Anatomy: Shoulder and Axilla, Pectoral, Clavipectoral, and Axillary Fasciae

Shoulder and Axilla, Pectoral, Clavipectoral, and Axillary Fasciae, 416
Anterior view

1. Costocorocoid membrane 
2. Suspensory Ligament of the axilla
3. Brachial Fascia covering the coracobrachialis and biceps brachii muscles

1. The Axilla
1. A Space, pyramidal in shape, between the arm and the thoracic wall
2. Boundaries:
1. Apex: directed upward and medialward, ending in the cervicoaxillary canal, which leads into the posterior triangle of the neck
2. Base: formed by the axillary fascia and skin
3. Anterior Wall: pectoralis major and minor muscles, clavipectorial fascia
4. Posterior Wall:  subscapularis, teres major, latissimus dorsi muscles
5. Medial Wall: first 4 ribs and intercostal muscles, upper part of serratus anterior muscle
6. Lateral Wall: humerus, coracobrachialis and biceps muscle
3. Contents
1. Axillary vessels and their branches
2. Brachial plexus and its branches
3. Lymph nodes, embedded in fat
2. The Fascia
1. Axillary. 
2. Clavipectorial.
1. Costocoracoid ligament
2. Coracoclavicular fascia
3. Axillary Sheath.

Oblique parasagittal section of the axilla

The most significant observations:

1. Relation of the Brachial Plexus and its Lateral, Posterior and Medial Cords to the Axillary Artery
2. Relation of the Central and Anterior Pectoral Lymph nodes
3. The Lateral and Medial Pectoral Nerves
4. The Arch formed Anteriorly by Trapezius Muscle, Omohyoid Muscle, Clavicle, Subclavius Muscle and Fascia, Costocoracoid Membrane, Pectoralis minor muscle and fascia, Suspensory  ligament of the axilla and the axillary fascia that is fenestrated

Anatomy: Shoulder and Axilla, Axillary Artery and Anastomoses around the Scapula

Collateral Circulation for ligation of or obstruction in any artery is important and is accomplished through the anastomosing of arteries that arise from the main channel above the stoppage with those that arise below that point.

 

Shoulder and Axilla, Axillary Artery and Anastomoses around the Scapula, 415
Anterior View - Axillary Artery and Anastomoses around the Scapula

1. Axillary Artery has 3 parts before becoming the Brachial Artery
1. Superior Thoracic artery
2. Thoracoacromial artery has 4 branches and the Lateral Thoracic Artery
1. Pectorial branch
2. Clavicular branch
3. Acromial Branch to the Acromion and acromial anastomosis
4. Deltoid Branch
3. 3 Arteries
1. Subscapular Artery with its 2 branches
1. Thoracodorsal Artery and
2. Circumflex Scapular Artery
2. Anterior Circumflex Humeral Artery
3. Posterior Circumflex Humeral Artery 

Posterior View - Axillary Artery and Anastomoses around the Scapula

1. Dorsal Scapular Artery - from around the Levator Scapulae Muscle to the Infraspinous area of the Scapula
2. Suprascapular Artery above the Trasverse Scapula Ligament and its Infraspinous Branch 
3. Acromial Branch of the thoracoacromial artery
4. Posterior circumflex Humeral Artery in the quadrangular space and ascending and descending branches
• Quadrangular space - Teres Minor, Lateral Head and Long Head of Triceps and the Teres Major Muscles
5. Circumflex Scapular Artery

Sites where anastomosis can occur

1. BETWEEN THE SUPRASCAPULAR AND THE CIRCUMFLEX SCAPULAR in the infraspinous fossa
2. BETWEEN THE DESCENDING SCAPULAR AND CIRCUMFLEX SCAPULAR along the medial border of scapular
3. BETWEEN PECTORAL BRANCHES, INTERCOSTALS, LATERAL THORACIC, OR THORACODORSAL on thoracic walls
4. BETWEEN ACROMIAL AND POSTERIOR CIRCUMFLEX HUMERAL around acromion
5. BETWEEN CIRCUMFLEX HUMERAL AND DEEP BRACHIAL in or under the triceps muscle

Special Features

1. The CIRCUMFLEX SCAPULAR ARTERY leaves the axilla through the triangular space
2. The POSTERIOR CIRCUMFLEX HUMERAL ARTERY leaves the axilla via the quadrilateral space with the axilla nerve
3. SUPRASCAPULAR NERVE AND SUPRASCAPULAR ARTERY run together, but the nerve goes under and the artery passes over the transverse scapular ligament
4. The DORSAL SCAPULAR NERVE descends with the descending branch of the transverse cervical artery.

Anatomy: Shoulder and Axilla, Scapulothoracic and Scapulohumeral Dissection

Shoulder and Axilla, Scapulothoracic and Scapulohumeral Dissection 414
Lateral view

1. Nerves:
1. Note the Accessory Nerve (XI) overlying the Levator Scapulae muscle is different to the Axillary Nerve.
2. Retraction of the Subscapularis Muscle and the Scapula to expose the Serratus anterior Muscle and the Long Thoracic Nerve
3. Look at the beautiful Phrenic nerve overlying the Anterior Scalene Muscle as it snuggles behind the Subclavian Vein.
4. Intercostal Nerve: Lateral Cutaneous branches and Anterior Cutaneous Branches of the Intercostal Nerve
2. Arteries
1. Branches of the Subclavian Artery: Lateral Thoracic Artery and the Superior Thoracic Artery
2. Perforating branches of the Internal Thoracic Artery

Anterior View

1. Triangular Space and 
1. Trangular Space is made up from the Subscapularis Muscle, Teres Major Muscle and the Long head of Biceps Brachii Muscle
2. Contains the Circumflex Scapular Artery branch from the Subscapular Artery. The Subscapular Artery goes on to become the Thoracodorsal Artery and with the Thoracodorsal Nerve to Latissimus Dorsi Muscle. 
2. the Quadrangular Space
1. Contains the Auxillary Nerve and the Posterior Circumflex Humeral Artery
3. Anterior circumflex Humeral Artery under the tendon of the long head of Biceps Brachii
4. Note the Intimate Relationship of the cut Biceps Brachii and the Coracobrachialis muscles.
5. Suprascapular Artery goes under the Transverse Scapular Ligament in the suprascapular notch and the Suprascapular Nerve goes over the Subscapular Ligament
6. Note the visible Rotator Cuff Muscle Tendons

Posterior View 414, 465

1. Note the Suprascapular Artery and Nerve and how they move under the Scapular Spine - to the Joint Capsule of the Shoulder, Infraspinatus Muscle and Teres Minor Muscle. Note the Circumflex Scapular Artery deep to the Teres Minor muscle in the Triangular Space
2. Note the Quadrangular Space and its contents
3. Radial nerve between the Lateral head and Long Head of Triceps Brachii Muscle

Anatomy: Upper Limb: Shoulder and Axilla

Muscles of the Rotator Cuff 413  (SITS Muscles plus Ligaments)

1. Ligaments
1. Coracoclavicular Ligament: Conoid and the Trapezoid ligaments
2. Coracoacromial Ligament
2. Muscles tendons
1. Subscapularis tendon
2. Supraspinatus tendon
3. Infraspinatus tendon
4. Teres Minor Tendon
3. Auxillary Nerve emerges inferior to the Teres Minor Muscle