Condensed Muscle List: Origins, Insertions, and Actions (click images to open)

Comprehensive vocabulary flashcards detailing the anatomical origins, insertions, and primary actions for all 64 muscles from the condensed human muscular system reference.

Temporalis

Origin: Temporal fossa and deep surface of temporal fascia.

Insertion: Coronoid process and anterior border of mandibular ramus.

Action: Elevates mandible; posterior fibers retract mandible.

Masseter

Origin: Zygomatic arch.

Insertion: Lateral surface of mandibular ramus and angle; deep fibers also reach the coronoid process.

Action: Elevates mandible; superficial fibers assist protrusion.

Buccinator

Origin: Alveolar regions of maxilla and mandible opposite the molars; pterygomandibular raphe.

Insertion: Angle of mouth, blending with orbicularis oris.

Action: Compresses cheek against teeth; keeps food between chewing surfaces and assists blowing.

Orbicularis oculi

Origin: Medial orbital margin, medial palpebral ligament, and lacrimal bone.

Insertion: Skin around orbit, eyelids, and lateral palpebral raphe.

Action: Closes eyelids: gently for blinking and firmly for squinting.

Orbicularis oris

Origin: Maxilla, mandible, and interlacing fibers of surrounding facial muscles at the mouth angles.

Insertion: Skin and mucous membrane of lips.

Action: Closes, compresses, and protrudes lips.

Zygomaticus major

Origin: Lateral surface of zygomatic bone.

Insertion: Skin and muscle at angle of mouth (modiolus).

Action: Elevates and draws the mouth angle laterally, as in smiling.

Depressor anguli oris

Origin: Oblique line of mandible.

Insertion: Angle of mouth (modiolus).

Action: Depresses mouth angle.

Procerus

Origin: Fascia over lower nasal bone and upper lateral nasal cartilage.

Insertion: Skin of lower forehead between eyebrows.

Action: Depresses medial eyebrows and wrinkles skin across the bridge of the nose.

Platysma

Origin: Superficial fascia over upper pectoralis major and deltoid.

Insertion: Inferior border of mandible and skin and muscles of lower face.

Action: Tenses neck skin; depresses lower lip and mouth angle; assists mandibular depression.

Sternocleidomastoid

Origin: Manubrium of sternum and medial third of clavicle.

Insertion: Mastoid process and lateral superior nuchal line.

Action:

a) Unilateral: bends neck to same side and rotates head to opposite side.

b) Bilateral: flexes neck; can extend head depending on posture.

• Assists forced inspiration when head is fixed.

Levator scapulae

Origin: Transverse processes of C1-C4.

Insertion: Medial scapular border between superior angle and root of scapular spine.

Action: Elevates and downwardly rotates scapula; with scapula fixed, bends neck to same side.

Multifidus

Origin: Posterior sacrum, posterior superior iliac spine and sacroiliac ligaments; lumbar mammillary processes; thoracic transverse processes; cervical articular processes C4-C7.

Insertion: Spinous processes generally 2-4 vertebral levels above the origins.

Action: Stabilizes vertebrae; extends vertebral column bilaterally and rotates it to opposite side unilaterally.

Erector spinae group

Origin: Common inferior tendon from posterior iliac crest, sacrum, and lower vertebral spinous processes; additional vertebral and rib attachments vary by subdivision.

Insertion: Ribs, vertebral transverse and spinous processes, and skull, depending on subdivision.

Action: Extends and laterally flexes vertebral column and head; maintains posture. Group comprises iliocostalis, longissimus, and spinalis.

Quadratus lumborum

Origin: Posterior iliac crest and iliolumbar ligament.

Insertion: Inferior border of rib 12 and transverse processes L1-L4.

Action: Laterally flexes trunk to same side; assists trunk extension and stabilizes rib 12 during respiration.

External intercostals

Origin: Inferior border of each rib, ribs 1-11.

Insertion: Superior border of rib immediately below, ribs 2-12.

Action: Elevate ribs during inspiration and support intercostal spaces.

Internal intercostals

Origin: Internal surface and inferior border of each upper rib and its costal cartilage.

Insertion: Superior border of rib immediately below.

Action: Interosseous parts depress ribs during forced expiration; interchondral (parasternal) parts elevate ribs during inspiration. Support intercostal spaces.

