Search results
Results from the WOW.Com Content Network
The deep layer of the precursor extensor mass is known to be phylogenetically unstable and is undergoing evolution as high variability is seen in non-human primates. [5] [8] [9] [10] In humans, anomalous or additional muscles can be seen in small portion of population. Anomalous muscles in human extensor compartment are listed as follow:
It is considered an extrinsic hand muscle because it acts on the hand while its muscle belly is located in the forearm. Together the flexor pollicis longus, pronator quadratus, and flexor digitorum profundus form the deep layer of ventral forearm muscles. [2] The muscle is named from Latin 'deep bender of the fingers'.
The muscles of the hand can be subdivided into two groups: the extrinsic and intrinsic muscle groups. The extrinsic muscle groups are the long flexors and extensors. They are called extrinsic because the muscle belly is located on the forearm. The intrinsic group are the smaller muscles located within the hand itself. The muscles of the hand ...
The extrinsic extensor muscles of the hand are located in the back of the forearm and have long tendons connecting them to bones in the hand, where they exert their action. Extrinsic denotes their location outside the hand. Extensor denotes their action which is to extend, or open flat, joints in the hand.
The extensor digitorum muscle (also known as extensor digitorum communis) [2] is a muscle of the posterior forearm present in humans and other animals. It extends the medial four digits of the hand. Extensor digitorum is innervated by the posterior interosseous nerve, which is a branch of the radial nerve. [3]
Split tendons of the muscle inserting on both ulnar and the radial side of the common extensor digitorum was also reported. [2] Anomalous hand extensors including the extensor medii proprius and the extensor indicis et medii communis are often seen as variations of the extensor indicis [2] due to the shared characteristics and embryonic origin. [8]
The forearm contains many muscles, including the flexors and extensors of the wrist, flexors and extensors of the digits, a flexor of the elbow (brachioradialis), and pronators and supinators that turn the hand to face down or upwards, respectively. In cross-section, the forearm can be divided into two fascial compartments.
6.7 to 9.7 centimetres (2.6 to 3.8 in) in length, the tendon passes through a long and superficial synovial sheath which, passing obliquely from the radial border of the forearm into the thumb, extends from the proximal border of the extensor retinaculum to the first carpometacarpal joint.