The arm is divided into anterior, medial, and posterior compartments by intermuscular septae. The anterior compartment contains the biceps, brachialis, and coracobrachialis muscles. The posterior compartment contains the triceps muscle. Major nerves include the median, ulnar, radial, and musculocutaneous nerves. The brachial artery and its branches supply the arm, and lymph drainage involves the deltopectoral and supratrochlear lymph nodes.

1. The arm

2. Contents of the arm
The arm is part of the body between the
shoulder and elbow.
• Bone: Humerus
• Muscles:
Anterior compartment: Biceps, brachialis
Medial compartment: coracobrachialis
Posterior compartment: Triceps
Arteries: Brachial artery and its branches

3. • Veins: Cephalic, basilic, venae
commitantes
• Nerves: Median, ulna, radial,
musculocutaneus, medial cutaneus of
arm, medial cutaneus of fore arm
• Lymphnodes: deltopectoral and
supratrochlear

4. Compartments of the arm
• Divided into anterior, medial and posterior
compartments by the medial and lateral
inter muscular septae
• Medial septum extends along the medial
supracondylar line behind coracobrachialis
muscle and fades out above, btn this
muscle and the long head of triceps. Gives
orgin to brachialis and medial head of
triceps.pierced by ulna nerve and ulna
collateral artery

5. • Lateral septum: extends along the lateral
supracondylar line and fades out behind
the insertion of deltoid. Ant aspect gives
attachment to brachioradialis and extensor
carpi radialis longus.post aspect gives
attachment to medial head of triceps.
Pierced by radial nerve and profunda
brachii artery

6. Anterior compartment
• Muscles: biceps brachii, brachialis, and
coracobrachialis
• Artery: brachial artery
• Nerves: median, musculocutaneus, ulna
and radial(upper part)
• Lymphnodes: detopectoral nodes

7. Biceps brachii
• Origin:
long head; supraglenoid tubercle. Passes
through capsule of shoulder joint
short head; coracoid process with
coracobrachialis
• Insertion: post aspect of bicipital tuberosity
of radius, and deep fascia of fore arm to
ulna

8. • Nerve supply: musculocutaneus nerve,
C5,6
• Action: flexion when elbow is extended,
supination in any other position

11. Coracobrachialis
• Small muscle, functionally not so
important, represents the medial(adductor)
compartment of the arm. In lower animals,
it is a tricipital muscle. In humans the
upper two heads have fused together
entrapping musculocutaneus nerve. Lower
head may persist to form ligament of
struthers

12. • Origin: coracoid process
• Insertion: medial aspect of the humerus
above the nutrient foramen
• Nerve supply: musculocutaneus nerve, C7
• Action: neglible bcoz adduction of
shoulder is mainly by lattismus dorsi and
pectoralis major

13. coracobrachialis

14. Brachialis
• Runs from the lower 2/3 of humerus.
Upper fibres clasp the deltoid insertion.
Some fibres arise from lower part of spiral
groove. Covers anterior surface of elbow
joint to be inserted on the coroind process
and tuberosity of ulna.
• Nerve supply: musculocutenus nerve,
C5,6 and radial nerve
• Action: extensor of the elbow

15. Brachialis

16. Posterior compartment
• Muscles: triceps
• Artery: profunda brachii
• Nerves: radial and ulna(lower part)

17. Triceps
• Has three heads, medial, deep and lateral
but heads wrongly named; medial – long,
deep – medial
• Origin: long head; infraglenoid tubercle,
medial head; medial side of spiral groove,
lateral head; lateral side of spiral groove
below deltoid tuberosity
• Insertion; olecranon process and capsule
of shoulder joint

18. • Nerve supply: radial nerve
• Action: extansor of the elbow, stabilises
shoulder in abducted position.

20. Deltoid

21. DELTOID
• It is triangular in shape.
• It is functionally divided
into: anterior, middle and
posterior parts.
• Origin :
• Anterior fibers: lateral 1/3
of the anterior border of
the clavicle.

22. DELTOID
• Middle fibers : lateral
border of the acromion.
• Posterior fibers: lower
border of the spine of
the scapula.

23. DELTOID
• Insertion :
• deltoid tuberosity (middle
of the lateral surface of the
humerus).

24. DELTOID
• Nerve supply :
• Axillar nerve.

25. DELTOID
• Action:
• 1. Middle fibers: abduction
of the arm (helped by
supraspinatus).
• 2. Anterior fibers: flexion
and medial rotation.
• 3. Posterior fibers :
extension and lateral
rotation.

26. Nerves of the arm
• Median nerve; arises by medial and lateral
roots(with axillary artery btn)
• Initially lateral to the brachial artery, then
crosses it anteriorly and in the lower part it
is medial to the brachial artery
• Has no braches in the arm

27. Radial nerve
• Arises from the posterior cord of the
brachial plexus, accompanies profunda
brachii artery in the spiral groove where it
gives off the lower cutaneus nerve of the
arm and posterior cutaneus nerve of
forearm, passes btn medial and lateral
heads of triceps there by supplying them,
pierces lateral intermuscular septum to
enter the cubital fossa

28. Ulna nerve
• Lies posterior to the vessels. Pieces the
medial intermuscular septum with the ulna
collateral artery and a branch of the radial
nerve to the medial head of triceps.Passes
thro the lower part of the extensor
compartment and disappears by passing
thro the humeral and ulna heads of flexor
carpi ulnaris. Runs in a groove behind the
medial epicondyle

29. Ulna nerve

31. Radial nerve

33. Musculocutaneus nerve
• Gives a twig to shoulder and
coracobrachialis before entering the arm,
passes btn the two heads of
coracobrachialis, runs btn biceps and
brachialis ends by forming the lateral
cutaneus nerve of fore arm at the lateral
aspect of brachialis

34. Other nerves
• Medial cutaneus nerve of arm; lies anterior
to the vessels. Supplies skin over the
anterior and medial aspect of the upper
arm
• Medial cutaneus of fore arm: lies medial to
the vessels, pirces fascia to lie on medial
aspect of arm with basilic vein supplies
skin on lower part of arm, and medial side
of fore arm

35. Arteries
• Brachial artery; continuation of axillary
artery, has the median nerve lateral to it in
upper part but medial in lower part,
relatively superficial, gives off profunda
brachii, muscular branches, ulna collateral,
supractrochlear ant terminal branches:
radial and ulna

39. Lymphnodes
• Detopectoral: located btn pectoralis major
and deltoid. Receive lymphatics
accompanying veins
• Supratrochlear: located in subcutaneus fat
above medial epicondyle.receive
lymphatics frm medial aspect of arm and
fore arm. End in lateral axillary nodes. Can
become enlarged in secondary syphyllis.