Shoulder and Axilla Anatomy

Subacromial Bursitis & Supraspinatus Tendonitis

"Painful Arc Syndrome": pain during adduction in the 50-130 degree range of the arm Arm Drop Test: Patient lowers fully abducted arm slowly and smoothly, when reaching 90 degree abduction position, the arm will suddenly drop to side

Branches of Axillary Artery

1st: Superior Thoracic Artery 2nd: Thoracoacromial and Lateral Thoracic Arteries 3rd: Subscapular, Anterior and Posterior Circumflex humeral arteries. "Sixties Teens Love Sex, Alcohol, & Pot."

Circumflex Humeral Arteries

Anterior and Posterior anastomoses with each other, supplies shoulder muscles such as deltoid, teres major and minor, and the long head of the triceps.

"Winged Scapula"

Caused by injury to long thoracic nerve or any injury above this nerve's spinal cord level; paralysis of serratus anterior, cannot comb hair

Subacromial/subdeltoid bursa

Function: Prevents rubbing of SS muscle and acromion head. Wear and tear (rotator cuff injury) (seen in construction workers) can result in bursitis and tendonitis.

Arteries around the Scapula

If one is ligated in surgery, no biggie because they all circumflex

Do not ligate the axillary/brachial artery in this location:

If you ligate between the circumflex humeral arteries and deep artery of the arm, you will completely cut off blood supply to the upper limb.

Rotator Cuff Muscles (SITS) Supraspinatus (SS) Infraspinatus (IS) Teres Minor (TM) Subscapularis (SC)

Insertion SIT: Greater Tubercle Insertion of S: Lesser Tubercle Function of all: Fixes head of humerus in glenoid cavity, stabilizes shoulder joint. Function of SS: Aids in initial 15 degrees abduction along with deltoid. Function of SC: ad-ducts arm along with TM, medially rotates arm. Function of IS and TM: laterally rotates the arm. Subscapularis forms part of the posterior wall of the axilla.

Supscapular Artery (consistent)

Largest branch of axillary artery, divides into circumflex scapular and thoracodorsal arteries, supplies subscapularis, teres major, serratus anterior, and latissimus dorsi.

Pectoralis Minor

Lies underneath pectoralis major. Origin: Coracoid process of the scapula. Insertion: Ribs 3, 4, and 5. Function: Fixes the scapular to the thoracic wall, stretches the arm forward to touch an object that is just out of reach, helps with inspiration by lifting ribs.

Lateral Thoracic Artery (Varies)

May rise variously, supplies pectoral muscles, axillary lymph nodes, and the breast. It is an important source of blood to the lateral part of the mammary gland in women.

Extrinsic Shoulder Muscles (Thoracoappendicular): Anterior Group

Muscles attached to thoracic wall. -Pec. major, pec. minor, subclavius, serratus anterior

Extrinsic Shoulder Muscles (Thoracoappendicular): Posterior Group

Muscles attached to thoracic wall. -Superficial: Trapezius and Latissiumus Dorsi -Deep: Levator Scapulae and Rhomboids

Intrinsic Shoulder Muscles

Muscles only attach to shoulder bones. -Deltoid, Teres major, 4 rotator cuff muscles (Supraspinatus, Infraspinatus, Teres minor, and Subscapularis = SITS)

Triangle of Ausculation

Near the inferior angle of the scapula, bordered by superior border of the latissimus dorsi, inferior border of trapezius, and the medial border of the scapula. Function: place for examining the posterior segments of the lungs w/ stethoscope. Triangle enlarges when folding arms across the chest and bent forward.

Rhomboids (Major and Minor)

Origin: C7 - T5 Insertion: Medial border of the scapula. Function: pull the scapula to the central line. Minor is superior to major Lies deep to the trapezius. Test rhomboid by putting hand on gluteal region and move elbow towards each other.

Deltoid

Origin: acromion, spine of scapula, clavicle Insertion: Deltoid tuberosity Function: Stabilizes the shoulder joint by holding the head of the humerus in the glenoid cavity during movement especially when carrying heavy objects with hands. Abduction of arm >15 degrees. Innervation: Axillary nerve The anterior (together w/ the pec. major) and posterior (together w/ latissimus dorsi) parts swing the arm during walking.

Pectoralis Major

Origin: clavicular head and sternocostal head Insertion: lateral lip of the intertubercular groove of the humerus. Function: adduct and medially rotate humerus, flexes clavicle head and sternocostal head extends the humerus. Forms the deltopectoral groove with deltoid muscle = Cephalic vein runs in this groove.

Teres Major

Origin: inferior angle of scapula. Insertion: medial lip of intertubercular groove. Function: Stabilizes the humeral head in its socket and counteracts the deltoid during abduction of the arm. Adducts humerus and medially rotates it. Innervation: Lower subscapular nerve

Serratus Anterior

Origin: ribs 1-8 external lateral surface. Insertion: medial border of scapula. Function: pulls the scapula forward when punching or reaching anteriorly, rotates the inferior angle of the scapula so the glenoid cavity is raised up (raising arm above shoulder/combing hair), holds scapula against thoracic wall (when doing pushups or pushing objects). Innervated by: Long thoracic Nerve

Latissimus Dorsi

Origin: starts at T7, Thoracolumbar Fascia, iliac crest. Insertion: floor of intertubercular groove of humerus. (inferior part of humerus) Function: Extends, adducts, and medially rotates the humerus. Brings body toward arms when climbing (monkey bars, rock climbing). Forms part of posterior wall of the axilla. Innervation: Thoracodorsal nerve

Trapezius

Origin: superior nuchal line (C7 - T12) Insertion: lateral clavicle, acromion, spine of scapula Function: superior fibers elevates scapula, middle fibers retract scapula, inferior fibers depress the scapula and lower the shoulder, cooperation of superior and inferior fibers can rotate the scapula. Innervation: CN 11 (spinal accessory nerve) (comes off brainstem) Test: ask patient to shrug shoulder against resistance.

Levator Scapulae

Origin: transverse process of C1-C4. Insertion: medial border superior part of scapula. Function: Elevates scapula Innervation: Dorsal scapular nerve. Superior third lies deep to the sternocleidomastoid, the inferior third lies deep to the trapezius.

Axillary Vein

Receives directly or indirectly blood from the thoracoepigastric vein which collects blood from the superficial veins of anterior abdominal wall. Blood returns to the heart through either SVC or IVC.

Thoracoacromial Artery

Short wide trunk, deep to the clavicular head of pectoralis minor, divides into four branches: acromial, deltoid, pectoral, clavicular. "All Dudes Pick Chicks."

Superior Thoracic Artery

Small Vessel, supplies muscles in 1st and 2nd rib intercostals spaces and serratus anterior, anastomoses with intercostal arteries.

Axillary Artery

Starts from Subclavian Artery. Has 3 segments with 6 branches off each segment: 1 = 1 branch; 2 = 2 branches, 3 = 3 branches. Once subclavians travel beyond first rib, it changes name to become the axillary artery.

During removal and dissection of axillary lymph nodes, two vulnerable nerves to watch for are _____________ and ___________.

long thoracic nerve, thoracodorsal nerve

Axillary lymph nodes ultimately all drain into _________.

subclavian lymphatic trunk