WINDSOR UNIVERSITY SCHOOL OF MEDICINE St.Kitts DEPARTMENT OF ANATOMY UPPER LIMB SHOULDER

SHOULDER The shoulder is the region of upper limb attachment to the trunk and neck.

1 A large muscle that arises from two heads flexes and medially rotates the arm. It is innervated by nerves arising from different cords of the brachial plexus. This is the: A.Latissimus dorsi B.Trapezius C.Deltoid D.Subscapularis E.Pectoralis major

Bones of the Shoulder Girdle Clavicle and scapula, which form the pectoral girdle (shoulder girdle) The proximal end of the humerus.

Muscles Shoulder Region

Anterior Axioappendicular Muscles of the Upper Limb PECTORALIS MAJOR PECOTORALIS MINOR SUBCLAVIUS SERRATUS ANTERIOR

PECTORALIS MAJOR N. supply: Medial and lateral pectoral nerves Origin: Clavicle, sternum, and upper six costal cartilages Insertion : Lateral lip of bicipital groove of humerus N. supply: Medial and lateral pectoral nerves Action : Adducts arm and rotates it medially; clavicular fibers also flex arm

PECTORALIS MAJOR

PECOTORALIS MINOR N. supply: Medial pectoral nerve Origin: Third, fourth, and fifth ribs Insertion : Coracoid process of scapula N. supply: Medial pectoral nerve Action: Stabilizes scapula by drawing it inferiorly

SUBCLAVIUS N. supply: Nerve to subclavius Origin: First costal cartilage Insertion : Clavicle N. supply: Nerve to subclavius Action: Depresses the clavicle

SERRATUS ANTERIOR N. supply: Long thoracic nerve Origin: Upper eight ribs Insertion :Anterior surface of medial border of scapula N. supply: Long thoracic nerve Action: Protracts scapula and rotates scapula

Paralysis of the Serratus Anterior(winged scapula ) Due to loss of Innervation-long thoracic nerve When the serratus anterior is paralyzed owing to injury to the long thoracic nerve, the medial border of the scapula moves laterally and posteriorly away from the thoracic wall, giving the scapula the appearance of a wing.

2 All the following muscles have a relationship to the scapula. If paralyzed, which muscle results in winging of the scapula with inability to elevate the arm above the horizontal? A .Serratus anterior B. Latissimus dorsi C .Levator scapulae D. Rhomboid major E .Deltoid

Posterior Axioappendicular Muscles The posterior axioappendicular muscles attach the superior appendicular skeleton (of the upper limb) to the axial skeleton (in the trunk). 1.Trapezius 2.Latissimus dorsi 3. Rhomboid major and minor 4. Levator scapulae

Trapezius N. supply: Spinal part of accessory nerve (motor) Origin: Occipital bone, ligamentum nuchae, spine of seventh cervical vertebra, spines of all thoracic vertebrae Insertion : Upper fibers into lateral third of clavicle; middle and lower fibers into acromion and spine of scapula N. supply: Spinal part of accessory nerve (motor) Action: Upper fibers elevate the scapula; middle fibers pull scapula medially; lower fibers pull medial border of scapula downward

Injury of the Accessory Nerve (CN XI) The primary clinical manifestation of accessory nerve palsy is a marked ipsilateral weakness when the shoulders are elevated (shrugged) against resistance.

Latissimus dorsi N. supply:Thoracodorsal nerve Origin: Iliac crest, lumbar fascia, spines of lower six thoracic vertebrae, lower three or four ribs, and inferior angle of scapula Insertion: Floor of bicipital groove of humerus N. supply:Thoracodorsal nerve

Latissimus dorsi Action: Extends, adducts, and medially rotates the arm

Injury of the Thoracodorsal Nerve Surgery in the inferior part of the axilla puts the thoracodorsal nerve supplying the latissimus dorsi at risk of injury. With paralysis of the latissimus dorsi, the person is unable to raise the trunk with the upper limbs, as occurs during climbing.

