1. skull
2. mandible
3. cervical spine
4. thoracic spine
5. lumbar spine
6. sacrum
7. ilium bone (pelvis)
8. ischial tuberosity (sit bone)
9. femur
10. patella
11. tibia
12. fibula
13. ribs
14. sternum
15. clavicle
16. scapula
17. humerus
18. radius
19. ulna
20. hindfoot
21. midfoot
22. forefoot
23. carpals (wrist)
24. metacarpals
25. phalanges
The axial skeleton is composed of the skull, spine, and ribcage. It links the upper and lower appendicular skeletons. Thus, the two subdivisions of the skeleton can be used to affect and influence each other.
For example, in Parighasana, connecting the hands to the straight-leg foot laterally flexes the trunk (axial skeleton).
The upper appendicular skeleton is composed of the shoulder (pectoral) girdle and the upper extremities. The shoulder girdle, which is composed of the scapulae and clavicle, connects the arms to the trunk and thereby links the upper appendicular and axial skeletons.
The lower appendicular skeleton is composed of the pelvic girdle and lower extremities. The pelvic girdle is composed of the iliac bones, the ischia, the pubic bones, and the pubic symphysis. The pelvic girdle connects the lower extremities to the axial skeleton.
It is important to understand the subdivisions of the skeleton because the appendicular skeleton can be used to leverage and move the axial skeleton. Put another way, connecting the hand to the foot affects the spine.
Legend
O = Origin. the proximal site where a muscle attaches to a bone.
I = Insertion. the distal site where a muscle attaches to a bone.
A = Action. the joint movement produced when the muscle contracts.
1. Semispinalis capitis
O: Transverse processes of lower cervical and upper thoracic vertebrae.
I: Occipital bone.
A: Extends head (tilts it back), assists in turning head.
2. Splenius capitis
O: Spinous processes of C7 and T1-4.
I: Mastoid process of skull, behind ear.
A: Extends head and neck; when one side contracts, laterally flexes neck; turns head toward side of individual muscle.
1. Quadratus lumborum
O: Posterior (back) of iliac crest.
I: Back part of rib 12, transverse processes of L1-4.
A: Laterally flexes spine (bends to side); extends and stabilizes lumbar spine; stabilizes rib 12, drawing it down during deep inhalation.
2. Multifidus
O: Back of sacrum and posterior superior iliac spine, transverse processes of lumbar, thoracic, and cervical vertebrae (all the way up the spine).
I: Two vertebrae above the vertebrae of origin; fibers are directed diagonally toward the midline and onto the spinous processes of the vertebrae of insertion.
A: Stabilizes spine during extension, flexion, and rotation.
3. Semispinalis thoracis
O: Transverse processes of T6-10.
I: Spinous processes of lower cervical and upper thoracic vertebrae.
A: Extends and rotates upper thoracic and lower cervical spine.
4. Lateral intertransversi
O: Transverse processes of lumbar vertebrae.
I: Transverse process of vertebrae immediately above vertebrae of origin.
A: Laterally flexes lumbar spine.
1. Serratus posterior superior
O: Ligamentum nuchae and spinous processes of C7-T4.
I: Ribs 2-5 on upper border.
A: Expands back of chest during deep inhalation by lifting ribs (is an accessory muscle of breathing).
2. Serratus posterior inferior
O: Spinous processes of T11-12, L1-3, thoracolumbar fascia.
I: Lower borders of ribs 9-12.
A: Stabilizes lower ribs during inhalation.
3. Spinalis thoracis
O: Transverse processes of T6-10.
I: Spinous processes of C6-7, T1-4.
A: Extends upper thoracic and lower cervical spine.
4. Longissimus thoracis
O: Posterior sacrum, spinous processes of T11-12, L1-5.
I: Transverse processes of T1-12, medial part of ribs 4-12.
A: Laterally flexes and extends spine, aids to expand chest during inhalation.
5. Iliocostalis lumborum
O: Posterior sacrum.
