A Cadaveric Study of Palmaris Longus Muscle

Background: Aim: To assess the palmaris longus muscle.Methods:40 formalin fixed cadavers of both genders were included. Routine dissection of the upper limb was carried following the Cunnigham’s Manual of Practical Anatomy. During the dissection of the anterior compartment of forearm, the Palmaris longus muscle was identified & carefully dissected.Results:Out of 40 cadavers, 22 were of males and 18 were of females. Morphology of Palmaris longus found to be normal in 18, agenesis in 6, fusiform in 4, hybrid in 6, bifurcated tendon in 5 and fleshy in 1 case. A significant difference was observed (P< 0.05).Conclusions:Surgeon must be aware of the variations of palmaris longus muscle. Morphology of Palmaris longus found to be normal, agenesis, fusiform, hybrid, bifurcated tendon and fleshy.

Prevalence of agenesis of palmaris longus in male and female genders on clinical examination – a review

Palmaris longus is a muscle that is located in the anterior compartment of the forearm. Among the muscles belonging to the flexor compartment of forearm, palmaris longus is located at the most superficial position and that is why it is easy to access. It exhibits high variability and its prevalence ranges between 1.5% and 63.9%. The knowledge of prevalence of agenesis of palmaris longus is essential both in terms of updating anatomical information and also for physicians, radiologists, physiotherapists and surgeons. The surgeons must know about the variability as it may be beneficial while they plan surgeries involving the palmaris muscle as a graft. The current narrative review was planned to highlight the variability pattern of palmaris longus muscle in terms of prevalence, gender and laterality. Palmaris longus agenesis is more common in females and on the left side. Besides, unilateral agenesis is more common compared to bilateral agenesis.

PALMARIS LONGUS MUSCLE CONTRIBUTION TO MAXIMUM TORQUE AND STEADINESS IN HIGHLY SKILLED GRIP AND NON-GRIP SPORT POPULATIONS

Background: The anatomy, origin, function, and appearance of the Palmaris Longus Muscle (PLM) in different populations are well studied. However, little is known about its contribution to wrist flexion movements in sports. This study investigates whether the existence or absence of the PLM affects maximal torque output or torque consistency of submaximal wrist flexion moment. Methods: One hundred ninety-seven well-trained sports students were clinically examined to ascertain the presence of the PLM. Forty of them from different sport disciplines were assigned to two groups (athletes in handgrip sports: HG, athletes in non-handgrip sports: NHG). Their 80 upper limbs were divided based on the PLM-presence/absence and hand-dominance/non-dominance. Maximal Isometric Torque (MIT) at 150º, 180º, and 210º wrist angle, and torque steadiness at 150º and 180º, at 25%, 50%, and 75% of MIT were measured on a Humac Norm dynamometer. Results: In all MIT tests, HGs significantly surpassed NHGs, independently of the dominant or non-dominant side in presence of the PLM (p <.05). Steadiness was significantly higher in HGs than in NHGs in dominant hands having the PLM, at 25% and 75% of MIT at both angles (p <.05). Conclusions: It is concluded that the existence of the PLM provides an advantage in sustained handgrip sports (throwers, racquet sports, basketball, handball players), contributing positively to decreased torque variability and higher maximal torque independently of muscular length. Important implications for sports performance and injury prevention have also resulted.

Clinical Significance of a Duplicated Palmaris Longus Muscle with One Reversed Muscle: A Case Report

BACKGROUND: Multiple variations of the palmaris longus (PL) muscle are reported throughout literature and include variations such as double muscle bellies, inversion of muscle belly and tendon, and the absence of the muscle. The muscle functions as a weak flexor of the wrist. It originates from the medial epicondyle of the humerus, projects as a superficial muscle of the anterior compartment of the forearm, lies over the transverse carpal ligament, and inserts into the palmar aponeurosis. CASE REPORT: Routine dissection of the right forearm of a 70-year-old Caucasian male revealed a rare duplicated PL muscle with the medial PL muscle being reversed. The left forearm appeared normal, with no such variations. The cadaver showed no significant pathological findings due to this variation. Innervation and vasculature of the variant muscle appeared normal. CONCLUSION: The PL muscle is highly variable, and clinicians need to be aware of its many possible presentations due to its involvement in surgery, symptomatic clinical presentations, and as an anatomical landmark.

Clinical Assessment of Existence of Palmaris Longus Muscle among South Indian Population

Background: Palmaris longus tendon is often used as a donor tendon by surgeons in tendon grafts. It is one of the flexor muscles of the forearm and documented well for its variations in both morphology and number of tendons. Prevalence of absence of this muscle varies among the individuals of same population and individuals of various ethnic groups. The aim of this study was to assess the existence of Palmaris longus muscle within a group of students and its association with side of the limb and gender of the individual. Methods: Three hundred medical students of 150 males and 150 females with age group of 18–21 years were clinically assessed. The standard Schaffer’s test was used for the assessment of PL tendon. If the tendon was not found in this test, the confirmation was done by other four tests. Results: Results of this study shows that an overall absence of palmaris longus muscle in both sexes was found to be 32%, out of which 21% absence was found in males and 43% absence found in females. Among the males, the unilateral agenesis was seen in 16% and bilateral agenesis in 4% and in females the unilateral agenesis was seen in 29% and bilateral agenesis seen in 14%. Conclusions: To conclude; in the present study, prevalence of Palmaris longus muscle agenesis was found to be more in female subjects on their left side. Surgeons who plan for tendon reconstructive procedures should know variations of Palmaris longus muscle and its clinical assessment.

Hypertrophied reverse palmaris longus muscle: a rare cause of carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is usually secondary to compression or irritation of the median nerve in the fibro-osseous canal formed by the flexor retinaculum (transverse carpal ligament) and the carpal bones. The prevalence of CTS in the general population is about 7 to 19%. Several causes both local and systemic have been described, but CTS due to aberrant musculature are rare. Here we report a case of a middle-aged female with paresthesia of the hand and a positive Phalen’s test with nerve conduction study of the median nerve showing sensorimotor neuropathy. The patient underwent surgery for open CTS release where we found a hypertrophied reverse palmaris longus muscle attached to the palmar aponeurosis which was excised along with its proximal tendon. On post-operative follow up all the symptoms of CTS were completely resolved. Muscle abnormalities concern three muscles: the palmaris longus, the flexor digitorum superficialis of index, and the lumbricals. These muscles can be hypertrophied, bifid, duplicated, digastric, inverted or have an abnormal insertion, thus creating a mechanical restriction of the carpal tunnel. Surgical resection of abnormal muscle provides excellent functional recovery.