4 arm region and cubital

anatomy of the arm

1. The anatomy of the arm By: Mehrdad asgari Ph.D of Anatomical Sciences, Department of Anatomy, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran 30 july , 2021 In The Name Of Allah

2. Arm Region Arm Region

3. Cutaneous Nerves of Arm 1- Supraclavicular nerves (C4,C5) supply skin over shoulder & upper ½ of deltoid 2- Superior lateral cutaneous nerve (C5,C6 ) Branch of axillary supplies skin over lower ½ of deltoid. 3- Inferior lateral cutaneous nerve (C5,C6) Cutaneous branch of radial nerve Supplies skin over lower lateral arm below deltoid 4- Intercostobrachial nerve (T2) Lateral cutaneous branch of second intercostal nerve supplies skin of upper part of medial side of arm (close to axilla). 5-Medial brachial cutaneous (C8-T1) Branch of brachial plexus supplies medial side of arm below axilla. 6- Posterior brachial cutaneous nerve (C5-C8) Branch of radial nerve Supplies lower posterior medial arm

4. Fascia of the Arm Superficial fascia

5. Fascia of the Arm Brachial fascia deep fascia around the arm Continuous with the antebrachial fascia of the forearm Medial and lateral Intermuscular septa -Extend from deep surface of brachial fascia to humerus -Divide arm into anterior ( flexor ) and posterior ( extensor ) compartments Medial septum: medial lip of intertubercular sulcus (superiorly) → medial epicondyle Lateral septum: lateral lip of intertubercular sulcus (superiorly) → lateral epicondyle

6. Compartment of the arm Medial intermuscular septa: It is perforated by ulnar nerve - superior ulnar collateral artery - posterior branch of the inferior ulnar collateral artery Lateral intermuscular septa: It is perforated by radial nerve radial collateral artery branch of the profunda brachii artery

7. Muscles of the Arm Anterior (flexor) compartment Biceps brachii Flexes and supinates Coracobrachialis : Flexes and adducts arm Pierced by the musculocutaneous nerve Brachialis: main flexor of forearm

8. Biceps brachii Muscle Origin: a) Short head; Corachoid process b) Long head; supraglenoid tubercle Insertion Radial tuberosity fascia of forearm via bicipital aponeurosis Innervation Musculocutaneous nerve (C5,C6 ) Action   Supinates forearm and, when it is supine, flexes forearm Weak flexion of arm 

9. Coracobrachialis Origin: Corachoid process Insertion Middle third of medial surface of humerus Innervation Musculocutaneous nerve (C5,C6 ) Action  Helps to flex and adduct arm

10. Brachialis Muscle Origin: Distal half of anterior surface of humerus med. & Lat. Intermuscular septum Insertion ulnar tuberosity anterior aspect of Coronoid process Innervation Musculocutaneous nerve ( C5,C6) Radial nerve Action Major flexor of the forearm flexes forearm in all positions

11. Attachments of muscles of the front of the arm Action Nerve Insertion Origin Muscles Flexion & adduction of arm Musculocutaneus C5-7 The middle 5cm of the medial border of humerus Corachoid process Coracobrachialis Flexion & supination of forearm Musculocutaneus C5-7 Radial tuberosity & bicipital aponeurosis to deep facia of the forearm a) Short head; Corachoid process b) Long head; supraglenoid process Biceps brachii Flexion of forearm Musculocutaneus C5-7 Radial nerve Ulnar tuberosity Lower ½ of the front of humerus & med. & Lat. Intermuscular septum Brachialis

12. Posterior ( extensor) compartment Triceps brachii Main extensor of arm Stabilizes head of humerus in glenohumeral joint Anconeus : extends arm resists adduction of the ulna during pronation

13. Attachments of muscles of the back of the arm Action Nerve Insertion Origin Muscle   Chief extensor of forearm; long head steadies head of abducted humerus Radial nerve C6-8 Posterior part of superior surface of olecranon process of ulna Long head infraglenoid tubercle of scapula b) Lateral head posterior surface of humerus , superior to radial groove c ) Medial head posterior surface of humerus , inferior to radial groove  triceps

14. Brachial Artery Continuation of the axillary artery , ends in cubital fossa Lies anterior to triceps and brachialis throughout its course Accompanied by median nerve, which crosses anterior to artery and lies medially in cubital fossa Divides into ulnar and radial arteries under bicipital aponeurosis

15. Branches of brachial A. Many Muscular branches Profonda brachii Accompanies radial nerve in radial groove D eltoid M iddle collateral R adial collateral Superior ulnar collateral Nutritional Inferior ulnar collateral Two terminal branches ( Radial & Ulnar )

16. 1-Profonda brachii

17. Anastomosis around elbow In front of lateral epicondyle : between Radial collateral & radial recurrent artery . Behind lateral epicondyle : between Middle collateral branch of profunda artery & interosseous recurrent artery . In front of medial epicondyle : between anterior branch of inferior ulnar collateral artery & anterior ulnar recurrent artery. Behind medial epicondyle : between superior ulnar collateral + posterior branch of inferior ulnar collateral artery & posterior ulnar recurrent artery.

