BRACHIUM

1. BRACHIUM

2. Fascial Septa • Divide arm into anterior and posterior compartments.

3. Medial Intermuscular Septum • From subcutaneous sheath to humerus. • Separates muscles of anterior arm from medial side of triceps complex.

4. Lateral Intermuscular Septum • From subcutaneous sheath to humerus. • Separates muscles of anterior arm from lateral side of triceps complex.

6. ANTERIOR BRACHIAL COMPARTMENT

7. Muscles • Components: Biceps brachii Coracobrachialis Brachialis • Function: Forearm flexors Biceps also supinates forearm

8. Innervation • Innervation and functional neurological level: Musculocutaneous nerve C5-6 • Nerves passing through compartment (not innervating anterior compartment structures): Median nerve. Ulnar nerve: Through proximal part of anterior compartment.

9. Vascularization • Brachial artery • Basilic vein and venae comitantes

10. POSTERIOR BRACHIAL COMPARTMENT

11. Muscles • Components: Triceps brachii. Anconeus. • Function: Forearm extensors. Long head of triceps can extend shoulder (brachium). Synergists in forearm supination.

12. Innervation/Vascularization • Innervation and functional neurological level: Radial nerve C7 • Vascular supply to compartment: Deep brachial artery

13. NERVES and VESSELS IN THE BRACHIUM

14. Median Nerve • Supplies flexor muscles on the radial side of the forearm. • Travels with the brachial artery: Lateral to artery in upper half of brachium. Medial to artery in lower half of brachium. • Crosses cubital fossa superficially: With brachial artery Deep to bicipital aponeurosis

15. Ulnar Nerve • Supplies flexor muscles on the ulnar side of the forearm. • Starts in anterior brachial compartment: Medial to brachial artery Runs with superior ulnar collateral artery.

16. Ulnar Nerve • Pierces medial intermuscular septum: Enters posterior compartment of the brachium. Passes around (superficial) medial epicondyle. Passes into forearm between two heads of flexor carpi ulnaris muscle.

17. Radial Nerve • Supplies extensor muscles in posterior compartment of brachium as well as extensor muscles of the wrist and hand. • Also supplies brachioradialis muscle. • Descends posterior to the axillary artery: Spirals around the posterior surface of the humerus in the spiral (radial) groove. Accompanied by deep brachial artery.

18. Radial Nerve • Pierces lateral intermuscular septum distal to deltoid insertion. • Passes into forearm: Between the brachialis medially and the brachioradialis laterally. • Divides into superficial and deep branches near lateral epicondyle.

19. Radial Nerve • Branches in the axilla and upper third of the arm: Muscular branch to long head of triceps. Muscular branch to medial head of triceps. Posterior brachial cutaneous nerve.

20. Radial Nerve • Branches in the radial groove in middle third of arm: Branch to lateral and medial triceps and anconeus. Lower lateral brachial cutaneous nerve. Posterior cutaneous nerve of the forearm.

21. Radial Nerve • Branches in the distal third of the arm: Branch to brachioradialis. Branch to extensor carpi radialis longus (brevis?) Articular branches to elbow joint.

22. Musculocutaneous Nerve • Pierces coracobrachialis in upper half or third of brachium. • Innervates muscles of anterior brachial compartment. • Pierces fascia lateral to biceps tendon: Continues as lateral cutaneous nerve of the forearm. Supplies skin on lateral forearm as far as wrist.

23. Nerves in the Brachium • Medial brachial cutaneous nerve: Direct branch from medial cord. • Medial antebrachial cutaneous nerve: Direct branch from medial cord.

24. Cephalic Vein • Lateral continuation of dorsal venous arch. • Ascends in superficial fascia along lateral aspect of forearm and arm. • Passes through deltopectoral triangle. • Empties into axillary vein.

25. Basilic Vein • Medial continuation of dorsal venous arch. • Ascends in superficial fascia along lateral aspect of forearm and arm to middle of arm. • Pierces deep fascia and ascends in upper aspect of arm in deep fascia. • Joins venae comitantes to form axillary vein: Usually near inferior border of teres major.

26. Median Cubital Vein • Connects cephalic and basilic vein. • Extends diagonally across bicipital aponeurosis. • Receives blood from median antebrachial vein. • Drains blood from palmar hand.

27. Venae Comitantes • Veins that parallel arteries: • Usually two per artery. • Countercurrent heat exchange.

28. Brachial Artery • Direct continuation of axillary artery. • Begins at inferior border of teres major. • Main branch is deep brachial artery. • Other branches: Superior ulnar collateral: To posterior ulnar recurrent. Inferior ulnar collateral: To anterior ulnar collateral.

29. Relationships • Radial nerve to deep brachial artery in radial (spiral groove). • Brachial artery to median nerve. • Brachial artery to bicipital aponeurosis. • Superior ulnar collateral artery to medial epicondyle.

30. Relationships • Inferior ulnar collateral artery to medial epicondyle. • Radial collateral artery to lateral epicondyle. • Median cubital vein to bicipital aponeurosis.

31. Relationships • Ulnar nerve to medial epicondyle. • Musculocutaneous nerve to coracobrachialis muscle. • Musculocutaneous nerve to biceps and brachialis muscles. • Lateral cutaneous nerve of the forearm to the bicipital tendon.

32. CUBITAL FOSSA

33. Cubital Fossa Boundaries • Lateral: Brachioradialis muscle • Medial: Pronator teres muscle • Superior base: Line between two humeral epicondyles • Floor: Supinator and brachialis muscles

34. Cubital Fossa Contents • Lateral to medial: Biceps Tendon Brachial Artery Median Nerve