Exam 4 muscles Flashcards
external oblique
Origin: external surfaces of ribs 5-12
Insertion: Linea alba, pubic crest and tubercle, and another anterior half of the iliac crest.
innervation: Thoracoabdominal nerve
action: compresses and supports abdominal viscera, and flexes and rotates the trunk
internal oblique
O: Thoracolumbar fascia, iliac crest, and lateral half of inguinal ligament
I: Inferior border of ribs 10-12, linea alba, pubic crest, and pecten pubis, via conjoint tendon.
Innerve: Thoracoabdominal nerve
compresses and supports abdominal viscera, and flexes and rotates the trunk
Transversus Abdominis
O: internal surfaces of costal cartilages 7-12, thoracolumbar fascia, and iliac crest.
I: linea alba with internal oblique, pubic crest, and pecten pubis via conjoint tendon.
Innerve: Thoracoabdominal
Action:compresses and supports abdominal viscera, and flexes and rotates the trunk
Rectus abdominis
O: xiphoid process, costal cartilage 5-7
I: pubic symphysis and pubic crest.
Innerve: Thoracoabdominal
Action:compresses and supports abdominal viscera, and flexes and rotates the trunk
innermost intercostals
O:inner surface of the costal groove of the ribs, deep to the origin of the internal intercostal muscles.
I: superior border of the inferior rib.
innervation: intercostal nerve
action: depress the ribs
pectoralis major
O: medial half of clavicle, sternum, costal cartilages 1-7
I: lateral lip of intertubercular sulcus.
Action: medially rotates, flexes, and adducts the humerus
innervation: medial and lateral pectoral nerve
pectoralis minor
O: ribs 1-5
I: Coracoid process of scapula
Actions: anteriorly tilts and depresses the scapula.
innervation: medial pectoral nerve
serratus anterior
O: anterior surface of the medial border of the scapula
I: ribs 1-9 lateral parts
actions: rotates glenoid cavity superiorly and protracts scapula
innervation: long thoracic
external intercostals
O: inferior border of the scapula
I: superior border of the rib below
action: elevates the rib below
innervation: intercostal
internal intercostal
O: inferior border of the rib above
I:inferior border of the scapula
action: depresses the rib below
innervation: intercostal
innermost intercostal
O: inferior border of the rib above
I:inferior border of the scapula
action: depresses the rib below
innervation: intercostal
rectus abdominis
O: xiphoid process and costal cartilages 5-7
I: pubic symphysis and pubic crest
action: flexes trunk, assists in pelvic tilt, and compresses the abdominal viscera
innervation: thoracoabdominal nerve and subcostal nerve
transverse abdominis
O: Internal surfaces of costal cartilages of ribs 7-12, thoracolumbar fascia, anterior two thirds of iliac crest, iliopectineal arch
I: Linea alba, aponeurosis of internal abdominal oblique muscle; pubic crest, pectinal line of pubis
action: Compresses abdominal viscera, expiration
Unilateral contraction - Trunk rotation (ipsilateral)
innervation: Intercostal nerves (T7-T11), subcostal nerve (T12), iliohypogastric nerve (L1), ilioinguinal nerve (L1)
diaphragm
O :Sternal part: Posterior aspect of xiphoid process
Costal part: Internal surfaces of lower costal cartilages and ribs 7-12
Lumbar part: Medial and lateral arcuate ligaments (lumbocostal arches), bodies of vertebrae L1-L3 (+intervertebral discs), anterior longitudinal ligament
I: Central tendon of diaphragm
action: Depresses costal cartilages, primary muscle of breathing (inspiration)
innervation: Phrenic nerves (C3-C5) (sensory innervation of peripheries via 6th-11th intercostal nerves)
Mnemonic: C3, 4, 5 keeps the diaphragm alive!
sternocleidomastoid
O: Sternal head: superior part of anterior surface of manubrium sterni
Clavicular head: superior surface of medial third of the clavicle
I: Lateral surface of mastoid process of the temporal bone, Lateral half of superior nuchal line of the occipital bone
action: Unilateral contraction: cervical spine: neck ipsilateral flexion, neck contralateral rotation
Bilateral contraction: atlantooccipital joint/ superior cervical spine: head/neck extension; Inferior cervical vertebrae: neck flexion; sternoclavicular joint: elevation of clavicle and manubrium of sternum
innervation: Accessory nerve (CN XI), branches of cervical plexus (C2-C3)
Levator Ani
O: Puborectalis: Posterior surface of bodies of pubic bones (also known as puboanalis)
Pubococcygeus: Posterior surface of bodies of pubic bones (lateral to puborectalis)
Iliococcygeus: Tendinous arch of interal obturator fascia, Ischial spine
I: Puborectalis: None (forms ‘puborectal sling’ posterior to rectum)
Pubococcygeus: Anococcygeal ligament, Coccyx, Perineal body and musculature of prostate/ vagina
Iliococcygeus: Anococcygeal ligament, Coccyx
action: Stability and support of the abdominal and pelvic organs, resistance against increased intra-abdominal pressure, opening and closing of the levator hiatus
innervation: Pubococcygeus N.
