Exam 2 Muscles Flashcards
pectoralis major
origin: medial half of clavicle and anterior surface of sternum, first seven costal cartilages, aponeurosis of external oblique
insertion: lateral lip of intertubercular sulcus of humerus
innervation: medial and lateral pectoral nerves
function: adduction, medial rotation, and flexion of the humerus at the shoulder joint
subclavius
origin: rib I at junction between rib and costal cartilage
insertion: groove on inferior surface of middle third of clavicle
innervation: nerve to subclavius
function: pulls clavicle medially to stabilize sternoclavicular joint; depresses tip of shoulder
pectoralis minor
origin: anterior surfaces of the third, fourth, and fifth ribs, and deep fascia overlying the related intercostal spaces
insertion: coracoid process of scapula
innervation: medial pectoral nerves
function: depresses tip of shoulder; protracts scapula
external intercostal
superior attachment: inferior margin of rib above
inferior attachment: superior margin of rib below
innervation: intercostal nerves; T1–T11
function: most active during inspiration; supports intercostal space; moves ribs superiorly
internal intercostals
superior attachment: lateral edge of costal groove of rib above
inferior attachment: superior margin of rib below deep to the attachment of the related external intercostal
innervation: intercostal nerves; T1–T11
function: most active during expiration; supports intercostal space; moves ribs inferiorly
innermost intercostal
superior attachment: medial edge of costal groove of rib above
inferior attachment: internal aspect of superior margin of rib below
innervation: intercostal nerves; T1–T11
function: acts with internal intercostal muscles
subcostales
superior attachment: internal surface (near angle) of lower ribs
inferior attachment: internal surface of second or third rib below
innervation: related intercostal nerves
function: may depress ribs
transversus thoracis
superior attachment: inferior margins and internal surfaces of costal cartilages of second to sixth ribs
inferior attachment: inferior aspect of deep surface of body of sternum, xiphoid process, and costal cartilages of ribs 4–7
innervation: related intercostal nerves
function: depresses costal cartilages
psoas major
origin: lateral surface of bodies of T12 and L1 to L5 vertebrae, transverse processes of the lumbar vertebrae, and the intervertebral discs between T12 and L1 to L5 vertebrae
insertion: lesser trochanter of the femur
innervation: anterior rami of L1 to L3
function: flexion of thigh at hip joint
psoas minor
origin: lateral surface of bodies of T12 and L1 vertebrae and intervening intervertebral disc
insertion: pectineal line of the pelvic brim and iliopubic eminence
innervation: anterior rami of L1
function: weak flexion of lumbar vertebral column
quadratus lumborum
origin: transverse process of L5 vertebra, iliolumbar ligament, and iliac crest
insertion: transverse processes of L1 to L4 vertebrae and inferior border of rib 12
innervation: anterior rami of T12 and L1 to L4
function: depress and stabilize rib 12 and some lateral bending of trunk
illiacus
origin: upper two-thirds of iliac fossa, anterior sacro-iliac and iliolumbar ligaments, and upper lateral surface of sacrum
insertion: lesser trochanter of femur
innervation: femoral nerve (L2 to L4)
function: flexion of thigh at hip joint
external oblique
origin: muscular slips from the outer surfaces of the lower eight ribs (ribs 5 to 12)
insertion: lateral lip of iliac crest; aponeurosis ending in midline raphe (linea alba)
innervation: anterior rami of lower six thoracic spinal nerves (T7 to T12)
function: compress abdominal contents; both muscles flex trunk; each muscle bends trunk to same side
internal oblique
origin: thoracolumbar fascia; iliac crest between attachments of external oblique and transversus abdominis; lateral two-thirds of inguinal ligament
insertion: inferior border of the lower three or four ribs; aponeurosis ending in linea alba; pubic crest and pectineal line
innervation: anterior rami of lower six thoracic spinal nerves (T7 to T12) and ilioinguinal and iliohypogastric nerves (L1)
function: compress abdominal contents; both muscles flex trunk; each muscle bends trunk to same side
transversus abdominus
origin: thoracolumbar fascia; medial lip of iliac crest; lateral one-third of inguinal ligament; costal cartilages lower six ribs (ribs 7 to 12)
