A bilateral gastrocnemius tertius muscle and a unilateral accessory soleus muscle were encountered during the routine educational dissection studies. The right gastrocnemius tertius muscle consisted of one belly, but the left one of two bellies. On the left side, the superficial belly of the gastrocnemius tertius muscle had its origin from an area just above the tendon of the plantaris muscle, the deep belly from the tendon of the plantaris muscle. The accessory soleus muscle originated from the posteromedial aspect of the tibia and soleal line of the tibia and inserted to the medial surface of the calcaneus. On the right side, the gastrocnemius tertius muscle had its origin from the lateral condyle of the femur, and inserted to the medial head of the gastrocnemius muscle. The co-existence of both gastrocnemius tertius and accessory soleus muscle has not, to our knowledge, been previously reported.
*Abnormalities, Multiple ; Adult ; Humans ; Leg/*abnormalities ; Male ; Muscle, Skeletal/*abnormalities

A variation of the trapezius muscle was observed in a Korean female adult cadaver during routine student dissection. The lateral, upper three-fourths of the descending portion of the trapezius muscle were separated from the remainder of the muscle. This single, isolated bundle fused above the insertion of the midpoint of the clavicle, and attached to the clavicle as a separate tendon. The remaining descending portion inserted into the clavicle and scapula as usual. This abnormal muscle bundle is considered as a variant of the cleido-occipitalis cervicalis, and formation of this variation is discussed based on the embryological development of the relative muscular structures.
Female ; Human ; Korea ; Middle Aged ; Muscle, Skeletal/*abnormalities/pathology ; *Shoulder

An unusual variation creates interest among anatomists, but is a cause of concern among clinicians when it mimics a pathology. The sternalis muscle is one such variant of the anterior chest wall located subcutaneously over the pectoralis major, ranging from a few short fibers to a well-formed muscle. We observed a bilateral case, which was accompanied by an atypical presentation on the left side where a huge, bulky sternalis muscle was associated with the absence of the sternal fibers of the pectoralis major. The fibers arose as a lateral strip from the upper two-thirds of the body of the sternum and costal cartilages 2 through 6 with the intervening fascia and aponeurosis of the external oblique. The right sternalis was strap-like and was placed vertically over the sternal fibers of the pectoralis major, arising from the underlying fascia and aponeurosis of the external oblique. The sternalis muscles, on each side, converged into an aponeurosis over the manubrium that was continuous with the sternal heads of the right and left sternocleidomastoid muscle, respectively. This rare anomaly has puzzled radiologists and surgeons in confirming diagnosis, missing it all together or mistaking it for a tumor on mammography or CT scan. These findings prompted us to review its topography, development, and application in relation to the anterior chest wall.
Adult ; Human ; Male ; Muscle Fibers/pathology ; Muscle, Skeletal/*abnormalities/pathology ; *Thorax

During imaging studies or surgical procedures, anomalous forearm and wrist muscles are occasionally encountered. Among them, the flexor carpi radialis brevis is very rare. Because the trend is growing toward treating distal radius fractures with volar plating, the flexor carpi radialis brevis is worth knowing. Here, we report two cases with a review of the literature.
Female ; Forearm/*abnormalities ; Fractures, Comminuted/surgery ; Humans ; Middle Aged ; Muscle, Skeletal/*abnormalities ; Radius Fractures/surgery ; Ulna Fractures/surgery ; Wrist/*abnormalities

The embryologic origin of the omohyoid muscle is different from that of the other neck muscles. A number of variations such as the absence of muscle, variable sites of origin and insertion, and multiple bellies have been reported. However, variations in the inferior belly of the omohyoid muscle are rare. There have been no reports of the combined occurrence of the omohyoid muscle variation with the appearance of the levator glandulase thyroideae muscle. Routine dissection of a 51-year-old female cadaver revealed a duplicated omohyoid muscle and the appearance of the levator glandulae thyroideae muscle. In this case, the two inferior bellies of the omohyoid muscle were found to originate inferiorly from the superior border of the scapula. One of the inferior bellies generally continued to the superior belly with the tendinous intersection. The other inferior belly continued into the sternohyoid muscle without the tendinous intersection. In this case, the levator glandulae thyroideae muscle appeared on the left side, which attached from the upper border of the thyroid gland to the inferior border of the thyroid cartilage. These variations are significant for clinicians during endoscopic diagnosis and surgery because of the arterial and nervous damage due to iatrogenic injuries. The embryologic origins of the omohyoid and levator glandulae thyroideae muscles may be similar based on the descriptions in the relevant literature.
Cadaver ; Female ; Humans ; Middle Aged ; Models, Anatomic ; Models, Biological ; Muscle, Skeletal/*abnormalities/pathology ; Neck Muscles/*abnormalities/*anatomy & histology

The anomalous orientation of musculature of the first dorsal fibro-osseous compartment of the wrist is clinically relevant to De Quervian's stenosing tenosynovitis and reconstructive surgeries. Split insertion of the abductor pollicis longus (APL) is commonly found in chimpanzees, gorillas and gibbons. A comparable identical pattern of anomalous slips in humans is of anthropological and phylogenetic importance and could be a result of atavism. This case report describes an unusual fused muscle belly of the APL and extensor pollicis brevis (EPB), which split into three slips--medial, intermediate and lateral. Further, the medial slip was seen to divide into two tendons, inserting on the base of the first metacarpal along with the intermediate slip. The lateral slip divided into three tendons, inserting into the base of the proximal phalanx, base of the first metacarpal and abductor pollicis brevis muscle. The fusion and unusual insertion pattern of the APL and EPB merits documentation for reconstructive procedures such as tendon transfer and interposition arthroplasty.
Arthroplasty ; Cadaver ; Female ; Humans ; Middle Aged ; Muscle, Skeletal ; abnormalities ; anatomy & histology ; Phylogeny ; Tendons ; abnormalities ; anatomy & histology ; physiopathology ; Wrist ; abnormalities ; anatomy & histology

