General Medicine
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12503/21736
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Browsing General Medicine by Author "Holmes, Victor L."
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Item A Variant of Extensor Medii Proprius: A Case Report(2015-03) Holmes, Victor L.; Liu, Hao (Howe); Rosales, Armando; Kirchhoff, Claire A.Purpose: The extensor medii proprius (EMP), a documented variation of human hand extensor muscles, originates from the distal 1/3 of the ulna and inserts on the dorsal aponeurosis (extensor expansion) of the 3rd manual digit. This case report describes an anomaly in which the EMP originates from the lunate, an origination reported in the medical literature. Methods: During routine gross anatomy dissection of the left hand of a 67-year old female who died of “stroke,” an unusual EMP muscle was observed and documented. Results: The flat, fleshy muscle originated from the lunate bone, narrowed into a flat tendon near the 3rd metacarpophalangeal joint, and continued distally to insert on the extensor expansion of the 3rd digit. A branch from the posterior interosseous nerve was traced to the EMP. We propose that this previously unreported variation be termed extensor medii proprius brevis (EMPB). Conclusions: Several anomalies found here have not been previously reported in the literature. First, the EMP originated at the lunate, which means the muscle does not cross the radiocarpal joint as described in previous reports. Second, the co-existence of the EMP with the extensor indicis or related muscles was not observed in this case. Third, the EMP tendon traveled deep to the intertendinous connection between the 2nd and 3rd tendon slips of the extensor digitorum muscle. Finally, this is the first time that the EMP was found to be innervated by a branch from the posterior interosseous nerve. In functional terms, the EMP/EMPB may act as an accessory MCP extensor. Due to its small size, however, the impact of EMP/EMPB on MCP extension may be negligible. Clinicians should still be aware of this variation, since swelling or tenderness of the muscle may lead to misdiagnoses of ganglion cysts or adipose tumors around this area of the dorsal hand.Item Variation of Sternalis Muscle: A Case Report(2015-03) Liu, Hao (Howe); Holmes, Victor L.; Kirchhoff, Claire A.; Reeves, RustinPurpose: The sternalis muscle was first documented in the 19th century and since has been shown to have variations in its origins, insertions, direction, extra muscle slips, and nerve innervations. This case report describes anomalous features not previously reported in the medical literature. Methods: During routine gross anatomy dissection of the anterior chest wall of an 100-year old woman who died of “natural causes” at UNTHSC, obvious anomalies in the bilateral appearance of the sternalis muscle were observed and documented. Results: The left sternalis originated from the clavicular origin of the left sternocleidomastoid (SCM) muscle, while the right emerged from the sternal origin of the right SCM muscle. Both the left and right original tendons of the sternalis’ were separated but wrapped in a tight connective tissue band. The fleshy muscle bellies of each sternalis travelled down inferolaterally to insert on the aponeurosis of the left and right external oblique muscles, respectively. The innervation to the muscle could be traced to the 4th, 5th, and 6th anterior intercostal nerves. Conclusions: Several anomalies found here have not been previously reported in the literature including (1) the sternalis muscles originating from the clavicular head of the SCM muscle, (2) the tendinous band suspended over and slightly left of the sternal angle with only a loose connection to the underlying sternal angle, and (3) the inferolateral and nearly symmetrical 30 degree angle traveled by the sternalis to the sternum. Awareness of the location of the sternalis will help radiologists and reconstructive surgeons avoid misdiagnosis during mammography or misjudgment during breast surgery. Because of its superior attachment to the sternocleidomastoid muscle, therapists may need to be aware that a person with such an anomaly may have an automatic accessory inspiration with head rotation.