Unilateral variant motor innervations of flexure muscles of arm

Unusual bilateral sensory innervation of the dorsum of hand by lateral antebrachial cutaneous nerve: a case report

A 68-year-old male cadaver showed bilateral variation in the sensory innervation of the dorsum of hand. On the dorsum of right hand, first digit and lateral half of second digit were supplied by lateral antebrachial cutaneous nerve (LABCN); medial side of second digit and lateral side of third digit were supplied by superficial branch of radial nerve (SBRN) and medial side of third digit, the fourth and fifth digits were supplied by dorsal cutaneous branch of ulnar nerve (DBUN). On the dorsum of the left hand, lateral side of first digit was supplied by LABCN, medial side of first digit, the second and third digits as well as the lateral side of fourth digit were supplied by SBRN; medial side of fourth digit and fifth digit were supplied by DBUN. These variations would be helpful in understanding peripheral neuropathy, in interpretation of conduction velocity studies and in reconstructive surgery of hand.

Variations in innervation of muscles in anterior compartment of arm - a cadaveric study

AIMS AND OBJECTIVE

Study was undertaken to observe the variation in the innervation of muscles in the front of arm. The results were compiled. Embryological basis and clinical applications of encountered variations were tried to explain with the help of available literature.

MATERIAL AND METHODS

Thirty upper limbs from fifteen cadavers were dissected to observe the contents of front of arm. Musculocutaneous nerve, median nerve and innervation of the muscles of front of arm were observed.

RESULTS

Variations were observed in 13% of cases. Commonly seen variation was the absence of musculocutaneous nerve and innervation of muscles of front of arm by branches of median nerve. This variation was seen bilaterally in 3.3% of cases and unilaterally in 6.6% cases. Bilateral presence of this variation in one out of fifteen cadavers is rare finding. Variation is more common on right side as compared to the left side.

CONCLUSION

Bilateral absence of musculocutaneous nerve and innervation of muscles of front of arm from the branches of median nerve is a rare variation. Knowledge of such anatomical variations is of interest to the anatomist and clinician alike. Variations assume significance during surgical exploration of the axilla and can even fail nerve block of infraclavicular part of brachial plexus. Surgeons who perform procedures involving neoplasm or repairing trauma need to be aware of these variations.

Anomalous cutaneous branch of median nerve in arm: a report of anatomical variation with clinical implications

The objective of the study was to observe and document the variation on the subject of branches of the median nerve. This report will assist clinicians and surgeons by considering anatomical variation associated with the median nerve in interpreting atypical clinical presentations. The arm and forearm region of a 55 year embalmed male cadaver during educational gross anatomy dissection. We found that an anomalous cutaneous branch arising from the median nerve in the right arm which was passing deep to the tendon of the biceps brachii. Later it enters the cubital fossa and then it is accompanied by the superficial vein of the forearm. The other limb of the cadaver did not show any such variation. No other neural, arterial or muscular variation was observed in either of the limbs. A rare anatomical variation in which the anomalous cutaneous branch arising from the median nerve in the right arm which is later accompanied by a superficial vein in the forearm. Such knowledge is advantageous in nerve grafting and neurophysiological evaluation for diagnosing peripheral neuropathies.

Musculocutaneous nerve substituting for the distal part of radial nerve: A case report and its embryological basis

In the present case, we have reported a unilateral variation of the radial and musculocutaneous nerves on the left side in a 64-year-old male cadaver. The radial nerve supplied all the heads of the triceps brachii muscle and gave cutaneous branches such as lower lateral cutaneous nerve of the arm and posterior cutaneous nerve of forearm. The radial nerve ended without continuing further. The musculocutaneous nerve supplied the brachioradialis, extensor carpi radialis longus and extensor carpi radialis brevis muscles. The musculocutaneous nerve divided terminally into two branches, superficial and deep. The deep branch of musculocutaneous nerve corresponded to usual deep branch of the radial nerve while the superficial branch of musculocutaneous nerve corresponded to usual superficial branch of the radial nerve. The dissection was continued to expose the entire brachial plexus from its origin and it was found to be normal. The structures on the right upper limb were found to be normal. Surgeons should keep such variations in mind while performing the surgeries of the upper limb.