The Arm (2)
Dr. Ali Alaloosy
Contents of the Posterior Fascial Compartment
of the Upper Arm
 Muscle: The three heads of the triceps
muscle
 Nerve supply : Radial nerve
 Blood supply: *Profunda brachii
*ulnar collateral arteries
Structures passing through the
compartment:
 Radial nerve
 Ulnar nerve
 Profunda Brachii Artery
 Superior and Inferior Ulnar Collateral
Arteries
Muscles
Triceps muscle
Origin:
 Long head: Infraglenoid tubercle
of scapula
 Lateral head: Upper half of posterior
surface of shaft of
humerus
 Medial head: Lower half of posterior surface
of shaft of humerus
Insertion:
Olecranon process of ulna
Nerve supply:
Radial nerve
Action:
Extensor of elbow joint
Structures Passing through the Posterior
Fascial Compartment:
Radial Nerve
 The origin of the radial nerve from the
posterior cord of the brachial plexus.
 The nerve winds around the back of the arm
in the spiral groove on the back of the
humerus
 In the spiral groove, the nerve is in direct
contact with the shaft of the humerus.
 Above the elbow, It pierces
the lateral fascial septum to
enter the anterior compartment.
Branches:
 In the axilla:
*Long and medial heads of the triceps
*posterior cutaneous nerve of the arm
 In the spiral groove
*lateral and medial heads of the triceps
*The anconeus.
*The lower lateral cutaneous nerve of
the arm
 In the anterior compartment:
*The brachialis
*The brachioradialis muscles
*The extensor carpi
radialis longus
*articular branches to the elbow joint.
Ulnar Nerve
 It pierces the medial fascial septum at
midpart of arm.
 On descending, it lies on:
*heads of triceps posteriorly
*medial fascial septum anteriorly
 At the elbow, it lies behind the medial
epicondyle of the humerus.
 It enter the forearm between the two heads
of origin of the flexor carpi ulnaris.
Branches:
Articular branch to
the elbow joint
Profunda Brachii Artery
 Arises from the brachial
artery near its origin
 It accompanies the radial
nerve through the spiral
groove.
Superior & Inferior Ulnar
Collateral Arteries:
 Arise from the brachial artery.
 Superior ulnar collateal artery
accompanies the ulnar nerve
in posterior compartment.