Trapezius

Origin: External occipital protuberance, medial superior nuchal line, nuchal ligament, and spinous processes C7-T12.

Insertion: Lateral third of clavicle, acromion, and scapular spine.

Action: Upper fibers elevate, middle fibers retract, and lower fibers depress scapula. Upper and lower fibers cooperate in upward rotation.

Rhomboid major

Origin: Spinous processes T2-T5 and associated supraspinous ligaments.

Insertion: Medial scapular border inferior to root of scapular spine.

Action: Retracts, elevates, and downwardly rotates scapula; holds it against thoracic wall.

Rhomboid minor

Origin: Lower nuchal ligament and spinous processes C7-T1.

Insertion: Medial scapular border at root of scapular spine.

Action: Retracts, elevates, and downwardly rotates scapula; stabilizes it against thoracic wall.

Serratus anterior

Origin: External surfaces of ribs 1-8 or 1-9.

Insertion: Anterior (costal) surface of medial scapular border.

Action: Protracts and upwardly rotates scapula; holds scapula against thoracic wall.

Pectoralis minor

Origin: Anterior surfaces of ribs 3-5 near costal cartilages.

Insertion: Medial border and superior surface of scapular coracoid process.

Action: Draws scapula anteriorly and inferiorly; stabilizes scapula. Assists inspiration when scapula is fixed.

Supraspinatus

Origin: Supraspinous fossa of scapula and overlying fascia.

Insertion: Superior facet of greater tubercle of humerus and shoulder joint capsule.

Action: Initiates and assists arm abduction; stabilizes humeral head in glenoid cavity.

Infraspinatus

Origin: Infraspinous fossa of scapula and overlying fascia.

Insertion: Middle facet of greater tubercle of humerus and shoulder joint capsule.

Action: Laterally rotates arm; stabilizes humeral head in glenoid cavity.

Teres minor

Origin: Upper two-thirds of posterior aspect of lateral scapular border.

Insertion: Inferior facet of greater tubercle of humerus and shoulder joint capsule.

Action: Laterally rotates arm, assists adduction, and stabilizes humeral head.

Deltoid

Origin: Lateral third of clavicle, acromion, and scapular spine.

Insertion: Deltoid tuberosity of humerus.

Action: Middle fibers abduct arm. Anterior fibers flex and medially rotate arm; posterior fibers extend and laterally rotate arm.

Teres major

Origin: Posterior surface of inferior scapular angle and adjacent lateral border.

Insertion: Medial lip of intertubercular sulcus of humerus (crest of lesser tubercle).

Action: Adducts, medially rotates, and extends arm.

Latissimus dorsi

Origin: Spinous processes T7-T12; thoracolumbar fascia, iliac crest, and lower 3-4 ribs.

Insertion: Floor of intertubercular sulcus of humerus.

Action: Extends, adducts, and medially rotates arm.

Pectoralis major

Origin: Medial half of clavicle, sternum, upper six costal cartilages, and external oblique aponeurosis.

Insertion: Lateral lip of intertubercular sulcus of humerus (crest of greater tubercle).

Action: Adducts and medially rotates arm. Clavicular part flexes arm; sternocostal part extends a flexed arm.

Biceps brachii

Origin: Long head: supraglenoid tubercle of scapula. Short head: coracoid process of scapula.

Insertion: Radial tuberosity and forearm fascia through bicipital aponeurosis.

Action: Supinates forearm and flexes elbow; assists shoulder flexion.

Triceps brachii

Origin: Long head: infraglenoid tubercle of scapula. Lateral head: posterior humerus superior to radial groove. Medial head: posterior humerus inferior to radial groove.

Insertion: Olecranon of ulna and forearm fascia.

Action: Extends elbow. Long head also assists shoulder extension and adduction.

Pronator teres

Origin: Humeral head: medial epicondyle of humerus. Ulnar head: coronoid process of ulna.

Insertion: Middle of lateral surface of radius.

Action: Pronates forearm; assists elbow flexion.

Palmaris longus

Origin: Medial epicondyle of humerus via common flexor tendon.

Insertion: Flexor retinaculum and palmar aponeurosis.

Action: Flexes wrist and tenses palmar aponeurosis.

Flexor digitorum superficialis

Origin: Humeroulnar head: medial humeral epicondyle, ulnar collateral ligament, and coronoid process. Radial head: anterior border of radius.

