| Fascial compartments of arm | |
|---|---|
 Cross section showing the fascial compartments of the upper and lower arm | |
| Identifiers | |
| TA98 | A04.6.01.001 |
| FMA | 265176 |
| Anatomical terminology | |
Thefascial compartments of arm refers to the specific anatomical term of the compartments within the upper segment of theupper limb (the arm) of thebody. The upper limb is divided into two segments, thearm and theforearm. Each of these segments is further divided into two compartments which are formed bydeep fascia – toughconnective tissue septa (walls). Each compartment encloses specific muscles and nerves.
The compartments of the arm are the anterior compartment of the arm and the posterior compartment of the arm, divided by the lateral and the medial intermuscular septa. The compartments of the forearm are theanterior compartment of the forearm andposterior compartment of the forearm.
Thelateral intermuscular septum extends from the lower part of the crest of thegreater tubercle of thehumerus, along thelateral supracondylar ridge, to thelateral epicondyle; it is blended with the tendon of thedeltoid muscle, gives attachment to thetriceps brachii behind, and to thebrachialis,brachioradialis, andextensor carpi radialis longus muscles in front. It is perforated by theradial nerve and profunda branch of thebrachial artery.
Themedial intermuscular septum, is thicker than the lateral intermuscular septum. It extends from the lower part of the crest of thelesser tubercle of the humerus below theteres major, and passes along themedial supracondylar ridge to themedial epicondyle; it is blended with the tendon of thecoracobrachialis, and gives attachment to thetriceps brachii behind and thebrachialis in front.
It is perforated by theulnar nerve, thesuperior ulnar collateral artery, and the posterior branch of theinferior ulnar collateral artery.
Theanterior compartment of the arm is also known as theflexor compartment of the arm as its main action is that of flexion. The anterior compartment is one of the two anatomic compartments of the upper arm, the other being the posterior compartment.
The compartment contains three muscles; thebiceps brachii, thebrachialis and thecoracobrachialis. These muscles are all innervated by themusculocutaneous nerve[1] which arises from thefifth andsixth and seventhcervical spinal nerves. The blood supply is from thebrachial artery.
Theposterior compartment of the arm is also known as theextensor compartment, as its main action isextension.
The muscles of this compartment are thetriceps brachii andanconeus muscle and these are innervated by theradial nerve. Their blood supply is from theprofunda brachii.
Thetriceps brachii is a large muscle containing three heads a lateral, medial, and middle. Theanconeus is a small muscle that stabilizes the elbow joint during movement. Someembryologists consider it as the fourth head of the triceps brachia as the upper and lower limbs have similar embryological origins, and the lower limb contains thequadriceps femoris muscle which has four heads, and is the lower limb equivalent of the triceps.
