Extrinsic Back Muscles Flashcards
List the superficial muscles of the back
Trapezius
Latissimus Dorsi
Levator Scapulae
Rhomboideus Major
Rhomboideus Minor
Trapezius is superficial to:
- splenius muscles of neck
- lower fibers Levator scapulae
- rhomboids
Origins of trapezius
External occipital protuberance
Medial 1/3 of superior nuchal line
Ligamentum nuchae
Spinous processes of C7- T12
Trapezius superior fibers insertion
Lateral 1/3 of clavicle
Trapezius middle fibers insertion
Spine and acromion of scapula
Trapezius inferior fibers insertion
Base of spine of scapula
Innervation of trapezius
CN XI accessory: motor
Ventral rami of C3 and C4 nerves: proprioception
Trapezius blood supply
superficial branch of transverse cervical artery
Trapezius actions on scapula
Raises, retracts, rotates scapula
Trapezius actions on head
Bilateral contraction of superior fibers extends head
Unilateral contraction of upper fibers laterally flexes head and cervical vertebrae
Trapezius superior fibers action on scapula
Elevate scapula, form force couple to rotate the scapula (upwards)
Trapezius middle fibers action
Retract the scapula
Trapezius inferior fibers action
Depress scapula
Latissimus dorsi origins
Spinous processes of T7-T12
All lumbar and sacral vertebrae (spinous processes)
Posterior part of iliac crest
From lower 3-4 ribs via muscular slips that interdigitate with external oblique muscle
Latissimus dorsi insertion
Crest of lesser tubercle, floor of bicipital groove of humerus
Latissimus dorsi innervation
Thoracodorsal nerve (posterior cord of brachial plexus, C6-C8 fibers)
Latissimus dorsi blood supply
Thoracodorsal artery (branch of subscapular artery)
Latissimus dorsi actions
Extension, medial rotation, adduction of arm
Levator scapulae origin
Posterior tubercles of transverse processes of C1- C3/4
Levator scapulae insertion
Medial border of scapula from superior angle to base of spine
Levator scapulae innervation
Ventral rami C3, C4 from deep branches of cervical plexus
Twig from dorsal scapular nerve (C5)
Levator scapulae blood supply
Deep branch of transverse cervical artery
Levator scapulae actions
Elevates and retracts scapula with trapezius
Laterally flexes cervical vertebral column when scapula is fixed
Both r. major and r. minor lie deep to:
Trapezius
Which Rhomboideus is more superior
Rhomboid minor
Rhomboideus minor origins
Lower part of ligamentum nuchae
Spinous processes of C7 and T1
Rhomboideus minor insertion
Medial border of scapula at base of spine
Rhomboideus minor innervation
Dorsal scapular nerve (C4, C5)
Rhomboideus minor blood supply
Deep branch of transverse cervical artery
Rhomboideus minor actions
Elevates medial border of scapula
Retracts scapula
Rotation of scapula (downwards)
Rhomboideus major origin
Spinous processes of T2- T5
Rhomboideus major insertion
Medial border of scapula between base of spine and inferior angle
Rhomboideus major innervation
Dorsal scapular nerve (C4, C5)
Rhomboideus major blood supply
Deep branch of transverse cervical artery
Rhomboideus major actions
Elevates medial border of scapula
Retracts scapula
Rotation of scapula (downwards)
Serratus posterior superior origin
Lower end of ligamentum nuchae
SpInous processes of C7- T2/T3
Serratus posterior superior insertion
Ribs 2-5 lateral to angle
Serratus posterior superior innervation
First four intercostal nerves (ventral rami of first four thoracic nerves)
Serratus posterior superior blood supply
Highest intercostal artery, posterior intercostal arteries
Serratus posterior superior action
Elevates upper ribs during inspiration
Serratus posterior inferior origin
Spinous processes of T10 – L2
Serratus posterior inferior insertion
Lower 3-4 ribs lateral to angles
Serratus posterior inferior innervation
Lowest 4 intercostal nerves (ventral rami of lower thoracic)
Serratus posterior inferior blood supply
Posterior intercostal arteries
Serratus posterior inferior action
Depresses lower ribs down and back during inspiration