I: Posterior part of ribs 7-12.
A: Laterally flexes and extends lumbar spine.
Transversus abdominis
O: Front of iliac crest, inguinal ligament, thoracolumbar fascia, costal cartilage (front) of ribs 7-12.
I: Xiphoid process of sternum, linea alba (aponeurotic white line at front of abdomen), pubic bone.
A: Supports and compresses abdomen.
Internal oblique
O: Iliac crest, thoracolumbar fascia, inguinal ligament.
I: Lower border of ribs 9-12, linea alba, pubis.
A: Laterally flexes trunk, rotates torso towards side of muscle, compresses abdomen.
External oblique
O: Ribs 5-12.
I: Via aponeurosis onto linea alba at front of abdomen, inguinal ligament, asIs, pubic bone.
A: Laterally flexes trunk, rotates torso away from side of muscle, compresses abdomen.
Rectus abdominis
O: Pubic bone and pubic symphysis.
I: Xiphoid process of sternum, costal cartilage of ribs 5-7.
A: Flexes lumbar spine, stabilizes and draws ribcage downward, stabilizes and tilts pelvis backward (retroversion), compresses abdomen.
1. Teres major
O: Lower lateral border of scapula.
I: Bicipital groove of humerus.
A: Adducts and internally rotates humerus.
2. Latissimus dorsi
O: Thoracolumbar fascia, posterior portion of iliac crest, ribs 9-12, inferior border of scapula.
I: Bicipital groove of humerus.
A: Extends, adducts, and internally rotates humerus.
1. Upper trapezius
O: Occipital bone, ligamentum nuchae.
I: Upper border of spine of scapula.
A: Elevates (lifts) shoulder girdle, with lower trapezius rotates scapula to lift arm overhead.
2. Middle trapezius
O: Spinous processes of C7-T7.
I: Medial edge of acromion, posterior part of lateral third of clavicle.
A: Adducts (retracts) scapula.
3. Lower trapezius
O: Spinous processes of T8-12.
I: Medial edge of acromion, posterior part of lateral third of clavicle.
A: Depresses scapula, aids to hold body in arm balancing, with upper trapezius rotates scapula to lift arm overhead.
1. Levator scapulae
O: Transverse processes of C1-4.
I: Upper medial border of scapula.
A: Elevates scapula.
2. Rhomboid minor
O: Spinous processes of C7 and T1, ligamentum nuchae.
I: Upper medial border of scapula.
A: Adducts (retracts) scapula, depresses lateral border of scapula by elevating medial border.
3. Rhomboid major
O: Spinous processes of T2-5.
I: Medial border of scapula.
A: Adducts (retracts) scapula (opens chest forward).
4. Serratus anterior
O: Ribs 1-9.
I: Anterior (front) surface of scapula on medial border.
A: Draws scapula forward on chest wall, stabilizes scapula during push-up type movements, rotates scapula for abducting and raising arm.
1. Coracohumeral ligament
2. Coracoacromial ligament
3. Acromioclavicular ligament
4. Trapezoid ligament
5. Conoid ligament
6. Glenoid labrum
1. Supraspinatus
O: Supraspinatus fossa of scapula.
I: Greater tuberosity of humerus.
A: Initiates abduction of humerus (raising arm to side), stabilizes head of humerus in socket of shoulder joint.
2. Subscapularis
O: Front surface of scapula in subscapular fossa.
I: Lesser tuberosity of humerus.
A: Internally rotates humerus, stabilizes head of humerus in socket of shoulder joint.
3. Teres minor
O: Upper part of lateral border of scapula.
I: Back and lower part of greater tuberosity of humerus.
A: Externally rotates humerus, stabilizes head of humerus in socket of shoulder joint.
1. Supraspinatus
O: Supraspinatus fossa of scapula.
I: Greater tuberosity of humerus.
A: Initiates abduction of humerus (raising arm to side), stabilizes head of humerus in socket of shoulder joint.
