Axial Muscles

Both origin and insertion are on axial skeleton

What must be present in order to classify a muscle as axial?

Occipitofrontalis and galea aponeurotica

What two structure make up the epicranius?

O: Skin and subcutaneous layer of forehead and eyebrows

I: Galea aponeurotica

A: Move scalp, wrinkle forehead, elevate eyebrows

Name origin, insertion and action of the frontal belly of the occipitofrontalis

O: Superior nuchal line

I: Galea aponeurotica

A: Retracts scalp (move scalp posteriorly)

Name origin, insertion and action of the occipital belly of the occipitofrontalis

O: mandible, maxilla, fascia and fibers from other facial muscles

I: Lips and skin surrounding the mouth

A: close/pucker lips

Name origin, insertion and action of the Orbicularis Oris

O: Fascia of deltoid and pectoralis major and acromion

I: Skin of cheek and mandible

A: Pull lower lip inferiorly, tense skin of neck, contributes to depression of mandible

Name origin, insertion and action of the Platysma

O: Alveolar processes of mandible/maxilla

I: Orbicularis Oris

A: Compresses cheeks, holds food between teeth when chewing, aids in sucking/blowing

Name origin, insertion and action of the Buccinator

Temporalis, Lateral/Medial Pterygoids, Masseter

Name the muscles of mastication

O: Superior and inferior portions of temporal bone

I: Coronoid process of mandible

A: Elevate and retract mandible

Name origin, insertion and action of the Temporalis

O: Zygomatic arch

I: Lateral surface of ramus and angle of mandible

A: Elevates and protracts the mandible, prime mover of jaw closer

Name origin, insertion and action of the Masseter

O: Maxilla, palatine and medial surface of lateral pterygoid plate of sphenoid

I: Medial surface of ramus of mandible

A: Elevates/protracts mandible, side to side movement of mandible

Name origin, insertion and action of the Medial Pterygoid

O: Greater wing of sphenoid and lateral surface of lateral pterygoid plate of sphenoid

I: Condylar process of mandible

A: Protracts and side to side movement of mandible

Name origin, insertion and action of the Lateral Pterygoid

Anaerobic bacteria

Often found in soil or feces, can produce deadly toxins that can alter the function of muscles

Tetanus

Disease commonly referred to as "lockjaw"

Tetany

Term for involuntary skeletal muscle contractions

Muscles that move the mandible

Which muscles are usually affected by tetanus first?

O: Manubrium and sternal ends of clavicle

I: Mastoid process of temporal bone

A: When both contract pulls head forward and down. When one contracts turns head to opposite side of which the side the muscle is located

Name origin, insertion and action of the Sternocleidomastoid

O: ligamentum nuchae

I: Occipital bone and mastoid process

A: When both contract pulls head back and extends/hyperextends cervical vertebrae. When one contracts neck is turned towards that side

Name origin, insertion and action of the Splenius Capitis

O: Articular processes of C4-C6 and transverse processes of C7-T6

I: Between superior and inferior nuchal lines

A: When both contract pulls head back and extends/hyperextends cervical vertebrae. When one contracts neck is turned towards that side

Name origin, insertion and action of the Semispinalis Capitis

Transversospinalis muscles

Group of muscles deep to the erector spinae muscles

Extend the vertebral column or cause lateral flexion

What is the action of both the erector spinae muscles and the transversospinalis muscles?

O: Inferior border of superior rib

I: Superior border of inferior rib

A: Elevates ribs by causing them to move up and out during inhalation

Name origin, insertion and action of the external intercostals

Elastic recoil of lung tissue

What causes the ribs to return to their original position during passive exhalation?

O: Superior border of inferior rib

I: inferior border of superior rib

A: Depresses the ribs during forceful exhalation

Name origin, insertion and action of the internal intercostals

O: Inferior internal surface and costal cartilage of lower ribs, xiphoid process, lumbar vertebrae

I: Central tendon

A: Contracts during inhalation moving diaphragm downwards increasing volume of thoracic cavity

Name origin, insertion and action of the diaphragm

External oblique, internal oblique, transverse abdominis

What muscles form the rectus sheath?

O: External inferior borders of lower ribs

I: Linea alba and some to iliac crest

A: When both contract they compress the abdomen. When one side contracts it causes lateral flexion and rotation to the SAME side

Name origin, insertion and action of the external oblique

O: lumbar fascia, inguinal ligament and iliac crest

I: Linea alba, pubic crest, costal cartilage and surfaces of lower ribs

A: When both contract they compress the abdomen. When one side contracts it causes lateral flexion and rotation to the OPPOSITE side

Name origin, insertion and action of the internal oblique

O: Iliac crest, lumbar fascia, inguinal ligament, cartilage of lower ribs

I: linea alba and pubic crest

A: When both contract they compress the abdomen. When one side contracts it causes lateral flexion and rotation to the SAME side

Name origin, insertion and action of the transversus abdominis

O: superior surface of pubis near symphysis

I: xiphoid process and inferior surface of middle ribs

A: Flexes vertebral column and compresses abdominal wall, used in forceful exhalation

Name origin, insertion and action of the rectus abdominis

Pelvic diaphragm

The three layers of muscles and associated fasciae of the floor of the pelvic cavity are collectively referred to as the...

Levator ani

Group of muscles that support the pelvic viscera and functions as sphincter at the anorectal juction, urethra and vagina

Pubococcygeus

Muscle made famous by Dr. Arnold Kegal who advocated exercises to strengthen them to help control urinary incontinence and compress vagina for sexual pleasure