Facial Expression Muscles
| Muscle |
Origin |
Insertion |
Innervation |
Action |
| Orbicularis oculi |
Medial orbital margin, medial palpebral ligament |
Lateral palpebral raphe, skin around orbit |
Facial nerve (CN VII) |
Closes eyelid, blinking |
| Orbicularis oris |
Modiolus and surrounding tissues near angle of mouth |
Skin and mucous membrane of lips |
Facial nerve (CN VII) |
Closes/purses lips |
| Buccinator |
Alveolar processes of maxilla and mandible |
Orbicularis oris and angle of mouth |
Facial nerve (CN VII) |
Compresses cheek, holds food between teeth during chewing |
| Frontalis |
Galea aponeurotica |
Skin of eyebrows and root of nose |
Facial nerve (CN VII) |
Raises eyebrows, wrinkles forehead |
Muscles of Mastication
| Muscle |
Origin |
Insertion |
Innervation |
Action |
| Masseter |
Zygomatic arch |
Angle and ramus of mandible |
Trigeminal nerve (CN V3) |
Elevates mandible (closes jaw) |
| Temporalis |
Temporal fossa |
Coronoid process of mandible |
Trigeminal nerve (CN V3) |
Elevates and retracts mandible |
| Medial pterygoid |
Medial surface of lateral pterygoid plate |
Medial surface of mandibular angle |
Trigeminal nerve (CN V3) |
Elevates and protrudes mandible |
| Lateral pterygoid |
Greater wing of sphenoid, lateral pterygoid plate |
Neck of mandible, TMJ disc |
Trigeminal nerve (CN V3) |
Protrudes mandible, opens mouth |
Neck Muscles
| Muscle |
Origin |
Insertion |
Innervation |
Action |
| Sternocleidomastoid |
Manubrium of sternum, medial clavicle |
Mastoid process of temporal bone |
Accessory nerve (CN XI) |
Unilateral: rotates head to opposite side; Bilateral: flexes neck |
| Scalenes (anterior, middle, posterior) |
Transverse processes of C2-C7 |
First and second ribs |
Cervical spinal nerves (C3-C8) |
Flex and rotate neck, elevate ribs during inspiration |
| Platysma |
Fascia of pectoralis major and deltoid |
Mandible, skin of lower face |
Facial nerve (CN VII) |
Depresses mandible, tenses skin of neck |
Trunk Muscles - Anterior
| Muscle |
Origin |
Insertion |
Innervation |
Action |
| Rectus abdominis |
Pubic crest and symphysis |
Xiphoid process, costal cartilages 5-7 |
Thoracoabdominal nerves (T7-T12) |
Flexes trunk, compresses abdomen |
| External oblique |
External surface of lower 8 ribs |
Iliac crest, linea alba |
Thoracoabdominal nerves (T7-T12) |
Compresses abdomen, rotates trunk |
| Internal oblique |
Inguinal ligament, iliac crest |
Linea alba, lower ribs |
Thoracoabdominal nerves (T7-T12) |
Compresses abdomen, rotates trunk |
| Transversus abdominis |
Inguinal ligament, thoracolumbar fascia, iliac crest, lower 6 costal cartilages |
Linea alba, pubic crest |
Thoracoabdominal nerves (T7-T12) |
Compresses abdomen, stabilizes core |
Trunk Muscles - Posterior (Superficial Layer)
| Muscle |
Origin |
Insertion |
Innervation |
Action |
| Trapezius |
Occipital bone, nuchal ligament, spinous processes of C7-T12 |
Lateral clavicle, acromion and spine of scapula |
Accessory nerve (CN XI), C3-C4 |
Upper: elevates scapula; Middle: retracts scapula; Lower: depresses scapula |
| Latissimus dorsi |
Spinous processes of T7-T12, thoracolumbar fascia, iliac crest, lower 3-4 ribs |
Intertubercular groove of humerus |
Thoracodorsal nerve (C6-C8) |
Adducts, extends, and medially rotates humerus |
| Rhomboid major |
Spinous processes of T2-T5 |
Medial border of scapula |
Dorsal scapular nerve (C5) |
Retracts and elevates scapula |
| Rhomboid minor |
Spinous processes of C7-T1 |
Medial border of scapula above spine |
Dorsal scapular nerve (C5) |
Retracts and elevates scapula |
| Levator scapulae |
Transverse processes of C1-C4 |
Superior angle of scapula |
Dorsal scapular nerve (C5), cervical nerves (C3-C4) |
Elevates scapula, rotates glenoid cavity downward |
Trunk Muscles - Posterior (Deep Layer)
| Muscle |
Origin |
Insertion |
