Anatomy Of Axilla And Shoulder Dr. Fadel Naim Orthopedic Surgeon Faculty of Medicine IUG

SURFACE ANATOMY ACROMION CLAVICLE DELTOID ( IM INJECTIONS) HUMERUS BICEPS MUSCLE BICIPTAL GROOVE BRACHILA PULSE( BLOOD PRESSURE) TRICEPS OLECRNON PROCESS( PT OF THE ELBOW) MEDIAL /LATERAL EPICONDYLES TRIANGLE CUBITAL FOSSA MEDIAN CUBITAL VEIN- IV CEPHALIC VEIN ULNA RADIUS STYLOID PROCESS RADIAL ARTERY( PULSE) ULNAR ARTERY ANATOMICAL SNUFF BOX THENAR EMINENC HYPOTHENAR EMINENCE CARPAL TUNNEL

CUBITAL FOSSA

STYLOID PROCESS

Axilla(Arm pit)

AXILLA A pyramid-shaped space between the upper part of the arm and the side of the chest through which major neurovascular structures pass between neck & thorax and upper limbs. Axilla has an apex, a base and four walls.

Axillary Walls Bones Anterior Posterior Medial Lateral Clavicle Scapula Ribs Humerus

Muscles Anterior Posterior Medial Lateral Pectoralis major pectoralis minor subclavius Subscapularis teres minor teres major latissimus dorsi Serratus anterior Tendon of long head of biceps

Contents Of The Axilla Axillary artery Axillary vein Cords of brachial plexus Axillary lymph nodes Fat Axillary sheath

Pectoralis Major Origin INSERTION Action Nerve Clavicular head: Medial half clavicle. Sternocostal head: Lateral manubrium Sternum Six upper costal cartilages External oblique aponeurosis INSERTION Lateral lip of bicipital groove of humerus Action Flexes and adducts arm. Sternal head: Adducts and medially rotates arm . Accessory for inspiration Nerve Medial pectoral nerve (from medial cord) Lateral pectoral nerve (from lateral cord)

Subclavius Origin INSERTION Action Nerve Costochondral junction of 1st rib INSERTION Subclavian groove on inferior surface of middle third of clavicle Action Depresses clavicle and steadies it during shoulder movements Nerve Nerve to subclavius (upper trunk of brachial plexus)

Pectoralis Minor Origin 3, 4, 5 ribs INSERTION Action Nerve Medial and upper surface of coracoid process of scapula Action Elevates ribs if scapula fixed Pulls shoulder downward and forward Nerve Medial pectoral nerve (from medial cord of brachial plexus)

Subscapularis Origin INSERTION Action Nerve Medial two thirds of subscapular fossa INSERTION Lesser tuberosity of humerus Upper medial lip of bicipital groove Capsule of shoulder joint Action Medially rotates arm Stabilizes shoulder joint Nerve Upper and lower subscapular nerves (from posterior cord of brachial plexus)

Teres Major ORIGIN INSERTION ACTION NERVE Lower third of lateral side of inferior angle of scapula below teres minor INSERTION Medial lip of bicipital groove of humerus ACTION Medially rotates and adducts arm. Stabilizes shoulder joint NERVE Lower subscapular nerve (from posterior cord of brachial plexus)

Latissimus Dorsi ORIGIN INSERTION ACTION NERVE Spine T7 lumbar fascia spinous processes and supraspinous ligaments of all lower thoracic, lumbar and sacral vertebrae lumbar fascia posterior third iliac crest last four ribs (interdigitating with external oblique abdominis) inferior angle of scapula INSERTION Floor of bicipital groove of humerus after spiraling around teres major ACTION Extends, adducts and medially rotates arm. Costal attachment helps with deep inspiration and forced expiration NERVE Thoracodorsal nerve (from posterior cord of brachial plexus)

Serratus Anterior ORIGIN INSERTION Upper 8 ribs and anterior intercostal membranes from midclavicular line. INSERTION Inner medial border scapula 1 and 2: upper angle 3 and 4: length of costal surface 5-8: inferior angle

Serratus Anterior Action Nerve A strong protractor of the scapula that is used when punching or reaching anteriorly ("boxer's muscle") Inferior part rotates the scapula, elevating its glenoid cavity so the arm can be raised above the shoulder Holds the scapula against the thoracic wall when doing push ups or when pushing against resistance Nerve Long thoracic nerve

