Muscles of the anterior compartment of
arm
Biceps Brachii
Origin-
• Long head from supraglenoid tubercle
• Short from the tip of the coracoid process
Insertion-
• Rough part of the radial tuberosity.
Nerve supply- Musculocutaneous nerve
Action-
• Strong supinator when the forearm is flexed. All screwing
movements are done with it.
• Flexor of the elbow
• Short head is flexor of the arm
• Long head prevents upward displaced of the head of humerus.
Coracobrachialis
Origin-
• Tip of the coracoid process in common with the
short head of the biceps brachii
Insertion-
• Middle 5cm of medial border of the humerus
Nerve supply
• Musculocutaneous nerve
Action-
• Flexes the arm
Imp- Musculocutaneous nerve pierces the
coracobrachilis.
Brachialis
Origin-
• Lower ½ of the front of humerus both anteriomedial
and anterolateral surfaces and the anterior border.
Insertion-
• Ulnar tuberosity & rough anterior surface of the
coronoid process of the ulna.
Nerve supply-
• Musculocutaneous nerve is motor
• Radial nerve is proprioreceptor
Action-
Flexes the forearm at the elbow joint
Musculocutaneous nerve
• Root value-C5,6,7
• Branch of lateral cord of the brachial plexus.
• It supplies- coracobrachialis, biceps and brachialis,
& also lateral cutaneous nerve of the forearm,
articular branches to the elbow joint,
communicating branches to the neighbouring
nerves.
Musculocutaneous nerve
Course & relation-
• Lower part of axilla-
3rd part of axillary artery, ant-pectoralis major;
post-subscapularis; med-axillary artery and lateral
root of median nerve; lat- coracobrachialis.
Leaves the axilla by piercing the coracobrachialis.
• Arm-
runs downwards & laterally betwn biceps &
brachialis to reach the lateral side of the tendon of
biceps & ends piercing deep fascia 2cm above the
bend of forearm.
Musculocutaneous nerve
Branches and distribution-
Muscular- it supplies the muscles of the front of
the arm i.e coracobrachialis, biceps brachii and
brachialis
Cutaneous- through the lateral cutaneous of the
forearm it supplies the skin of the lateral side of
the forearm from below the elbow to the wrist.
Articular branch-elbow joint
Communicating branches- superficial branch of
radial nerve, posterior cutaneous branch of
forearm and palmar cutaneous branch of median
nerve.
Brachial artery
Brachial artery
Course and relation-
• Runs downwards & laterally, from the medial side
of the arm to the front of elbow.
• Superficial throughout its extent and accompanied
by 2 venae comitantes.
• Anteriorly- in upper part of arm related with
medial cutaneous nerve of forearm.
• Middle of arm- crossed by median nerve from
lateral to medial side.
Brachial artery with venae comitantes
Brachial artery
• In front of elbow- covered by bicipital aponeurosis
and median cubital vein.
• Posteriorly- related to triceps, radial nerve &
profunda brachii artery, insertion of
coracobrachialis & brachialis.
• Medially- upper part related to ulnar nerve &
basilic vein and in lower part to the median nerve.
• Laterally- coracobrachialis, biceps & median nerve
& tendons of biceps at elbow.
• At elbow structures from lateral to medial sides are
i)radial nerve, ii) biceps tendon, iii)brachial artery
&iv) median nerve.
Brachial artery
Brachial artery
Branches
1. Unnamed muscular branches
2. Profunda brachii artery
3. Superficial ulnar collateral branch
4. Nutrient artery
5. Inferior ulnar collateral artery(supratrochlear
artery)
Applied anatomy of brachial artery
1. Brachial pulse are felt or auscultated in front of
the elbow just medial to the tendon of biceps
while recording the blood pressure.
2. Brachial artery can be compressed anywhere
along its course but most favourably it can be
compressed in the middle of the arm where
artery lies on the tendon of the coracobrachialis.
