MUSCLE | ORIGIN | INSERTION | INNERVATION | ACTION(S) |
Rectus Abdominis | Pubic symphysis & pubic crest | Xiphoid process and 5-7 costal cartilage | N/A (rec) | Flexes trunk (lumbar) and compress abdominal viscera; stabilizes and controls pelvis tilt |
Pyramidalis | Anterior surface of pubis and anterior pubic ligament | Linea alba | N/A (pyr) | Tenses linea alba |
Serratus posterior superior | Lower part of ligamentum nuchae & spinous processes of C7-T2/3 | 2nd-5th ribs | First 3 or 4 intercostal nerves | Assists in elevating ribs, increasing size of thorax |
Serratus posterior inferior | T11 - L2 spinous processes | 9th - 12th ribs | 9th - 12th intercostal nerves | Draws lower ribs downwards to enlarge thoracic cavity & stabilize ribs against pull of diaphragm |
Splenius capitis | Lower half of ligamentum nuchae & spinous process of C7 & T1-T3/4 | Mastoid process and occipital bone | Dorsal rami of middle & inferior cervical spinal nerves | Unilateral: rotates head and cervical spine towards same side of the muscle
Bilateral: assist in extension of head and neck |
Splenius cervicis | Spinous processes of T3 - T6 | Transverse processes of C1 & C2-C4 | Dorsal rami of middle & inferior cervical spinal nerves | Unilateral: rotates head and cervical spine toward same side of the muscle
Bilateral: assist in extension of head and neck |
Erector spinae | Posterior surface of sacrum, iliac crest, and spinous processes of T11 - L5 | Split into subgroups - next | Dorsal rami of spinal nerves | Extends thoracic vertebral column |
1. Iliocostalis lumborum | Iliac crest and sacrum | Slips into lower 6/7 ribs | Dorsal rami of spinal nerves | Extends thoracic vertebral column |
1. Iliocostalis thoracis | Upper border of lower 6/7 ribs (medial to IL insertion) | Lower borders of upper 6 ribs | Dorsal rami of spinal nerves | Extends thoracic vertebral column |
1. Iliocostalis cervicis | Angles of upper 6 ribs (medial to IT insertion) | Transverse processes of C4-C6 | Dorsal rami of spinal nerves | Extends thoracic vertebral column |
2. Longissimus thoracis | Common tendon of erector spinae | Lower 9 or 10 ribs and adjacent transverse processes | Dorsal rami of spinal nerves | Extends thoracic vertebral column |
2. Longissimus cervicis | Transverse processes of T1 - T4/6 | Transverse processes of C2-C6 | Dorsal rami of spinal nerves | Extends thoracic vertebral column |
2. Longissimus capitis | Medial to superior end of cervicis | Mastoid process (lateral) | Dorsal rami of spinal nerves | Extends thoracic vertebral column |
3. Spinalis thoracis | Common tendon and spinous processes of T11 - L2 | Upper thoracic spinous processes (T1 - T4) | Dorsal rami of spinal nerves | Extends thoracic vertebral column |
3. Spinalis cervicis | Ligamentum nuchae and spinous processes of C7 - T1/2 | Spinous processes of axis (maybe 3/4) | Dorsal rami of spinal nerves | Extends thoracic vertebral column |
3. Spinalis capitis | Not a separate muscle - medial part of the semispinalis capitis | N/A | N/A | N/A |
Transversospinalis Muscles (TM): Semispinalis capitis | Transverse processes of T1-T6/7 and articular process of lower cervical vertebrae | Occipital bone | N/A(sem cap) | Extend head (keep head upright) |
TM: Semispinalis cervicis | Transverse processes of T1-T5/6 | Spinous processes of C2-C5 (mostly C2) | N/A (sem cer) | Extend spine |
TM: Semispinalis thoracis | Transverse processes of T7 - T12 | Spinous processes of C6 - T4 | N/A (sem tho) | Extend spine |
Deep to semispinalis muscles | Sacrum and transverse processes of lumbar to lower cervical vertebrae | Spinous processes of lumbar vertebrae to C2 | N/A (deep) | Bilaterally: extend spine
Unilaterally: rotate spine towards opposite side and lateral flexion |
Rotatores (Rotators) | Single transverse process | Singles spinous process | N/A (rot) | Rotate and extend spine |
Anterior group of leg | N/A | N/A | Femoral nerve | Flexion at hip and extension at knee |
Medial/Adductor group of leg | N/A | N/A | Obturator nerve | Adduction and flexion of thigh |
Posterior group of leg | N/A | N/A | Sciatic nerve | Extension at hip and flexion at knee |
Ant: Sartorius | ASIS (anterior superior iliac spine) | Medial surface of shaft of tibia (below tibial tuberosity) | Femoral nerve | Flexion at the hip, flexion at the knee, lateral rotation of thigh & (abduction of thigh) |
Ant: Tensor fascia lata | Iliac crest | Iliotibial tract | Superior gluteal nerve | Assist in flexion of thigh at hip and medially rotates thigh as it flexes (occurs during locomotion - swing phase) |
