posterior axio-appendicular muscles

Question 1

(superficial)

Answer 1

Trapezius

• *medial attachment** : medial third of superior nuchal line, external occipital protuberance, nuchal ligament, spinous processes of C7-T12 vertebrae
• *lateral attachment:** lateral third of clavicle, acromion and spine of scapula
• *main action**: descending (superior) part elevates, ascending (inferior) part depresses, and middle part (or all parts together) retracts scapula; descending and ascending parts act together to rotate glenoid cavity superiorly

Innervation : Spinal accessory nerve and C3, C4 spinal nerves

Question 2

(superficial)

Answer 2

Latissimus dorsi

Medial attachment: spinous processes of inferior six thoracic vertebra, thoracolumbar fascia, iliac crest, and inferior three or four ribs

Lateral attachment: floor of interbercular sulcus (groove) of humerus

Main action : extends, adducts, and medially rotates shoulder joint; raises body toward arms during climbing

innervation: thoracodorsal nerve (C6, C7, C8)

Question 3

Answer 3

Levator scapulae

Medial attachment : posterior tubercles of transverse processes of C1-C4 vertebrae

lateral attachment : medial border of scapula superior to root of spine

main action: elevates scapula and rotates glenoid cavity inferiorly

innervation: Dorsal scapular C5, and cervical spinal nerves

Question 4

Answer 4

Rhomboids minor and major

Medial attachment

Minor : nuchal ligament; spinous processes of C7 an T1 vertebrae

Major : spinous processes of T2-T5 vertebrae

lateral attachment

minor : triangular area at medial end of scapular spine

major: medial border of scapula from level of spine to inferior angle

Main action : retracts scapula and rotates glenoid cavity inferiorly; fix scapula to thoracic wall

Innervation: dorsal scapular nerve (C4, C5)