Is there something new regarding triceps brachii muscle insertion?

PURPOSE: Previous studies have questioned whether the triceps brachii muscle tendon (TBMT) has a double or single insertion on the ulna. Aiming to provide an answer, we describe the anatomy of the TBMT and review a magnetic resonance imaging (MRI) series of the elbow. METHODS: Forty-one elbows were dissected to assess the details of the triceps brachii insertion. Elbow plastination slices were analyzed to determine whether there was a space on the TBMT. Magnetic resonance imaging from the records of the authors were also obtained to demonstrate the appearance of the pre-tricipital space on MRI. RESULTS: A virtual space on the medial aspect near the TBTM insertion site in the olecranon was consistently found on anatomic dissections. It was a distal pre-tricipital space. Magnetic resonance imaging demonstrated the appearance of the pre-tricipital space on MRI, and its extension was measured longitudinally either in elbow flexion or extension. There was no statistically significant difference between the measurements of this space in the right and left elbows or between flexion and extension (p > 0.05). The coefficient of variation was <10% for all measurements. CONCLUSION: Knowledge of this structure may be essential to avoid incorrect diagnosis and unnecessary therapeutic interventions.

Correction to: Distal insertional anatomy of the triceps brachii muscle: MRI assessment in cadaveric specimens employing histologic correlation and Play-doh® models of the anatomic findings.

Figures 9, 10, 11, 12 and 15 corrected.

Distal insertional anatomy of the triceps brachii muscle: MRI assessment in cadaveric specimens employing histologic correlation and Play-doh® models of the anatomic findings.

OBJECTIVES: Assess the insertional anatomy of the distal aspect of the triceps brachii muscle using magnetic resonance imaging (MRI) in cadavers with histologic correlation and Play-doh® models of the anatomic findings. MATERIALS: Elbows were obtained from twelve cadaveric arm specimens by transverse sectioning through the proximal portion of the humerus and the midportion of the radius and ulna. MRI was performed in all elbows. Two of the elbow specimens were then dissected while ten were studied histologically. Subsequently, Play-doh® models of the anatomic findings of the distal attachment sites of the triceps brachii muscle were prepared. RESULTS: MRI showed a dual partitioned appearance of the distal attachment sites into the olecranon in all specimens. In the deeper tissue planes, the medial head muscle insertion was clearly identified while superficially, the terminal portion of the long and lateral heads appeared as a conjoined tendon. Histologic analysis, however, showed continuous tissue rather than separate structures attaching to the olecranon. CONCLUSION: Although MRI appeared to reveal separate and distinct attachments of the triceps brachii muscle into the olecranon, histologic analysis delineated complex but continuous tissue related to the attachments of the three heads of this muscle. The Play-doh® models were helpful for the comprehension of this complex anatomy and might serve as a valuable educational tool when applied to the analysis of other musculoskeletal regions.