Lab 4 – 3.2: Shoulder

Deltoid Origin: spine of scapula, acromion, anterior lateral 1/3 clavicle Insertion: Deltoid tuberosity (humerus) Innervation: Axillary Nerve (C5,C6) Function: abduction of arm

Deltoid (cont) Note: posterior humeral circumflex artery supplies deltoid

Supraspinatus Origin: supraspinous fossa Insertion: Greater tubercle of the humerus (superior surface) Innervation: Suprascapular nerve (C5,C6) Function: abduction of arm at glenohumeral joint Greater tubercle

Supraspinatus (cut) Note: Superior transverse scapular ligament Suprascapular Nerve (inferior to ligament) Suprascapular artery (superior to ligament)

Suprascapular Artery Right Subclavian artery  thyrocervical trunk  suprascapular artery Supplies suprascapular muscle and glenohumeral joint Greater tubercle

Infraspinatus Origin: medial 2/3 of intraspinous fossa Insertion: Greater tubercle of the humerus (middle posterior surface) Innervation: Suprascapular nerve (C5,C6) Function: lateral rotation of arm at glenohumeral joint Greater tubercle

Circumflex scapular Artery Branch from suprascapular artery – supplies infraspinatus muscle and glenohumeral joint Greater tubercle

Suprascapular Vein Drains posterior scapular region Greater tubercle

Teres Minor Muscle Origin: lateral border of the scapula Insertion: greater tubercle of the humerus Innervation: Axillary nerve Function: Rotator Cuff Muscle lateral rotation of the arm at the glenohumeral joint Gray’s anatomy for students (GS): pg. 656

Teres Major Muscle Origin: Scapula (inferior angle and lateral border) Insertion: humerus (medial lip of the intertubercular sulcus) Innervation: lower subscapular nerve Function: medial rotation of arm extension of the arm Adduction of the arm GS: pg. 679

Long head of the triceps brachii Origin: scapula (infraglenoid tubercle) Insertion: olecranon of ulna Innervation: Radial nerve Function: extension of the forearm Accessory adductor/extensor of the arm

Serratus anterior Origin: lateral surface of ribs 1-9 Insertion: scapula (medial border) Innervation: long thoracic nerve Function: Abduction of the scapula Medial rotation of scapula Keeps medial border and inferior angle of scapula opposed to thoracic wall GS: pg. 689

Pectoralis Major *active during forced inspiration Origin: medial clavicle sternum, costal cartilages 1-7, aponeurosis of external abdominal oblique muscle Insertion: intertubercular sulcus of humerus (lateral lip) Innervation: Lateral pectoral nerve (C5-7) Medial pectoral nerve (C8-T1) Function: Adduction, medial rotation, and flexion of humerus (shoulder joint) *active during forced inspiration

Pectoralis Minor Origin: ribs 3-5 Insertion: Coracoid process of scapula Innervation: Medial pectoral nerves Function: Depresses tip of shoulder; protracts scapula Active during forced inspiration

Deltopectoral Triangle Also known as “clavipectoral” triangle Bordered by pectoralis major muscle, deltoid muscle, and clavicle Passageway for cephalic vein Greater tubercle

Axillary Vein Drainage: Pectoral, shoulder, and scapular regions

Axillary Nerve Motor Innervates the deltoid muscle

Latissimus Dorsi Origin: Spinous processes of TVII through LV and sacrum, iliac crest, ribs X–XII Insertion: Humerus (floor of intertubercular sulcus) Innervation: Thoracodorsal nerve (C6–C8)

Latissimus Dorsi Function: Extends, adducts, and medially rotates humerus

Quadrangular Space Location: Shoulder (posterior scapular region) Boundaries: Superior boundary: Inferior margin of teres minor Lateral boundary: Surgical neck of the humerus Inferior boundary: Superior margin of teres major Medial boundary: Lateral margin of the long head of the triceps brachii Function: Passageway for posterior circumflex humeral artery and vein and axillary nerve Quadrangular space

Triangular Space Location: shoulder (posterior) Boundaries: Superior boundary: inferior teres minor muscle Inferior boundary: superior teres major muscle Lateral boundary: medial long head of triceps brachii muscle Function: Passageway for circumflex scapular artery and vein

Deltoid

Axillary Nerve

Supraspinatus

Infraspinatus

Teres Minor Muscle Gray’s anatomy for students (GS): pg. 656

Teres Major Muscle GS: pg. 679

Long head of the triceps brachii

Serratus anterior GS: pg. 689

Pectoralis Major

Pectoralis Minor

Latissimus Dorsi

Arteries and Nerves 2 1 3 4