Muscles

• Diaphragm


  O: circumference of thoracic outlet- xiphoid— lower 6 costal cartilages - L1-L3 vertebrae

  I: central tendon of diaphragm

  A: draws central tendon down and forward during quiet inspiration - increases thoracic volume/ decreases pressure/ airflows in

  N: Phrenic - (ventral rami C3 - 5)
• Rectus Abdominis


  O: pubic crest, pubic symphysis

  I: xiphoid process, cartilage ribs 5-7

  A: flexes vertebral column, tenses abdominal wall, depresses ribs

  N: intercostal nerves T7-T11 and subcostal nerve
• External abdominal oblique


  O: external inferior 8 lower ribs

  I: iliac crest, ASIS, aponeurosis, pubic body

  A: abdominal compression, bilateral flexion of the vertebral column, unilateral rotation and bending

  N: intercostal (T7-T11) subcostal nerve, iliohypogastic and ilioinguinal nerves
• Internal oblique


  O: inguinal ligaments iliac crest, thoracolumbar fascia

  I: last 3-4 costal cartilages, linea alba, pectineal line, broad aponeurosis

  A: compresses abdominal contents, bilaterally flexes, unilaterally rotates and bends

  N: intercostal (T7-T11), subcostal, iliohypogastric and ilioinguinal nerves
• Transversus Abdominis


  O: lower costal cartilages iliac crest, inguinal ligament

  I: aponeurosis, pubic symphysis

  A: abdominal compression

  N: intercostal nerves (T7-T11):subcostal nerve and iliohypogastic and ilioinguinal
• cremaster muscle


  O: middle of inguinal ligament

  I: pubic tubercle and crest, cremasteric fascia

  A: draws testis upward

  N: Genitofemoral nerve (L1-L2)
• Quadratus lumborum


  O: transverse processes of L3 - L5, iliolumbar ligament andiliac crest

  I: lower borders of ribs and transverse processes L1-L3

  A: laterally bends lumbar column and helps extend lumbar spine

  N: subcostal nerve and branches of L1-L3
• iliopsoas

  O: transverse lumbar vertebrae, sides and discs of T12-L5

  I: lesser trochanter

  A:flexes hip, trunk, abducts hip, ER hip

  N: lumbar ventral rami L1-L3
• Iliacus


  O: iliac fossa

  I: lesser trochanter

  A: flexes hip, trunk, abducts hip, ER hip

  N: femoral nerve (L2-L4)
• External intercostals


  O: lower border of rib

  I: upper border of rib below

  A: elevate during inspiration

  N: intercostal nerves
• Internal intercostals


  O: inner lower rib

  I: upper border of rib below

  A: depresses during expiration

  N: intercostal nerves
• Muscles of the Forearm - Anterior Superficial


  • Pronator Teres
  • Flexor Carpi Radialis
  • Palmaris Longus
  • Flexor Carpi Ulnaris
  • Flexor Digitorum Superficialis
• Muscles of the Forearm - Anterior Deep


  • Flexor Digitorum Profundus
  • Flexor Pollicis Longus
  • Pronator Quadratus
• Muscles of the Forearm - Posterior Superficial


  • Brachioradialis
  • Extensor Carpi Radialis Longus
  • Extensor Carpi Radialis Brevis
  • Extensor Digitorum
  • Extensor Digiti Minimi
  • Extensor Carpi Ulnaris
• Muscles of the Forearm - Posterior Deep


  • Supinator
  • Abductor Pollicis Longus
• Extensor Carpi Ulnaris (ECU)


  • Origin: Lateral epicondyle of humerus and posterior border of ulna
  • Insertion: Base of 5th metacarpal (medial side)
  • Innervation: Posterior Interosseous Nerve (from Radial Nerve) (C7, C8)
  • Action: Extends and adducts the hand at wrist joint
• Supinator


  • Origin: Lateral epicondyle of humerus, radial collateral ligament, annular ligament, supinator fossa, crest of the ulna
  • Insertion: Proximal third of radius (lateral, posterior, and anterior surfaces)
  • Innervation: Deep radial nerve (C7, C8)
  • Action: Supinates the forearm
• Abductor Pollicis Longus (AbPL)


