The lacertus fibrosus or distal bicipital aponeurosis is an aponeurotic structure originating and enveloping the distal biceps tendon as well as the proximal flexor muscle group of the forearm.
On this page:
Gross anatomy
The lacertus fibrosus has been described as a multilayered structure with a superficial, middle and deep layer originating and encircling the middle zone of the distal biceps musculotendinous unit thus adding stability to it 1-3. The layers merge and continue further distally forming an aponeurosis that envelopes the whole proximal flexor muscle group and inserts to both sides of the proximal ulna as well as to the antebrachial fascia 1-3.
Relations
On the forearm, the lacertus fibrosus also crosses the median nerve and brachial artery.
Radiographic features
Ultrasound
On ultrasound, the lacertus fibrosus is seen as a hyperechogenic structure 3.
MRI
On MRI the lacertus fibrosus appears as a thin hypointense structure fanning out from the distal biceps tendon to the pronator fascia conveniently appreciated on axial images 4.
Unable to process the form. Check for errors and try again.