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The extensor carpi radialis brevis is a short, wide, flattened muscle. It arises from the humerus and narrows into a long, flat tendon about two-thirds of the way down the arm. It lies between the extensor carpi radialis longus and the extensor digitorum along the outer surface of the radius. This muscle extends and radially deviates the hand at the wrist joint.
 Research Extensor Carpi Radialis Brevis
The extensor carpi radialis longus is a short, flat muscle that originates from the supracondylar ridge of the humerus and extends down the arm. The muscle belly narrows into a long flat tendon at the upper third of the forearm and continues down to the outer edge of the radius and inserts in the posterior base of the second metacarpal bone. It is innervated by the radial nerve and supplied by the radial artery. This muscle helps to extend and radially deviate hand at the wrist. It also helps flex (bend) the elbow joint.
Research Extensor Carpi Radialis Longus
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 extensor hallucis brevis is actually the most medial portion of the extensor digitorum brevis muscle. The extensor digitorum brevis muscle narrows into tendons, three insert in the middle toes, and one, the extensor hallucis brevis, inserts into the base of the first phalanx of the big toe. The extensor hallucis brevis is innervated by deep branches of the peroneal nerves and supplied by by the dorsal pedis artery. The muscle works to extend the big toe.
Research Extensor Hallucis Brevis
The flexor digitorum superficialis (flexor digitorum sublimis; flexor sublimis) is a large, wide muscle that lies partially deep and partially superficial on the forearm. It consists of two heads. One head (the caput humeroulnare) originates from the medial epicondyle of the humerus and the medial border of the coronoid process. The other head (the caput radiale) originates from the radius. The muscle narrows to insert by way of four tendons into the sides of the middle phalanx of each finger. It does not have an attachment to the thumb. The
flexor digitorum superficialis is innervated by the median nerve and supplied by the ulnar artery and the radial artery.
Research Flexor Digitorum Superficialis
The flexor pollicis longus is a deep forearm muscle. It originates from the shaft of the radius and the interosseus membrane and extends down the arm where it narrows into a flat tendon and inserts on the palmar side of the base of the distal (last) phalanx of the thumb. It is innervated by the median palmar interosseous, a branch of the median nerve and is supplied by branches from the radial artery. This muscle bends the last phalanx of the thumb.
Research Flexor Pollicis Longus
The infraspinatus muscle is attached along the broad inner edge of the scapula. It originates from the infraspinous fossa of the scapula and narrows into a strong tendon that inserts firmly to the top of the humerus. This muscle is innervated by the suprascapular nerve from the fifth to sixth cervical nerves and supplied by the circumflex artery. The infraspinatus muscle sits on the back of the shoulder blade below the spine and under the deltoid muscle. It works with the supraspinatus muscle to help lift and twist the upper arm. These two muscles also help support and protect the shoulder joint by keeping the head of the humerus in place.
Research Infraspinatus
The longus capitis (rectus capitis anticus major) is a broad thick muscle that originates from the transverse processes of the third to sixth cervical (neck) vertebrae. It narrows to insert in the basilar process of the occipital bone. The longus capitis is innervated by the cervical plexus and is supplied by muscular branches of the aorta. This muscle helps twist the neck and bend the neck forward.
Research Longus Capitis
The obturatorius internus lies partly within the cavity of the pelvis and partly at the back of the hip joint. It originates from the margin of the obturator foramen and narrows into a single, flattened tendon at its point of insertion in the great trochanter of the femur. This muscle is innervated by the sacral plexus and supplied bythe inferior gluteal artery. It helps rotate the thigh and steady it when sitting up.
Research Obturator Internus
The opponens pollicis is a deep muscle. It is a small triangular muscle that lies just beneath the abductor pollicis brevis. It originates from the ridge of the trapezium and from the flexor retinaculum in the wrist. The muscle narrows into a tendon that inserts in the first metacarpal bone. It is innervated by motor branches of the median nerve. The opponens pollicis is part of the thenar eminence.
Research Opponens Pollicis
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The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
©1993 - 2009 The Probert Encyclopaedia
Southampton, United Kingdom
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