Muscles Encountered During Dissection of the Supracondylar Region of the Humerus
During dissection of the supracondylar region of the humerus, the primary muscles encountered are the brachialis anteriorly, the triceps posteriorly, and the brachioradialis laterally.
Anatomical Approach and Muscle Identification
Anterior Aspect
- Brachialis muscle: The primary muscle on the anterior surface of the distal humerus
- Biceps brachii: Located more superficially and anteriorly, with its tendon passing across the antecubital fossa
Posterior Aspect
- Triceps brachii: The main posterior muscle covering the distal humerus
- Medial head
- Lateral head
- Long head
Lateral Aspect
- Brachioradialis: Originates from the lateral supracondylar ridge
- Extensor carpi radialis longus: Originates just distal to the brachioradialis
Neurovascular Structures Related to Muscles
When dissecting this region, several important neurovascular structures are encountered in relation to these muscles:
- Brachial artery: Runs anterior to the brachialis muscle in the antecubital fossa
- Median nerve: Courses alongside the brachial artery
- Radial nerve: Located between the brachialis and brachioradialis muscles 1
- The inferior lateral cutaneous nerve of the arm and posterior cutaneous nerve of the forearm branch from the radial nerve in this region
- Ulnar nerve: Passes posterior to the medial epicondyle
Clinical Significance in Fracture Management
The muscular anatomy of the supracondylar region is particularly important in the management of pediatric supracondylar fractures. The American Academy of Orthopaedic Surgeons (AAOS) guidelines emphasize the importance of understanding this anatomy when treating these fractures 2, 3.
When vascular compromise occurs with supracondylar fractures, exploration of the antecubital fossa may be necessary to identify potential brachial artery entrapment between muscle planes or fracture fragments 2, 3.
Anatomical Variants and Considerations
- Occasionally, a supracondylar process may be present on the anteromedial aspect of the distal humerus, which can serve as an attachment point for Struthers' ligament 4, 5
- This anatomical variant can potentially cause compression of the brachial artery and median nerve 5
- Variations in muscle patterns may exist, such as a three-headed biceps brachii, which can alter the normal anatomical relationships 6
Surgical Approach Considerations
When approaching the supracondylar region surgically:
- A lateral approach can be utilized by identifying the superficial branches of the radial nerve between the triceps and brachioradialis muscles 1
- The inferior lateral cutaneous nerve of the arm typically arises from the radial nerve at the lower part of the spiral groove
- The posterior cutaneous nerve of the forearm usually emerges about 6.9 cm proximal to the lateral epicondyle 1
Understanding the muscular anatomy of this region is essential for proper surgical management of supracondylar fractures and for avoiding iatrogenic neurovascular injury during surgical approaches.