insertion: aponeurosis ending in linea alba; pubic crest and pectineal line
innervation: anterior rami of lower six thoracic spinal nerves (T7 to T12) and ilioinguinal and iliohypogastric nerves (L1)
action: compress abdominal contents
rectus abdominis
origin: pubic crest, pubic tubercle, and pubic symphysis
insertion: costal cartilages of ribs 5 to 7; xiphoid process
innervation: anterior rami of lower seven thoracic spinal nerves (T7 to T12)
function: compress abdominal contents; flex vertebral column; tense abdominal wall
pyramidalis
origin: front of pubis and pubic symphysis
insertion: into linea alba
innervation: anterior ramus of T12
function: tenses the linea alba
obturator internus
origin: anterolateral wall of true pelvis (deep surface of obturator membrane and surrounding bone)
insertion: medial surface of greater trochanter of femur
innervation: nerve to obturator internus L5, SI
function: lateral rotation and abduction of hip joint
piriformis
origin: anterior surface of sacrum between anterior sacral foramina
insertion: medial side of superior border of greater trochanter of femur
innervation: nerve to piriformis SI, S2
function: lateral rotation and abduction of hip joint
pubococcygeus
origin: pubis
insertion: midline at anococcygeal ligament
puborectalis
origin: pubis
insertion: forms sling around rectum
function: maintains the perineal flexure (angle) at anorectal junction; helps close off GI tract
illiococcygeus
origin: fascia covering obturator internus, tendinous arch and ischial spine
insertion: pubococcygeus on other side at midline at anococcygeal ligament
coccygeus
origin: ischial spine and pelvic surface of the sacrospinous ligament
insertion: lateral margin of coccyx and related border of sacrum
innervation: branches from the anterior rami of S3 and S4
function: contributes to the formation of the pelvic floor, which supports the pelvic viscera; pulls coccyx forward after defecation
levator ani (group)
origin: in a line around the pelvic wall beginning on the posterior aspect of the pubic bone and extending across the obturator internus muscle as a tendinous arch (thickening of the obturator internus fascia) to the ischial spine
insertion: the anterior part is attached to the superior surface of the perineal membrane; the posterior part meets its partner on the other side at the perineal body, around the anal canal, and along the anococcygeal ligament
innervation: branches direct from the anterior ramus of S4, and by the inferior rectal branch of the pudendal nerve (S2 to S4)
function: contributes to the formation of the pelvic floor, which supports the pelvic viscera; maintains an angle between the rectum and anal canal; reinforces the external anal sphincter and, in women, functions as a vaginal sphincter
external urethral sphincter
origin: inf ramus of pubis on each side and adjacent walls of deep perineal pouch
insertion: surrounds membranous part of urethra
innervation: perineal branches of pudendal nerve (S2-S4)
function: compresses the membranous urethra; relaxes during micturition
deep transverse perineal
origin: medial aspect of ischial ramus
insertion: perineal body
innervation: perineal branches of pudendal nerve (S2-S4)
function: stabilizes the position of the perineal body
compressor urethrae (in women only)
origin: ishiopubo ramus on each side
insertion: blends with partner on other side anterior to the urethra
innervation: perineal branches of the pudendal nerve (S2-S4)
function: functions as an accessory sphincter of the urethra
sphincter urethrovaginalis (only in women)
origin: perineal body
insertion: passes forward lateral to the vagina to blend with partner on other side anterior to the urethra
innervation: perineal branches of the pudendal nerve (S2-S4)
function: functions as an accessory sphincter of the urethra (may also facilitate closing the vagina)
ischiocavernosus muscles
cover crura of penis and clitoris
anchored to ischial tuberosity
forces blood from crus to body of erect penis and clitoris
bulbospongiosus muscles
women:
- anchored to perineal body
- travels over bulb of vestibule
men:
-joined at midline to raphe anchored to perineal membrane
- cover each side of bulb of penis
- attach to perineal membrane
- facilitate emptying of urethra
- contract during ejaculation to expel semen
