Muscles MD3 Flashcards
Deltoid
origin: lateral 1/3 of clavicle, acromion, spine of scapula
insertion: deltoid tuberosity
innervation: axillary nn. (C5, C6)
action:
anterior deltoid: humeral flexion & internal rotation
lateral/middle deltoid: humeral abduction
posterior deltoid: humeral extension & external rotation
Teres Major
origin: posterior surface of inferior angle of scapula
insertion: medial lip of intertubercular/bicipital groove
innervation: lower subscapular nn (C5, C6)
action: adduction & internal rotation of humerus
Teres Minor
origin: mid part of lateral border of scapula
insertion: inferior facet of greater tubercle of humerus
innervation: axillary nn (C5, C6)
actions:
controls internal rotation of humerus (functional action)
external rotation of humerus
*part of rotator cuff (provide dynamic stability via eccentric contraction for shoulder stabilization/re-enforcement of GH joint capsule)
Infraspinatus
origin: infraspinous/infraspinatus fossa of scapula
insertion: middle facet of greater tubercle of humerus
innervation: suprascapular nn (C5, C6)
actions:
controls IR of humerus (functional action)
ER of humerus
*part of rotator cuff (provide dynamic stability via eccentric contraction for shoulder stabilization/re-enforcement of GH joint capsule)
Supraspinatus
origin: supraspinous/supraspinatus fossa of scapula
insertion: superior facet of greater tubercle of humerus
innervation: suprascapular nn (C5, C6)
actions:
prevent superior translation of humeral head during abduction (protect supraspinatus, bursae, etc. from getting pinched by humeral head & acromion) (functional action)
initiate abduction & assist deltoid in abduction of humerus
*part of rotator cuff (provide dynamic stability via eccentric contraction for shoulder stabilization/re-enforcement of GH joint capsule)
Subscapularis
origin: subscapular fossa of scapula (anterior)
insertion: lesser tubercle of humerus
innervation: upper & lower subscapular nn (C5-C7)
actions:
control ER of humerus (functional action)
IR & adduction of humerus
*part of rotator cuff (provide dynamic stability via eccentric contraction for shoulder stabilization/re-enforcement of GH joint capsule)
Pectoralis Minor
origin: ribs 3-5 (highly variable)
insertion: coracoid process of scapula
innervation: medial pectoral nn (C8, T1)
actions:
stabilizes shoulder, draws scapula anterior & depresses it inferiorly towards the thorax (helps upper extremity reach out forward)
divides axillary aa into its 3 parts
(1st part medial to pec minor, 2nd part posterior, 3rd part lateral)
Serratus Anterior
origin: lateral aspects of ribs 1-8
insertion:
upper 4 heads- anterior surface of medial border of scapula,
lower 4- inferior angle of scapula
innervation: long thoracic nn (C5-C7)
actions:
protraction of scapula, holds medial border against thoracic wall, upward rotation/external rotation
long thoracic nn can be damaged during mastectomy (winged scapula), unable to raise arm above horizontal
Pectoralis Major
origin:
clavicular- ant, medial 1/2 of clavicle
sternal- ant sternum, 1st 6 costal cartilages, external oblique aponeurosis
insertion: lateral lip of intertubercular/bicipital groove
innervation: lateral & medial pectoral nn (clavicle C5, C6, sternum C7-T1)
actions:
adduction & IR of humerus, draws scapula anterior & inferior
Triceps brachii
origin:
long head- infraglenoid tubercle of scapula
lateral head- posterior humerus, superior to spiral groove (radial groove)
medial head- posterior humerus, inferior to spiral groove (radial groove)
insertion: olecranon process of ulna
innervation: radial nn (C6-C8)
actions: extension at elbow
heads recruited additively as needed, medial first (workhorse), lateral (strongest), long (last)
Latissimus Dorsi
origin: spinous processes of T7-L5, inferior angle of scapula, thoracolumbar fascia, iliac crest of sacrum, inferior 3 or 4 ribs
insertion: floor of intertubercular/bicipital groove of humerus
innervation: thoracodorsal nn (C6-C8)
actions: adduction, IR & extension of the humerus
Biceps brachii
brachial aa, musculocutaneous nn (C5, C6)
Long head
origin: supraglenoid tubercle, thru glenoid labrum (constant tension causes slap lesions)
Short head
