The arm is divided into anterior and posterior compartments by intermuscular septa. The anterior compartment contains the biceps, coracobrachialis, brachialis muscles and vessels like the brachial artery and basilic vein. The posterior compartment contains muscles like the triceps and vessels like the profunda brachii artery and radial nerve. Both compartments are surrounded by fascia and separated by intermuscular septa, with the neurovascular structures passing through their respective compartments.

2.  Superiorly = conditional line connecting the
lower borders of the pectoralis major muscle
and latissimus dorsi.
 Inferiorly = conditional line passing above
epicondyles on two transverse finger.
 It is divide into anterior and posterior by two
vertical line drowing up from epicondyles.

3.  Laterally and medially sulcuses are located
on skin.
 Deep fascia form sheath for muscles and
neurovascular bundles.
 It form two fascial septa, and with humerus
form two fasical compartments.
 Sulcuses are located btw muscles of anterior
and posterior facial compartments.

4.  Skin is thin and mobile.
 Lateral surface is supplied by lower lateral
cutaneous nerve of arm (radial nerve branch)
below the deltoid.
 Medially by medial cutaneous nerve and
intercostobrachial nerves.
 Subcutaneous tissue contain cutaneous
nerve.

5.  Btw superficial and deep fascia superficial
veins lies.
 Lateral side of biceps = Cephalic vein
ascends, reaching infraclavicular fossa,
pierces clavipectoral fascia to drains into
axillary vein.
 Medially side = Basilica vein ascends, pierces
the deep fascia and contribute to formation
of axillary vein.

6.  Superficial lymph vessels draining superficial
tissue of upper arm pass upward to axilla.
 Cephalic vein follow to interclavicular group
of nodes on lateral side.
 Basilica vein follow to lateral group of axillary
nodes.
 Deep lymphatic vessels draining the muscles
and deep structure of arm drain into lateral
group of axillary nodes.

7.  Brachial fascia surround the arm, where
anterior side is thin and posterior is thick.
 It gives lateral intermuscular septum that
extends from the lateral lip of intertubercularis
sulcus to the lateral epicondyle.
 Medial intermuscular septum extends from
medial lip of intertubercularis sulcus to medial
epicondyle.
 These septum gives anterior and posterior
flexor/fascial compartment.

8.  Anterior fascial compartment formed anterior
by deep fascia, posteriorly by humerus ,
medially and laterally by intermuscular septa.
 It contains biceps brachii, coracobrachialis
and brachialis muscles.
Musculocutaneous, median and ulnar nerve
brachial artery and basilica vein.
 Radial nerve present on lower part of
compartment.

9.  Skin is thick and mobile.
 Supplied by upper lateral cutaneous nerve of
arm (branch of axillary nerve) and posterior
cutaneous nerve of arm( branch of radial
nerve).
 Superficial fascia is thin.
 Deep and brachial fascia is thick on posterior
facial compartment than on anterior region.

10.  Posterior fascial compartment formed by
anteriorly by humerus, posteriorly by deep
fascia, medially and laterally by intermuscular
septa.
 Profunda brachii artery and its branch, vein
and radial nerve pass through posterior
fascial compartment.
 Ulnar nerve present in lower part of
compartment.