Exam 2 Muscles Flashcards
(81 cards)
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