Lateral Intermuscular Septum of Arm
Septum intermusculare laterale brachii
Read moreAnatomical Relations
The lateral intermuscular septum of the arm is continuous with the lateral part of the deltoid fascia, and blends with part of the deltoid muscle. The radial nerve and radial collateral branch of the profundus brachii artery pierce the septum to enter the anterior compartment of the arm from the posterior compartment.
Related parts of the anatomy
Structure
The lateral intermuscular septum is composed of tough connective tissue, which extends from the greater tubercle of the humerus to the lateral epicondyle of the humerus, passing along the supracondylar ridge. A thin extension of the lateral intermuscular septum is attached to the lateral crest of the intertubercular groove. The lateral intermuscular septum is thinner than the medial septum.
Function
The medial and lateral intermuscular septum of the arm ensures the muscles are contained within anterior or posterior neuromuscular compartments. Each compartment house’s muscles of similar function and common innervation. Muscles in the anterior compartment of the arm are mainly flexors (biceps brachii, brachialis, and coracobrachialis), while muscles in the posterior compartment are mainly extensors (triceps brachii and anconeus). The fascial compartments of the upper limb are important clinically because they contain and direct the flow and spread of infection and hemorrhages in the limb.
The lateral intermuscular septum of the arm provides additional muscle attachments for the lateral head of the triceps brachii, brachialis, brachioradialis, and extensor carpi radialis muscles. This increases the bulk of the muscles, improving the efficiency and effectiveness of their actions (Standring, 2016).
References
Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41st edn.: Elsevier Limited.