2. Infraspinatus
O: Infraspinatus fossa of scapula.
I: Greater tuberosity of humerus.
A: Externally rotates shoulder.
3. Teres minor
O: Upper part of lateral border of scapula.
I: Back and lower part of greater tuberosity of humerus.
A: Externally rotates humerus, stabilizes head of humerus in socket of shoulder joint.
1. Pectoralis minor
O: Front of ribs 3-5.
I: Coracoid process of scapula.
A: Rolls shoulder forward and down (via scapula), lifts ribcage when scapula is stabilized by rhomboids (expands chest) through closed chain contraction.
2. Sternocleidomastoid
O: Sternal head: manubrium of sternum; clavicular head: upper surface of medial third of clavicle.
I: Mastoid process behind and below ear.
A: When both sides contract together flexes neck and tilts head forward; if head is stabilized, lifts upper ribcage during inhalation; contracting one side tilts head to side of muscle, rotates head to face away from muscle.
1. Pectoralis major
O: Sternocostal head: front of manubrium and body of sternum; clavicular head: medial half of clavicle.
I: Outer edge of bicipital groove on upper humerus.
A: Adducts and internally rotates humerus. Sternocostal head draws humerus down and across the body towards opposite hip. Clavicular head forward flexes and internally rotates the humerus, draws humerus across body towards opposite shoulder.
2. Coracobrachialis
O: Coracoid process of scapula.
I: Inner surface of humerus at mid-shaft.
A: Assists pectoralis in adduction of humerus and shoulder.
Triceps brachii
O: Long head from infraglenoid tubercle at bottom of shoulder socket; medial and lateral heads from posterior surface of humerus and intermuscular septum.
I: Olecranon process of ulna.
A: Extends elbow, long head moves arm back and adducts it.
Brachialis
O: Front part of lower humerus.
I: Coronoid process on front of upper part of ulna.
A: Flexes elbow.
Biceps brachii
O: Long head: upper part of glenoid (socket) of shoulder joint; short head: coracoid process of scapula.
I: Radial tuberosity on upper part of radius.
A: Flexes elbow and supinates forearm.
1. Flexor digitorum profundis
O: Upper two thirds of anterior and medial surface of ulna and interosseous membrane (between radius and ulna).
I: Palmar (anterior) surface of distal phalanges of fingers.
A: Flexes distal phalanges, synergizes flexion of more proximal phalanges and wrist.
2. Flexor pollicis longus
O: Anterior surface of mid-shaft of radius, coronoid process of ulna, medial epicondyle.
I: Palmar (anterior) surface of distal phalanx of thumb.
A: Flexes thumb and synergizes flexion of wrist.
1. Flexor carpi ulnaris
O: Medial epicondyle of humerus, medial border and upper two thirds of ulna.
I: Pisiform bone of wrist, base of fifth metacarpal.
A: Flexes and adducts wrist, synergizes elbow flexion.
2. Flexor carpi radialis
O: Medial epicondyle of humerus.
I: Base of second metacarpal.
A: Flexes and abducts wrist, synergizes elbow flexion and pronation.
Flexor digitorum superfi cialis
O: Medial epicondyle, coronoid process of ulna, upper anterior border of radius.
I: Two slips of tendon insert onto either side of middle phalanges of four fingers.
A: Flexes middle phalanges of fingers, synergizes wrist flexion.
1. Brachioradialis
O: Lateral supracondylar ridge of humerus.
I: Lower outside surface of radius, proximal to styloid process.
A: Flexes elbow.
2. Extensor carpi radialis longus
O: Lateral supracondylar ridge of humerus.
I: Dorsal surface of base of second metacarpal.
A: Extends and abducts wrist.
3. Extensor carpi radialis brevis
O: Lateral epicondyle via common extensor tendon.
I: Dorsal surface of base of third metacarpal.
A: Extends and abducts wrist.
4. Extensor carpi ulnaris
O: Lateral epicondyle via common extensor tendon.
