Superficial Layer

• Trapezius
  • Bony Attachments:
    • 1. Superior nuchal line and occipital protruberance, Ligamentum nuchae and C1-C3 SP, SP T1-T12
    • 2. Clavicle, Acromion, Spine of scapula
  • Innervation: Spinal accessory Nerve (CN XI), Cervical Nerves (C3, C4)
  • Arterial Supply: Transverse Cervical a., Descending scapular a., Post. intercostal a.
  • Action: Elevates, retracts, and rotates scapula
• Latissimus Dorsi
  • Bony Attachments:
    • 1. SP of T7-T12, thoracolumbar fascia, iliac crest, ribs 9-12
    • 2. Floor of bicipital groove of humerus
  • Innervation: Thoracodorsal nerve (C6, C7, C8)
  • Arterial Supply: Thoracodorsal a., Descending scapular a., Trans. Cervical a.
  • Action: Adducts, extends shoulder, internally rotates arm
• Levator scapulae
  • Bony Attachments:
    • 1. TP of C1-C4
    • 2. Vertebral border of the scapula
  • Innervation: Dorsal scapular nerve
  • Arterial Supply: Trans. cervical a., Descending (dorsal) scapular a., Post. intercostal a.
  • Action: Elevates and downwardly rotates scapula
• Rhomboid minor
  • Bony Attachments:
    • 1. Nuchal lig., SP C7-T1
    • 2. Vertebral border of scapula
  • Innervation: Dorsal scapular nerve
  • Arterial Supply: Transverse cervical a., Descending (dorsal) scapular a.
  • Action: Retracts scapula
• Rhomboid major
  • Bony Attachments:
    • 1. SP T2-T5
    • 2. Vertebral border of scapula
  • Innervation: Dorsal scapular nerve
  • Arterial Supply: Transverse cervical a., Descending (dorsal) scapular a., Post. intercostal a.
  • Action: Retracts scapula
• Serratus Anterior
  • Bony Attachments:
    • 1. External surface of Upper 8 ribs
    • 2. Vertebral border of the scapula
  • Innervation: Long Thoracic nerve
  • Arterial Supply: Lateral thoracic a. of axillary a.
  • Action: Lifts the ant. Rib cage, Protracts the scapula