Variations of pronator teres muscle. A morphological study.

The muscles of shoulder girdle and elbow act together to position the hand accurately for manipulative functions. The superior extremity of man has undergone various modifications during evolution one of which is the lateral rotation of forelimbs at joints with pectoral girdle. The aim of the present study was to study the variations of pronator teres muscle. The present study was done on 60 upper limbs (56 Males and 4 Females) of embalmed adult human cadavers obtained from Deptt of Anatomy, Govt. Medical College Patiala. The humeral head of PT was found in all the cases, while Ulnar head was present in 52(86.7%) cases. The Humeral head was muscular in all the cases. The Ulnar origin was muscular in 15 cases (28.84%), tendinous in 7 cases (13.46%) & mixed in 30 cases (57.7%). In 2 (3%) cases there was double humeral head and the median nerve was passing between them. In 3cases (5%) there was high origin of humeral head of Pronator teres from medial intermuscular septum. Anatomy instructors and health professionals should be aware of the common variations in muscles and tendons of the forearm, not only for their academic interest but also for their clinical and functional implications.

Anatomic Variations of Ligaments and Muscles Related with the Ulnar Nerve Entrapment Syndrome in the Upper Arm / 대한해부학회지

Compressive neuropathy of the ulnar nerve occurs commonly at the cubital tunnel, but it can also be occurred by the anatomic variations of the structures on the ulnar nerve passage. This study was thus performed to clarify the variations of the ligaments and muscles, which can cause the ulnar nerve entrapment syndrome in the upper arm. One hundred arms of 50 Korean adult cadavers were used. The arcade of Struthers, a musculo-tendinous band from the medial head of the triceps brachii to the medial intermuscular septum, was observed in 34% of the cases. This arcade was mostly in a narrow-band shape, but a broad-band shaped arcade was sometimes observed. The internal brachial ligament was observed in 17% of cases. The epitrochleoanconeus muscle between the medial epicondyle and the olecranon was observed in 3% of cases. The ulnar nerve was wrapped or covered by the medial head of triceps brachii in 5% of cases. This study is expected to further the current understanding of the anatomic variations of ligaments and muscles on the ulnar nerve passage, and to be helpful data for the diagnosis and treatment of the ulnar nerve entrapment syndrome in the upper arm.