Trapezius Origin INSERTION Action Nerve Medial third superior nuchal line on the occipital bone External occipital protuberance Ligament nuchae Spine of 7th cervical vertebra Spinous processes and supraspinous ligaments to T12 INSERTION Upper fibers to lateral third of posterior border of clavicle Middle fibers to medial acromion and superior lip of spine of scapula Lower fibers to medial end of spine of scapula Action Laterally rotates, elevates and retracts scapula. If scapula is fixed, extends and laterally flexes neck Nerve Motor fibers form spinal accessory nerve (Cranial nerve XI) Sensory fibers spinal nerves C3 and C4

Levator Scapulae Origin INSERTION Action Nerve Posterior tubercles of transverse processes of C1-4 INSERTION Upper part of medial border of scapula opposite the supraspinous fossa Action Raises medial border of scapula In conjunction with middle fibers of trapezius and rhomboids, pulls the scapula medially and upward Nerve Anterior primary rami of C3 and C4 and dorsal scapular nerve (C5)

Rhomboid Minor Origin INSERTION Action Nerve Lower ligamentum nuchea Spines of C7 and T1 INSERTION Small area of posteromedial border of scapula at level of spine, below levator scapulae Action Elevates the medial border of the scapula and pulls it medially Nerve Dorsal scapular nerve (C5)

Rhomboid Major Origin INSERTION Action Nerve Spines of T2-T5 and supraspinous ligaments INSERTION Lower half of posteromedial border of scapula, opposite the infraspinous fossa Action Elevates the medial border of the scapula and pulls it medially Nerve Dorsal scapular nerve (C5) (from root )

Deltoid ORIGIN INSERTION ACTION NERVE Anterior fibers: Lateral third of clavicle Middle fibers: Acromion Posterior fibers: spine of scapula to deltoid tubercle INSERTION Deltoid tuberosity Middle of lateral surface of humerus ACTION Abducts arm anterior fibers flex and medial rotate posterior fibers extend and lateral rotate NERVE Axillary nerve (C5, 6) (from posterior cord)   Forms the rounded contour of the shoulder

Supraspinatus Origin INSERTION Action Nerve Medial three quarters of supraspinous fossa of scapula Upper surface of spine INSERTION Superior facet on greater tuberosity of humerus Capsule of shoulder joint Action Abducts arm Stabilizes shoulder joint Nerve Suprascapular nerve

Infraspinatus Origin INSERTION Action Nerve Medial three quarters of infraspinous fossa of scapula INSERTION Middle facet of greater tuberosity of humerus Capsule of shoulder joint Action Laterally rotates arm Stabilizes shoulder joint Nerve Suprascapular nerve

Teres Minor Origin INSERTION Action Nerve Middle third lateral border of scapula above teres major INSERTION Inferior facet of greater tuberosity of humerus (below infraspinatus) Capsule of shoulder joint Action Laterally rotates arm Stabilizes shoulder joint Nerve Axillary nerve

Rotator Cuff Muscles Four of the scapulohumeral muscles Supraspinatus Infraspinatus Teres minor Subscapularis Referred to as SITS muscles Called rotator cuff muscles because they form a musculotendinous cuff around the glenohumeral joint {Dynamic stabilizers (“cuff”)} All except the supraspinatus are rotators of the humerus

The tendons of the muscle blend with the fibrous capsule of the glenohumeral joint to form a musculotendinous rotator cuff, which reinforces the capsule on three sides: Anteriorly Superiorly Posteriorly The cuff is weakest antero-inferiorly, making shoulder dislocation most common in this direction.

The pectoral girdle involves the: SC joint AC joint Glenohumeral joint Generally, these joints move at the same time Functional defects in any of the joints impair movements of the pectoral girdle.

Sternoclavicular Joint The only articulation between the upper limb and the axial skeleton A saddle type of synovial joint functions as a ball and socket joint The sternal end of the clavicle articulates with the manubrium of the sternum and the 1st costal cartilage Can be palpated because the sternal end of the clavicle lies superior to the manubrium of the sternum

Ligaments of the SC Joint Anterior and posterior SC ligaments: The interclavicular ligament The costoclavicular ligament

Articular Disc Divides the SC joint into two compartments The articular disc serves as a shock absorber of forces transmitted along the clavicle from the upper limb

Movements of the SC Joint Although the SC joint is extremely strong, it is significantly mobile to allow movements of the pectoral girdle and upper limb Mobility of the clavicle at the sternoclavicular joint is essential for the freedom of movement of the upper limb. During full elevation of the limb, the clavicle is raised to approximately a 60 ° angle. The SC joint moves up to 25 to 30 ° along its long axis in several direction: anteriorly Posteriorly Inferiorly

Acromioclavicular Joint The AC joint is a plane type of synovial joint It is located 2 to 3 cm from the point of the shoulder formed by the lateral part of the acromion The acromial end of the clavicle articulates with the acromion The articular surfaces, are separated by an incomplete wedge-shaped articular disc.