Insertion: Sides of middle phalanges of digits 2-5; each tendon splits around the profundus tendon.

Action: Flexes proximal interphalangeal joints of digits 2-5; also assists metacarpophalangeal and wrist flexion.

Flexor pollicis longus

Origin: Anterior surface of radius and adjacent interosseous membrane.

Insertion: Palmar base of distal phalanx of thumb.

Action: Flexes thumb, especially at interphalangeal joint; assists wrist flexion.

Brachioradialis

Origin: Proximal two-thirds of lateral supracondylar ridge of humerus.

Insertion: Lateral distal radius at base of styloid process.

Action: Flexes elbow, especially with forearm in neutral position (thumb up); helps return forearm toward neutral from pronation or supination.

Supinator

Origin: Lateral humeral epicondyle, radial collateral and annular ligaments, and supinator crest and fossa of ulna.

Insertion: Anterior, lateral, and posterior surfaces of proximal third of radius.

Action: Supinates forearm.

Extensor digitorum

Origin: Lateral epicondyle of humerus via common extensor tendon.

Insertion: Extensor expansions of digits 2-5, reaching bases of middle and distal phalanges.

Action: Extends digits 2-5, primarily at metacarpophalangeal joints; assists interphalangeal and wrist extension.

Extensor pollicis longus

Origin: Middle third of posterior ulna and adjacent interosseous membrane.

Insertion: Dorsal base of distal phalanx of thumb.

Action: Extends thumb, especially at interphalangeal joint; also assists extension at its other joints.

External oblique

Origin: External surfaces of ribs 5-12.

Insertion: Linea alba, pubic tubercle, and anterior half of iliac crest.

Action: Compresses abdominal contents and flexes trunk bilaterally. On one side, bends trunk to same side and rotates it to opposite side.

Internal oblique

Origin: Thoracolumbar fascia, iliac crest, and lateral inguinal ligament.

Insertion: Inferior borders of ribs 10-12, linea alba, and pubic crest and pecten pubis via conjoint tendon.

Action: Compresses abdominal contents and flexes trunk bilaterally. On one side, bends and rotates trunk to same side.

Transversus abdominis

Origin: Internal surfaces of costal cartilages 7-12, thoracolumbar fascia, iliac crest, and lateral third of inguinal ligament.

Insertion: Linea alba, pubic crest, and pecten pubis via conjoint tendon.

Action: Compresses and supports abdominal contents; increases intra-abdominal pressure and stabilizes trunk.

Rectus abdominis

Origin: Pubic crest and pubic symphysis.

Insertion: Xiphoid process and costal cartilages 5-7.

Action: Flexes trunk, compresses abdominal contents, and assists posterior pelvic tilt.

Gluteus maximus

Origin: Ilium posterior to posterior gluteal line, posterior sacrum and coccyx, and sacrotuberous ligament.

Insertion: Iliotibial tract and gluteal tuberosity of femur.

Action: Extends and laterally rotates thigh; helps stabilize hip and knee through iliotibial tract.

Gluteus medius

Origin: External ilium between anterior and posterior gluteal lines.

Insertion: Lateral surface of greater trochanter of femur.

Action: Abducts thigh and stabilizes pelvis during single-leg stance. Anterior fibers assist medial rotation.

Gluteus minimus

Origin: External ilium between anterior and inferior gluteal lines.

Insertion: Anterior surface of greater trochanter of femur and hip capsule.

Action: Abducts and medially rotates thigh; stabilizes pelvis during single-leg stance.

Iliopsoas group

Origin: Psoas major: bodies and discs T12-L5 and lumbar transverse processes. Iliacus: iliac fossa and adjacent iliac crest.

Insertion: Lesser trochanter of femur, chiefly through iliopsoas tendon.

Action: Flexes thigh at hip; with femur fixed, assists trunk flexion. Supports hip and lumbar stability.

Adductor longus

Origin: Body of pubis, inferior to pubic crest.

Insertion: Middle third of linea aspera of femur.

Action: Adducts thigh and assists hip flexion.

Gracilis

Origin: Body and inferior ramus of pubis.

Insertion: Superior medial tibia via pes anserinus.

Action: Adducts thigh; flexes knee and medially rotates leg when knee is flexed.

