Action Axial Muscles (BIO 201, Practical 2), Axial Muscles (BIO 201, Practical 2)

Elevation of mandible, mastication

Temporalis, Masseter

Sphincter of eyelids, closes eyes, aids in flow of tears

Orbicularis occuli

Elevates upper eyelid, opens eye

Levator palpabrae superioris

Elevates corner of mouth when smiling or laughing

Zygomaticus major

Elevation of upper lip

Zygomaticus minor

Encircles mouth, closes lips, protrudes lips, speech

Orbicularis oris

Draws lower lip and angle of mouth downward with horror or surprise, may aid in opening mouth widely

Platysma

Contralateral rotation of head, flexion of neck

Sternocleidomastoid

Bilateral: neck flexion, if spine is fixed, elevation of ribs 1-2; aid in breathing. Unilateral: lateral flexion of neck

Scalenes

Elevates hyoid, retracts hyoid

Stylohyoid

Spands mandible from side to side and forms floor of mouth, elevates floor of mouth in initial stage of swallowing

Mylohyoid

Depresses hyoid after it has been elevated

Omohyoid

Depresses mandible when hyoid is fixed. Elevates hyoid when mandible is fixed.

Digastric

Depresses hyoid after it has been elevated

Sternohyoid

Depresses larynx after it has been elevated in swallowing and vocalization

Sternothyroid

Depresses hyoid after it has been elevated

Omohyoid

Depresses hyoid

Thyrohyoid

When scalenes fix rib 1, elevation and protraction of ribs 2-12, expanding the thoracic cavity

External Intercostals

In forced expiration, the interosseous part depresses and retracts the ribs, compelling the thoracic cavity and expelling air

Internal Intercostals

Prime mover of inspiration, contraction compresses abdominal viscera and aids in childbirth and expulsion of urine and feces

Diaphragm

Flexion of trunk, stabilizes pelvic region during walking, compresses abdominal viscera

Rectus abdominis

Support viscera, stabilizes vertebral column, maintains posture, contralateral rotation of waist

External Abdominal Oblique

Support viscera, stabilizes vertebral column, maintains posture, ipsilateral rotation of waist

Internal Abdominal Oblique

Compresses abdominal contents

Transverse abdominis

Contralateral rotation of neck, extension of head and neck

Semispinalis

Lateral flexion of vertebral column. Extension of vertebral column

Illiocostalis

Retracts scapula

Rhomboideus Major

Elevates scapula if cervical vertebrae are fixed. Lateral flexion of neck if scapula are fixed

Levator Scapulae

Stabilizes scapula and shoulder during arm movements, elevates and depresses shoulder, rotates and retracts scapula

Trapezius

With pectoralis minor, protracts scapula. Prime mover in all forward reaching and pushing actions. Fixes scapula during abduction of arm

Serratus Anterior

With serratus anterior, protracts the scapula

Pectoralis minor

Flexion of shoulder, adduction of shoulder, medial rotation of shoulder

Pectoralis major

Adduction of shoulder, extension of shoulder, medial rotation of the shoulder

Latissimus Dorsi

Temporalis

Masseter

Zygomatic arch

origin of masseter

Lateral surface of mandibular ramus and angle

insertion of masseter

Orbicularis Oculi

Levator Palpabrae Superioris

Zygomaticus Major

Zygomaticus Minor

Orbicularis Oris

Platysma

Sternocleidomastoid

Manubrium of sternum, medial one third of clavicle

Origin of sternocleidomastoid

Mastoid process of temporal bone

insertion of sternocleidomastoid

Scalenes

Digastric

Digastric fossa of mandible

origin of anterior belly of digastric

Mastoid process of temporal bone

origin of posterior belly of digastric

Hyoid bone via fascial sling

insertion of digastric

Stylohyoid

Styloid process of temporal bone

Origin of stylohyoid

Hyoid bone

Insertion of stylohyoid

Mylohyoid

Sternohyoid

Manubrium end of sternum, medial end of clavicle

origin of sternohyoid

Hyoid bone

insertion of sternohyoid

Sternothyroid

Omohyoid

Thyrohyoid

External Intercostals

Internal Intercostals

Diaphragm

Rectus Abdominis

Pubic symphysis and superior margin of pubis

origin of rectus abdominus

Xiphoid process, costal cartilages 5-7

insertion of rectus abdominis

External Abdominal Oblique

Internal Abdominal Oblique

Transverse Abdominis

Linea Alba

Semispinalis

Illiocostalis

Longissimus

Spinalis

Rhomboideus Major

Levator Scapulae

Trapezius

External occipital protuberance, medial one third of superior nuchal line, nuchal ligament, spinous processes of vertebrae T1-T12

Origin of trapezius

Acromion and spine of scapula, lateral one third of clavicle

Insertion of trapezius

Serratus Anterior

All or nearby all ribs

Origin of serratus anterior

Medial border of scapula

Insertion of serratus anterior

Pectoralis Minor

Ribs 3-5 and overlying fascia

origin of pectoralis minor

Coracoid process of scapula

insertion of pectoralis minor

Pectoralis Major

Medial half of clavicle, lateral margin of sternum, costal cartilages 1-7, aponeurosis of external oblique

Origin of pectoralis major

Intertubercular sulcus of humerus

Insertion of pectoralis major

Latissimus Dorsi

Unilateral: lateral flexion of vertebral column, ipsilateral rotation of head, bilateral: extension of vertebral column and head

Longissimus

Unilateral: lateral flexion of vertebral column, bilateral: extension of vertebral column

Spinalis