Innervation |
Action |
| Erector spinae (iliocostalis, longissimus, spinalis) |
Sacrum, iliac crest, spinous/transverse processes of vertebrae |
Ribs and vertebrae above origin |
Dorsal rami of spinal nerves |
Extension and lateral flexion of spine |
| Multifidus |
Sacrum, transverse processes of vertebrae |
Spinous processes 2-4 vertebrae above |
Dorsal rami of spinal nerves |
Stabilizes spine during local movements |
| Quadratus lumborum |
Iliac crest, iliolumbar ligament |
12th rib, transverse processes of L1-L4 |
Thoracoabdominal nerves (T12-L3) |
Lateral flexion of spine, stabilizes 12th rib during inspiration |
Respiratory Muscles
| Muscle |
Origin |
Insertion |
Innervation |
Action |
| Diaphragm |
Lower 6 costal cartilages, xiphoid process, lumbar vertebrae |
Central tendon |
Phrenic nerve (C3-C5) |
Primary muscle of inspiration |
| External intercostals |
Inferior border of rib above |
Superior border of rib below |
Intercostal nerves |
Elevate ribs during inspiration |
| Internal intercostals |
Superior border of rib below |
Inferior border of rib above |
Intercostal nerves |
Depress ribs during forced expiration |
| Serratus posterior superior |
Nuchal ligament, spinous processes of C7-T3 |
Upper ribs (2-5) |
Intercostal nerves |
Elevates ribs during inspiration |
| Serratus posterior inferior |
Spinous processes of T11-L2 |
Lower ribs (9-12) |
Intercostal nerves |
Depresses ribs, assists in forced expiration |
Pelvic Floor Muscles
| Muscle |
Origin |
Insertion |
Innervation |
Action |
| Levator ani (pubococcygeus, iliococcygeus, puborectalis) |
Pubic bone, ischial spine, obturator fascia |
Coccyx, anococcygeal ligament, perineal body |
Pudendal nerve (S2-S4), direct branches from S3-S4 |
Supports pelvic organs, controls defecation and urination |
| Coccygeus |
Ischial spine |
Lower sacrum, coccyx |
Branches from S4-S5 |
Supports pelvic floor, pulls coccyx forward |
Shoulder Muscles
| Muscle |
Origin |
Insertion |
Innervation |
Action |
| Deltoid |
Lateral clavicle, acromion, spine of scapula |
Deltoid tuberosity of humerus |
Axillary nerve (C5-C6) |
Anterior: flexion, medial rotation; Middle: abduction; Posterior: extension, lateral rotation |
| Supraspinatus |
Supraspinous fossa of scapula |
Greater tubercle of humerus |
Suprascapular nerve (C5-C6) |
Initiates abduction of humerus, stabilizes shoulder joint |
| Infraspinatus |
Infraspinous fossa of scapula |
Greater tubercle of humerus |
Suprascapular nerve (C5-C6) |
Lateral rotation of humerus, stabilizes shoulder joint |
| Teres minor |
Lateral border of scapula |
Greater tubercle of humerus |
Axillary nerve (C5-C6) |
Lateral rotation of humerus, stabilizes shoulder joint |
| Teres major |
Inferior angle of scapula |
Intertubercular groove of humerus |
Lower subscapular nerve (C5-C6) |
Extension, adduction, medial rotation of humerus |
| Subscapularis |
Subscapular fossa |
Lesser tubercle of humerus |
Upper and lower subscapular nerves (C5-C6) |
Medial rotation of humerus, stabilizes shoulder joint |
Arm Muscles (Brachium)
| Muscle |
Origin |
Insertion |
Innervation |
Action |
| Biceps brachii |
Long head: supraglenoid tubercle; Short head: coracoid process |
Radial tuberosity, bicipital aponeurosis |
Musculocutaneous nerve (C5-C6) |
Flexes elbow, supinates forearm, weak flexor of shoulder |
| Brachialis |
Distal half of anterior humerus |
Coronoid process of ulna |
Musculocutaneous nerve (C5-C6) |
Flexes elbow |
| Triceps brachii |
Long head: infraglenoid tubercle; Lateral head: posterior humerus above radial groove; Medial head: posterior humerus below radial groove |
Olecranon process of ulna |
Radial nerve (C7-C8) |
Extends elbow, long head also extends shoulder |
| Anconeus |
Lateral epicondyle of humerus |
Lateral olecranon and posterior ulna |
Radial nerve (C7-C8) |
