A hamstring is any one of the three posterior thigh muscles in between the hip and the knee (from medial to lateral: semimembranosus,Ā semitendinosusĀ andĀ biceps femoris). The hamstrings are quite susceptible to injury.
The Quadriceps FemorisĀ is the knee extensor muscle. Ā As a group, the quadriceps femoris is crucial in walking, running, jumping and squatting. ItĀ“s subdivided intoĀ four separate āheadsā.
TheĀ gluteal musclesĀ are a group of threeĀ musclesĀ which make up theĀ buttocks: theĀ gluteus maximus,Ā gluteus mediusĀ andĀ gluteus minimus. The three muscles originate from theĀ iliumĀ andĀ sacrumĀ and insert on theĀ femur. The functions of the muscles includeĀ extension,Ā abduction,Ā external rotation, andĀ internal rotationĀ of theĀ hip joint.
TheĀ Erector Spinae is not just one muscle, but a bundle of muscles and tendons. Paired, they run more or less vertically. It extends throughout the lumbar, thoracic and cervical regions, and lies in the groove to the side of the vertebral column.
TheĀ External ObliqueĀ is situated on the lateral and anterior parts of the abdomen. It is broad, thin, and irregularly quadrilateral. ItĀ is the largest and the most superficial (outermost) of the three flat muscles of the lateral anterior abdomen.Ā
The Rectus AbdominisĀ is the most superficial of the abdominal muscles. It is this muscle which forms the six-pack shape! It is a paired muscle running vertically on each side of the anterior wall of the abdomen. There are two parallel muscles, separated by a midline band of connective tissue called the linea alba.
TheĀ Extensor DigitorumĀ muscle helps in the movements of the wrists and the elbows. It extends the phalanges, then the wrist, and finally the elbow. It acts principally on the proximal phalanges. It tends to separate the fingers as it extends them.
The Pronator teresĀ pronates the forearm, turning the hand posteriorly. If the elbow is flexed to a right angle, then pronator teres will turn the hand so that the palm faces inferiorly. It is assisted in this action by pronator quadratus.
TheĀ Triceps Brachii musclesĀ have three muscle heads: Lateral, Medial and Long head. Primarily responsible for the extension of the elbow joint. The lateral head is used for movements requiring occasional high-intensity force, while the medial fascicle enables more precise, low-force movements.
TheĀ Biceps brachii isĀ actually two separate bundles of muscles (heads). The two heads of the Biceps vary in length and as a result, are called the Short and the Long Biceps heads.
TheĀ Infraspinatus muscle is one of the four rotator cuff muscles crossing the shoulder joint and is commonly injured. It is the main external rotator of the shoulder joint.
TheĀ Deltoid muscleĀ is the muscle forming the rounded contour of the shoulder.Ā It is divided into three portions, anterior, lateral and posterior, with the fibers having different roles due to their orientation.
TheĀ latissimus dorsiĀ is the larger, flat, dorsolateral muscle on the trunk, posterior to the arm, and partly covered by the trapezius on its median dorsal region.
TheĀ trapeziusĀ is a broad, flat and triangular muscle. The muscles on each side form a trapezoid shape. It is the most superficial of all the back muscles.