Question | Answer |
Frontalis | Origin: Aponeurosis
Insertion: Skin of eyebrow
Action: Elevates eyebrows; Wrinkles forehead |
Orbicularis oculi | Origin: Frontal & maxillary bones
Insertion: Tissue of eyelids
Action: Closes eyes as in blinking |
Buccinator | Origin: Maxilla & mandible
Insertion: Orbicularis oris
Action: Compresses cheeks inward (whistling and sucking) |
Zygomaticus | Origin: Zygomatic bone
Insertion: Skin & muscle at corner of mouth
Action: Raises corners of mouth (smiling) |
Orbicularis oris | Origin: Maxilla & mandible
Insertion: Skin & muscle around mouth
Action: Puckers & closes the lips |
Temporalis | Origin: Temporal bone
Insertion: Mandible (coronoid process)
Action: Elevates mandible |
Masseter | Origin: Zygomatic arch
Insertion: Mandible (ramus)
Action: Elevates mandible |
Sternocleidomastoid | Origin: Sternum (manubrium); Clavicle
Insertion: Temporal bone (mastoid process)
Action: Rotates the head to the opposite side (one); Flexes head (both) |
Trapezius | Origin: Occipital bone; Thoracic vertebrae
Insertion: Clavicle; Scapula (spine & acromion process)
Action: Elevates & adducts scapula; Extends neck |
Levator scapulae | Origin: Vertebrae (upper cervical)
Insertion: Superior scapula
Action: Elevates & adducts scapula at superior angle |
Rhomboid major & minor | Origin: Vertebrae (C7-T5)
Insertion: Scapula (medial border)
Action: Adducts scapula |
Pectoralis minor | Origin: Ribs (3-5)
Insertion: Scapula (coracoid process)
Action: Oulls scapula downward & forward (abduct) |
Serratus anterior | Origin: Ribs (upper 8)
Insertion: Scapula (anterior vertebral border)
Action: Pulls scapula against the chest wall |
Supraspinatus | Origin: Scapula (supraspinous fossa)
Insertion: Humerus (greater tubercle)
Action: Hold head of humerus stable in glenoid cavity; Abduction of humerus (30°) |
Infraspinatus | Origin: Scapula (infraspinous fossa)
Insertion: Humerus (greater tubercle)
Action: Hold head of humerus stable in glenoid cavity; Lateral rotation & adduction of humerus |
Teres minor | Origin: Scapula (axillary border)
Insertion: Humerus (greater tubercle)
Action: Hold head of humerus stable in glenoid cavity; Lateral rotation of humerus |
Subscapularis | Origin: Scapula (subscapular fossa)
Insertion: Humerus (lesser tubercle)
Action: Hold head of humerus stable in glenoid cavity; Medial rotation |
Pectoralis major | Origin: Clavicle, sternum & ribs (1-6)
Insertion: Humerus (intertubercular groove)
Action: Adducts, flexes & medially rotates humerus at shoulder joint |
Deltoid | Origin: Lateral clavicle; scapula (spine & acromion process)
Insertion: Humerus (deltoid tuberosity)
Action: Abducts, flexes & medially rotates humerus at shoulder joint |
Coracobrachialis | Origin: Scapula (coracoid process)
Insertion: Humerus (shaft)
Action: Adducts & flexes humerus at shoulder joint (synergist to pectoralis major) |
Latissimus dorsi | Origin: Vertebrae (lumbodorsal fascia); Iliac crest & ribs (lower 4)
Insertion: Humerus (intertubercular groove)
Action: Adducts, extends & medially rotates humerus at shoulder joint |
Teres major | Origin: Scapula (inferior border & lateral border)
Insertion: Humerus (intertubercular groove)
Action: Adducts, extends & medially rotates humerus at shoulder joint (synergist to latissimus dorsi) |
Biceps brachii | Origin: Short head - Scapula (coracoid process); Long head - Scapula (supraglenoid tubercle)
Insertion: Radius (radial tuberosity)
Action: Flexes forearm at elbow (synergist to brachiallis); Supinates forearm |
Barchialis | Origin: Humerus (anterior shaft)
Insertion: Ulna (coronoid process)
Action: Flexes forearm at elbow |
Brachioradialis | Origin: Humerus (lateral supracondylar ridge)
Insertion: Radius (styloid process)
Action: Flexes forearm at elbow (synergist to biceps brachii) |
Triceps brachii
(long, lateral, medial) | Origin: Scapula (infraglenoid tubercle); Posterior proximal humerus
Insertion: Ulna (olecranon process)
Action: Extends forearm at elbow |
Flexor carpi muscles
(radialis, ulnaris) | Origin: Humerus (medial epicondyle)
Insertion: Metacarpals
Action: Flex hand at wrist |
Flexor digitorum muscles
(superficialis, profundus, flexor pollicis) | Origin: Distal humerus; Proximal radius or ulna
Insertion: Middle or distal phalanges
Action: Flex the fingers |
Extensor carpi muscles
(radialis, ulnaris) | Origin: Distal, lateral humerus
Insertion: Metacarpals
Action: Extend hand at wrist |
Extensor digitorum | Origin: Humerus (lateral epicondyle)
Insertion: Distal phalanges
Action: Extends the hands & fingers |
Rectus abdominis | Origin: Pubic bone (crest & symphysis)
Insertion: Sternum (xiphoid process); Ribs (costal cartilages of ribs 5-7)
Action: Flexes & rotates lumbar vertebrae; Stabilizes pelvis |
External oblique | Origin: Ribs (lower 8)
Insertion: Ilium (iliac crest); Linea alba
Action: Flexes vertebrae & compresses abdomen; Lateral trunk flexion & rotation |