I: Base of fifth metacarpal.
A: Extends and adducts wrist.
1. Extensor digitorum
O: Lateral epicondyle via common extensor tendon.
I: Dorsal surfaces of phalanges of all four fingers.
A: Extends fingers, synergizes finger abduction away from midline.
2. Extensor digiti minimi
O: Lateral epicondyle via common extensor tendon.
I: Combines with tendon of extensor digitorum to insert onto dorsum of little finger.
A: Extends little finger.
1. Abductor pollicis longus
O: Posterior surface of ulna and radius covering middle third of bones, interosseous membrane.
I: Lateral surface of first metacarpal.
A: Extends and abducts thumb, synergist of forearm supination and wrist flexion.
2. Extensor pollicis brevis
O: Posterior surface of distal radius, interosseous membrane.
I: Dorsal surface of base of proximal phalanx of thumb.
A: Extends thumb, synergizes wrist abduction.
3. Extensor pollicis longus
O: Posterior surface of middle third of ulna, interosseous membrane.
I: Dorsal surface at base of distal phalanx of thumb.
A: Extends thumb, synergizes wrist extension.
4. Extensor indicis
O: Posterior surface of distal ulna, interosseous membrane.
I: Dorsal aponeurosis of index finger, onto proximal phalanx.
A: Extends index finger.
1. Dorsal interosseous muscles
O: Two heads, one from each side of adjacent metacarpal bones.
I: Base of proximal phalanx and dorsal digital expansions of fingers.
A: Abduct index and ring fingers away from middle finger, flex metacarpals, extend phalanges.
2. Abductor digiti minimi
O: Pisiform bone.
I: Ulnar side of proximal phalanx of little finger.
A: Abducts little finger.
1. Adductor pollicis
O: Palmar surface of capitate and trapezoid bones of the wrist, second and third metacarpals.
I: Base of proximal phalanx of thumb on ulnar side.
A: Adducts thumb.
2. Flexor pollicis brevis
O: Trapezium and capitate bones of wrist.
I: Base of proximal phalanx of thumb on radial side.
A: Flexes carpometacarpal and metacarpophalangeal joints of thumb, synergizes opposing thumb to little finger.
3. Abductor pollicis brevis
O: Trapezium and scaphoid bones of wrist, flexor retinaculum.
I: Base of proximal phalanx of thumb on radial side.
A: Abducts and moves thumb in palmar direction, synergizes opposing thumb to little finger.
4. Lumbrical muscles
O: Flexor digitorum profundus tendon.
I: Tendon of extensor digitorum.
A: Simultaneous flexion of metacarpophalangeal and extension of interphalangeal joints.
5. Flexor digiti minimi brevis
O: Hamate bone of wrist.
I: Base of proximal phalanx of little finger on ulnar side.
A: Flexes little finger.
6. Abductor digiti minimi
1. Iliolumbar ligament
2. Sacroiliac ligament
3. Sacrospinous ligament
4. Inguinal ligament
1. Iliolumbar ligament
2. Sacroiliac ligament
3. Sacrotuberous ligament
4. Sacrospinous ligament
1. Zona orbicularis (hip capsule)
2. Lateral iliofemoral ligament
3. Anterior iliofemoral ligament
4. Pubofemoral ligament
1. Lateral iliofemoral ligament
2. Ischiofemoral ligament
3. Zona orbicularis (hip capsule)
Gluteus maximus
O: Posterolateral surface of ilium and lateral surface of the sacrum.
I: Upper fibers onto iliotibial tract; lower fibers onto gluteal tuberosity.
A: Extends, externally rotates, and stabilizes hip.
Gluteus medius
O: Outer surface of ilium.
I: Greater trochanter.
A: Abducts hip, anterior fibers internally rotate and flex hip, posterior fibers externally rotate and extend hip.
1. Piriformis
O: Posterior surface of sacrum.
I: Greater trochanter.
A: Externally rotates, abducts, extends, and stabilizes hip.