piriformis
origin: anterior surface of sacrum between anterior sacral foramina
insertion: greater trochanter of femur
innervation: nerve to piriformis branches from S1 and S2
function: laterally rotates the extended femur at hip joint; abducts flexed femur at hip joint
obturator internus
origin: deep surface of obturator membrane and surrounding bone
insertion: greater trochanter of femur
innervation: nerve to obturator internus (L5, S1)
function: laterally rotates the extended femur at hip joint; abducts flexed femur at hip joint
gamellus superior
origin: ischial spine
insertion: greater trochanter
innervation: nerve to obturator internus (L5, S1)
function: laterally rotates the extended femur at hip joint; abducts flexed femur at hip joint
gamellus inferior
origin: ischial tuberosity
insertion: greater trochanter
innervation: nerve to quadratus femoris (L5, S1)
function: laterally rotates the extended femur at hip joint; abducts flexed femur at hip joint
quadratus femoris
origin: ischium just anterior to the ischial tuberosity
insertion: quadrate tubercle on the intertrochanteric crest of the proximal femur
innervation: nerve to quadratus femoris (L5, S1)
function: laterally rotates femur at hip joint
gluteus minimus
origin: ilium between inferior and anterior gluteal lines
insertion: anterolateral aspect of the greater trochanter
innervation: superior gluteal nerve (L4, L5, S1)
function: abducts femur at hip joint; holds pelvis secure over stance leg and prevents pelvic drop on the opposite swing side during walking; medially rotates thigh
gluteus medius
origin: ilium between anterior and posterior gluteal lines
insertion: lateral surface of the greater trochanter
innervation: superior gluteal nerve (L4, L5, S1)
function: abducts femur at hip joint; holds pelvis secure over stance leg and prevents pelvic drop on the opposite swing side during walking; medially rotates thigh
gluteus maximus
origin: fascia covering gluteus medius, ilium behind posterior gluteal line, fascia of erector spinae, dorsal surface of lower sacrum, lateral margin of coccyx, sacrotuberous ligament
insertion: posterior aspect of iliotibial tract of fascia lata and gluteal tuberosity of proximal femur
innervation: inferior gluteal nerve (L5, S1, S2)
function: powerful extensor of flexed femur at hip joint; lateral stabilizer of hip joint and knee joint; laterally rotates and abducts thigh
tensor fascia latae
origin: crest of ilium between anterior superior iliac spine and tubercle of the crest
insertion: iliotibial tract of fascia lata
innervation: superior gluteal nerve (L4, L5, S1)
function: stabilizes the knee in extension
psoas major
origin: posterior abdominal wall (lumbar transverse processes, intervertebral discs, and adjacent bodies from T12 to L5 and tendinous arches between these points)
insertion: lesser trochanter of femur
innervation: anterior rami (L1, L2, L3)
function: flexes the thigh at the hip joint
illiacus
origin: posterior abdominal wall (iliac fossa)
insertion: lesser trochanter of femur
innervation: femoral nerve (L2, L3)
function: flexes the thigh at the hip joint
vastus medialis
origin: femur—medial part of intertrochanteric line, pectineal line, medial lip of the linea aspera, medial supracondylar line
insertion: quadriceps femoris tendon and medial border of patella
innervation: femoral nerve (L2, L3, L4)
function: extends the leg at the knee joint
vastus intermedius
origin: femur—upper two-thirds of anterior and lateral surfaces
insertion: quadriceps femoris tendon, lateral margin of patella, and lateral condyle of tibia
innervation: femoral nerve (L2, L3, L4)
function: extends the leg at the knee joint
vastus lateralis
origin: femur—lateral part of intertrochanteric line, margin of greater trochanter, lateral margin of gluteal tuberosity, lateral lip of the linea aspera
insertion: quadriceps femoris tendon and lateral margin of patella
innervation: femoral nerve (L2, L3, L4)
function: extends the leg at the knee joint
rectus femoris
origin: straight head originates from the anterior inferior iliac spine; reflected head originates from the ilium just superior to the acetabulum
insertion: quadriceps femoris tendon
innervation: femoral nerve (L2, L3, L4)
function: flexes the thigh at the hip joint and extends the leg at the knee joint
sartorius
origin: anterior superior iliac spine
