1 ANTERIOR & POSTERIOR COMPARTMENTS OF ARM BY PROF. ANSARI 23/10/07, LECTURE- 2.30/3.30 PM.

2 ARM  Topography:- It lies between shoulder joint and elbow joint.  Anatomically it is also called brachium.  It has two fascial compartments, anterior and posterior.  The anterior compartment is called as flexor compartment of arm.  The posterior compartment is called as extensor compartment of arm.

3 ARM LOCATION

4 IMPORTANT LAND-MARKS

5 SURFACE FEATURES  The tip of the shoulder is due to acromian process.  Head of the humerus, the greater tubercle & intertubercular sulcus and the whole length of shaft of humerus is palpable.  Medial epicondyle is more prominent and posterior to it lies the ulnar nerve.  Lateral epicondyle is palpable at the posterior aspect of elbow joint.  Axillary artery can be palpable in the axilla, brachial artery at the medial border of biceps brachii & radial and ulnar arteries at the cubital fossa.

6 BRACHIAL FASCIA  It is the deep fascia of the brachium/arm.  Superiorly it is continuous with the deep fascia of deltoid, pectoral fascia & clavi -pectoral fascia.  Inferiorly it merges with the antebrachial fascia and forming the bicipital aponeurosis.  It is attached to the lateral and medial supra condylar ridges forming the lateral and medial intermuscular septa between the flexor and extensor compartments of the arm.

7 MUSCLES OF THE ANTERIOR COMPARTMENT OF ARM Coracobrachialis.Brachialis. Biceps brachii.

8 THE NERVE OF THE ANTERIOR COMPARTMENT OF ARM Musculocutaneous nerve. It supplies coracobrachialis, brachialis, and biceps brachii. It arises from lateral cord of the brachial plexus. It pierces the coracobrachialis. It gives lateral cutaneous nerve of forearm.

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15 ARTERIES OF THE ARM  The artery of the upper limb is the subclavian artery.  Right subclavian artery is the branch arising from right brachiocephalic trunk.  Left subclavian artery is a direct branch from the arch of aorta.  At the outer border of first rib it is renamed as axillary artery.

16 The axillary artery  It starts at the outer border of first rib and passes through the axilla, as axillary artery.  In relation with the pectoralis minor the axillary artery is divided in to three parts.  First part lies proximal to pectoralis minor, second part lies posterior to the muscle,& the third part lies distal to the muscle.  Branches are :- superior thoracic, acromio- thoracic, lateral thoracic, anterior and posterior circumflex humeral and sub- scapular arteries.

17 Branches from brachial artery/collateral circulation around elbow joint

18 ATTACHMENTS OF THE MUSCLES OF THE ANTERIOR COMPARTMENT

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23 POSTERIOR COMPARTMENT OF ARM  It is the extensor compartment of the arm.  It includes the muscles, vessels and nerves.  The muscles are triceps brachii, and anconeus.  The vessels are the profunda brachii.  The nerve is the radial nerve.

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26 The muscles of the posterior compartment  Triceps brachii.  Anconeus.

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30 ANCONEUS

31 RADIAL NERVE  It is the nerve of the posterior compartment of arm.  It arises from the posterior cord of the brachial plexus.  It supplies the triceps, anconeus, and extensor muscles of the forearm.  Its root value is C T1.

32 RADIAL NERVE – SPIRAL GROOVE

33 WRIST DROP DUE TO INJURY TO RADIAL NERVE

34 MUSCLE REFLEXES  BICEPS REFLEX:-It is a deep tendon reflex to test the integrity of the nerve supply to the muscle, the root value is C5+6.  It is tested by tapping the tendon of biceps at the cubital fossa, there will be sudden jerk contraction by biceps muscle for flexion at elbow joint.

35 ELICITATION OF BICEPS REFLEX

36 TRICEPS REFLEX  This tendon reflex is used to test the segmental integrity of radial nerve/root value C7+8.  It is done by tapping at the tendon of triceps at olecranon process of ulna.  The result is extension of the elbow joint.

37 ELICITATION OF TRICEPS REFLEX

38 CROSS SECTIONAL ANATOMY OF ARM

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40 APPLIED ANATOMY  Fracture of humerus at surgical neck will damage axillary nerve, resulting of paralysis of deltoid.  Fracture of shaft of humerus will damage the radial nerve in spiral groove, resulting in wrist drop/ Saturday night palsy.  Erb-Duchenne palsy is due to injury to the superior roots of the brachial plexus, (C5+6) resulting in paralysis of supraspinatus, infraspinatus, deltoid, biceps, brachialis, coracobrachialis, brachioradialis, teres minor and subscapularis.

41 WRIST DROP

42 THANK YOU