The arm contains 3 muscles - biceps brachii, corachobrachialis, and brachialis. It is supplied by the musculocutaneous, median, ulnar, and radial nerves. The brachial artery travels through the arm, giving off branches including the profunda brachii and collateral arteries. The triceps muscle acts as the main elbow extensor. The radial nerve supplies the triceps and travels through the spiral groove in the humerus.

1. Sanjay Kumar Yadav
BDS 1: 24/06/2020

2. Extend from shoulder to the elbow

3. Divides into 2 compartments- anterior and posterior by
med. and lat. intermuscular septa.
Extension of deep fascia enter to form lateral and medial
intermuscular septum.
Provide muscular attachment and the passage for the
neurovascular structures

4. Muscles -Biceps Brachii, Corachobrachialis
and Brachialis.
Arteries- Brachial Artery.
Nerves- Musculocutaneous, Median, Ulnar
and part of Radial Nerves

5. Biceps brachii-
Origin- short head- tip of coracoid process and
long head-supraglenoid tubercle and the
glenoidal labrum.
Insertion- radial tuberosity, also gives an expansion called bicipital aponeurosis and
attached to the deep fascia of forearm.
Nerve supply- musculocutaneous nerve.(C5,6,7)
Action- powerful supinator of the forearm and flexor of elbow Joint. Long head
prevents upward displacementof the head of the humerus.

6. Coracobrachialis
Origin- tip of coracoid process.
Insertion- medial border of the middle of shaft of
humerus.
Nerve supply- musculocutaneous nerve
Action- flexes the forearm, weak flexor of shoulder
joint and also weak adductor of arm.

7. Brachialis
Origin- anteromedial and anterolateral surface of the lower
½ of shaft of humerus.
Insertion- anterior surface of the coronoid process of ulna
and ulnar tuberosity.
Nerve supply- musculocutaneous nerve.
Action- main flexor of forearm

8. Musculocutaneous nerve- Branch of the lateral cord of brachial
plexus. In the lower part of axilla it passes along the 3rd part of axillary
artery.
medially related to axillary artery and laterally with coracobrachialis
muscle.
It pierces the coracobrachialis muscle to enter inside the arm.

10. • Musculocutaneous nerve:
• It runs downward and laterally
between the biceps and
brachialis and ends above the
elbow and continuous as the
lateral cutaneous nerve of
forearm.
• Branches-
• Muscular branches• Muscular branches
• Cutaneous branch
• Articular branch to elbow.
• Communicating branches e.g.
superficial branch of radial
nerve, posterior cutaneous
branch of the median nerve.

11. Brachial artery
Continuation of axillary artery.
Start - inferior border of the teres major
Terminate : cubital fossa opposite neck of radius
Palpable and superficial throughout its course.

12. Unnamed muscular branches.
Deep artery of arm (profunda
brachii)
Superior ulnar collateral
Nutrient artery
Inferior ulnar collateral
Branches of brachial artery
Inferior ulnar collateral
Terminal branches( radial and
ulnar artery)
Applied anatomy- Pulsation of
the brachial artery is felt in
front of the elbow during
recording the blood pressure.

13. Triceps muscle- 3 heads- long, lateral and medial
Origin- long head- from infraglenoid tubercle of the scapula.
Lateral head- from upper half of the post. surface of the shaft of the humerus above
the spiral groove.
Medial head- lower half of the post. surface of the shaft of the humerus below the
spiral groove and med. and lat. Intermuscular septa.
Insertion- into the posterior part of the superior surface of the olecranon process the
ulna.
Nerve supply- radial nerve.
Action- powerful extensor of the elbow joint and long head supports the humeral
head in abducted shoulder joint.

14. Branch from the posterior
cord of brachial plexus.
Enter in the lower
triangular space and
traverse through the radial
groove with deep branch
Radial nerve in the arm
groove with deep branch
of brachial artery.
Pierces the lateral
intermuscular septum
comes on the front of arm
between the brachialis and
brachioradialis.

15. Muscular Spaces
Quadrangular Space
Superior Triangular space
Inferior Triangular space

16. Muscular branches-
Spiral groove above: Long and
medial head of triceps
Spiral groove : Lateral head and
medial heads of triceps
Below spiral groove: Brachialis
Brachioradialis
Extensor carpi radialis longusExtensor carpi radialis longus
Cutaneous branches
Above radial groove: post
Cutaneous nerve of arm,
In radial groove: lower lateral
cutaneous branch,
Post. Cutaneous nerve of the
forearm.
Articular branch- to elbow Joint

17. Branches of
profunda artery:
1.Radial collateral
artery.
2.Middle collateral
artery.
3.Deltoid branch3.Deltoid branch
4.Nutrient artery to
humerus.