Muscle Origin Insertion



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Muscle

Origin

Insertion

Action

Frontalis

Galea aponeurosis, anterior to the vertex

skin above the nose and eyes

draws back the scalp to raise the eyebrows and wrinkle the brow

Occipitalis

lateral 2/3 of superior nuchal line external occipital protuberance

galea aponeurosis, over the occipital bone

draws back the scalp to raise the eyebrows and wrinkle the brow

Orbicularis oculi

orbital portion: nasal process of frontal bone

palpebral portion: palpebral ligament

lacrimal portion: lacrimal crest of lacrimal bone


circumferentially around orbit meeting in palpebral raphe

powerfully closes the eye

Depressor anguli

Oris


along the oblique line of mandible

lateral aspect of mental tubercle of the mandible



modiolus

lowers the angle(s) of the mouth (as in frowning)

Orbicularis oris

alveolar border of maxilla

lateral to midline of mandible



circumferentially around mouth

blends with other muscles



closes the lips

protrudes the lips



Masseter

Superficial:

zygomatic process of the maxilla

inferior border of zygomatic arch

Intermediate: inner surface of zygomatic arch

Deep: posterior aspect of inferior border of zygomatic arch


Superficial:

angle of mandible

lateral surface of mandibular ramus

Intermediate: ramus of mandible

Deep:

superior ramus of mandible



coronoid process of mandible

closes the lower jaw (clenches the teeth)

may deviate mandible to opposite side of contraction

Blood: masseteric artery

Nerve: masseteric nerve



Temporalis

Temporal fossa between inferior temporal line and infratemporal crest

Medial and anterior aspect of coronoid process of mandible

Elevates mandible and posterior fibers retract

Platysma

Skin over lower neck and upper lateral chest

Inferior border of mandible and skin over lower face and angle of mouth

Depresses and wrinkles skin of lower face and mouth. Aids forced depression of mandible

Sternocleidomastoid

Anterior and superior manubrium and superior medial third of clavicle

Lateral aspect of mastoid process and anterior half of superior nuchal line

Flexes and laterally rotates cervical spine. Protracts head when acting together . Extends neck when neck already partially extended

Muscles of Trunk

Muscle

Origin

Insertion

Action

Pectoralis major

Clavicular head-medial half clavicle. Sternocostal head-lateral manubrium and sternum, six upper costal cartilages and external oblique aponeurosis

Lateral lip of bicipital groove of humerus and anterior lip of deltoid tuberosity

Clavicular head:flexes and adducts arm. Sternal head: adducts and medially rotates arm . Accessory for inspiration

Serratus anterior

Upper eight ribs and anterior intercostal membranes from midclavicular line. Lower four interdigitating with external oblique

Inner medial border scapula. 1 and 2: upper angle; 3 and 4: length of costal surface ; 5-8: inferior angle

Laterally rotates and protracts scapula

Deltoid

Anterior: Lateral third of clavicle

Middle: lateral acromion

Posterior: spine of scapula


Deltoid tuberosity of humerus

Anterior: flexion, horizontal adduction, medial rotation of humerus

Middle: abduction of humerus to 90 degrees



Posterior: extension horizontal abduction, lateral rotation of humerus

Pectoralis minor

3, 4, 5 ribs

Medial and upper surface of coracoid process of scapula

Elevates ribs if scapula fixed, protracts scapula (assists serratus anterior)

Trapezius

Medial third superior nuchal line, ligament nuchae, spinous processes and supraspinous ligaments to T12

Upper fibers to lateral third of posterior border of clavicle; lower to medial acromion and superior lip of spine of scapula to deltoid tubercle

laterally rotates, elevates and retracts scapula. If scapula is fixed, extends and laterally flexes neck

Latissmus dorsi

Spine T7, spinous processes and supraspinous ligaments of all lower thoracic, lumbar and sacral vertebrae, lumbar fascia, posterior third iliac crest, last four ribs (interdigitating with external oblique abdominis) and inferior angle of scapula

Floor of bicipital groove of humerus after spiraling around teres major

Extends, adducts and medially rotates arm. Costal attachment helps with deep inspiration and forced expiration




Muscle

Location

Action only

Diaphragm

The lungs are located anterior to the diaphragm.

The diaphragm is the means by which the lungs inflate and deflate.

External intercostals

Inferior border of ribs as far back as posterior angles

Fix intercostal spaces during respiration. Aids forced inspiration by elevating ribs

Internal intercostals

Inferior border of ribs as far back as posterior angles

Fix intercostal spaces during espiration. Aids forced inspiration by elevating ribs

Infraspinatus

Medial three quarters of infraspinous fossa of scapula and fibrous intermuscular septa

Laterally rotates arm and stabilizes shoulder joint

Rotator cuff muscle

Supraspinatus

Medial three quarters of supraspinous fossa of scapula, upper surface of spine (bipennate)

Abducts arm and stabilizes shoulder joint

Rotator cuff muscle



Subscapularis

Medial two thirds of subscapular fossa

Medially rotates arm and stabilizes shoulder joint

Rotator cuff muscle



Teres minor

Upper axillary border of scapula

lateral rotation

Extension of humerus



Rotator cuff muscle

Muscles of anterior abdominal wall

Muscle

Location and fibers only

Rectus abdominis

Pubic crest and pubic symphysis Anterior primary rami (T7-12)

External oblique

Anterior angles of lower eight ribs Anterior primary rami (T7-12)

Internal oblique

Lumbar fascia, anterior two thirds of iliac crest and lateral two thirds of inguinal ligament Anterior primary rami (T7-12) (conjoint tendon ilioinguinal nerve (L1))

Transverses abdominis

Costal margin, lumbar fascia, anterior two thirds of iliac crest and lateral half of inguinal ligament Anterior primary rami (T7-12). Conjoint tendon ilioinguinal


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