2. Superior gemellus
O: Ischial spine.
I: Greater trochanter.
A: Externally rotates and adducts hip.
3. Obturator internus
O: Obturator membrane and ischium.
I: Greater trochanter.
A: Externally rotates and adducts hip.
4. Inferior gemellus
O: Ischial tuberosity.
I: Greater trochanter.
A: Externally rotates and adducts hip.
5. Quadratus femoris
O: Ischial tuberosity.
I: Intertrochanteric crest.
A: Externally rotates and adducts hip.
6. Obturator externus
O: Obturator membrane and ischium.
I: Greater trochanter.
A: Externally rotates and adducts hip.
1. Psoas major
O: T12-L4 vertebral bodies and discs.
I: Lesser trochanter.
A: Flexes and externally rotates hip, stabilizes lumbar spine.
2. Iliacus
O: Inner surface of ilium.
I: Lesser trochanter.
A: Flexes and externally rotates hip, with psoas major tilts pelvis forward.
1. Pectineus
O: Pubic bone.
I: Linea aspera of femur.
A: Adducts, externally rotates, and synergizes femur flexion.
2. Adductor brevis
O: Pubic bone.
I: Linea aspera of femur.
A: Adducts and flexes femur, stabilizes pelvis.
3. Adductor longus
O: Pubic bone.
I: Linea aspera of femur.
A: Adducts and flexes femur, stabilizes pelvis.
4. Adductor magnus
O: Pubic bone and ischial tuberosity.
I: Linea aspera and medial epicondyle of femur.
A: Adducts, externally rotates, and extends femur.
5. Gracilis
O: Pubic bone.
I: Medial tibia.
A: Adducts and flexes hip, flexes and internally rotates knee.
1. Adductor magnus
2. Gracilis
1. Knee joint capsule
2. Patellar retinaculum
3. Medial collateral ligament
4. Lateral collateral ligament
1. Biceps femoris long head
O: Ischial tuberosity.
I: Fibular head.
A: Extends hip, flexes and externally rotates knee.
2. Biceps femoris short head
O: Posterior surface of femur.
I: Fibular head.
A: Extends hip, flexes and externally rotates knee.
3. Semitendinosus
O: Ischial tuberosity.
I: Pes anserinus of medial tibia.
A: Extends hip, flexes and internally rotates knee.
4. Semimembranosus
O: Ischial tuberosity.
I: Back of medial tibial condyle.
A: Extends hip, flexes and internally rotates knee.
5. Popliteus
O: Lateral femoral condyle.
I: Posterior surface of tibia, below knee joint.
A: Flexes and internally rotates knee.
Lower leg (anterior view)
1. superior extensor retinaculum
2. Inferior extensor retinaculum
Lower leg (posterior view)
1. Peroneus longus
O: Head and proximal two thirds of lateral fibula.
I: Base of first metacarpal and medial cuneiform.
A: Plantar flexes ankle and everts subtalar joint, supports transverse arch of foot.
2. Peroneus brevis
O: Distal half of lateral surface of fibula, intermuscular membrane.
I: Base of fifth metatarsal.
A: Plantar flexes ankle and everts subtalar joint.
3. Peroneus tertius
O: Front of distal fibula.
I: Base of fifth metatarsal.
A: Dorsiflexes ankle and everts subtalar joint.
Tibialis anterior
O: Upper two thirds of anterior tibia and interosseous membrane.
I: Medial cuneiform, base of first metatarsal.
A: Dorsiflexes ankle, inverts subtalar joint.
1. Gastrocnemius
O: Medial head from medial epicondyle of femur; lateral head from lateral epicondyle.
I: Calcaneous via achilles tendon.
A: Plantar flexes and inverts ankle, flexes knee.
2. Soleus
O: Posterior surface of head and neck of fibula.
I: Calcaneous via achilles tendon.
A: Plantar flexes ankle, inverts subtalar joint, and flexes knee.
