Unit 2: The Thorax Flashcards
what are the muscles of the posterior thorax?
- splenius muscles
- trapezius
- latissimus dorsi
- rhomboids
- levator scapulae
- serratus posterior
- erector spinae
- multifidus
what are the regions of the splenius muscles?
- capitis
- cervicis
what are the OIAIs of the splenius capitis?
- origin: nuchal ligament, spinous processes of C7-T3
- insertion: mastoid process (temporal bone), lateral third of superior nuchal line
- action: bilaterally - extends the neck; unilaterally - rotates and laterally flexes the neck
- innervation: posterior/dorsal rami C2-C3
what are the OIAIs of the splenius cervicis?
- origin: spinous processes of T3-T6
- insertion: transverse processes of C1-C2
- action: bilaterally - extends the neck; unilaterally - rotates and laterally flexes the neck
- innervation: posterior/dorsal rami C4-T1
what are the relative location of the splenius muscles?
capitis is superficial and superior to cervicis
what are the regions of the trapezius?
- superior (descending) part
- middle (transverse) part
- inferior (ascending) part
where is the trapezius and what is it innervated by?
- most superficial muscle
- spinal accessory nerve (CN XI)
what are the OIAs of the superior trapezius?
- origin: superior nuchal line, external occipital protuberance
- insertion: lateral third of the clavicle
- action: elevate and retract the scapula
what are the OIAs of the middle trapezius?
- origin: spinous processes of T1-T4
- insertion: spine and acromion of scapula
- action: retract scapula
what are the OIAs of the inferior trapezius?
- origin: spinous processes of T5-T12
- insertion: spine of the scapula
- action: depresses and retracts scapula
what are the regions of the latissimus dorsi?
- vertebral part
- iliacal part
- costal part
- scapular part
what is the origin of the vertebral part of the latissimus dorsi?
spinous processes T7-T12 and the thoracolumbar fascia
what is the origin of the iliacal part of the latissimus dorsi?
iliac crest
what is the origin of the costal part of the latissimus dorsi?
body of ribs 9-12
what is the origin of the scapular part of the latissimus dorsi?
inferior angle of the scapula
what are the IAIs of the latissimus dorsi?
- insertion: medial side of the floor of the intertubercular (bicipital) groove of the humerus
- action: adducts and medial rotates the arm at the glenohumeral joint (GHJ); extends humerus at the GHJ; elevates the trunk (pull up) and moves the truck anteriorly (cross-country skiiing)
- thoracodorsal nerve of the brachial plexus (C6-C8)
what are the OIAIs of the rhomboid major?
- origin: spinous processes T2-T5
- insertion: medial border of the scapula, inferior to the spine
- action: retract and elevate the medial border of the scapula
- innervation: dorsal scapular nerve (C4-C5)
what are the OIAIs of the rhomboid minor?
- origin: spinous processes C6-C7
- insertion: medial border of the scapula, superior to the spine
- action: retract and elevate the medial border of the scapula
- innervation: dorsal scapular nerve (C4-C5)
where are the splenius muscles relative to the rhomboids?
deep
what are the OIAIs of the levator scapula?
- origin: transverse processes C1-C4
- insertion: medial border of the scapula, superior to the spine
- action: elevates medial border of the scapula; if scapula is fixed, flexes the neck laterally
- innervation: dorsal scapular nerve (C4-C5)
where is the levator scapula relative to the splenius muscles?
deep
what are the regions of the serratus posterior and where do they lie relative to surrounding muscles?
- superior; lies deep to rhomboids and levator scapula and superficial to splenius muscles
- inferior; deep to latissimus dorsi
what are the OIAIs of the serratus posterior superior?
- origin: spinous processes C7-T3
- insertion: upper border of ribs 2-5
- action: elevates ribs (contributes to inhalation)
- innervation: intercostal nerves
what are the OIAIs of the serratus posterior inferior?
- origin: spinous processes T11-L2
- insertion: inferior border of ribs 9-12
- action: depresses ribs (contributes to exhalation
- innervation: intercostal nerves