Internal oblique | Origin: Ilium (iliac crest)
Insertion: Pubic bone & lower ribs; Linea alba
Action: Flexes vertebrae & compresses abdomen; Lateral trunk flexion & rotation |
Tansversus abdominis | Origin: Ilium (iliac crest); Ribs (lower 6)
Insertion: Pubic bone; Linea alba
Action: Compresses abdomen |
External intercostals | Origin: Inferior border of rib above
Insertion: Superior border of rib below
Action: Pulls ribs towards one another to elevate rib cage; Aid in inspiration (synergist to diaphragm) |
Internal intercostals | Origin: Superior border of rib below
Insertion: Inferior border of rib above
Action: Draws ribs together to depress rib cage |
Diaphragm | Origin: Inferior border of rib cage & sternum; Margins of thoracic cage
Insertion: Central tendon of diaphragm
Action: Contract to cause inspiration |
Sartorius | Origin: Ilium (anterior superior iliac spine)
Insertion: Tibia (medial surface)
Action: Flexes & laterally rotates thigh; Flexes knee |
Tensor fasciae latae | Origin: Ilium (iliac crest)
Insertion: Iliotibial tract
Action: Flexes & abducts thigh; Rotates thigh medially |
Iliopsoas | Origin: Ilium; Lumbar vertebrae
Insertion: Femur (lesser trochanter)
Action: Flexes thigh towards the trunk; Rotates thigh laterally |
Gluteus maxiumus | Origin: Posterior ilium; Sacrum & coccyx
Insertion: Femur (gluteal tuberosity); Iliotibial tract
Action: Extends thigh at the hip; Rotates thigh laterally |
Gluteus medius | Origin: Ilium (lateral surface)
Insertion: Femur (greater trochanter)
Action: Abducts & medially rotates thigh |
Gluteus minimus | Origin: Ilium (lateral surface)
Insertion: Femur (greater trochanter)
Action: Abducts & medially rotates thigh |
Adductor longus | Origin: Pubic bone (pubic symphysis)
Insertion: Femur (linea aspera)
Action: Adducts, flexes & medially rotates thigh |
Adductor brevis (humans)
Adductor femoris (cats) | Origin: Pubic bone (inferior ramus)
Insertion: Femur (linea aspera)
Action: Adducts, flexes & medially rotates thigh |
Adductor magnus | Origin: Ischium & pubic bone
Insertion: Femur (adductor tubercle & linea aspera)
Action: Adducts, flexes & medially rotates thigh (anterior part); Extends thigh (posterior part) |
Pectineus | Origin: Pubic bone (pubic spine)
Insertion: Posterior femur
Action: Adducts, flexes & medially rotates thigh |
Gracilis | Origin: Pubic bone (pubic symphysis)
Insertion: Tibia (proximal medial surface)
Action: Adducts thigh; Flexes & medially rotates leg |
QUADRICEPS
Rectus femoris | Origin: Ilium (iliac spine)
Insertion: Patella & tibia via the patellar ligament
Action: Extends leg at knee & flexes thigh at hip |
QUADRICEPS
Vastus lateralis | Origin: Femur (greater trochanter)
Insertion: Patella & tibia via the patellar ligament
Action: Extends leg at knee |
QUADRICEPS
Vastus medialis | Origin: Femur (medial surface)
Insertion: Patella & tibia via the patellar ligament
Action: Extends leg at knee; Stabilizes patella |
QUADRICEPS
Vastus intermedius | Origin: Femur (anterior & lateral surface)
Insertion: Patella & tibia via the patellar ligament
Action: Extends leg at knee |
HAMSTRINGS
Biceps femoris
(2 heads) | Origin: Long head - Ischium (ischial tuberosity); Short head - Femur (linea aspera)
Insertion: Tibia (lateral condyle); Fibula (head)
Action: Flexes & rotates leg laterally; Extends thigh |
HAMSTRINGS
Semitendinosus | Origin: Ischium (ischial tuberosity)
Insertion: Tibia (upper medial surface of shaft)
Action: Flexes & rotates leg medially; Extends thigh |
HAMSTRINGS
Semimembranosus | Origin: Ischium (ischial tuberosity)
Insertion: Tibia (medial condyle)
Action: Flexes & rotates leg medially; Extends thigh |
Tibialis anterior | Origin: Tibia (lateral condyle & surface)
Insertion: Medial cuneiform & 1st metatarsal
Action: Dorsiflexes & inverts foot at angle |
Extensor digitorum longus | Origin: Tibia (lateral condyle)
Insertion: Middle & distal phalanges
Action: Dorsiflexes foot at ankle; Extends toes |
Fibularis (Peroneus) longus | Origin: Fibula (head)
Insertion: By tendon curving under the foot to 1st metatarsal & medial cuneiform
Action: Plantar flexes & everts foot at ankle |
Gastrocnemius
(2 heads) | Origin: Femur (lateral & medial condyles)
Insertion: Calcaneus via calcaneal (Achilles) tendon
Action: Plantar flexes at ankle; Flexes leg at knee |
Soleus | Origin: Tibia (posterior surface); Fibula (posterior surface)
Insertion: Calcaneus via calcaneal (Achilles) tendon
Action: Plantar fleses foot at ankle |
Flexor digitorum longus
(tendon posterior to medial malleolus) | Origin: Tibia (posterior surface)
Insertion: Distal phalanges of toes 2-5
Action: Plantar flexes & inverts foot at ankle; Flexes toes |
Tibialis posterior | Origin: Tibia (posterior surface); Fibula (posterior surface)
Insertion: Under foot medially into tarsals & metatarsals
Action: Plantar flexes & inverts foot at ankle |