origin: coracoid process
insertion: radial tuberosity (medial radius) & bicipital aponeurosis
action: primary supinator of forearm, also resistive elbow flexion (hand position dependent)
Coracobrachialis
brachial aa, musculocutaneous nn (C5-C7)
origin: coracoid process
insertion: mid 1/3 of medial humerus
actions: humeral adduction, flexion @ GH joint (shoulder)
- musculocutaneous nn pierces it
Brachialis
radial recurrent aa, musculocutaneous nn (C5, C6)
origin: anterior humerus
insertion: coronoid process & tuberosity of ulna
actions: primary elbow flexor (active throughout elbow flexion)
- musculocutaneous nn runs between biceps brachii & brachialis
Brachioradialis
radial recurrent aa, radial nn (C5, C6)
origin: lateral supracondylar ridge of humerus
insertion: radial styloid process (distal radius)
actions: elbow flexion
only flexor in the posterior compartment, superficial layer
Pronator teres
ulnar & radial aa, median nn (C6, C7)
origin: medial epicondyle of humerus & coronoid process of ulna
insertion: lateral aspect of mid radius
actions: pronation of forearm, elbow flexion
- superficial anterior compartment
Flexor Carpi Radialis
radial aa, median nn (C6, C7)
origin: medial epicondyle of humerus
insertion: base of 2nd & 3rd metacarpals
actions: flexion & abduction of wrist
- superficial anterior compartment
Flexor Carpi Ulnaris
ulnar aa, ulnar nn (C8, T1)
origin: medial epicondyle of humerus
insertion: pisiform, hook of hamate, base of 5th metacarpal
actions: flexion and adduction of wrist
- anterior superficial compartment
Palmaris Longus
ulnar aa, median nn (C7, C8)
origin: medial epicondyle of humerus
insertion: flexor retinaculum & palmar aponeurosis
actions: wrist flexion, tenses palmar aponeurosis
- anterior superficial compartment
Abductor Pollicis Longus
origin: proximal ulna, radius, interosseus membrane
insertion: base of 1st metacarpal
action: abduction & extension of thumb
innervation: radial nn (deep radial nn) (C7, C8)
*deep layer on posterior forearm
Flexor Digitorum Superficialis
origin: anterior oblique line of radius, coronoid process of ulna, medial epicondyle of humerus
insertion: middle phalanges
innervation: median nn (C7, C8, T1)
action: flexion of middle phalanges @ PIP, then flexion of proximal phalanges @ MCP
Flexor Digitorum Profundus
origin: ulna & interosseus membrane
insertion: distal phalanges (2-5)
innervation: median nn & ulnar nn (4th & 5th digits)
action: flexion of distal phalanges @ DIP
*deep anterior forearm
Flexor Pollicis Longus
origin: radius
insertion: distal phalanx of thumb
innervation: median nn
action: flexion of thumb
*deep anterior forearm
Pronator Quadratus
origin: ulna
insertion: radius
innervation: median nn
action: pronation of forearm
*deep anterior forearm
square “quad” shaped muscle
Abductor pollicis brevis
origin: flexor retinaculum, scaphoid, trapezium
insertion: lateral proximal phalanx of thumb
innervation: median nn
action: abduction of thumb
*thenar (palmar base of thumb)
-intrinsic muscle
Flexor Pollicis Brevis
origin: flexor retinaculum, scaphoid, trapezium
insertion: proximal phalanx of thumb
innervation: median nn
action: flexion of thumb @ MCP joint
*thenar, intrinsic
Opponens Pollicis
origin : flexor retinaculum, scaphoid, trapezium
insertion: lateral 1st metacarpal
innervation: median nn
action: opposition of thumb
*thenar, intrinsic
*deep to flexor and abductor pollicis brevis
Adductor Pollicis
-ulnar nn.
Abductor Digiti Minimi
origin: pisiform
insertion: medial 5th proximal phalanx
innervation: ulnar nn
action: abduction of 5th digit, aids in flexion of proximal 5th phalanx
*hypothenar (muscles on medial side of palm, pinky)
Flexor Digiti Minimi
origin: hook of hamate & flexor retinaculum
insertion: medial 5th proximal phalanx
innervation: ulnar nn.
action: flexion of 5th proximal phalanx
*hypothenar
Opponens digiti minimi
origin: hook of hamate & flexor retinaculum
insertion: medial border of 5th metacarpal
innervation: ulnar nn.
action: opposition of 5th digit/pinky
*hypothenar
*deep to flexor & abductor digiti minimi
Extensor Pollicis Longus
origin: posterior middle 1/3 of ulna
insertion: distal phalanx of thumb
innervation: radial nn.
