arm

Anterior compartment

muscles
Coracobrachialis

·      functionally unimportant adductor

Origin

·      apex of coracoid process

·      medial to short head of biceps

Path

·      musculocutaneous nerve passes through muscle

·      through 2 fused heads

Insertion

·      middle 1/3 of medial border of humerus

·      may be associated with ligament of Struthers

·      attaches to supracondylar spur

·      passes to medial epicondyle

·      represents degenerated 3rd head

·      may entrap median nerve and brachial artery

Nerve supply

·      musculocutaneous nerve

Biceps

Origin

·      long head

·      supraglenoid tubercle of scapula

·      adjoining glenoid labrum

·      short head

·      apex of coracoid process

·      lateral to coracobrachialis

Path

·      long head

·      passes through synovial cavity of shoulder joint

·      beneath transverse ligament in intertubercular groove

·      range of mobility under ligament is 6 cm

·      short head

·      lies side by side with long head

·      bellies fuse and form flattened tendon

·      just above elbow joint

·      tendon rotates laterally

·      bicipital aponeurosis

·      arises from medial side of tendon

·      at level of elbow joint

Insertion

·      tendon inserted into posterior part of tuberosity of radius

·      separated from anterior border by bursa

·      aponeurosis inserted into subcutaneous border of ulna

·      via deep fascia

Nerve supply

·      musculocutaneous nerve (C5,6)

Brachialis

Origin

·      front of lower 2/3 of humerus

·      clasps deltoid insertion

·      some fibres from lower part of spiral groove

·      medial intermuscular septum

Path

·      covers anterior part of elbow joint

Insertion

·      coronoid process and tuberosity of ulna

septae
Medial intermuscular septum

·      extends along medial supracondylar line

·      separates coracobrachialis and triceps

·      gives origin to some fibres of

·      brachialis

·      medial head of triceps

·      pierced by

·      ulnar nerve

·       ulnar collateral artery

Lateral intermuscular septum

·      extends along lateral supracondylar line

·      separates brachialis and triceps

·      gives origin to some fibres of

·      brachioradialis

·      ECRL

·      medial head of triceps

·      pierced by

·      radial nerve

·      anterior descending branch of profunda brachii artery

nerves and vessels
Brachial artery

·      continuation of axillary artery

·      lies in groove between biceps and brachialis

·      median nerve

·      lies lateral to it above

·      crosses it in front

·      lies medial to it below

·      ulnar nerve

·      lies posterior to artery above

·      leaves it and pierces medial IM septum

·      lies in groove between biceps and triceps

Branches

Profunda brachii

·      leaves through lower triangular space

·      with radial nerve

·      runs in spiral groove with radial nerve

·      supplies triceps

·      ends as anterior and posterior anastomotic branches

·      join cubital anastomosis

Superior ulnar collateral

·      accompanies ulnar nerve

Inferior ulnar collateral

·      divides into anterior and posterior branches

·      join cubital anastomosis

Muscular

·      to flexor muscles

Nutrient

·      to humerus

Veins

·      brachial vein (venae comitantes)

·      accompany brachial artery

·      basilic vein

·      pierces deep fascia in middle of arm

·      joins brachial vein

·      cephalic vein

·      lies in groove between deltoid and pectoralis minor

·      pierces clavipectoral fascia

·      enters axillary vein

Median nerve

·      clasps 3rd part of axillary artery at formation

·      lies lateral to artery

·      medial root crosses vessel

·      nerve crosses artery and lies on medial side

·      gives twig to elbow joint

Musculocutaneous nerve

·      gives

·      twig to shoulder joint

·      branch to coracobrachialis

·      pierces coracobrachialis

·      between conjoined heads

·      lies between biceps and brachialis

·      supplies both muscles

·      appears at lateral margin of biceps tendon

·      as lateral cutaneous nerve of forearm

Ulnar nerve

·      lies posterior to brachial artery

·      inclines backwards

·      pierces medial IM septum at lower 1/3

·      accompanied by

·      ulnar collateral artery

·      branch of radial nerve to medial head of triceps

·      gives off branch to elbow joint behind medial epicondyle

Medial cutaneous nerve of arm

·      lies anterior to vessels

·      pierces deep fascia in upper part of arm

·      supplies anteromedial skin

Medial cutaneous nerve of forearm

·      lies medial to vessels

·      passes anterior to vessels

·      pierces deep fascia on medial arm with basilic vein

·      supplies skin over medial forearm

Intercostobrachial nerve

·      lateral cutaneous branch of 2nd intercostal nerve

·      supplies skin of axilla