Rectus femoris

Origin: Anterior inferior iliac spine and ilium superior to acetabulum.

Insertion: Patella via quadriceps tendon; tibial tuberosity via patellar ligament.

Action: Extends knee and flexes thigh at hip.

Vastus lateralis

Origin: Greater trochanter, gluteal tuberosity, and lateral lip of linea aspera of femur.

Insertion: Patella via quadriceps tendon; tibial tuberosity via patellar ligament.

Action: Extends knee and helps stabilize patella.

Vastus medialis

Origin: Intertrochanteric line, medial lip of linea aspera, and medial supracondylar line of femur.

Insertion: Patella via quadriceps tendon; tibial tuberosity via patellar ligament.

Action: Extends knee and helps stabilize patella medially.

Sartorius

Origin: Anterior superior iliac spine and adjacent notch.

Insertion: Superior medial tibia via pes anserinus.

Action: Flexes, abducts, and laterally rotates thigh; flexes knee and medially rotates leg when knee is flexed.

Biceps femoris

Origin: Long head: ischial tuberosity. Short head: lateral linea aspera and lateral supracondylar line of femur.

Insertion: Lateral side of fibular head.

Action: Flexes knee and laterally rotates flexed leg. Long head extends thigh at hip; short head does not cross hip.

Semitendinosus

Origin: Ischial tuberosity.

Insertion: Superior medial tibia via pes anserinus.

Action: Extends thigh, flexes knee, and medially rotates leg when knee is flexed.

Semimembranosus

Origin: Superolateral impression of ischial tuberosity.

Insertion: Posterior surface of medial tibial condyle, with expansions including oblique popliteal ligament.

Action: Extends thigh, flexes knee, and medially rotates leg when knee is flexed.

Tibialis anterior

Origin: Lateral tibial condyle, proximal lateral tibia, and adjacent interosseous membrane. Insertion:

Medial and plantar surfaces of medial cuneiform and base of first metatarsal.

Action: Dorsiflexes ankle and inverts foot; supports medial longitudinal arch.

Extensor hallucis longus

Origin: Middle anterior fibula and adjacent interosseous membrane.

Insertion: Dorsal base of distal phalanx of great toe.

Action: Extends great toe and dorsiflexes ankle; assists inversion.

Extensor digitorum longus

Origin: Lateral tibial condyle, proximal anterior fibula, and interosseous membrane.

Insertion: Middle and distal phalanges of toes 2-5 through extensor expansions.

Action: Extends toes 2-5 and dorsiflexes ankle.

Gastrocnemius

Origin: Medial head: posterior femur superior to medial condyle. Lateral head: lateral femoral condyle and adjacent posterior femur.

Insertion: Posterior calcaneus through calcaneal (Achilles) tendon.

Action: Plantar flexes ankle and flexes knee.

Soleus

Origin: Posterior fibular head and proximal fibula, soleal line and medial border of tibia, and tendinous arch between tibia and fibula.

Insertion: Posterior calcaneus through calcaneal (Achilles) tendon.

Action: Plantar flexes ankle and helps maintain standing posture.

Flexor digitorum longus

Origin: Posterior tibia inferior to soleal line.

Insertion: Plantar bases of distal phalanges of toes 2-5.

Action: Flexes toes 2-5, especially distal interphalangeal joints; assists plantar flexion and inversion and supports longitudinal arches.

Flexor hallucis longus

Origin: Distal two-thirds of posterior fibula and adjacent interosseous membrane.

Insertion: Plantar base of distal phalanx of great toe.

Action: Flexes great toe; assists plantar flexion and supports medial longitudinal arch during push-off.

Fibularis longus (peroneus longus)

Origin: Head and proximal two-thirds of lateral fibula.

Insertion: Plantar surfaces of medial cuneiform and base of first metatarsal.

Action: Everts foot and assists ankle plantar flexion; supports transverse and longitudinal foot arches.

Dorsal interossei of foot

Origin: Adjacent sides of metatarsals 1-5; four bipennate muscles.

Insertion: Proximal phalangeal bases and extensor expansions: first to medial side of toe 2; remaining three to lateral sides of toes 2-4.

Action: Abduct toes 2-4 relative to axis of toe 2; flex metatarsophalangeal joints and assist interphalangeal extension.