action: extension of thumb (IP, MCP, CMC jts)
*deep posterior forearm
Extensor Pollicis Brevis
origin: posterior distal 1/3 of radius
insertion: proximal phalanx of thumb
innervation: radial nn.
action: extension of thumb @ MCP & CMC
*deep muscle of forearm (extrinsic)
Extensor Carpi Radialis Longus
origin: lateral supraepicondylar ridge of humerus
insertion: posterior base of 2nd metacarpal
innervation: radial nn.
action: flexion & abduction of wrist, active during fist clenching
*medial to brachioradialis
Extensor Carpi Radialis Brevis
origin: lateral epicondyle of humerus (common extensor tendon)
insertion: posterior base of 3rd metacarpal
innervation: radial nn
action: extension & abduction @ wrist
Extensor Digitorum
origin: lateral epicondyle of humerus (common extensor tendon)
insertion: distal phalanges 2-5 (via extensor expansions)
innervation: radial nn.
action: extension of wrist & digits 2-5 primarily @ MCP joint
Extensor Indicis
origin: posterior distal 1/3 of ulna
insertion: extensor hood of 2nd digit
innervation: radial nn.
action: independent extension of 2nd digit
*deep posterior forearm
Supinator
origin: lateral epicondyle of humerus, ulna, radial collateral & annular ligaments
insertion: lateral, posterior & anterior proximal radius
innervation: radial nn.
action: supination of forearm
*deep posterior forearm
Lumbricals
origin:
lateral 2: lateral side of FDP tendons of 2 & 3rd digits
medial 2: FDP tendons of 3-5th digits
insertion: lateral extensor expansions
innervation:
lateral 2: median nn.
medial 2: ulnar nn.
action: flexion @ MCP, extension @ IP joints
Interosseus Muscles
DAB (dorsal) & PAD (palmar)
innervation: ulnar nn.
Extensor Hood
tendonous aponeurosis of 2-5th digits flatten and wrap around distal metacarpals & proximal phalanges forming a dorsal hood that holds extensor tendons in place
Pectineus
O/I: superior pubic ramus -> pectineal line of humerus
innervation: Femoral nn.
Actions: adduction & flexion of thigh, internal rotation of humerus
Iliopsoas
psoas major + iliacus (join @ midpoint)
O/I: lumbar vertebrae, iliac crest-> lesser trochanter of femur
innervation: lumbar rami (L1-3), femoral nn.
actions: flexion of thigh, trunk flexion when legs grounded, maintains lordosis of lumbar spine (tightness of muscle = incr lordosis)
Sartorius
longest muscle in body, spans two joints (hip & knee)
O/I: anterior superior iliac spine-
> pes anserine
innervation: femoral nn.
actions: “tailor’s muscle”, flexion of thigh/hip, flexion of knee, weak ext rotation of thigh, weak abduction of thigh, primarily synergistic
Quadriceps Femoris
Rectus Femoris:
O: anterior inferior iliac spine
-spans two joints (hip & knee), longest muscle in quadriceps femoris, “kicking muscle”
Vastus Lateralis:
O: greater trochanter of femur, lateral lip of linea aspera
Vastus Intermedius:
O: anterolateral shaft of femur
Vastus Medialis:
O: intertrochanteric line & medial lip of linea aspera of femur
All come together to insert on quadriceps tendon-> patella-> patellar ligament to attach onto tibial tuberosity
Should be 3:2 stronger than hamstring, commonly 3 x stronger
Actions: flexion of hip/thigh (only rectus femoris), extension of knee (all)
Innervation: femoral nn.
Adductor Brevis, Adductor Longus, Adductor Magnus
O/I: inferior ischial & pubic ramus-> linea aspera & adductor tubercle of femur (adductor magnus, hamstring part)
innervation: obturator nn. (all), magnus = obturator nn. (adductor part), tibial nn. (hamstring part)
actions: adduct thigh (brevis, longus, adductor part of magnus), may flex thigh (brevis), ext thigh (hamstring part of magnus)
*obturator nn splits ant/post @ brevis
magnus is most powerful adductor
adductor hiatus (magnus) allows transmission of femoral aa & vv from adductor canal to popliteal fossa
Gracilis
O/I: inferior pubic ramus-> pes anserine
innervation: obturator nn.
actions: adduction of thigh, flexion of knee, internal rotation of humerus when knee flexed
Obturator Externus
O/I: obturator membrane in obturator foramen-> trochanteric fossa on greater trochanter of humerus
innervation: obturator nn.
