L 4 A B O R A T O R Y Axilla and Brachial Region BRACHIAL PLEXUS 5 Roots/Rami (ventral rami C5 T1) 3 Trunks Superior (C5, C6) Middle (C7) Inferior (C8, T1) 3 Cords Lateral Cord (Anterior Superior and Anterior Middle Divisions) gives rise to median and musculocutaneous nerves Medial Cord (Anterior Inferior Division) gives rise to ulnar and median nerves Posterior Cord (Posterior Superior, Posterior Middle and Posterior Inferior Divisions) gives rise to axillary and radial nerves 5 MAJOR BRANCHES Median Nerve Innervates forearm flexor muscles and hand musculature (thumb side) Except flexor carpi ulnaris and medial 1 /2 of flexor digitorum profundus Musculocutaneous Nerve - Innervates the arm (brachium) flexor muscles Including biceps brachii, brachialis, and coracobrachialis Ulnar Nerve - Innervates flexor carpi ulnaris, medial 1 /2 flexor digitorum profundus, and hand mus culature (pinkie side) Axillary Nerve - Innervates deltoid and teres minor Radial Nerve - Innervates extensor muscles of the arm (brachium) and forearm (antebrachium)
22 Laboratory 4 Axilla and Brachial Region Supraclavicular Branches (may not be easily seen) Infraclavicular Branches Long thoracic nerve - serratus anterior Lateral pectoral nerve - pectoralis major Dorsal scapular nerve - rhomboids and levator scapulae Medial pectoral nerve - pectoralis muscles Suprascapular nerve - supraspinatus and Subscapular nerves infraspinatus Upper - subscapularis Middle - thoracodorsal - latissimus dorsi Nerve to subclavius - subclavius Lower - subscapularis/teres major BRACHIAL REGION Identify the muscles that comprise the anterior compartment of the brachial region. Identify the attachment points and actions of the anterior brachial muscles. Identify the innervation source and the primary blood supply to these muscles. Locate and describe the anatomical significance of the bicipital aponeurosis. Anterior Brachium Muscles Muscle Origin Insertion Innervation Blood Supply Action Biceps Brachii Short: coracoid process of Scapula Long: supraglenoid tubercle of Scapula Radial tuberosity and deep forearm fascia via bicipital aponeurosis Musculocutaneous N (C5-C6) Brachial A Circumflex Humeral A Supinates forearm, Flexes forearm at elbow Flex arm at shoulder Brachialis distal, anterior Ulnar tuberosity and coronoid process Musculocutaneous N (C5-C6) Brachial A Ulnar A Flexes forearm at elbow Coracobrachialis coracoid process of Scapula Mid-medial Musculocutaneous N (C5-C7) Brachial A Circumflex Humeral A Flex arm at shoulder, Stabilize Scapula Identify the muscles of the posterior compartment of the brachial region. Identify the attachment points for the posterior brachial muscles. Identify the innervation source and the primary blood supply to these muscles.
Laboratory 4 Axilla and Brachial Region 23 Posterior Brachium Muscles Muscle Origin Insertion Innervation Blood Supply Action Triceps Brachii Anconeus Long: infraglenoid tubercle of Scapula Lateral: posterosuperior Medial: posteroinferior Lateral epicondyle of Proximal olecranon of Ulna forearm fascia Lateral & posterior olecranon of Ulna Radial N (C6-C8) Radial N (C7-T1) Circumflex Humeral A Profunda Brachii (deep A of arm) Profunda Brachii (deep A of arm) Extends forearm at elbow Extend arm at shoulder Resist abduction of Olecranon, Extend forearm & Stabilize elbow VASCULATURE Discuss arterial supply to the arm, including division between arteries. Subclavian Artery Internal thoracic artery Vertebral artery Thyrocervical trunk suprascapular transverse cervical inferior thyroid dorsal scapular artery Costocervical trunk Axillary Artery Superior thoracic artery Thoracoacromial trunk deltoid acromial pectoral clavicular Lateral thoracic artery Subscapular artery Circumflex scapular artery Thoracodorsal artery Circumflex humeral arteries Discuss venous drainage from the arm, including both superficial and deep veins. Deep Superficial Axial brachial vein basilic vein jugular veins axillary vein cephalic vein brachiocephalic veins subclavian vein medial cubital vein superior vena cava
24 Laboratory 4 Axilla and Brachial Region Upper Extremity Clavicle acromial end conoid tubercle subclavian groove sternal end Scapula spine borders acromion coracoid process glenoid cavity subscapular fossa infraspinous fossa supraspinous fossa suprascapular notch supra-/infra-glenoid tubercles head greater/lesser tubercle intertubercular (bicipital) groove deltoid tuberosity trochlea capitulum radial groove ulnar groove med/lat epicondyles med/lat supracondylar ridges olecranon fossa Ulna olecranon trochlear notch radial notch ulnar tuberosity interosseous border head styloid process coronoid process Radius head radial tuberosity interosseous border styloid process Carpal bones (ulnar) (proximal) pisiform triquetrum lunate scaphoid hamate capitate trapezoid trapezium (distal) (radial) Metacarpals (5) Phalanges (14)
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