insertion: medial surface of tibia just inferomedial to tibial tuberosity
innervation: femoral nerve (L2, L3)
function: flexes the thigh at the hip joint and flexes the leg at the knee joint
gracilis
origin: body of the pubis, the inferior pubic ramus, and the ramus of the ischium
insertion: medial surface of proximal shaft of tibia
innervation: obturator nerve (L2, L3)
function: adducts thigh at hip joint and flexes leg at knee joint
pectineus
origin: pectineal line (pecten pubis) and adjacent bone of pelvis
insertion: pectineal line of femur
innervation: femoral nerve (L2, L3)
function: adducts and flexes thigh at hip joint
adductor longus
origin: body of pubis
insertion: linea aspera on middle one-third of shaft of femur
innervation: obturator nerve (anterior division) (L2, L3, L4)
function: adducts and medially rotates thigh at hip joint
adductor brevis
origin: body of pubis and inferior pubic ramus
insertion: posterior surface of proximal femur and upper one-third of linea aspera
innervation: obturator nerve (L2, L3)
function: adducts and medially rotates thigh at hip joint
adductor magnus (adductor part)
origin: ischiopubic ramus
insertion: posterior surface of proximal femur, linea aspera, medial supracondylar line
innervation: obturator nerve (L2, L3, L4)
function: adducts and medially rotates thigh at hip joint
adductor magnus (hamstring part)
origin: ischial tuberosity
insertion: adductor tubercle
innervation: sciatic nerve (tibial division) (L2, L3, L4)
obturator externus
origin: external surface of obturator membrane and adjacent bone
insertion: trochanteric fossa
innervation: obturator nerve (posterior division) (L3, L4)
function: laterally rotates thigh at hip joint
biceps femoris
origin: long head—ischial tuberosity; short head—lateral lip of linea aspera
insertion: head of fibula
innervation: sciatic nerve (L5, S1, S2)
function: flexes leg at knee joint; extends and laterally rotates thigh at hip joint and laterally rotates leg at knee joint
semitendinosus
origin: ischial tuberosity
insertion: medial surface of proximal tibia
innervation: sciatic nerve (L5, S1, S2)
function: flexes leg at knee joint and extends thigh at hip joint; medially rotates thigh at hip joint and leg at knee joint
semimembranosus
origin: ischial tuberosity
insertion: medial tibial condyle
innervation: sciatic nerve (L5, S1, S2)
function: flexes leg at knee joint and extends thigh at hip joint; medially rotates thigh at hip joint and leg at knee joint
gastrocnemeus
origin: medial head—posterior femur superior to medial condyle; lateral head—superior of lateral femoral condyle
insertion: via calcaneal tendon, to posterior surface of calcaneus
innervation: tibial nerve (S1, S2)
function: plantarflexes foot and flexes knee
plantaris
origin: lateral supracondylar line of femur and oblique popliteal ligament of knee
insertion: via calcaneal tendon, to posterior surface of calcaneus
innervation: tibial nerve (S1, S2)
function: plantarflexes foot and flexes knee
soleus
origin: soleal line and medial border of tibia; fibular head and adjacent bone
insertion: via calcaneal tendon, to posterior surface of calcaneus
innervation: tibial nerve (S1, S2)
function: plantarflexes the foot
popliteus
origin: lateral femoral condyle
insertion: posterior surface of proximal tibia
innervation: tibial nerve (L4 to S1)
function: closed chain = lateral rotation of femur on tibia
open chain = medially rotates tibia
flexor hallicus longus
origin: posterior surface of fibula and adjacent interosseous membrane
insertion: plantar surface of distal phalanx of great toe
innervation: tibial nerve (S2, S3)
function: flexes great toe
flexor digitorum longus
origin: posterior surface of the tibia
insertion: plantar surfaces of distal phalanges of the lateral four toes
innervation: tibial nerve (S2, S3)
function: flexes lateral four toes
tibialis posterior
origin: posterior surfaces of interosseous membrane and adjacent regions of tibia and fibula
insertion: navicular and medial cuneiform
innervation: tibial nerve (L4, L5)
function: inversion and plantarflexion of foot; support of medial arch of foot during walking
fibularis longus
origin: upper lateral surface of head and shaft of fibula
insertion: plantar side of medial cuneiform and base of metatarsal 1
innervation: superficial fibular nerve (L5, S1, S2)
function: eversion and plantarflexion of foot; supports arches of foot
