Arm Compartments PDF

COMPARTMENTS OF THE ARM  ANTERIOR compartment MUSCLES NERVES VESSELS 1. Median Nerve 1. Biceps Brachii 2. Musculocutaneous nerve 2. Coracobrachialis...

COMPARTMENTS OF THE ARM  ANTERIOR compartment MUSCLES NERVES VESSELS 1. Median Nerve 1. Biceps Brachii 2. Musculocutaneous nerve 2. Coracobrachialis 3. Ulnar Nerve 3. Brachialis 4. Medial cutaneous nerve of arm 5. Medial cutaneous nerve of forearm 1. Brachial Artery 2. Basilic Vein 3. Cephalic Vein ANTERIOR compartment…. MUSCLES BICEPS BRACHI Has 2 heads: long & short head LONG HEAD Arises from the supraglenoid tubercle & glenoid labrum of scapula Tendon passes through the synovial joint of the shoulder joint Emerges beneath the transverse ligament at the upper end of the intertubercular groove. ANTERIOR compartment…. MUSCLES BICEPS BRACHII SHORT HEAD Arises from the apex of the coracoid process to the lateral side of coracobrachialis. ANTERIOR compartment…. MUSCLES BICEPS BRACHII- INSERTION The tendinous origins of each head flattens into a fleshy belly Just above the elbow joint the 2 heads merge There is rotation of this flattened part ie. the anterior surface turns laterally Passes through the cubital fossa Inserts on the posterior border of the radial tuberosity. At the elbow joint the tendon has a medial expansion ie. the BICIPITAL APONEUROSIS Definition: APONEUROSIS :are layers of flat broad tendons. They have a shiny, whitish-silvery color ANTERIOR compartment…. MUSCLES BICEPS BRACHII – ACTION Powerful Flexor of the elbow joint Supinator of the forearm Weak flexor of the shoulder – tendon of long head helps with stabilisation of the joint as it runs on the top of the head of humerus To test the functioning of the biceps: with the forearm supinated, the elbow is flexed against resistance – this allows the contracted biceps, its tendon & aponeurosis to be easily palpable Definition: SUPINATION :rotation of the forearm so that the palm faces anteriorly or up BICEPS BRACHII – NERVE SUPPLY Musculocutaneous nerve (C5, C6) – one branch to each belly ANTERIOR compartment…. MUSCLES CORACOBRACHIALIS Arises from the apex of the coracoid process (it is fused here with the medial side of short head of biceps) Inserted midway along medial border of humerus ANTERIOR compartment…. MUSCLES CORACOBRACHIALIS - ACTION Weak flexor of shoulder joint Adductor of shoulder CORACOBRACHIALIS – NERVE SUPPLY Musculocutaneous nerve (C5, C6) ANTERIOR compartment…. MUSCLES BRACHIALIS Arises from the front & lower half of the humerus & medial intermuscular septum Some fibres arise from the lower end of the radial groove It is a broad muscle that flattens to cover the elbow joint Inserts into coronoid process & tuberosity of ulna ANTERIOR compartment…. MUSCLES BRACHIALIS - ACTION Flexor of the elbow joint BRACHIALIS – NERVE SUPPLY Musculocutaneous nerve (C5, C6) A small lateral part of the muscle is innervated by a branch of the Radial nerve (C7) ANTERIOR compartment…. MUSCLES MEDIAL INTERMUSCULAR SEPTUM Fibrous Attached along the medial supracondylar ridge Extends proximally behind the coracobrachialis insertion Gives origin to most medial fibres of brachialis & medial head of triceps Pierced by the ulnar nerve, superior ulnar collateral artery & radial nerve LATERAL INTERMUSCULAR SEPTUM Attached along the lateral supracondylar ridge Pierced by the radial nerve & profunda brachii artery ANTERIOR compartment…. MUSCLES ANTERIOR compartment…. VESSELS BRACHIAL ARTERY Continuation of the axillary artery Above: Median nerve lies lateral to artery, then it crosses obliquely in front of the artery at middle of arm Below: Median nerve lies medial to artery Above: Ulnar nerve lies posterior to artery, then it leaves the artery in the lower part of arm to pierce the medial intermuscular septum. Brachial artery had a superficial course in the arm It passes deep into the cubital fossa & at the level of the head of radius, it divides into Radial & Ulnar arteries ANTERIOR compartment…. VESSELS BRACHIAL ARTERY - BRANCHES Profunda brachii artery : runs in the radial groove with radial nerve Superior ulnar colateral artery : accompanies ulnar nerve Radial & Ulnar arteries: terminal branches of the brachial artery  ANTERIOR compartment…. VESSELS BASILIC VEIN Perforates the deep fascia in the middle of the arm Ascends medially to become the axillary vein CEPHALIC VEIN Lies in the groove between deltoid & pectoralis major Ascends laterally & ends by piercing the clavipectoral fascia to enter axillary vein  ANTERIOR compartment…. NERVES MEDIAN NERVE Formed at the lower border of the axilla by the union of the medial & lateral roots, from the corresponding cords of the brachial plexus ie. C5-T1 At its commencements it lies lateral to the brachial artery Passing down the arm, it lies in front of the brachial artery At the elbow it lies on the medial side of the artery  ANTERIOR compartment…. NERVES MUSCULOCUTANEOUS NERVE This is a nerve of the flexor compartment of arm It gives a branch to & pierces the coracobrachalis mucle Then it comes to lie between biceps brachii & brachailis – supplies both these muscles At the lateral margin of the biceps tendon it appears as the lateral cutaneous nerve of the forearm  ANTERIOR compartment…. NERVES ULNAR NERVE Lies posterior to the vessels of the arm, inclines backwards away from the vessels & pierces the medial intermuscular septum in the lower third of arm Accompanied by the superior ulnar collateral artery As it lies in the groove behind the medial epicondyle, it is easily palpable. ANTERIOR compartment…. NERVES MEDIAL CUTANEOUS NERVE OF THE ARM Lies medial to the vessels Pierces the deep fascia in the middle of arm Supplies skin on the front & medial side of arm MEDIAL CUTANEOUS NERVE OF THE FOREARM Passes anterior to the vessels Pierces the deep fascia with basilic vein Divides into anterior & posterior branches The anterior branch passes in front of the median cubital vein Supplies skin over the lower part of the front of arm & medial side of forearm INTERCOSTOBRACHIAL NERVE Is the lateral cutanenous branch of the 2nd intercostal nerve Supplies skin of the axilla & skin on medial side of upper arm  POSTERIOR compartment MUSCLES NERVES 1. Triceps Brachii 2. Anconeus 1. Radial Nerve POSTERIOR compartment…. MUSCLES TRICEPS Has 3 heads: long, lateral & medial LONG HEAD Arises from the infraglenoid tubercle at the upper end of the scapula LATERAL HEAD Has linear origin from back of humerus (above the groove for radial nerve) extending to the surgical neck MEDIAL HEAD Arises from the back of the humerus below radial groove & from both intermuscular septa Inserts into upper surface of olecranon POSTERIOR compartment…. MUSCLES TRICEPS POSTERIOR compartment…. MUSCLES TRICEPS - ACTION Extensor of the elbow joint Long head supports the capsule of the shoulder joint when arm is abducted To test the functioning of the triceps: the flexed forearm is extended against resistance & muscle is felt & seen TRICEPS – NERVE SUPPLY Radial nerve (C7, C8) POSTERIOR compartment…. MUSCLES ANCONEUS Small triangular muscle that stabilises the elbow joint during movement ACTION Assist with extension of forearm NERVE SUPPLY Radial nerve POSTERIOR compartment…. NERVES RADIAL NERVE Passes across the back of the humerus from medial to lateral in a shallow groove between long & medial heads of triceps with the profunda brachii artery It then pierces the intermuscular septum to enter anterior compartment of arm Runs towards the elbow, first medially between brachialis and brachioradialis and then extensor carpi radialis longus laterally Then it divides into a superficial branch and a deep posterior interossues branch at the level of the lateral epiondyle POSTERIOR compartment…. NERVES RADIAL NERVE