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The radius can thus glide on the capitulum during elbow flexion-extension while simultaneously rotate about its own main axis during supination-pronation. [2] Between the capitulum and the trochlea of the humerus is the capitulotrochlear groove. A semi-lunar surface around the circumference of head is shaped to articulate continuously with this ...
The humerus (/ ˈ h juː m ər ə s /; pl.: humeri) is a long bone in the arm that runs from the shoulder to the elbow.It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections.
The accurate adaptation of the trochlea of the humerus, with its prominences and depressions, to the trochlear notch of the ulna, prevents any lateral movement. Flexion in the humeroulnar joint is produced by the action of the biceps brachii and brachialis , [ 3 ] assisted by the brachioradialis , with a tiny contribution from the muscles ...
It involves an articulation between the glenoid fossa of the scapula (shoulder blade) and the head of the humerus (upper arm bone). Due to the very loose joint capsule , it gives a limited interface of the humerus and scapula, it is the most mobile joint of the human body.
From its neutral position, the shoulder girdle can be rotated about an imaginary vertical axis at the medial end of the clavicle (the sternoclavicular joint). Throughout this movement the scapula is rotated around the chest wall so that it moves 15 centimetres (5.9 in) laterally and the glenoid cavity is rotated 40–45° in the horizontal plane.
of arm/humerus at shoulder [1] Deltoid muscle; Supraspinatus; Infraspinatus; Teres minor; of thigh/femur at hip [2] Gluteus maximus; Lateral rotator group. piriformis; gemellus superior; obturator internus; pectineus ; gemellus inferior; obturator externus; quadratus femoris; Sartorius; of leg at knee [3] Biceps femoris; of eyeball (motion is ...
It gives attachment to the capsular ligament of the shoulder joint except at the upper inferior-medial aspects. It is best marked in the lower half of its circumference; in the upper half it is represented by a narrow groove separating the head of the humerus from the two tubercles, the greater tubercle and the lesser tubercle.
Opposition is a complex combination of thumb flexion and abduction that also requires the thumb to be rotated 90° about its own axis. Without this complex movement, humans would not be able to perform a precision grip. [11] In addition, the central group of intrinsic hand muscles give important contributions to human dexterity.