actions: external rotation of thigh, stabilizes femoral head in acetabulum
Gluteus maximus
-largest and most superficial (superficial gluteal, primary movers of hip)
O/I; iliac crest, sacrum, coccyx -> iliotibial (IT) band, some fibers to gluteal tuberosity of femur
innervation: inferior gluteal nn
actions: mainly hip extension (esp. up inclines) & external rotation of femur
Gluteus Medius & Minimus
O/I: gluteal surface of ilium (beneath iliac crest, deep to gluteus maximus)-> greater trochanter of femur
innervation: superior gluteal nn.
actions: abduction of thigh, internal rotation of femur, medius stabilizes pelvis during gait
Trendelenburg sign/gait: weakness of these muscles
Tensor Fasciae Latae
O/I: anterior superior iliac spine -> iliotibial band
innervation: superior gluteal nn.
actions: flexion @ hip, abduction and internal rotation of femur
- fusiform muscle (wide in middle, narrow at ends)
Piriformis
O/I: Sacrum -> greater trochanter of femur
innervation: anterior rami of S1 & S2
actions: external rotation of extended thigh, abductor of flexed thigh
- superior gluteal nn & vessels travel above piriformis
- inferior gluteal nn. & vessels travel below piriformis, along w/ sciatic nn.
- piriformis syndrome (sciatica)- irritation of sciatic nn by piriformis causes pain in butt radiating down leg (sciatic nn.)
Triceps Coxae
Obturator Internus:
O/I: ischiopubic ramus & obturator membrane -> medial part of greater trochanter of femur
innervation: nn to obturator internus (L5, S1)
actions: external rotation of extnded thigh, abduction of flexed thigh
*located b/w superior & inferior gemelli
Gemelli:
O/I: ischial spine (superior) & ischial tuberosity (inferior) -> medial part of greater trochanter of femur (all 3 tendons of triceps coxae join and insert onto the medial greater trochanter)
innervation: nn to obturator internus (superior), nn. to quadratus femoris (inferior) (L5, S1)
actions: external rotation of thigh
Quadratus Femoris
O/I: ischial tuberosity -> intertrochanteric crest
innervation: nn. to quadratus femoris (L5, S1)
actions: strong external rotation of thigh
- located inferior to inferior gemellus
Semitendinosus, Semimembranosus (part of hamstring)
O/I: ischial tuberosity -> pes anserine (semitendinosus), posterior medial condyle of tibia, popliteal fossa, popliteal ligament (semimembranosus)
innervation: tibial branch of sciatic nn.
actions: extension of hip, flexion of knee, internal rotation w/ flexed knee
- commonly used in ACL repair (semitendinosus)
Biceps Femoris (workhorse of the hamstring)
O/I: ischial tuberosity (long head), linea aspera & lateral supracondylar line of femur (short head) -\> fibular head, LCL of knee
innervation: tibial branch of sciatic (long head), common peroneal branch of sciatic (short head)
actions: hip extension, knee flexion, external rotation of flexed knee
*hamstring strains are twice as likely as quads, commonly d/t co-contracture (e.g. running), avulsion at ischial tuberosity
Pes Anserine
- insertion of tendons from Sartorius, Gracilis, SemiTendinosus (Say Grace SomeTimes) onto anteriomedial upper tibia
- looks like a goose’s foot
- common site of tendinitis/bursitis
Tibialis Anterior
O/I: upper 1/3 & lateral condyle of tibia -> medial cuneiform & base of 1st metatarsal
innervation: deep peroneal nn (branch off common peroneal)
actions: dorsiflexion, inversion of ankle
- on lateral surface of tibia, most superficial, strongest dorsiflexor
Extensor Digitorum Longus
O/I: lateral condyle of tibia & anterior shaft of fibula-> middle and distal phalanges
innervation: deep peroneal nn.
actions: extension of 4 digits (not hallicus), dorsiflexion
- most lateral anterior leg muscle, lies on medial side of fibula
Extensor Hallucis Longus
O/I: anterior interosseus membrane-> distal 1st phalanx
innervation: deep peroneal nn.
actions: extension of great toe, dorsiflexion
- deep muscle, lies between EDL & tibialis anterior
Peroneus (Fibularis) Tertius
O/I: distal anterior fibula-> 5th metatarsal
innervation: deep peroneal nn.
actions: aids in dorsiflexion, eversion of foot, ankle proprioception
Peroneus Longus
O/I: upper lateral fibula-> 1st metatarsal & medial cuneiform
innervation: superficial peroneal nn.
