The abductor digiti minimi manus is the largest of the hypothenar eminence, the muscle mass of the little finger. The hypothenar eminence is located on the outside of the palm and hand. It consists of the abductor digiti minimi, the flexor digiti minimi, the opponens digiti minimi, and the palmaris brevis. The abductor digiti minimi is a superficial muscle that originates from the tip of pisiform bone and from the flexor carpi ulnaris. It wraps around the ulnar side of the hand and up to the side of the metacarpal of the little finger, inserting in the ulnar side of the base of the little finger. It is innervated by the ulnar nerve and supplied the ulnar artery. This muscle abducts and flexes the little finger. Research Abductor Digiti Minimi Manus
The abductor hallucis flexes more than it abducts the big toe. It has an elongated, rectangular form that begins from a wide origin on the bottom of the calcaneous, the edge of the flexor retinaculum, and the plantar aponeurosis (a strong fibrous band of fascia that extends along the bottom of the foot) and inserts on the inside of the base of the first phalanx of the big toe. It is innervated by the medial plantar nerve and supplied by the plantar artery. Research Abductor Hallucis
The abductor pollicis brevis is one of the muscles forming the thenar eminence, the muscle mass of the thumb. The abductor pollicis brevis is the largest of the thenar eminence muscle group and is flat, elongated and triangular in shape. It lies just below the skin and slightly overlaps the flexor pollicis brevis and mostly covers the opponens pollicis. The abductor pollicis brevis originates from the tubercle of the trapezium and from the flexor retinaculum. It inserts in the proximal phalanx of the thumb. This muscle is innervated by the median nerve and supplied by palmar branches of the radial artery. It moves the metacarpal bone of the thumb away from the palm. Research Abductor Pollicis Brevis
The adductor transversus hallucis (adductor hallucis) is a narrow, flat band of muscle tissue that originates from the medial process of the tuber calcanei, the flexor retinaculum, and the plantar aponeurosis. It stretches across the metatarsal bones and lies between the bones and the flexor tendons and inserts in the side of the proximal phalanx of the big toe. The adductor transversus hallucis is innervated by the medial plantar nerve and supplied by the plantar artery. The muscle is named after the direction of its muscle fibres. Research Adductor Transversus Hallucis
The arm is the upper limb in man, connected with the thorax or chest by means of the scapula or shoulder-blade, and the clavicle or collar-bone. It consists of three bones, the arm-bone (Humerus), and the two bones of the forearm (radius and ulna), and it is connected with the bones of the hand by the carpus or wrist. The head or upper end of the arm-bone fits into the hollow called the glenoid cavity of the scapula, so as to form a joint of the ball-and-socket kind, allowing great freedom of movement to the limb. The lower end of the humerus is broadened out by a projection on both the outer and inner sides (the outer and inner condyles), and has a pulley-like surface for articulating with the fore-arm to form the elbow-joint. This joint somewhat resembles a hinge, allowing of movement only in one direction. The ulna is the inner of the two bones of the fore-arm. It is largest at the upper end, where it has two processes, the coronoid and the olecranon, with a deep groove between to receive the humerus. The radius - the outer of the two bones - is small at the upper and expanded at the lower end, where it forms part of the wrist-joint. The muscles of the upper arm are either flexors or extensors, the former serving to bend the arm, the latter to straighten it by means of the elbow-joint. The main flexor is the biceps, the large muscle which may be seen standing out in front of the arm when a weight is raised. The chief opposing muscle of the biceps is the triceps. The muscles of the fore-arm are, besides flexors and extensors, pronators and supinators, the former turning the hand palm downwards, the latter turning it upwards. The same fundamental plan of structure exists in the limbs of all vertebrate animals. Research Arm
The biceps brachii (biceps flexor cubiti) is a two-headed arm muscle that consists of the long head (caput longum), and the short head (caput breve). The long head originates from the supraglenoid tuberosity of the scapula and the short head originates from the coracoid process. The muscle extends from the shoulder to the elbow where the biceps tapers into a flat, strong tendon that inserts in the tuberosity on the upper end of the radius. It is innervated by the musculocutaneous nerves (5th and 6th crevical nerves) and is supplied by branches of the brachial artery. This muscle is the main flexor of the elbow joint. When working with other nearby muscles, it can also move the shoulder, since its upper ends are attached to the scapula. In addition it can twist the lower arm so that the palm faces outward, a movement called supination. The biceps and the triceps work together to control the up and down movement of the forearm. Research Biceps Brachii
The biceps femoris (biceps flexor cruris) muscle is included with the hamstring muscle group. The biceps femoris is a large muscle comprised of two heads (two points of attachment to the bone), the long head (caput longum) and the short head (caput breve). The long head originates from the tuberosity of the ischium near the semitendinosus muscle and the short head originates from the linea aspera between the adductor magnus and the vastus lateralis muscles. The two muscles converge to a single tendon and insert in the fibula. This common tendon is located on the outer back corner of the knee and forms the outer hamstring. The long head of the biceps femoris is innervated by the tibial nerve and the short head is innervated by the peroneal nerves. This muscle is supplied by a deep branch of the femoral artery, the profunda femoris. Both heads of the muscle flex the lower leg at the knee joint and rotate the tibia outward. The long head also assists with the extension and outward rotation of the thigh at the hip joint, making it a two-joint muscle, while the short head is a single-joint muscle. Research Biceps Femoris
The movement of the fingers is achieved by flexors and adductors. The flexors, such as the flexor digitorum superficialis and the flexor digitorum profundus, contract to draw the fingers into a curl. Adductors are on the backs of the fingers and contract to draw the fingers out straight. Collateral ligaments pass along the sides of the digits and work in fine-tuning side-to-side flexions. Research Collateral Ligaments
The extensor carpi ulnaris originates by two heads: one from the lateral epicondyle of the humerus and the other from the border of the ulna (forearm bone). It narrows into a tendon three-fourths of the way down the arm and inserts on the ulnar side of the base of the metacarpal bone of the little finger. It is innervated by the radial nerve and supplied by the posterior interosseous artery. This muscle is the most superficial muscle on the ulnar side of the forearm. The
extensor carpi ulnaris works with the flexor carpi ulnaris to bend the hand at the wrist. Research Extensor Carpi Ulnaris
The wrist area contains about 10 blood vessels and nerves and more than 20 tendons. These vessels, nerves and tendons are bound by two fibrous muscle bands that surround the entire wrist and lie just under the skin. The two bands, the flexor retinaculum and the
extensor retinaculum work together. The flexor retinaculum is a deep, thick fibrous band that lies on the palm side of the wrist and creates the carpal tunnel for the passage of the long flexor tendons of the fingers. The
extensor retinaculum attaches to the ulna (the forearm bone on the index finger side) and crosses the back of the wrist and attaches to the ridges on the distal end of the radius. Research Extensor Retinaculum
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Abductor Digiti Minimi Manus