  • Origin: Posterior aspect of ulna, radius, and interosseous membrane
  • Insertion: Base of the proximal phalanx of digit I (thumb)
  • Innervation: Posterior Interosseous Nerve (from Radial Nerve) (C7, C8)
  • Action: Abducts, extends, and laterally rotates the pollex (thumb) at carpometacarpal (CMC) joint
• Extensor Pollicis Brevis (EPB)


  • Origin: Posterior surface of radius and interosseous membrane
  • Insertion: Base of the proximal phalanx of digit I (thumb)
  • Innervation: Posterior Interosseous Nerve (from Radial Nerve) (C7, C8)
  • Action: Extends the proximal phalanx of pollex (thumb) at the MCP joint, extends wrist and CMC joint
• Extensor Pollicis Longus (EPL)


  • Origin: Posterior surface of ulna and interosseous membrane
  • Insertion: Base of the distal phalanx of digit I (thumb)
  • Innervation: Posterior Interosseous Nerve (from Radial Nerve) (C7, C8)
  • Action: Extends the distal phalanx of the thumb at the IP joints, extends wrist, CMC and MCP joints, contributes the adduction of thumb
• Extensor Indicis (EI)


  • Origin: Posterior surface of ulna and interosseous membrane
  • Insertion: Extensor expansion of digit II
  • Innervation: Posterior Interosseous Nerve (from Radial Nerve) (C7, C8)
  • Action: Extends all joints of digit II (index finger)
• Abductor Pollicis Brevis (AbPB)


  • Origin: Flexor retinaculum and tubercles of scaphoid and trapezium
  • Insertion: Lateral side of base of proximal phalanx of digit I (thumb)
  • Innervation: Recurrent branch of the Median Nerve (C8, T1)
  • Action: Abducts the pollex (thumb) at the carpometacarpal joint and metacarpophalangeal joint
• Flexor Pollicis Brevis (FPB)


  • Origin: Flexor retinaculum and tubercles of scaphoid and trapezium
  • Insertion: Lateral side of the 1st metacarpal and base of proximal phalanx of digit I (thumb)
  • Innervation: Recurrent branch of the Median Nerve (C8, T1)
  • Action: Flexes the proximal phalanx of the pollex (thumb) at the metacarpophalangeal joint; indirectly rotates metacarpal I at the carpometacarpal joint
• Opponens Pollicis


  • Origin: Flexor retinaculum and tubercles of scaphoid and trapezium, deep to AbPB and FPB
  • Insertion: Lateral side of 1st metacarpal
  • Innervation: Recurrent branch of the Median Nerve (C8, T1)
  • Action: Pulls and rotates 1st metacarpal across palm in a medial fashion, opposing the thumb and digit V
• Adductor Pollicis


  • Origin: Oblique head- base of metacarpals II and III and capitate bone, Transverse head- anterior surface of body of metacarpal III
  • Insertion: Base of proximal phalanx of digit I (thumb)
  • Innervation: Deep branch of ulnar nerve (C8, T1)
  • Action: Adducts the proximal phalanx of the pollex (thumb)
• Abductor Digiti Minimi


  • Origin: Pisiform
  • Insertion: Medial side of base of proximal phalanx of digit V
  • Innervation: Deep branch of ulnar nerve (C8, T1)
  • Action: Abducts digit V
• Flexor Digiti Minimi


  • Origin: Hook of hamate bone and flexor retinaculum
  • Insertion: Medial side of base of proximal phalanx of digit V
  • Innervation: Deep branch of ulnar nerve (C8, T1)
  • Action: Flexes proximal phalanx of digit V at the metacarpophalangeal joint
• Opponens Digiti Minimi


  • Origin: Hook of hamate bone and flexor retinaculum, deep to abductor digiti minimi and flexor digiti minimi
  • Insertion: Medial side of base of proximal phalanx of digit V
  • Innervation: Deep branch of ulnar nerve (C8, T1)
  • Action: Abducts, flexes, and laterally rotates metacarpal V, opposing the little finger to the thumb
• Lumbricals 1-2 (lateral, radial)