Levator Scapulae N. supply:dorsal scapular nerve Origin: Transverse processes of first four cervical vertebrae Insertion: Medial border of scapula N. supply:dorsal scapular nerve Action:Elevates scapula

Rhomboids minor and major N. supply: Dorsal scapular nerve Action: Retracts scapula

1. An 34 year old man, bleeding from a stab wound in the neck, is brought to the emergency department. After the bleeding has been controlled, further examination indicates that her left shoulder is lower than the right shoulder. Which of the following nerve is most likely injured? A Long thoracic B  Dorsal scapular C Axillary D Suprascapular E Spinal accessory

2. A 22 year old woman sustains a traumatic injury to the axilla that severely damages the thoracodorsal nerve. Which of the following movements is most likely affected in this patient?  a Adduction B. Flexion C Lateral rotation D  Protraction E Supination

Scapulohumeral Muscles The six scapulohumeral muscles are relatively short muscles that pass from the scapula to the humerus and act on the glenohumeral joint. 1.Deltoid 2.Teres major 3.Teres minor 4.Supraspinatus 5.Infraspinatus 6.Subscapularis

Deltoid N. supply: Axillary nerve Origin: Lateral third of clavicle, acromion, spine of scapula Insertion: Middle of lateral surface of shaft of humerus N. supply: Axillary nerve

Deltoid Action: Anterior part: flexes and medially rotates arm Middle part: abducts arm Posterior part: extends and laterally rotates arm

Testing deltoid muscle The examiner resists the patient's abduction of the limb by the deltoid. If the deltoid is acting normally, contraction of the middle part of the muscle can be palpated.

Injury to the Axillary Nerve The deltoid is a common site for the intramuscular injection of drugs. The axillary nerve runs transversely under cover of the deltoid at the level of the surgical neck of the humerus. The deltoid atrophies when the axillary nerve (C5 and C6) is severely damaged.

Deltoid atrophy

Teres Major N. supply:Lower subscapular nerve Origin: Lower third of lateral border of scapula Insertion:Medial lip of bicipital groove of humerus N. supply:Lower subscapular nerve Action:Adducts and medially rotates arm

Rotator Cuff Muscles Four of the scapulohumeral muscles supraspinatus, infraspinatus, teres minor, and subscapularis (referred to as the SITS muscles) are called rotator cuff muscles because they form a musculotendinous rotator cuff around the glenohumeral joint.

Supraspinatus N. supply: Suprascapular nerve Origin: Supraspinous fossa of scapula Insertion: Superior facet of greater tubercle of humerus N. supply: Suprascapular nerve Action: Initiates and assists deltoid in abduction of arm and acts with rotator cuff muscles.

Infraspinatus N. supply: Suprascapular nerve Origin: Infraspinous fossa of scapula Insertion: Middle facet of greater tubercle of humerus N. supply: Suprascapular nerve Action: Laterally rotates arm and stabilizes shoulder joint

Teres minor N. supply:Axillary nerve Origin: Middle part of lateral border of scapula Insertion: Inferior facet of greater tubercle of humerus N. supply:Axillary nerve Action:Laterally rotates arm and stabilizes shoulder joint

Subscapularis N. supply: Upper and lower subscapular nerves Origin: Subscapular fossa (most of anterior surface of scapula) Insertion: Lesser tubercle of humerus N. supply: Upper and lower subscapular nerves Action: Medially rotates and adduct arm

Rotator Cuff Injuries and the Supraspinatus Trauma may tear or rupture one or more of the tendons of the SITS muscles; that of the supraspinatus is most commonly involved.

1. Which of the following muscles listed below is the rotator cuff muscle involved in medial rotation of the humerus? A Supraspinatus B Subscapularis C Infraspinatus D Teres minor E Teres major

2. A 31 year old man is unable to raise his right arm above his head 3 weeks after dislocating his shoulder in a foot ball game. Examination shows absence of rounded contour of the shoulder. Which of the following nerves was most likely injured? A. Musculocutaneous B. Median C. Axillary D. Ulnar E.Radial

Gateways to the posterior scapular region

Arteries and nerves associated with gateways in the posterior scapular region

QUADRANGULAR SPACE: Superior border: Teres Minor Inferior border: Teres Major Lateral border: Surgical neck of the humerus Medial border: Long Head of Triceps

CONTENTS 1- Axillary Nerve 2- Posterir Circumflex Humeral Artery

Quadrilateral Space Syndrome Quadrilateral space syndrome usually happens from overuse, especially with overhead sports like throwing and swimming. The syndrome can also be caused by an injury, like a shoulder dislocation.

TRIANGULAR [upper] space LATERAL BORDER: Long Head of the Triceps Upper border: Teres Minor and subscapularis Lower border: Teres Major CONTENTS Circumflex Scapular Branch of the Subscapular artery

Lower Triangular Space Medially long head of the triceps brachii Latterly shaft of the humerus Superiorly teres major

Contents 1-Radial nerve 2-Profunda brachii artery