Shoulder/Back muscle O/I/A

• Trapezius attachments

  Origin: Occipital bone and C1-C7 SP (descending)

  Insertion: Lateral 1/3 of clavicle (descending)

  Ascending:

  Origin: T1-T4 SP, aponeurosis

  Insertion: Acromion Process

  Transverse:

  Origin: T5-T12 SP

  Insertion: Scapular spine
• Trapezius actions:

  Descending - Rotates glenoid cavity

  superiorly (upward rotation), head tilt to same

  side and rotation to opposite side, elevates

  scapula

  Transverse - Retraction of scapula

  Ascending - Depresses scapula, works with upper

  trapezius to rotate scapula laterally (upward

  rotation)
• Trapezius innervation

  CN XI Accessory Nerve (motor);

  C3-C4 spinal nerves (sensory; pain and proprioception)
• Trapezius blood supply

  Descending - Occipital artery

  Transverse - Transverse cervical artery (superficial branch)

  Ascending - Dorsal scapular artery
• Levator scapulae attachments

  O: Transverse processes of C1-C4

  I: Superior medial border of scapula
• Levator scapulae innervation and blood supply

  Inn: Dorsal scapular nerve and cervical nerves C3-C4 (thyrocervical trunk)

  Blood supply: Transverse cervical and ascending cervical arteries (branches of
• Levator scapulae actions

  Elevates scapula; Medially rotates scapula, tilts glenoid cavity inferiorly; Works with trapezius bilaterally to extend the neck; Unilateral contraction – contributes to lateral flexion of the neck (same side)
• Rhomboid Major and Minor attachments

  O: Spinous processes of T1-T4 (major)Spinous processes of C6-C7 (minor)

  I: Medial border of scapula (major – below spine, minor – above spine)
• Latissimus Dorsi attachments

  O: Spinous processes of T7-T12; Thoracolumbar fascia, Inferior angle of scapula Iliac crest, Inferior 3-4 ribs

  I: Floor of intertubercular groove (bicipital groove) of humerus
• Latissimus Dorsi innervation and blood supply

  Inn: Thoracodorsal nerve

  Blood supply: Thoracodorsal artery, lower intercostal arteries, lumbar arteries
• Latissimus Dorsi actions

  Extension, adduction and internal rotation of arm
• Serratus anterior attachments

  O: External surface of lateral portion of ribs 1-9

  I: Medial border of scapula (anterior surface); superior and inferior angle both anterior and posterior surfaces
• Serratus Anterior innervation and blood supply

  Inn: Long thoracic nerve

  Blood supply: Superior thoracic artery; lateral thoracic artery; branches of thoracodorsal artery
• Serratus Anterior actions

  Protraction of scapula; lateral rotation of scapula (rotates glenoid cavitysuperior to allow for abduction greater than 90°); holds scapula to thoracic wall
• Pec Minor attachments

  O: Ribs 3-5, near costal cartilage

  I: Medial border and coracoid process of scapula
• Pec Minor blood supply and innervation

  Inn: Lateral and medial pectoral nerves (medial is primary)

  Blood supply: Thoracoacromial artery (pectoral and deltoid branches); superior thoracic artery and lateral thoracic artery
• Pec Minor actions

  Stabilizes scapula on thoracic wall (draws it inferior and anterior)
• Pec Major attachments

  O: Medial half of clavicle (clavicular head); anterior surface of sternum, superior 6 costal cartilages (sternocostal head); anterior surface of rectus sheath (abdominal part)

  I: Lateral lip of intertubercular groove
• Pec Major blood supply and innervation

  Inn: Lateral and medial pectoral nerves

  Blood supply: Thoracoacromial artery (pectoral branch); perforating branches of internal thoracic artery
• Pec Major actions

  Adduction and internal rotation of arm (when arm is in anatomical position); Flexion of the humerus up to 90° (clavicular head); Extension from flexed position (sternocostal head)