Assists in elbow extension, stabilizes elbow joint |
Forearm Muscles - Anterior Compartment (Flexors)
| Muscle |
Origin |
Insertion |
Innervation |
Action |
| Pronator teres |
Medial epicondyle of humerus, coronoid process of ulna |
Middle lateral radius |
Median nerve (C6-C7) |
Pronates forearm, assists in elbow flexion |
| Flexor carpi radialis |
Medial epicondyle of humerus |
Base of 2nd-3rd metacarpals |
Median nerve (C6-C7) |
Flexes and abducts wrist |
| Palmaris longus |
Medial epicondyle of humerus |
Palmar aponeurosis |
Median nerve (C7-C8) |
Flexes wrist, tenses palmar aponeurosis |
| Flexor carpi ulnaris |
Medial epicondyle of humerus, olecranon and posterior ulna |
Pisiform, hamate, 5th metacarpal |
Ulnar nerve (C7-T1) |
Flexes and adducts wrist |
| Flexor digitorum superficialis |
Medial epicondyle of humerus, coronoid process, radius |
Middle phalanges of fingers 2-5 |
Median nerve (C7-T1) |
Flexes middle phalanges of fingers, assists wrist flexion |
| Flexor digitorum profundus |
Anterior and medial ulna, interosseous membrane |
Distal phalanges of fingers 2-5 |
Median nerve (lateral half, C8-T1), Ulnar nerve (medial half, C8-T1) |
Flexes distal phalanges of fingers |
| Flexor pollicis longus |
Anterior radius, interosseous membrane |
Distal phalanx of thumb |
Anterior interosseous (from median, C8-T1) |
Flexes thumb |
| Pronator quadratus |
Distal anterior ulna |
Distal anterior radius |
Anterior interosseous (from median, C8-T1) |
Pronates forearm |
Hand Muscles
| Muscle |
Origin |
Insertion |
Innervation |
Action |
| Abductor pollicis brevis |
Scaphoid, trapezium, flexor retinaculum |
Lateral base of proximal phalanx of thumb |
Median nerve (C8-T1) |
Abducts thumb |
| Flexor pollicis brevis |
Trapezium, flexor retinaculum |
Lateral base of proximal phalanx of thumb |
Median nerve (superficial head, C8-T1), Ulnar nerve (deep head, C8-T1) |
Flexes thumb at MCP joint |
| Opponens pollicis |
Trapezium, flexor retinaculum |
Lateral shaft of 1st metacarpal |
Median nerve (C8-T1) |
Opposes thumb toward 5th finger |
| Adductor pollicis |
Capitate, 2nd-3rd metacarpals |
Medial base of proximal phalanx of thumb |
Ulnar nerve (C8-T1) |
Adducts thumb |
| Lumbricals (1-4) |
Tendons of flexor digitorum profundus |
Extensor expansions of fingers 2-5 |
Median nerve (1-2, C8-T1), Ulnar nerve (3-4, C8-T1) |
Flex MCP joints, extend IP joints of fingers |
| Dorsal interossei (1-4) |
Adjacent sides of metacarpals |
Proximal phalanges and extensor expansions of fingers 2-4 |
Ulnar nerve (C8-T1) |
Abduct fingers, flex MCP joints, extend IP joints |
| Palmar interossei (1-3) |
Metacarpals 2, 4, 5 |
Proximal phalanges and extensor expansions of fingers 2, 4, 5 |
Ulnar nerve (C8-T1) |
Adduct fingers toward middle finger, flex MCP joints, extend IP joints |
Hip Muscles
| Muscle |
Origin |
Insertion |
Innervation |
Action |
| Iliopsoas (Psoas major & Iliacus) |
Psoas: T12-L5 vertebrae; Iliacus: Iliac fossa |
Lesser trochanter of femur |
Lumbar plexus (L1-L3) |
Flexes hip |
| Gluteus maximus |
Posterior ilium, sacrum, coccyx, thoracolumbar fascia |
Gluteal tuberosity of femur, iliotibial tract |
Inferior gluteal nerve (L5-S2) |
Extends and laterally rotates hip |
| Gluteus medius |
Lateral surface of ilium |
Greater trochanter of femur |
Superior gluteal nerve (L4-S1) |
Abducts and medially rotates hip; stabilizes pelvis during gait |
| Gluteus minimus |
Lateral surface of ilium |
Greater trochanter of femur |
Superior gluteal nerve (L4-S1) |
Abducts and medially rotates hip; stabilizes pelvis during gait |
| Tensor fasciae latae |
Anterior iliac crest, ASIS |
Iliotibial tract |
Superior gluteal nerve (L4-S1) |
Flexes, abducts, and medially rotates hip; stabilizes knee |
| Adductor magnus |
Inferior pubic ramus, ischial tuberosity |