BACKGROUND: Popeye deformity is common after rupture of the biceps muscle's long head tendon. Herein, we report on histological changes in biceps brachii muscles following tenotomy of the long head biceps tendon. METHODS: Twelve Sprague-Dawley rats (12-week-old) underwent tenotomy of the long head biceps tendon in the right shoulder. At postoperative weeks 4, 7, and 10, the operative shoulders were removed by detaching the biceps brachii muscle from the glenoid scapula and humerus; the opposite shoulders were removed as controls. H&E staining was performed to elucidate histological changes in myocytes. Oil-red O staining was performed to determine fatty infiltration. Myostatin antibody immunohistochemistry staining was performed as myostatin is expressed by skeletal muscle cells during myogenesis. RESULTS: H&E staining results revealed no changes in muscle cell nuclei. There were no adipocytes detected. Compared with that of the control biceps, the cross-sectional area of the long head biceps was significantly smaller (p=0.00). Statistical changes in the total extent of the 100 muscle cells were significant (p=0.00). Oil-red O staining revealed no fatty infiltration. Myostatin antibody immunohistochemical staining revealed no significant difference between the two sides. CONCLUSIONS: Muscular changes after tenotomy of the long head biceps included a decrease in the size of the individual muscle cells and in relative muscle mass. There were no changes observed in muscle cell nuclei and no fatty infiltration. Moreover, there were no changes detected by myostatin antibody immunohistochemistry assay.
Adipocytes ; Animals ; Congenital Abnormalities ; Head ; Humerus ; Immunohistochemistry ; Models, Animal ; Muscle Cells ; Muscle Development ; Muscle, Skeletal ; Muscles ; Myostatin ; Rats ; Rats, Sprague-Dawley ; Rupture ; Scapula ; Shoulder ; Tendons ; Tenotomy

The Martin - Gruber Anastomosis (MGA) is probably the most well known of the anastomotic anomalies that occur at various levels between the median and ulnar nerves. It is formed by motor axons from the median nerve or its branch anterior interosseous nerve that cross in the upper forearm to join the ulnar nerve. The purpose of this study was to establish the frequency of MGA in healthy subjects and to draw the attention of clinicians working in the neurophysiological laboratory to the presence of this anastomosis, and thus to avoid possible misinterpretations of data from needle electromyography (EMG) and nerve conduction studies. 100 volunteers (60 women and 40 men) were selected for the study. Surface recording electrodes were placed on the right hand thenar, hypothenar and on the first dorsal interosseous (FDI) muscles. The median and ulnar nerves were stimulated supramaximally at the wrist and at the elbow and compound muscle action potentials (CMAPs) were recorded and their amplitudes evaluated. MGA was found in 27 of the 100 subjects. The type of anastomosis most frequently seen was type II, which was observed in 21 subjects. Type I anastomosis was observed in three, type I + type II in two and type III anastomosis in one subject. It can thus be concluded that MGA is frequently encountered and it should be borne in mind that abnormal innervation models may influence the electrophysiological findings and thus give rise to faulty interpretations, especially in the case of median and ulnar nerve lesions.
Abnormalities/epidemiology ; Adolescent ; Adult ; Electrophysiology ; Female ; Hand/*innervation ; Human ; Incidence ; Male ; Middle Age ; Muscle, Skeletal/*innervation ; Peripheral Nerves/*abnormalities/physiopathology ; Turkey

Anatomical variations are typically more common in the extensor compartment of the forearm, but uncommon in the flexor compartment. The presence of such anatomical anomalies is not usually noticed until the normal functions of an individual become hindered, or when these anomalies become a surgical problem. During routine dissection curriculum, we encountered a rare finding of bilateral Gantzer muscles in a cadaver. We describe the relationship between the Gantzer muscle and anterior interosseous nerve syndrome.
Cadaver ; Diagnosis, Differential ; Dissection ; Forearm ; abnormalities ; anatomy & histology ; innervation ; Humans ; Median Nerve ; anatomy & histology ; Models, Anatomic ; Muscle, Skeletal ; abnormalities ; anatomy & histology ; innervation

Rhabdomyomatous mesenchymal hamartoma is a rare skin lesion composed of a haphazard arrangement of skeletal muscle, adipocytes, and collagen. Lesions usually present as a solitary sessile papule or nodule on the head and neck in childhood. The etiology of this skin lesion is not clear, but it is thought to be caused by a migration error of the embryonic mesodermal tissues or a genetic defect predisposing to the formation of hamartoma. It may occur as part of Delleman syndrome or congenital malformations like thyroglossal duct cysts, low set ears, and sclerocornea. Herein, we present two cases of rhabdomyomatous mesenchymal hamartoma, including a 20-year-old man who had two asymptomatic erythematous papules on the chin since childhood and a 58-year-old woman with an asymptomatic solitary erythematous sclerotic plaque on the chin for 2 years. Histopathologically, the lesions exhibited normal epidermis, and mature striated muscle fibers arranged randomly within the dermis. Physical examination revealed no congenital abnormalities.
Adipocytes ; Chin ; Collagen ; Congenital Abnormalities ; Dermis ; Ear ; Epidermis ; Female ; Hamartoma* ; Head ; Humans ; Mesoderm ; Middle Aged ; Muscle, Skeletal ; Muscle, Striated ; Neck ; Physical Examination ; Skin ; Thyroglossal Cyst ; Young Adult