Shoulder Girdle and Brachial Plexus Anatomy

Presenter Dr Junaid AhmadPost Graduate Registrar JB&RSC

• Surface Anatomy• Sensory Supply• Bones• Muscle Attachments

Surface Anatomy

Dermatomes of Shoulder

Lymphatics and Superficial Veins

Bones and Joint

• Bones of Shoulder– Clavicle– Scapula– Humerus– Muscle also originate from skull, ribs, sternum and

spines

• Joint– Shoulder Joint– Acromio Clavicular Joint

Clavicle

Clavicle

Fractures of Clavicle

LocationMedial two third and lateral one third

junctionComplications

Nerve entrapments supraclavicular nerveMostly need little treatment

Non Fracture Conditions of Clavicle

Compressions due to narrow spaceBrachial plexusSubclavian Artery and Vien

HumerusScapula

HumerusScapula

HumerusScapula

HumerusScapula

Fractures of Scapula

Associated with high energy run oversAlso fractured ribs mostlyMostly need little treatment

Non fracture conditions of Scapula

DroppingDue to Trapezius paralysis

WingingDue to serratus anterior paralysis

How to check

Common Fractures of Humerus

• Humeral Head Fractures• Greater Tuberosity Fractures• Lesser Tuberosity Fractures• Surgical Neck Fractures• Fractures of the Shaft of the Humerus

• Radial Nerve

• Supracondylar fractures • VIC

• The medial epicondyle

Common Fractures of Humerus

AP X-Ray Shoulder

Axilla

• Pyramidal in shape• Apex in neck• Four walls• Contains vessles, nerves and lymphatics

Walls of Axilla

• Anterior wall• By the pectoralis major, subclavius, and pectoralis minor muscles

• Posterior wall• By the subscapularis, latissimus dorsi, and teres major muscles

from above down

• Medial wall• By the upper four or five ribs and the intercostal spaces covered by the

serratus anterior muscle

• Lateral wall• By the coracobrachialis and biceps muscles in the bicipital groove of

the humerus

Walls of Axilla

Pectoralis Major Muscle

• Origin• Sternum, Upper 6 costal cartilages, Clavicle

• Insertion• Lateral lip of bicipital groove of humerus

• Nerve Supply• Medial and lateral pectoral nerves from brachial

plexus (B.P) C6,7,8

• Function• Adduct and medially rotate the arm

Pectoralis Major Muscle

Pectoralis Minor Muscle

• Origin• 3rd 4th and 5th ribs

• Insertion• Coracoid process of scapula

• Nerve Supply• Medial pectoral nerve from B.P C7

• Function• Depress the shoulder / Elevate the ribs

Pectoralis Minor Muscle

Subclavius Muscle

• Origin• 1st costal cartilage

• Insertion• Clavicle

• Nerve Supply• Nerve to subclavius from upper trunk of B.P C5

• Function• Depress the clavicle

Serratus Anterior Muscle

• Origin• Upper 6 ribs

• Insertion• Medial border and inferior angle of scapula

• Nerve Supply• Nerve to serratus anterior from roots of B.P C6,7

• Function• Rotate scapula / Draw it forwards

Serratus Anterior Muscle

Trapezius Muscle

• Origin• Ligamentum nuchae of occipital bone, 7th spine and all thoracic

vertebrae

• Insertion• Lateral third of clavicle, acromion and spine of scapula

• Nerve Supply• Spinal part of accesory nerver IX

• Function• Upper fibers elevate scapula• Middle fibers pull the scapula medially• Lower fibers pull scapula downwards