  • Origin: From the two lateral tendons of flexor digitorum profundus
  • Insertion: Lateral sides of the extensor expansions of digits II and III
  • Innervation: Recurrent branch of the Median Nerve (C8, T1)
  • Action: Flex metacarpophalangeal joints and extend interphalangeal joints
• Lumbricals 3-4 (medial, ulnar)


  • Origin: From the two medial tendons of flexor digitorum profundus
  • Insertion: Lateral sides of the extensor expansions of digits IV and V
  • Innervation: Deep branch of ulnar nerve (C8, T1)
  • Action: Flex metacarpophalangeal joints and extend interphalangeal joints
• Palmar Interossei (3)


  • Origin: Palmar surfaces of metacarpals II, IV, and V, Unipennate muscles
  • Insertion: Extensor expansions and base of proximal phalanx of digits II, IV, and V
  • Innervation: Deep branch of ulnar nerve (C8, T1)
  • Action: Adduct digits II, IV, and V at the metacarpophalangeal joint; assist in flexion of MP joint and extension of IP joints
• Dorsal Interossei (4)


  • Origin: From adjacent sides of metacarpals I-V, Bipennate muscles
  • Insertion: Extensor expansions and base of proximal phalanx of digits II, III, and IV
  • Innervation: Deep branch of ulnar nerve (C8, T1)
  • Action: Abduct digits II, III, and IV; assist in flexion of MP joint and extension of IP joints
• Splenius Capitus


  • Origin: Nuchal ligament and spinous processes of C7-T6
  • Insertion: Mastoid process of temporal, and lateral third of superior nuchal line of occipital
  • Innervation: Dorsal rami
  • Action: Unilateral- Lateral bend and rotate head to same side, Bilateral- Extend neck
• Splenius Cervicis


  • Origin: Nuchal ligament and spinous processes of C7-T6
  • Insertion: Transverse processes of C1-C3 (or C4)
  • Innervation: Dorsal rami
  • Action: Unilateral- Laterally bend and rotate head to same side, Bilateral- Extend neck
• Spinalis


  • Origin: Broad common tendon, Spinous processes and suprasinous ligaments
  • Insertion: Spinous processes and supraspinous ligament
  • Innervation: Thoracis, cervicis, capitis sections, Dorsal rami
  • Action: Unilateral- lateral bend- ipsilateral, Bilateral- extends vertebral column and head
• Longissimus


  • Origin: Broad common tendon, posterior sacrum, spinous and transverse processes of vertebra
  • Insertion: Ribs between tubercles and angles, transverse process of vertebrae, mastoid process of temporal
  • Innervation: Thoracis, cervicis, capitis sections, Dorsal rami
  • Action: Unilateral- lateral bend- ipsilateral, Bilateral- extends vertebral column and head
• Iliocostalis


  • Origin: Broad common tendon, posterior sacrum, posterior iliac crest, sacroiliac ligaments, spinous processes of vertebrae
  • Insertion: Angles of lower ribs, cervical transverse processes
  • Innervation: Lumborus, thoracis, cervicis sections, Dorsal rami
  • Action: Unilateral- lateral bend- ipsilateral, Bilateral- extends vertebral column and head
• Semispinalis


  • Origin: Transverse processes of C4-T10
  • Insertion: Occiput, spinous processes in upper thoracic and cervical regions
  • Innervation: Capitis, cervicis, thoracis sections, Dorsal rami
  • Action: Extends head, cervical and thoracic regions, rotates them contralateral
• Multifidus


  • Origin: Posterior sacrum, PSIS, aponeurosis of erector spinae, SI ligaments, transverse processes of lumbar and thoracic vertebrae
  • Insertion: Spinous processes entire length, Thickest in lumbar, ends around C2-3
  • Innervation: Dorsal rami
  • Action: Unilateral rotates to contralateral, stabilizes vertebrae during local movements of column
• Rotatores


  • Origin: Transverse processes
  • Insertion: Junction of lamina and process or spinous process, Best developed in thoracic region
  • Innervation: Dorsal rami
  • Action: May be proprioceptors, stabilize vertebrae, assist with local extension and rotation