front 7

Masseter

Back 7

Origin= zygomatic arch

Insertion= lateral surface of coronoid process; lateral surface and angle of mandible

Action=Elevates and protracts mandible; prime mover of jaw closure

Front 8

Medial and Lateral Pterygoid

Back 8

Origin= pterygoid process of the sphenoid bone

Insertion= mandible

Action= elevate and protract the mandible and move it from side to side during chewing

Front 9

Anteriorlateral neck muscles

Back 9

Origin=manubruim and sternal ends of clavicles

Insertion= mastoid process of temporal bones

Action= when both contract, the head is pulled forward and down (flexion of cervical vertebrae and flexion of atlanto occipital joint). When one contracts, it turns the head sideways in a direction opposite the side on which the contracting muscle is located (lateral flexion of the cervical vertebrae and rotation of the atlantoaxial joint)

Front 10

Splenius capitus

Back 10

Origin=ligamentum nuchae

Insertion= occipital bone and mastoid process of temporal bone

Action=When both contract, it pulls the head back and extends and hyperextends the cervical vertebrae. When one contracts it turns the head sideways in a direction towards the same side on which the contracting muscle is located.

Front 11

Semispinalis capitus

Back 11

Origin= seventh cervical vertebrae and first six throracic vertebrae

Insertion= between the superior and inferior nuchal lines of the occipital bone

Action= same as the Splenuis capitus

Front 12

Diaphram

Back 12

Origin= inferior internal surface of lower ribs, xiphoid process of sternum, costal cartilages of inferior ribs, and lumbar vertebrae

Insertion= "central tendon" (strong aponeurosis that is the insertion for all peripheral muscle fibers of the diaphram)

Action=contraction during inhalation causes flattening of the diaphram (moves inferiorly), thereby expanding the thoracic cavity and compressing the abdominopelvic cavity. During exhalation the diaphram rocoils passively upwards, pulled by the elastic fibers in the lung tissue, to resume its dome shape.

Front 13

External Oblique

Back 13

Origin= external inferior borders of lower ribs

Insertion= linea alba by a broad aponeurosis; some to the iliac crest

Action=When both contract, they compress the abdomen and flex the vertebral column. When only one contracts, it causes lateral flexion of the vertebral column.

Front 14

Internal Oblique

Back 14

Origin= lumbar fascia, infuinal ligament, and iliac crest

Insertion= linea alba, pubic crest, costal cartilages and surfaces of lower ribs

Action=same as external oblique

Front 15

Transverse abdominis

Back 15

Origin= iliac crest, lumbar fascia, inguinal ligament, and cartilages of lower ribs

Insertion= linea alba and pubic crest

Action=primarily compresses the abdomen

Front 16

Rectus Abdominis

Back 16

Origin= superior surface of pubis near symphysis

Insertion= xiphoid process of sternum and inferior surfaces of middle ribs

Action=Flexes vertebral column and compresses the abdominal wall; used in forceful exhalation