Trapezius Muscle

Latismus Dorsi Muscle

• 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

• Nerve Supply• Thoracodorsal nerve C7

• Function• Extends, adducts, and medially rotates the arm

Latismus Dorsi Muscle

Rhomboid Major Muscle

• Origin• 2nd to 5th thoracic spines

• Insertion• Medial border of scapula

• Nerve Supply• Dorsal scapular nerve

• Function• Raises medial border of scapula upward and medially

Rhomboid Minor Muscle

• Origin• Ligamentum nuchae and spines of seventh cervical

and first thoracic vertebrae

• Insertion• Medial border of scapula

• Nerve Supply• Dorsal scapular nerve

• Function• Raises medial border of scapula upward and medially

Rhomboid Muscles

• Origin

• Insertion

• Nerve Supply

• Function

Levator scapulae Muscle

• Origin• Transverse processes of first four cervical vertebrae

• Insertion• Medial border of scapula

• Nerve Supply• dorsal scapular nerve

• Function• Raises medial border of scapula

Deltoid Muscle

• Origin• Lateral third of clavicle, acromion, spine of scapula (same as

insertion of trapezius)

• Insertion• Middle of lateral surface of shaft of humerus

• Nerve Supply• Axillary nerve C5

• Function• Anterior fibers medially rotate and flex arm• Posterior fibers extend and laterally rotate arm• Middle fibers abducts the arm

Deltoid Muscle

Supraspinatus Muscle

• Origin• Supraspinous fossa of scapula

• Insertion• Greater tuberosity of humerus

• Nerve Supply• Suprascapular nerve C5

• Function• Abducts arm and stabilizes the shoulder

Infraspinatus Muscle

• Origin• Infraspinous fossa of scapula

• Insertion• Greater tuberosity of humerus

• Nerve Supply• Suprascapular nerve C5

• Function• Laterally rotates arm and stabilizes shoulder

Teres minor Muscle

• Origin• Upper two thirds of lateral border of scapula

• Insertion• Greater tuberosity of humerus

• Nerve Supply• Axillary nerve

• Function• Laterally rotates arm and stabilizes shoulder joint

• Origin

• Insertion

• Nerve Supply

• Function

Teres Major Muscle

• Origin• Lower third of lateral border of scapula

• Insertion• Medial lip of bicipital groove of humerus

• Nerve Supply• Lower subscapular nerve C6

• Function• Medially rotates and adducts arm and stabilizes

shoulder joint

Teres Major Muscle

• Origin

• Insertion

• Nerve Supply

• Function

Subscapularis Muscle

• Origin• Subscapular fossa

• Insertion• Lesser tuberosity of humerus

• Nerve Supply• Upper and lower subscapular nerves C6

• Function• Medially rotates arm and stabilizes shoulder joint

• Origin

• Insertion

• Nerve Supply

• Function

First Part of the Axillary Artery

• This extends from the lateral border of the first rib to the upper border of the pectoralis minor

• Relations• Anteriorly: The pectoralis major and the skin. The

cephalic vein crosses the artery • Posteriorly: The long thoracic nerve (nerve to the

serratus anterior) • Laterally: The three cords of the brachial plexus • Medially: The axillary vein

Second Part of the Axillary Artery

• This lies behind the pectoralis minor muscle • Relations• Anteriorly: The pectoralis minor, the pectoralis major,

and the skin• Posteriorly: The posterior cord of the brachial plexus,

the subscapularis muscle, and the shoulder joint • Laterally: The lateral cord of the brachial plexus • Medially: The medial cord of the brachial plexus and the

axillary vein

Third Part of the Axillary Artery

• This extends from the lower border of the pectoralis minor to the lower border of the teres major

• Relations• Anteriorly: The pectoralis major for a short distance; lower down

the artery it is crossed by the medial root of the median nerve • Posteriorly: The subscapularis, the latissimus dorsi, and the teres

major. The axillary and radial nerves also lie behind the artery • Laterally: The coracobrachialis, the biceps, and the humerus. The

lateral root of the median and the musculocutaneous nerves Medially: The ulnar nerve, the axillary vein, and the medial cutaneous nerve of the arm

Quadrangular Space

• The quadrangular space is an intermuscular space, located immediately below the shoulder joint.

• It is bounded above by the subscapularis and capsule of the shoulder joint

• Below by the teres major muscle. • Medially by the long head of the triceps• Laterally by the surgical neck of the humerus.• The axillary nerve and the posterior circumflex humeral

vessels pass backward through this space

Triangular Space

• Teres minor above• Teres major below• Long head of tricepes laterally• Circumflex scapular atery pass through it

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