Back & Rotator Cuff Muscles Flashcards
Trapezius
Origin
- Superior Nuchal Line
- External occipital protuberance
- SP of C7 to T12
Trapezius
Insertion
- Lateral 1/3 of clavicle
- Acromion
- Spine of the scapula
Trapezius
Action
- Rotate and elevate scapula (superior part)
- retract scapula (middle)
- depress scapula (inferior)
Trapezius
innervation
Motor: spinal accessory nerve (CN XI)
Proprioception: Anterior/ventral rami of C3, C4
Trapezius, blood supply
Transverse cervical artery
Latissimus Dorsi
Origin
- SP T7-L5
- Thoracolumbar fascia
- sacrum
- iliac crest
- ribs 10-12
Latissimus dorsi
Insertion
Floor of the intertubercular sulcus of the humerus
Latissimus dorsi
Action
Extends, adducts, and medially rotates the humerus
Latissimus dorsi
Innervation
Thoracodorsal nerve (C6, C7, C8 of brachial plexus)
Latissimus dorsi
Blood supply
Thoracodorsal artery
Rhomboid major
Origin
SP T2-T5
Rhomboid major
Insertion
Medial border of scapula below its spine
Rhomboid major
Action
Retract and rotate scapula (to tilt glenoid cavity inferiorly)
Rhomboid major
Innervation
Dorsal scapular nerve (C5 of brachial plexus)
Rhomboid major
Blood supply
Dorsal scapular artery
deep branch of transverse cervical artery
Rhomboid minor
Origin
Ligamentum nuchae and SP C7-T1
Rhomboid minor
Insertion
Medial border of the scapula (at its spine)
Rhomboid minor
Action
Retract and rotate scapula (to tilt glenoid cavity inferiorly)
Rhomboid minor
Innervation
Dorsal scapular nerve (C5 of brachial plexus)
Rhomboid minor
Blood supply
Dorsal scapular artery
Levator scapulae
Origin
Transverse processes of C1-C4
Levator scapulae
Insertion
Superior angle of the scapula
Levator scapulae
Action
Elevates and rotates the scapula
to tilt the glenoid cavity inferiorly
Levator scapulae
Innervation
Dorsal scapular nerve (C5 of brachial plexus)
Levator scapulae
Blood supply
Dorsal scapular artery
deep branch of transverse cervical artery
Deltoid
Origin
- Spine of the scapula
- Acromion of the scapula
- Lateral 1/3 of the clavicle
Deltoid
Insertion
Deltoid tuberosity of the humerus
Deltoid
Action
Abducts, flexes, and extends the humerus
Deltoid
Innervation
Axillary nerve
Deltoid
Blood supply
Posterior circumflex humeral artery
Supraspinatus
Origin
Supraspinous fossa of the scapula
Supraspinatus
Insertion
Superior facet of the greater tubercle of the humerus
Supraspinatus
Action
Abducts the humerus (mostly first 15 degrees)
Supraspinatus
Innervation
Suprascapular nerve (C5, C6 of brachial plexus)
Supraspinatus
Blood supply
Suprascapular artery
Infraspinatus
Origin
Infraspinous fossa of scapula
Infraspinatus
Insertion
Middle facet of the greater tubercle of the humerus
Infraspinatus
Action
Laterally rotates humerus
Infraspinatus
Innervation
Suprascapular nerve (C5, C6 of brachial plexus)
Infraspinatus
Blood supply
Supracapular artery
Subscapularis
Origin
Subscapular fossa of scapula
Subscapularis
Insertion
Lesser tubercle of the humerus
Subscapularis
Action
Medially rotates the humerus
Subscapularis
Innervation
Upper subscapular nerve & lower subscapular nerve
C5 and C6 of brachial plexus, respectively
Subscapularis
Blood supply
Subscapular artery
Teres major
Origin
Inferior angle of the scapula
Teres major
Insertion
Medial lip of the intertubercular sulcus of the humerus
Teres major
Action
Adducts and medially rotates the humerus
Teres major
Innervation
Lower subscapular nerve (C6 of brachial plexus)
Teres major
Blood supply
Subscapular and circumflex scapular arteries