Search results
Results from the WOW.Com Content Network
The ring metacarpal is somewhat more mobile while the fifth metacarpal is semi-independent. [1] Each metacarpal bone consists of a body or shaft, and two extremities: the head at the distal or digital end (near the fingers), and the base at the proximal or carpal end (close to the wrist).
The dorsal surface of the body is divided by an oblique ridge, which extends from near the ulnar side of the base to the radial side of the head. The lateral part of this surface serves for the attachment of the fourth interosseus dorsalis ; the medial part is smooth, triangular, and covered by the extensor tendons of the little finger .
The first metacarpal bone is short and thick with a shaft thicker and broader than those of the other metacarpal bones. Its narrow shaft connects its widened base and rounded head; the former consisting of a thick cortical bone surrounding the open medullary canal; the latter two consisting of cancellous bone surrounded by a thin cortical shell.
The base of skull, also known as the cranial base or the cranial floor, is the most inferior area of the skull. It is composed of the endocranium and the lower parts of the calvaria . Structure
The head rests on the top part of the vertebral column, with the skull joining at C1 (the first cervical vertebra known as the atlas). The skeletal section of the head and neck forms the top part of the axial skeleton and is made up of the skull, hyoid bone, auditory ossicles, and cervical spine. The skull can be further subdivided into:
Superior view of the skull base. Middle cranial fossa shown in green. 1: Sphenoidal limbus (anterior margin of the chiasmatic groove) 2: Posterior borders of the lesser wings of the sphenoid 3: Dorsum sellae of the sphenoid bone. 4: Superior borders of the petrous part of the temporal bone
The extensor carpi radialis longus is one of the five main muscles that control movements at the wrist. [1] This muscle is quite long, starting on the lateral side of the humerus, and attaching to the base of the second metacarpal bone (metacarpal of the index finger).
The trapezium is distinguished by a deep groove on its anterior surface. It is situated at the radial side of the carpus, between the scaphoid and the first metacarpal bone (the metacarpal bone of the thumb). It is homologous with the first distal carpal of reptiles and amphibians.