Muscles (Origins, Insertions, & Actions) Flashcards
Orbicularis oculi muscle
Origin: orbit
Insertion: skin of eyelid
Action: Closes eyes, squints eyes
Orbicularis oris muscle
Origin: Maxilla and mandible
Insertion: Muscle and skin of lips
Action: Closes lips, purses lips
Temporalis muscle
Origin: Temporal fossa
Insertion: Mandible (coronoid process)
Action: Closes jaw, elevates and retracts mandible
Zygomaticus muscles (major and minor)
Origin: Zygomatic bone
Insertion: Corners of mouth
Action: raises corners of mouth (smiling muscle)
Epicranius muscle (aka occipitofrontalis)
Has two bellies (frontal and occipital)
Frontal belly origin: epicranial aponeurosis
Frontal belly insertion: skin of brow line
Frontal belly action: raises eyebrows
Occipital belly origin: occipital and temporal bones
Occipital belly insertion: epicranial aponeurosis
Occipital belly action: fixes aponeurosis and pulls scalp posteriorly
Sternocleidomastoid muscle
Major and minor Origins: sternum and clavicle Insertion: mastoid process of temporal bone Action of both: flexes neck Action of one: rotates head
Digastric muscle (THE digastric muscle)
Digastric means has two bellies
Origin: mandible and mastoid process (deep to the mandible, not superficial)
Insertion: hyoid
Action: elevates hyoid, depresses mandible (chewing)
Masseter muscle
Origin: zygomatic arch
Insertion: mandible
Action: elevates mandible - main mover of jaw closure
Splenius muscle
Origin: cervical and thoracic spine
Insertion: occipital bone
Action: extends head and neck
*Deep to the trapezius muscle
Erector spinae muscle
has multiple parts, but we don’t need to get more specific than that
Origin: pelvis and interior spine
Insertion: superior spine and ribs
Action: extends spine
External intercostal muscles
Origins: superior ribs
Insertions: inferior ribs
Action: elevate ribs (inhale)
Internal intercostal muscles
Origins: inferior ribs
Insertions: superior ribs
Actions: depress ribs (exhale)
Rectus abdominis muscle
Origin: anterior pubis
Insertions: xiphoid process and ribs
Action: flexes spine
External oblique muscle
Origin: anterior ribs
Insertion: linea alba and pelvis
Action: flexes and rotates spine
Internal oblique muscle
Origin: lumbar fascia and pelvis
Insertion: linea alba and ribs
Action: flexes and rotates spine (same as external oblique)
Transversus abdominis muscle
Origins: ribs, lumbar fascia, and pelvis
Insertion: linea alba
Action: compresses abdomen
Diaphragm muscle
Origin: inferior border of ribs and sternum
Insertion: central tendon
Action: inspiration
Trapezius muscle
Origins: occipital bone, and cervical and thoracic vertebrae
Insertions: clavicle and scapula
Actions: extends head, moves scapula
Levator scapulae muscle
Origin: cervical vertebrae
Insertion: scapula
Action: elevates scapula
*Deep to trapezius
Rhomboid major and minor muscles
Origins: cervical and thoracic vertebrae
Insertion: scapula
Action: adduct (retract) scapula
*Deep to trapezius
*Both major and minor are inferior to Levator Scapulae
*Minor (thin) is superior to major (thick)
Serratus anterior muscle
Origin: lateral ribs
Insertion: scapula
Action: anchors scapula to ribs (protracts)
*Wraps around the sides of the body to anchor the ribs to the scapula
Pectoralis minor muscle
Origin: anterior ribs
Insertion: scapula
Action: depresses scapula
*Deep to pectoralis major