Tibialis posterior
O: Interosseous membrane between tibia and fibula.
I: Navicular, cuneiform bones, and second through fourth metatarsals.
A: Plantar flexes ankle, inverts subtalar joint, and supports longitudinal and transverse foot arches.
1. Anterior tibiofi bular ligament
2. Anterior talofi bular ligament
3. Calcaneofi bular ligament
4. Anterior tibiotalar ligament
5. Dorsal metatarsal ligaments
6. Interphalangeal joint capsules
1. Extensor digitorum longus
O: Lateral tibial condyle, fibular head, interosseous membrane.
I: Dorsal aponeurosis and bases of the distal phalanges of second through fifth toes.
A: Dorsiflexes ankle, everts subtalar joint, and extends metatarsophalangeal and interphalangeal joints of toes.
2. Extensor hallucis longus
O: Medial surface of fibula, interosseous membrane.
I: Dorsal aponeurosis and base of distal phalanx of big toe.
A: Dorsiflexes ankle, everts subtalar joint, and extends big toe.
3. Extensor digitorum brevis
O: Dorsal surface of calcaneous.
I: Dorsal aponeurosis and bases of middle phalanges of second through fourth toes.
A: Extends metatarsophalangeal and proximal interphalangeal joints of second through fourth toes.
4. Extensor tendons sheath
1. Adductor hallucis (transverse head)
O: Metatarsophalangeal joints of third through fifth toes.
I: Base of proximal phalanx of big toe via sesamoid.
A: Adducts and flexes big toe, supports transverse foot arch.
2. Adductor hallucis (oblique head)
O: Bases of second through fourth metatarsals, lateral cuneiform, and cuboid.
I: Base of proximal phalanx of big toe via sesamoid.
A: Adducts and flexes big toe, supports longitudinal foot arch.
3. Abductor digiti minimi
O: Calcaneous, plantar aponeurosis.
I: Base of proximal phalanx of little toe.
A: Flexes metatarsophalangeal joint and abducts little toe, supports longitudinal foot arch.
4. Abductor hallucis
O: Calcaneous, plantar aponeurosis.
I: Base of proximal phalanx of big toe.
A: Flexes and abducts big toe, supports longitudinal foot arch.
1. Flexor hallucis longus
O: Posterior surface of fibula, interosseous membrane.
I: Base of distal phalanx of big toe.
A: Plantar flexes ankle, inverts subtalar joint, flexes big toe, supports longitudinal foot arch.
2. Lumbrical muscles
O: Medial borders of flexor digitorum longus tendons.
I: Dorsal aponeurosis of second through fifth toes.
A: Flexes metatarsophalangeal and extends interphalangeal joints of second through fifth toes, adducts toe.
3. Flexor digitorum longus
O: Posterior surface of tibia.
I: Bases of distal phalanges of second through fifth toes.
A: Plantar flexes ankle, inverts subtalar joint, plantar flexes toes.
4. Flexor digitorum brevis
O: Calcaneous, plantar aponeurosis.
I: Middle phalanges of second through fifth toes.
A: Flexes toes, supports longitudinal foot arch.
1. Diaphragm
O: Lower margin of costal arch, posterior surface of xiphoid process of sternum, arcuate ligament of aorta, L1-3 vertebral bodies.
I: Central tendon.
A: Primary muscle of respiration, aids in compressing abdomen.
2. Intercostals
O: Internal intercostals from surface of upper margin of rib; external intercostals from lower margin of rib.
I: Internals insert on lower margin of next higher rib; externals insert on upper margin of next lower rib.
A: Internal intercostals lower ribs during exhalation; externals raise ribs during inhalation.
1. Quadratus lumborum
2. Intercostals
3. Rectus abdominis
1. Sternocleidomastoid
2. Pectoralis minor
3. Serratus anterior
1. Sternocleidomastoid
2. Rhomboids
3. Serratus anterior
4. Quadratus lumborum
1. Serratus posterior superior
2. Serratus posterior inferior