Ant: Rectus femoris | Anterior inferior iliac spine and ilium above acetabulum | Upon patella and through patellar ligament to tibial tuberosity | Femoral nerve | Extension of leg at knee, only quadriceps to cross hip joint and so it flexes thigh at hip too |
Ant: Vastus medialis | Medial lip of linea aspera (posterior) and lower part of intertochanteric line (anterior) | Patella (pulls through patellar ligament) | Femoral nerve | Extend the leg at the knee |
Ant: Vastus lateralis | Lateral lip of linea aspera (posterior) and intertochanteric line (anterior) | Patella (pulls though patellar ligament) | Femoral nerve | Extend the leg at the knee |
Ant: Vastus intermedialis | Anterior and lateral surface of femur shaft | Patella (pulls through patellar ligament) | Femoral nerve | Extend the leg at the knee |
Ant: Articularis genus | Distal part of anterior femoral surface | Upper part of synovial membrane of knee joint | Nerve to vastus intermedius | Draws synovial membrane upwards as leg extends (to prevent it from getting pinched in between the two bones) |
Ant: Psoas major | Anteriolateral aspect of lumbar vertebral bodies and transverse processes of lumbar vertebrae | Lesser trochanter (medial surface of thigh) | L2-L4 ventral rami | Strong flexor at hip |
Ant: Iliacus | Inner surface of ilium | Lesser trochanter (medial surface of thigh) | Femoral nerve | Strong flexor at hip |
Med: Pectineus | Superior ramis of pubis | Femur below lesser trochanter | Usually femoral, sometimes obturator | Flex and adduct thight at hip (during swing phase, helps keeps leg in line - natural to step medially) |
Med: Adductor longus | Pubic tubercle | Medial lip of linea aspera | Obturator nerve | Adducts and flexes thigh |
Med: Adductor brevis | Body and inferior ramus of pubis | Lower part of line between lesser trochanter and linea aspera & upper portion of linea aspera | Obturator nerve | Flex and adduct thigh |
Med: Adductor magnus | Inferior ramus of pubis, ramus of ischium, and ischial tuberosity | Entire length of the linea aspera, adductor tubercle (from ischial tuberosity) | Anterior oblique fibres: obturator nerve (posterior branch) and straight posterior fibres: sciatic nerve | Adduct thigh (primary adductor - MAGnificent), anterior oblique fibres flex thigh, straight posterior fibres extend thigh |
Med: Gracilis | Inferior ramus of pubis of ischium | Medial surface of proximal end of tibia (close to sartorius and semitendinosus) | Obturator nerve | Adduct thigh and flex leg |
Med: Obturator externus | Outer surface of pelvis, around obturator foramen, and obturator membrane | Medial side of greater trochanter (posterior to hip joint) | Obturator nerve | Laterally rotate thigh |
Glut: Gluteus maximus | Sacrum, dorsal sacroiliac ligaments, small area of ilium, & sacrotuberous ligament | Lateral portion of fascia lata, iliotibial tract & gluteal tuberosity | Inferior gluteal nerve | Powerfully extend the thighm lateral rotation of thigh abduct thigh & adduct thigh |
Glut: Gluteus medius | major part of upper lateral surface of wing of ilium and covering fascia | Greater trochanter of the femur | Superior gluteal nerve | Strong abductor of the thigh, (anterior fibres) flex & medial rotation of thigh, (posterior fibres) extend & laterally rotate thigh |
Glut: Gluteus minimus | Lower part of lateral wing of ilium | Greater trochanter | Superior gluteal nerve | Strong abductor of thigh, medially rotate thigh (flexion of thigh) |
Glut: Piriformis | Pelvic surface of sacrum | Inner surface of superior part of greater trochanter | Branches of S1 (S2) ventral rami | Laterally rotate thigh, abductor when flexed |
Glut: Obturator Internus | Inner surface if pelvis (obturator membrane and edges if obturator foramen) | Medial surface of greater trochanter above fossa | Nerve to obturator internus | lateral rotation og thigh abducts thigh when flexed (same as piriformis) |
Glut: Gemellus superior | Ischial spine | Upper border of obturator internus | Nerve to obturator internus | Lateral rotation of thigh, abducts thigh when flexed (same as piriformis and obturator internus) |
Glut: Gemellus inferior | Ischial tuberosity | Lower border of obturator internus | Nerve to quadratus femoris | Lateral rotation of thigh, abducts thigh when flexed (same as piriformis and obturator internus) |
Glut: Quadratus femoris | Ischial tuberosity | Posterior surface of femur between greater and lesser trochanter | Nerve to quadratus femoris | Lateral rotation of thigh and adducts thigh (minor role) |
Post: Semitendinosus | Ischial tuberosity | Medial side of tibia, inferior to tibial tuberosity | Tibial part of sciatic nerve | extends thigh at hip, flexes leg at knee and medially rotates flexed leg |
