Potential compression of the musculocutaneous, median and ulnar nerves by a very rare variant of the coracobrachialis longus muscle

Olewnik, Łukasz; Paulsen, Friedrich; Tubbs, R. Shane; Zielinska, Nicol; Szewczyk, Bartłomiej; Karauda, Piotr; Polguj, Michał

doi:10.5603/fm.a2020.0085

Cited by 25 publications

(45 citation statements)

References 27 publications

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“…Embryological studies also suggest that the MCN is derived from the MN [22]. Case of absence of the musculocutaneous nerve associated with a supernumerary head of biceps brachii was described by Pacholczak et al Thus, combinations of anatomical variations should be taken into account in the clinical practice [6,7,14,19,[24][25][26][27][28].…”

Section: Discussionmentioning

confidence: 99%

“…Both the MCN and MN exhibit numerous anatomical variants with respect to their origins from the brachial plexus, topographical relationships, anastomotic connections with the neighboring nerves, and branching patterns [3, 5-8, 10-23, 25, 27, 30, 33]. A comprehensive understanding of the diverse anatomical variations of the upper limb nerves could be crucial for the safety and success of surgical procedures, especially procedures for reconstructing the brachial plexus or its branches, particularly since the distribution of brachial plexus lesions is also highly variable [9,11,15,18,24,29,34]. As stressed by Sinha Measurements were performed by two independent researchers.…”

Section: Introductionmentioning

confidence: 99%

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Unusual formation of the musculocutaneous and median nerves: a case report refined by intraneural dissection and literature review

et al. 2021

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This report presents a detailed anatomical investigation of an upper limb specimen showing an atypical formation of the musculocutaneous (MCN) and median (MN) nerves. The study was refined by intraneural dissection, which supplements earlier descriptions of similar anatomical variations and allows for revision of the accepted classification. The case described in this report was an incidental finding during routine dissection of a fixed isolated upper limb. Intraneural dissection revealed partial fusion between the MCN and aberrant bundles of the MN. Those aberrant bundles joined the main steam of the MN at the level at which the MCN branched off as an independent nerve. The procedure allowed the aberrant fibers of the MN to be differentiated from the MCN. The presence of separate bundles in a territory corresponding to the MCN was confirmed, although those bundles and the aberrant MN bundles were covered by a common epineurium. The aberrant MN bundles running within the MCN did not contribute to innervation of the forearm muscles. They rejoined the main nerve trunk in the arm. A comprehensive understanding of the diverse anatomical variations of the upper limb nerves could be crucial for the safety and success of surgical procedures, especially procedures for reconstructing the brachial plexus or its branches.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Unusual formation of the musculocutaneous and median nerves: a case report refined by intraneural dissection and literature review

et al. 2021

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“…In very rare cases, a coracobrachialis longus muscle may be observed [12,13,16], with the CRM being absent [22,26].…”

Section: Discussionmentioning

confidence: 99%

“…Any upper limbs with evidence of surgical intervention in the dissected area were excluded. All dissection of the shoulder and arm area were performed in accordance with an pre-established protocol [15][16][17][18][19].…”

Section: Methodsmentioning

confidence: 99%

A proposal for a new classification of coracobrachialis muscle morphology

et al. 2021

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Introduction The coracobrachialis muscle (CRM) originates from the apex of the coracoid process, in common with the short head of the biceps brachii muscle, and from the intermuscular septum. It inserts to the medial part of the humerus between the attachment of the medial head of the triceps brachii and the brachial muscle. Both the proximal and distal attachments of the CRM, as well as its relationship with the musculocutaneus nerve, demonstrate morphological variability. Material and methods One hundred and one upper limbs (52 left, and 49 right) fixed in 10% formalin solution were examined. Results Three main types, with subtypes, were identified. The most common was Type I (49.5), characterized by a single muscle belly with a classical origin from the coracoid process, medially and posteriorly to the tendon of the biceps brachii. Type II (42.6%), characterized by two heads, was divided into two subtypes (A-B) depending on its origin: Type IIA, where one head originated from the coracoid process posteriorly to the tendon of the biceps brachii and the second head from the short head of the biceps brachii, and Type IIB, in which both heads originated from the coracoid process; however, the superficial head fused with the insertion of a short head of the biceps brachii, while the deep head was directly originating. Finally, Type III (7.9%) was characterized by three heads: two originated from the coracoid process (superficial and deep), and the third from a short head of the biceps brachii. Two types of insertion and two types of musculocutaneous nerve (MCN) relative to CRM could be distinguished. Conclusion An adapted classification is needed for all clinicians working in this area, as well as for anatomists. The CRM demonstrates morphological variability in both its proximal and distal attachments, as well as the variable course of the MCN relative to the CRM. What is known about this subject "and" What this study adds to existing knowledge Not much is known about the variability of coracobrachialis muscle. The present paper introduces a completely new classification, both clinical and anatomical.

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“…Morphological variations can affect routine clinical procedures or important and complex surgeries. For example, the occurrence of a coracobrachialis longus muscle may influence potential compression on the median nerve, ulnar nerve or musculocutaneous nerve [ 22 , 23 ]. A similar situation can occur at the site of the median nerve ran between the two pronator teres heads, as well as the site where the median nerve crosses the palmaris longus tendon [ 20 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

Two muscular variations in the elbow associated with the anterior interosseous nerve

et al. 2021

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The coexistence of different muscular-neurovascular variations is of significant clinical importance. A male cadaver, 76 years old at death, was subjected to routine anatomical dissection; the procedure was performed for research and teaching purposes at the Department of Anatomical Dissection and Donation, Medical University of Lodz. The right forearm and hand were dissected using standard techniques according to a strictly specified protocol. The presence accessory head of the flexor pollicis longus may potentially compress the anterior interosseous nerve. The present case report describes a rare variant of the ulnar head of the pronator teres, characterized by two independent bands (i.e., two proximal attachments). The main band originates from the coronoid process and the second originates from the tendon of the biceps brachii. This type of attachment could potentially affect the compression of the ulnar artery running between the two bands. Additionally, the accessory head of the flexor pollicis longus was observed, which started on the medial epicondyle; its coexistence with a high division median nerve creates a potential pressure site on the anterior interesosseous nerve.

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Potential compression of the musculocutaneous, median and ulnar nerves by a very rare variant of the coracobrachialis longus muscle

Abstract: This article has been peer reviewed and published immediately upon acceptance.It is an open access article, which means that it can be downloaded, printed, and distributed freely, provided the work is properly cited. Articles in "Folia Morphologica" are listed in PubMed.

Cited by 25 publications

References 27 publications

Unusual formation of the musculocutaneous and median nerves: a case report refined by intraneural dissection and literature review

Unusual formation of the musculocutaneous and median nerves: a case report refined by intraneural dissection and literature review

A proposal for a new classification of coracobrachialis muscle morphology

Two muscular variations in the elbow associated with the anterior interosseous nerve

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