18. Venous Drainage of Arm 1- Superficial veins (drain into axillary vein ) Cephalic vein - On anterolateral surface Enters deltopectoral groove - Then deltopectoral triangle Basilic vein - Medial side, inferior arm - Pierces deep fascia at junction of inferior and middle third of arm Runs superiorly to axillary vein

19. 2- Deep veins Paired, accompany brachial artery ( venae comitantes ) Form at elbow from radial and ulnar veins Have valves - Merge with basilic vein to form axillary vein

20. Musculocutaneous nerve Origin : lateral cord of brachial plexus in axilla . Course : It descends downward and laterally, piercing coracobrachialis muscle, and then passes between biceps & brachialis . It appears at lateral margin of biceps tendon , piercing deep fascia above elbow, where it descends as lateral cut. N. of forearm on the lateral aspect of forearm . Branches : 1-muscular (biceps, coracobrachialis , +brachialis). .2-Cutaneous: lateral cutaneous nerve of forearm to supply skin of front & lateral sides of forearm down to the root of thumb . 3-articular : to elbow joint.

21. Median nerve origin : medial & lateral Cords of brachial plexus in axilla . Course : above , it descends on lateral side of brachial artery. - At the middle of arm, it crosses the brachial artery. Then it descends on the medial side of the artery. - At the elbow ,it is crossed by the biciptal aponeurosis . Has No branches in the upper arm .

22. Median nerve supplies Forearm flexors ( except flexor carpi ulnaris and the medial half of flexor digitorum profundus ) Thenar muscles and 1st and 2end lumbricals Skin over the lateral hand and 3½ digits

23. Ulnar nerve Origin : medial cord of brachial plexus in axilla . Course : above, it is covered posteriorly by medial head of triceps. - it descends medial to the brachial artery as far as the middle of the arm, where the insertion of coracobrachialis , it pierces medial facial septum , accompanied by superior ulnar collateral artery to descend in the post. compartment of arm, passing behind medial epicondyle to enter forearm bet. 2 heads of flexor carpi ulnaris . It has No branches in the arm . Only, it has articular to elbow joint.

24. Ulnar nerve supplies Flexor carpi ulnaris Medial half of FDP Hypothenar muscles 3rd and 4th lumbricals All interossei muscles Skin over the medial hand and 1½ digits

25. Radial nerve Origin : post.cord of brachial plexus in the axilla . Course : -on leaving axilla, it passes immediately into post. compartment of arm where it descends in spiral groove of humerus , accompanied by profunda brachii artery, deep to lateral head of triceps. - Then,it pierces lateral facial septum above elbow to enter anterior compartment of arm , between brachialis (medially) and brachioradialis & extensor carpi radialis longus (laterally). - At the front of lateral epicondyle , it terminates into superficial & deep branches.

26. In the axilla : 1- post. cut.N.of arm. 2-branches to long head of triceps . In the Spiral groove : 1-branches to lateral & medial heads of triceps. 2-branch to anconeus . 3- lateral cut. N. of arm. 4- post . Cut.n.of forearm . In anterior compartment of arm above elbow, ( in deep groove bet. brachialis & brachioradialis ): 1-Muscular : brachialis (lateral ½), brachioradialis , & extensor carpi radialis longus . 2-Articular : elbow joint. Branches of the Radial nerve

27. In front of lateral epicondyle of humerus , it divides into two terminal branches : 1-superficial branch. 2-deep branch (posterior interosseous N.).

28. Radial nerve supplies Triceps Anconeus Extensor muscles of forearm Skin over posterior arm and forearm

29. Axillary nerve Supplies Teres minor Deltoid Shoulder joint Skin over inferior deltoid

30. Elbow region 1- Cubital Fossa 2- olecranon fossa

31. Elbow region Cubital Fossa Boundaries Superiorly: Imaginary line connecting medial and lateral epicondyles of humerus Medially: Lateral border of pronator teres Laterally : medial border of Brachioradialis Apex : Site of overlap of pronator teres by brachioradialis

32. Roof : skin superficial fascia Cephalic vein Basilic vein Median cubital vein connecting the cephalic and basilic veins Lateral and medial cutaneous nerves of forearm Deep fascia with bicipital aponeurosis

33. floor Floor brachialis supinator muscles of arm and forearm

34. Cubital fossa Contents: Median nerve Brachial artery  dividing into  radial and ulnar arteries B iceps brachi tendon Radial nerve and  its two  terminal branches  (superficial and deep)

35. Olecranon Region Skin Olecranon bursa Anconeus muscle Para-olecranon grooves arteris

36. The elbow joint Humerus , radius and ulna form a hinge joint. Humeroradial joint The capitulum of the humerus articulates with the upper aspect of the head of the radius Humero -ulnar joint The trochlea of the humerus articulates with the trochlear notch of the ulna Proximal radio-ulnar joint

37. The elbow joint Flexion is done by biceps, brachialis and coracobrachialis. Extension is performed by triceps, particularly medial head. The extended ulna makes with the humerus an angle of 170 degrees . This is carrying angle. It is 10-15degrees It fits the elbow into the waist when the arm is at the side Movements

38. Capsule of Elbow Joint Capsule surrounds the joint: Anteriorly to the margins of the coronoid and radial fossae of the humerus Medially and laterally just beyond the articular margin Excluding the medial and lateral epicondyles to which the common flexor and extensor origins are attached Posteriorly to the margins of the olecranon fossa Inferiolaterally it is inserted into the annular ligament of the superior radioulnar joint

39. Medial or Ulnar Collateral Ligament  Lateral or Radial Collateral Ligament