Linea aspera, adductor tubercle of femur |
Obturator nerve (L2-L4), Sciatic nerve (ischial part, L4) |
Adducts hip, anterior part flexes hip, posterior part extends hip |
| Adductor longus |
Anterior pubis |
Middle third of linea aspera of femur |
Obturator nerve (L2-L4) |
Adducts, flexes, and assists in medial rotation of hip |
| Adductor brevis |
Inferior pubic ramus |
Proximal linea aspera of femur |
Obturator nerve (L2-L4) |
Adducts, flexes, and assists in medial rotation of hip |
| Gracilis |
Inferior pubic symphysis and ramus |
Medial proximal tibia |
Obturator nerve (L2-L3) |
Adducts hip, flexes knee, assists in medial rotation of flexed knee |
Thigh Muscles
| Muscle |
Origin |
Insertion |
Innervation |
Action |
| Quadriceps Femoris: |
|
|
|
|
| - Rectus femoris |
Anterior inferior iliac spine, superior acetabular rim |
Patella, tibial tuberosity via patellar ligament |
Femoral nerve (L2-L4) |
Extends knee, flexes hip |
| - Vastus lateralis |
Greater trochanter, linea aspera of femur |
Patella, tibial tuberosity via patellar ligament |
Femoral nerve (L2-L4) |
Extends knee |
| - Vastus medialis |
Linea aspera of femur |
Patella, tibial tuberosity via patellar ligament |
Femoral nerve (L2-L4) |
Extends knee |
| - Vastus intermedius |
Anterior and lateral femur |
Patella, tibial tuberosity via patellar ligament |
Femoral nerve (L2-L4) |
Extends knee |
| Hamstrings: |
|
|
|
|
| - Biceps femoris |
Long head: ischial tuberosity; Short head: linea aspera of femur |
Head of fibula, lateral condyle of tibia |
Tibial portion of sciatic nerve (long head, L5-S2), Common fibular portion of sciatic nerve (short head, L5-S2) |
Flexes knee, extends hip, laterally rotates leg when knee is flexed |
| - Semitendinosus |
Ischial tuberosity |
Medial proximal tibia |
Tibial portion of sciatic nerve (L5-S2) |
Flexes knee, extends hip, medially rotates leg when knee is flexed |
| - Semimembranosus |
Ischial tuberosity |
Medial condyle of tibia |
Tibial portion of sciatic nerve (L5-S2) |
Flexes knee, extends hip, medially rotates leg when knee is flexed |
| Sartorius |
Anterior superior iliac spine (ASIS) |
Medial surface of proximal tibia |
Femoral nerve (L2-L3) |
Flexes, abducts, and laterally rotates hip; flexes knee |
Leg Muscles
| Muscle |
Origin |
Insertion |
Innervation |
Action |
| Tibialis anterior |
Lateral tibia, interosseous membrane |
Medial cuneiform, base of 1st metatarsal |
Deep fibular nerve (L4-L5) |
Dorsiflexes and inverts foot |
| Extensor digitorum longus |
Lateral condyle of tibia, anterior fibula, interosseous membrane |
Middle and distal phalanges of toes 2-5 |
Deep fibular nerve (L5-S1) |
Extends toes 2-5, assists in dorsiflexion and eversion |
| Gastrocnemius |
Medial and lateral condyles of femur |
Calcaneus via Achilles tendon |
Tibial nerve (S1-S2) |
Plantarflexes ankle, assists in knee flexion |
| Soleus |
Posterior tibia and fibula |
Calcaneus via Achilles tendon |
Tibial nerve (S1-S2) |
Plantarflexes ankle |
| Fibularis (Peroneus) longus |
Head and lateral fibula |
Medial cuneiform, base of 1st metatarsal |
Superficial fibular nerve (L5-S2) |
Everts foot, assists in plantarflexion |
| Fibularis (Peroneus) brevis |
Lateral fibula |
Base of 5th metatarsal |
Superficial fibular nerve (L5-S2) |
Everts foot, assists in plantarflexion |
| Tibialis posterior |
Posterior tibia and fibula, interosseous membrane |
Navicular, cuneiforms, cuboid, metatarsals 2-4 |
Tibial nerve (L4-L5) |
Inverts foot, assists in plantarflexion |
| Flexor hallucis longus |
Posterior fibula, interosseous membrane |
Distal phalanx of big toe |
Tibial nerve (S2-S3) |
Flexes big toe, assists in plantarflexion and inversion |
| Flexor digitorum longus |
Posterior tibia |
Distal phalanges of toes 2-5 |
Tibial nerve (S2-S3) |
Flexes toes 2-5, assists in plantarflexion and inversion |