Post: Semimembranosus | Lateral aspect of ischial tuberosity | Posteriomedial aspect of medial tibial condyle | Tibial part of sciatic nerve | Extends thigh at hip, flexes leg at knee, and medially rotates flexed leg |
Post: Biceps femoris | (long head) ischial tuberosity, (short head) lateral lip of linea aspera | Posteriolateral aspect of knee joint onto head of fibula | Sciatic nerve (tibial to long head and common fibular to short head) | Flex leg at the knee, laterally rotate flexed knee, tilt the pelvis posteriorly, (long head) extend thigh at hip and assist to laterally rotate it |
Posterior of superficial muscle in calf: Gastrocnemius | Posterior surface of femur (proximal to medial and lateral condyles) | Lower part of projecting portion of calcaneus as calcaneal tendon | Tibial nerve | Powerful plantar flexor of foot (helps flex leg when not supporting weight), resists dorsiflexion during weight bearing and keeps leg in extension |
PoS: Soleus | (one head) soleal line across upper 1/3 and posterior surface of tibia & middle 1/3 of medial border, (other head) proximal 1/3 of posterior surface of fibula (there is no attachment between the tibia and the fibula that's why it has 2 heads) | Anterior surface of calcaneal tendon | Tibial nerve | Plantar flexion of foot (& can do this with bent knee - gastroc cannot), during stance prevents dorsiflexion |
PoS: Plantaris | Lateral epicondyle of femur above lateral gastrocnemius | Calcaneus (anteriomedial to calcaneal tendon) | Branch of tibial nerve | Flexion of leg at knee and plantar fexion of foot (weak at both, b/c the muscle belly is very small) |
PoDeep: Popliteus | Lateral condyle of femur in knee joint capsule | Proximal 1/3 of posterior surface of tibia | Branch of tibial nerve | Medial rotation of leg on femur, prevents, forwrad sliding of femur on tibia when knee is flexed |
PoD: Flexor hallucis longus | Lateral side of middle 1/2 of posterior aspect of fibula | Distal phalanx of the big toe | Tibial nerve | Flexes big toe (weak plantar flexor - anything that crosses the posterior side is considered this) |
PoD: Tibialis posterior | Proximal 2/3 of the lateral side of the posterior shaft of the tibia, promixal 2/3 of the medial side of the posterior shaft of the fibular, posterior aspect of the interosseus membrane | Navicular & to bases of the 2nd - 4th metatarsals | Tibial nerve | Adduct front of foot (aids in inversion and plantar flexion) |
PoD: Flexor digitorum longus | Medial 1/3 of the posterior aspect of the tibia | Distal phalanges of 4 lateral digits | Tibial nerve | Flex distal phalanges of 4 lateral toes, weak plantar flexor, assists with inversion and adduction |
Ant of leg: Tibialis anterior | Lateral condyle and proximal 2/3 of surface of tibia, deep fascia of the leg, and interosseus membrane (quite deep to the bone) | Medial cuneiform bone and base of 1st metatarsal | Deep fibular nerve | Strong inverter and dorsiflexor of the leg |
Ant of leg: Extensor digitorum longus | Lateral condyle of tibia, proximal 3/4 anterior surface of fibula, interosseus membrane, and crural fascia | Middle phalanx & two distal slips onto distal phalanx | Deep fibular nerve | Extend toesm dorsiflexes foot weak everter of foot |
Ant of leg: Extensor hallucis longus | Middle 1/3 of anterior surface of fibular and adjacent interosseus membrane | distal phalanx of big toe | Deep fibular nerve | Extend big toe (weak dorsiflexor and inverter of foot) |
Ant of leg: Fibularis tertius | Fibula | Dorsal surface of base of 5th metatarsal | Deep fibular nerve | Everts and dorsiflexes foot |
Lat: Fibularis longus | Proximal 2/3 of lateral surface of fibula, surrounding fascia & intermuscular septa | Base of 1st metatarsal | Superficial fibular nerve | Everts the foot, weak plantar flexor |
Lat: Fibularis brevis | Distal 2/3 of lateral surface of fibula & adjacent intermuscular septa | Dorsal part of base of 5th metatarsal | Superificial fibular nerve | Everts foot, weak plantar flexor |
External Oblique | External surface of 5-12 ribs | Linea alba, pubic tubercle, and anterior iliac crest | N/A (ex) | Assists in torsional rotations of trunk (twist trunk relative to hips) |
Internal Oblique | Thoracolumbar fascia, anterior 2/3 of iliac crest, & connective tissue of lateral 2.3 of inguinal ligament | Inferior border of 10-12 ribs (last 3), linea alba, and pecten pubis | N/A (in) | Compress and support abdominal viscera, flex & rotate trunk |
Transverse Abdominis | Internal costal cartilage, ribs 7-12, thoracolumbar facia, iliac crest, & lateral 1/3 inguinal ligament deep connective tissue | Linea alba & internal oblique aponeurosis, pubic crest, & pecten pubis | N/A (tran) | Compress contents of abdomen & increase intra-abdominal pressure |