fibularis brevis
origin: lower two-thirds of lateral surface of shaft of fibula
insertion: lateral base of metatarsal 5
innervation: superficial fibular nerve (L5, S1, S2)
function: eversion of foot
tibialis anterior
origin: lateral tibia and interosseous membrane
insertion: medial and inferior surfaces of medial cuneiform and metatarsal 1
innervation: deep fibular nerve (L4, L5)
function: dorsiflexion of foot at ankle joint; inversion of foot; dynamic support of medial arch of foot
extensor hallicus longus
origin: middle one-half of medial fibula and interosseous membrane
insertion: via dorsal digital expansion (extensor hood) to distal phalanx of great toe
innervation: deep fibular nerve (L5, S1)
function: extension of great toe and dorsiflexion of foot
extensor digitorum longus
origin: proximal one-half of fibula and lateral tibial condyle
insertion: via dorsal digital expansions (extensor hoods) into bases of distal and middle phalanges of lateral four toes
innervation: deep fibular nerve (L5, S1)
function: extension of lateral four toes and dorsiflexion of foot
fibularis turtius
origin: distal part of medial fibula
insertion: dorsal surface of metatarsal 5
innervation: deep fibular nerve (L5, S1)
function: dorsiflexion and eversion of foot
extensor digitorum brevis
origin: superolateral surface of the calcaneus
insertion: tendons of extensor digitorum longus of toes 2 to 4
innervation: deep fibular nerve (S1, S2)
function: extension of toes 2 to 4
extensor hallicus brevis
origin: superolateral surface of calcaneus
insertion: base of proximal phalanx of great toe
innervation: deep fibular nerve (S1, S2)
function: extension of metatarsophalangeal joint of great toe
abductor hallicus
origin: calcaneal tuberosity
insertion: medial side of base of proximal phalanx of great toe
innervation: medial plantar nerve from the tibial nerve (S1, S2, S3)
function: abducts and flexes great toe at metatarsophalangeal joint
flexor digitorum brevis
origin: calcaneal tuberosity
insertion: plantar surface of middle phalanges of lateral four toes
innervation: medial plantar nerve from the tibial nerve (S1, S2, S3)
function: flexes lateral four toes at proximal interphalangeal joint
abductor digiti minimi
origin: calcaneal tuberosity
insertion: lateral side of base of proximal phalanx of little toe
innervation: lateral plantar nerve from the tibial nerve (S1, S2, S3)
function: abducts little toe at the metatarsophalangeal joint
quadratus plantae
origin: medial surface of calcaneus and lateral process of calcaneal tuberosity
insertion: tendon of flexor digitorum longus
innervation: lateral plantar nerve from tibial nerve (S1, S2, S3)
function: assists flexor digitorum longus tendon in flexing toes 2 to 5
lumbricals
origin: tendons of flexor digitorum longus
insertion: extensor hoods of toes 2-5
innervation: first lumbrical—medial plantar nerve from the tibial nerve; second, third, and fourth lumbricals—lateral plantar nerve from the tibial nerve (S2, S3)
function: resist excessive extension of the metatarsophalangeal joints
flexor hallicus brevis
origin: cuboid and lateral cuneiform; tibialis posterior tendon
insertion: proximal phalanx of the great toe
innervation: medial plantar nerve from tibial nerve (S1, S2)
function: flexes metatarsophalangeal joint of the great toe
adductor hallicus
origin: transverse head—metatarsophalangeal joints of lateral three toes; oblique head—bases of metatarsals 2 to 4
insertion: proximal phalanx of great toe
innervation: lateral plantar nerve from tibial nerve (S2, S3)
function: adducts great toe at metatarsophalangeal joint
flexor digiti minimi
origin: base of metatarsal 5
insertion: proximal phalanx of little toe
innervation: lateral plantar nerve from tibial nerve (S2, S3)
function: flexes little toe at metatarsophalangeal joint
dorsal interossei
origin: sides of adjacent metatarsals
insertion: extensor hoods and bases of proximal phalanges of toes 2 to 4
innervation: lateral plantar nerve from tibial nerve (S2-S3)
function: abduction of toes 2 to 4 at metatarsophalangeal joints
plantar interossei
origin: medial sides of metatarsals of toes 3 to 5
insertion: extensor hoods and bases of proximal phalanges of toes 3 to 5
innervation: lateral plantar nerve from tibial nerve (S2, S3)
function: adduction of toes 3 to 5 at metatarsophalangeal joints