Ligaments of the AC Joint The integrity of the joint is maintained by extrinsic ligaments, distant from the joint itself. The superior and inferior AC ligament:

The coracoclavicular ligament The conoid ligament Its wide attachment is to the conoid tubercle on the inferior surface of the clavicle Trapezoid ligament extends laterally to the trapezoid line on the inferior surface of the clavicle. provides the means by which the scapula and free limb are (passively) suspended from the clavicular strut The rotatory movements of the scapula occur at this important ligament

Glenohumeral (Shoulder) Joint A ball-and-socket type of synovial joint Relatively unstable The large, round humeral head articulates with the relatively shallow glenoid cavity of the scapula The glenoid is deepened slightly but effectively by the ringlike glenoid labrum The glenoid cavity accepts little more than a third of the humeral head, which is held in the cavity by the tonus of the rotator cuff muscles Both articular surfaces are covered with hyaline cartilage.

It becomes taut when the arm is abducted. The inferior part of the articular capsule is the only part not reinforced by the rotator cuff muscles Its weakest area. Here the capsule is particularly lax and lies in folds when the arm is adducted It becomes taut when the arm is abducted.

Ligaments of the Glenohumeral Joint The glenohumeral ligaments: Superior , middle and inferior The coracohumeral ligament The transverse humeral ligament

The Coracoacromial Arch An extrinsic, protective osseoligamentous structure formed by: The smooth inferior aspect of the acromion The coracoid process of the scapula The coracoacromial ligament Overlies the head of the humerus, preventing its superior displacement The supraspinatus muscle passes under this arch

Movements of the Glenohumeral Joint The glenohumeral joint has more freedom of movement than any other joint in the body. This freedom results from: the laxity of its articular capsule the large size of the humeral head compared with the small size of the glenoid cavity. The glenohumeral joint allows movements around three axes and permits: Flexion-extension Abduction-adduction Rotation (medial and lateral) of the humerus Circumduction. Circumduction is an orderly sequence of flexion, abduction, extension, and adduction or the reverse.

Glenohumeral motions

Glenohumeral motions

Glenohumeral motions

Scapular motions

Scapular motions Protraction – Retraction

Scapular Motions Rotational Elevation Of Glenoid Cavity Rotational Depression Of Glenoid Cavity

Shoulder Girdle Movements Elevation Shoulder Girdle Movements Abduction Adduction Upward Rotation Downward Rotation Depression

The supraspinatus initiates abduction and the deltoid takes over once the humerus is abducted past 15 degrees During full abduction of the arm we have to laterally rotate our humerus to move the greater tuberosity out of the way. Even with this maneuver, space is too limited to allow for the range of motion that is seen in a normal individual. The remainder of the range of motion is made possible by scapular rotation. Once we have abducted the arm past 20 degrees or 30 degrees, for every 3 degrees of abduction at the glenohumeral joint, 1 degree occurs at the scapulothoracic surface and only 2 degrees occurs at the glenohumeral joint.

Bursae Around the Glenohumeral Joint Several bursae containing synovial fluid Bursae are located where Tendons rub against bone, ligaments, or other tendons Where skin moves over a bony prominence. Some of them communicate with the joint cavity (the subscapular bursa) opening a bursa may mean entering the cavity of the shoulder joint.

Subacromlal Bursa Large bursa lies between the deltoid, the supraspinatus tendon, and the fibrous capsule of the glenohumeral joint. The subacromial bursa is located inferior to the acromion and coracoacromial ligament, between them and the supraspinatus.

Subdeltoid Bursa This bursa lies between the deltoid muscle and the fibrous joint capsule over the head of the humerus.

Subscapular Bursa Located between the neck of the scapula and the subscapularis muscle Often communicates with the glenohumeral joint cavity through an opening in the fibrous joint capsule