The antebrachial fascia or deep fascia of the forearm is a thick connective tissue fascia investing the forearm muscles. It also forms the lateral intermuscular septum, which divides the forearm muscle into the anterior and posterior compartments together with the radius, ulna, and interosseous membrane.
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Summary
location: forearm
blood supply: radial and ulnar artery
innervation: branches of the median, radial, and ulnar nerves
relations: brachial fascia, lacertus fibrosus, transverse and dorsal carpal ligaments, palmaris longus muscle
Gross anatomy
The antebrachial fascia envelopes the forearm from the elbow to the wrist. The antebrachial fascia is thicker on its dorsal aspect and distally than on the volar side and proximally 2.
Besides the lateral intermuscular septum, which divides the muscles of the forearm together with the radius, ulna and interosseous membrane into an anterior and posterior compartment, it forms several intermuscular septa enclosing the different forearm muscles.
Proximally the antebrachial fascia is connected to the olecranon and the proximal ulna. On the inside of the elbow, the antebrachial fascia features an opening for the connection of the superficial and deep veins of the forearm 2.
Distally and volar it is continuous with the transverse carpal ligament forming a sheath for the palmaris longus muscle which inserts to the palmar aponeurosis 2. On the dorsal side, it is continuous with the dorsal carpal ligament.
Function
The antebrachial fascia ensheathes the muscles of the forearm separating extensor and flexor muscle groups together with the radius, ulna, and interosseous membrane.
It serves as an insertion site for the bicipital aponeurosis (lacertus fibrosus) and to the triceps tendon 2 and serves as a site of origin for the forearm muscles including extensor carpi ulnaris and extensor digiti minimi muscles 2.
Attachments
Musculotendinous
Musculotendinous attachments of the antebrachial fascia include the following 2:
brachial fascia
lacertus fibrosus
triceps tendon
extensor carpi ulnaris
extensor digiti minimi
transverse carpal ligament
dorsal carpal ligament
Ligamentous
Ligamentous or bony attachments of the crural fascia are:
olecranon
ulna
Boundaries
The antebrachial fascia borders and is continuous to the following structures 1,2:
proximal: brachial fascia, lacertus fibrosus, olecranon
distal: palmar (transverse) and dorsal carpal ligaments
anterior: palmaris longus
posterior: ulna
Arterial supply
The antebrachial fascia receives blood from the branches of the radial and ulnar arteries including the superficial palmar arch.
Innervation
The antebrachial fascia is richly innervated containing free nerve endings, Pacini and Ruffini corpuscles 3 from branches of the median, ulnar and radial nerves.
Histology
The antebrachial fascia appears as an irregular mesh essentially consisting of collagen fiber bundles intermixed with many elastic fibers 4 with internal and external layers showing characteristics of epimysial fasciae and an aponeurosis-like median layer consisting of layers of parallel undulating collagen fiber bundles 4,5.
Radiographic features
Ultrasound
The antebrachial fascia appears as a thick hyperechoic lamina of connective tissue on ultrasound.
Related pathology
The antebrachial fascia or deep fascia of the forearm is related to the following pathologies 6,7:
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