Superficial Extrinsic Back Mucles Flashcards
Superficial Posterior Axiopendicular Muscles
Trapezius, latissimus dorsi
Superficial
trapezius, latissimus dorsi, levator scapulae, rhomboids (major and minor)
Trapezius
- direct attachment of pectoral girdle to trunk
- attaches pectoral girdle to the cranium and vertebral column and assists in suspending the upper limb
Trapezius- 3 parts
Descending (superior part)- elevates scapula
Middle Part- retracts the scapula, pulls it posterorly
Ascending (inferior part)- depresses scapula and lowers shoulder
Descending ascending work together in rotating scapula towards thoracic wall
Trapezius (Medial attachment)
Medial attachment- medial third of superior nuchal line; external occipital protuberance; nuchal ligament; spinouus process of C7-T12
Trapezius (lateral attachment)
lateral attachment- lateral third of clavicle; acromion and spine of scapula
Trapezius (Innervation)
innervation- spinal accessory nerve (CN X1) (motor fibers) and C3, C4 (pain and proprioception fibers)
Trapezius ( Main actionss)
Main actions of trapezius- descending (superior) part elevates; ascending (inferior part) depresses; and middle part (or all parts together) retract scapula; descending and ascending parts act together to rotate glenoid cavity superiorly
Latissimus Dorsi
- large fan shaped muscle that covers wide area of back
- pases fromtrunk to the humerus and acts directly on the glenohumeral (shoulder) joint and indirectlyon pectoral girdle(scapulathoracic joint)
- raises trunk of arm
Latissimus dorsi (Medial Attachment)
-medially attaches to spinous processes of inferior 6 thoracic vertebrae , thoracolumbar fascia, iliac crest, and inferior 3 or 4 ribs
Latissimus Dorsi (lateral attachment)
-laterally attaches to the floor of intertubercular sulcus (groove) of humerus
Latissimus Dorsi (innervation)
Thoracodorsal nerve (C6, C7, C8)
Latissimus Dorsi (Main actions)
extends, adducts, and medially rotates humerus; raises body toward arm during climbing
Deep Posterior Axiopendicular Muscles
Levator scapulae and Rhomboids
Levator Scapulae
- superior 1/3 lies deep to SCM; the inferior third is deep to the trapezius
- acts with superior portion of trapezius to elevate the scapula
- with rhomboids and pectoralis minor the levator scapulae rotates the scapula
- acting bilaterally: they extend the neck
- acting unilaterally: contributes to lateral flexion of neck
Levator Scapulae (Medial Attachment)
Medially attaches to posterior tubercles of transverse processes of C1- C4
Levator Scapulae (lateral attachment)
Laterally attaches to the medial border of scapula superior to root of spine
Levator Scapulae (Innervation)
Dorsal scapular (C5) ad cervical (C3 and C4) nerves
Levator Scapulae (main actions)
elevates scapula and tilts its glenoid cavity inferiorly by rotating scapula
Rhomboids (Major and Minor)
-deep to trapezius form parallel bands that pass inferolaterally from vertebrae to the medial border of the scapulae
Rhomboid Major- thin flat and 2x’s wider than the thicker Rhomboid Minor lying superior to it
-retract and rotate the scapula
Rhomboid Minor (Medial attachment)
nuchal ligament; spinous process of C7 and T1 vertebrae
Rhomboid Minor (Later attachment)
rhomboid minor laterally attaches to the triangular area at medial end of scapular spine
Rhomboid Major (Medial attachment)
Rhomboid major medially attaches to the spinous proceses of T2- T5 vertebrae
Rhomboid Major (lateral attachment)
rhomboid major laterally attaches to the medial border of scapula from level of spine inferior to angle
