Tufts DPT Anatomy - Week 6 Origins, insertions, Innervation and actions

Posterior axio-appendicular muscles

Trapezius, Latissimus Dorsi, Levator Scapulae, Rhomboids,

Trapezius

Innervation: Spinal Accessory nerve (CN XI)

Action: elevate, depress and retract scapula

Latissimus Dorsi

Innervation: Thoracodorsal nerve

Action: Extends, adducts, and internally rotates humerus

Levator Scapulae

Innervation: Dorsal scapular nerve and cervical nerves

Action: Elevate and rotate scapula (rotates glenoid fossa inferiorly)

Rhomboid major and minor

Innervation: Dorsal Scapular nerve

Action: Stabilizes scapula on thoracic wall, retracts, and rotates scapula (rotates glenoid fossa inferiorly)

Scapulohumeral muscles

- Deltoid

- Teres Major

- Supraspinatus

- Infraspinatus

- Subscapularis

- Teres Minor

Deltoid

Origin: Lateral clavicle, acromion and spine of scapula

Insertion: Deltoid tuberosity of humerus

Innervation: Axillary nerve

Action: Flexion, Extension, Internal rotation, External rotation and Abduction

Teres Major

Origin: Posterior surface of inferior angle of scapula

Insertion: Medial lip of intertubercular sulcus of humerus

Innervation: Lower subscapular nerve

Action: Adduction and Internal Rotation

Rotator cuff muscles:

supraspinatus, infraspinatus, teres minor, subscapularis

Supraspinatus

Origin: supraspinous fossa of scapula

Insertion: Superior facet of greater tubercle of humerus

Innervation: Suprascapular nerve

Action: Abduction, GH stabilization

Infraspinatus

Origin: Infraspinous fossa of scapula

Insertion: Middle facet of greater tubercle of humerus

Innervation: Suprascapular nerve

Action: External Rotation and GH stabilization

Teres Minor

Origin: Middle part of lateral border of scapula

Insertion: Inferior facet of greater tubercle of humerus

Innervation: Axillary Nerve

Action: External rotation and GH stabilization

Subscapularis

Origin: Scapular fossa (anterior)

Insertion: Lesser tubercle of humerus

Innervation: Upper and lower subscapular nerves

Action: Internal rotation and GH stabilization

Anterior Axio-appendicular muscles:

pectoralis major, pectoralis minor, subclavius, serratus anterior

Pectoralis Major

Clavicular head Origin: Medial anterior clavicle surface

Sternocostal head Origin: Anterior sternal surface, superior 6 costal cartilages, external oblique aponeurosis

Insertion: Lateral lip of intertubercular sulcus

Innervation: Lateral and medial pectoral nerves (clavicular head C5-C6, Sternocostal head C7-T1)

Action: Adduction and internal rotation, scapular protraction and depression, humeral flexion and extension

Pectoralis Minor

Origin: Ribs 3-5 near costal cartilage

Insertion: Medial border of superior surface of coracoid process

Innervation: Medial Pectoral Nerve

Action: Stabilizes scapula by drawing it inferiorly and anteriorly against thoracic wall

Subclavius

Origin: Junction of 1st rib and costal cartilage

Insertion: Inferior surface of middle clavicle

Innervation: Nerve to Subclavius

Action: Anchors and depresses scapula

Serratus Anterior

Origin: External surface of lateral parts of ribs 1-8

Insertion: Anterior surface of medial border of scapula

Innervation: Long thoracic nerve

Action: Protracts scapula and stabilizes scapula against thoracic wall

Biceps Brachii

Long head Origin: Supraglenoid tubercle of scapula

Short Head Origin: tip of coracoid process

Insertion: Tuberosity of radius and forearm via bicepital aponeurosis

Innervation: Musculocutaneous nerve

Action: Elbow flexion, forearm supination, shoulder flexion and stabilization

Brachialis

Origin: distal 1/2 of Anterior humerus

Insertion: Coronoid Process and tuberosity of ulna

Innervation: Musculocutaneous nerve and radial nerve

Action: elbow flexion (main workhorse)

Coracobrachialis

Origin: Coracoid process

Insertion: middle 1/3 of medial side of humerus

Innervation: Musculocutaneous nerve

Action: Flexes and adducts shoulder, stabilizes GH

Triceps brachii

Long Head Origin: Infraglenoid tubercle of scapula

Lateral head Origin: Posterior surface of humerus, superior to radial groove

Medial Head Origin: Posterior surface of humerus, inferior to radial groove

Insertion: Olecranon Process of Ulna

Innervation: Radial Nerve

Action: Extends Elbow, stabilizes humerus, assist with shoulder extension

Anconeus

Origin: Lateral Epicondyle of humerus

Insertion: Lateral surface of Olecranon, posterior ulna

Innervation: Radial nerve

Action: Assists with tricep extension and stabilizes elbow