actions: plantar flexion & eversion of foot
- posterior to lateral malleolus, underneath foot, thru groove in cuboid
- antagonistic to peroneus tertius (plantar flexion) and agonistic (eversion)
- longer, more superficial, originates higher up on tibia vs brevis
Peroneus Brevis
O/I: lower lateral fibula-> lateral base of 5th metatarsal
innervation: superficial peroneal nn.
actions: eversion of foot, plantar flexion
- deep to peroneus longus, runs posterior to lateral malleolus
- common avulsion site (Jones fx)
Gastrocnemius
O/I: posterior condyles of femur-> achilles tendon
innervation: tibial nn.
actions: plantar flexion (propulsion phase of walking), knee flexion
- medial & lateral heads, fast-twitch muscle
Soleus
- deep to gastrocnemius, joins it distally to become achilles tendon (most powerful tendon)
- workhorse of plantar flexion, (active in standing and postural balance)
- popliteal aa & tibial nn lay underneath it
innervation: tibial nn
Plantaris
O/I: lateral supracondylar ridge of femur-> achilles
innervation: tibial nn
actions: weak plantar flexion, may be more significant in proprioception
- absent in 5-10%, used for grafting to hand tendons
Popliteus
O/I: lateral femoral condyle-> proximal posterior tibia
innervation: tibial nn.
actions: knee flexion, opposite screw home mechanism (turns femur laterally)
- inferior floor of popliteal fossa
Flexor Hallucis Longus
O/I: posterior mid fibula-> distal 1st phalanx
innervation: tibial nn.
actions: powerful great toe flexor, supports medial longitudinal arch of foot
- runs under flexor digitorum longus tendon under navicular bone
Flexor Digitorum Longus
O/I: posterior tibia-> distal lateral 4 phalanges
innervation: tibial nn.
actions: flexion of phalanges, plantar flexion, supports longitudinal arches
- passes over tibialis posterior @ distal tibia
Posterior Tibialis
deepest/most anterior muscle in posterior compartment
innervation: tibial nn.
actions: works w/ tibialis anterior to invert foot, supports medial longitudinal arch
- inserts on navicular and cuneiform bones
- b/w flexor digitorum longus & flexor hallucis longus
1st layer of plantar muscles
Abductor Hallucis
O/I: calcaneus-> medial 1st proximal phalanx
innervation: medial plantar nn.
actions: abduction & flexion of great toe
Flexor Digitorum Brevis
O/I: calcaneus-> both sides of middle phalanges 2-5
innervation: medial plantar nn.
actions: flexion of digits 2-5
Abductor Digiti Minimi
O/I: calcaneus-> lateral 5th proximal phalanx
innervation: lateral plantar nn.
actions: abduction & flexion of 5th digit
2nd layer of plantar muscles
Quadratus Plantae
O/I: calcaneus-> posterolateral flexor digitorum longus tendon
innervation: lateral plantar nn
actions: assists FDL in flexion of digits 2-5, keeps FDL stable when lumbricals pull on it during flexion
Lumbricals
O/I: FDL tendon to medial aspect of digits 2-5
innervation: lumbrical #1 = medial plantar nn, #2-4 = lateral plantar nn
actions: flexion of proximal phalanges, extension of middle & distal phalanges of digits 2-5
3rd layer of plantar muscles
Flexor Hallucis Brevis
O/I: cuboid & lateral cuneiform-> base of 1st proximal phalanx
innervation: medial plantar nn
actions: flexion of great toe
Adductor Hallucis (oblique & transverse heads)
O/I: Plantar ligaments of MTP joints (oblique), base of metatarsals 2-4 (transverse)-> lateral aspect of 1st proximal phalanx
innervation: lateral plantar nn.
actions: stabilizes transverse arch by bringin metatarsals medially
Flexor Digiti Minimi
O/I: base of 5th metatarsal-> proximal 5th phalanx
innervation: lateral plantar nn.
actions: flexion of 5th proximal phalanx
4th layer of plantar muscles
Plantar Interossei (3 muscles, PAD)
innervation: lateral plantar nn.
actions: adduction of digits 2-4
Dorsal Interossei (4 muscles, DAB)
innervation: lateral plantar nn.
actions: abduction of digits 2-4
*both involved in flexion @ MTP
*2nd toe is midline in the foot (cannot abduct)
Extensor Digitorum Brevis, Extensor Hallucis Brevis (dorsal foot muscles)
innervation: deep peroneal nn.
actions: aids ‘long’ counterparts in extension of digits 2-4 (EDB), 1st toe (EHB)