Profunda brachii artery
• It is a large branch of the brachial artery arise just below
the teres major.
• It accompanies the radial nerve through the radial groove
and before piercing the lateral intermuscular septum it
divides into anterior and posterior descending branches
which takes part in anastomosis around the elbow joint.
Branches-
1. Radial collateral artery (anterior descending)
2. Middle collateral artery( posterior descending)
3. Deltoid branch(ascending branch)
4. Nutrient artery to the humerus
Profunda brachii artery
Profunda brachii artery
Deltoid branch
Radial collateral artery
Middle collateral
Anastomosis around elbow joint
Anastomosis around elbow joint
Anastomosis around elbow joint
Anastomosis between brachial and with upper ends
of radial and ulnar arteries and supplies the
ligaments and bones of the elbow joint.
A) Anterior to lateral epicondyle of the humerus-
anterior descending(radial collateral) branch of
profunda brachii anastomosis with radial recurrent
branch of the radial artery.
B) Posterior to the lateral epicondyle of humerus- the
posterior descending(middle collateral) branch of
the profunda brachii artery (above) anastomosis
with the interosseous recurrent branch of the
posterior interosseous artery (below)
Anastomosis around elbow joint
C. Anterior to the medial epicondyle of the
humerus- inferior ulnar collateral branch of brachial
artery and occasionally a branch from the superior
ulnar collateral artery(above) anastomosis with the
anterior ulnar recurrent branch of the ulnar
artery(below)
D. Posterior to the medial epicondyle of the
humerus- superior ulnar collateral branch of the
brachial artery(above) anastomosis with the
posterior ulnar recurrent branch of the ulnar artery
and a branch from the inferior ulnar collateral artery
(above)
Anastomosis around elbow joint
E. Just above the olecranon fossa- a branch from the
posterior descending branch of the profunda brachii
artery(from lateral side) anastomoses with a branch
from the inferior ulnar collateral artery(from the
medial side)
Posterior compartment of arm
Triceps
Origin-
• Long head-Infraglenoid tubercle of the scapula,
• Lateral head- oblique ridge on the upper posterior surface of the
humerus, corresponding lateral lip of spiral(radial) groove
• Medial head- triangular area on the post surface of the humerus
below the radial groove and well as lateral and medial intermuscular
septa.
Insertion -Posterior part of the superior surface of olecranon process.
Nerve supply—Radial nerve
Action –
• Powerful extensor of the elbow.
• Long head supports the head of humerus in abducted position of arm.
Radial nerve
• Root valure-C5,C6,C7,T1
• Largest branch of posterior cord of the brachial
plexus.
Course and relations-
A. In the lower part of the axilla- it passes
downwards and has following relations
Anteriorly- 3rd part of axillary artery
Posteriorly- subscapularis, latissimus dorsi and teres
minor
Laterally- axillary nerve and coracobrachialis
Medially-axillary vein
Radial nerve
B. In the upper part of arm-
• it continue behind the brachial artery and passes
posterior-laterally(profuda brachii vessels)
through the lower triangular muscular space,
below the teres major and betwn the long head of
the triceps and the humerus.
• It then enters the radial groove with the
profunda brachii vessels.
Radial nerve
C. In the radial groove
• It runs downwards and laterally betwn the lateral
head of triceps in contact with the humans.
• At the lower end of the groove, 5cm below the
deltoid tuberosity, the nerve pierces the lateral
intermuscular septum and passes into the anterior
compartment of the arm.
Radial nerve
Radial nerve
Radial nerve
Radial nerve
Applied anatomy-
Radial nerve is commonly damaged in the region of
radial groove(spiral groove) and common cause of
injury are
1. Intramuscular injection in the arm(triceps)
2. Sleeping in an arm chair with the limb hanging
by the side of the chair (Saturday night palsy)
or even the (wrist drop) and sensory loss over a
narrow strip of the back of the forearm and on
the lateral side of the dorsum of the hand.
Wrist drop
