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The muscles of the hand are the skeletal muscles responsible for the movement of the hand and 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 ...
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'.
Is a simple hinge-joint, and allows of movements of flexion and extension only. Humeroradial joint: head of the radius: capitulum of the humerus: Is a ball-and-socket joint. Superior radioulnar joint: head of the radius: radial notch of the ulna: In any position of flexion or extension, the radius, carrying the hand with it, can be rotated in it.
In human anatomy, the dorsal interossei (DI) are four muscles in the back of the hand that act to abduct (spread) the index, middle, and ring fingers away from the hand's midline (ray of middle finger) and assist in flexion at the metacarpophalangeal joints and extension at the interphalangeal joints of the index, middle and ring fingers.
It is an abductor of the little finger [1] at the metacarpophalangeal joint. [6] It is also possible that the muscle contributes to extension of the middle phalanx of the little finger through its connection to finger's extensor mechanism. [5] It plays an important role when the hand is grasping large objects with outspread fingers. [7]
As its name suggests, it opposes the thumb, bringing it against the fingers. This is a very important movement, as most of human hand dexterity including grip comes from this action. The abductor pollicis brevis originates on the scaphoid tubercle and the flexor retinaculum. It inserts to the radial sesamoid bone and the proximal phalanx of the ...
The tendon to the index finger is accompanied by the EI, which lies on its ulnar side. On the back of the hand, the tendons to the middle, ring, and little fingers are connected by two obliquely placed bands, one from the third tendon passing downward and lateralward to the second tendon, and the other passing from the same tendon downward and ...
Handedness in and of itself tends to be a grey area. The requirements for someone to be right- as opposed to left-handed have been debated, and because individuals who identify as left-handed may also use their right hand for a large number of tasks, identifying two clearcut groups of subjects is a challenging task.