Hey everybody! It’s Matt from Kenhub, and the focus of this video tutorial is to present an overview of the bones of the upper extremity. We will review each bone from proximal to distal starting with the clavicle and ending with the phalanges.
The clavicle is a short bone that connects the bones of the trunk to the bones of the arm and is one of the most commonly fractured bones in the body. Next, the scapula connects the clavicle to the humerus seen here from the anterior view. The scapula is a flat, irregular bone and is highly mobile.
The humerus comes next. You can see it here from the anterior view and it forms the structure of the upper arm or brachial region. It is a long bone and the distal end of it is what people are referring to when they say they hit their funny bone. No one thinks it's funny at all.
There are two bones that make up the structure of the lower arm. In anatomical position, the radius – highlighted in green – is on the lateral side of the forearm and the ulna – now highlighted – lies medial to the radius and articulates or connects with the humerus at its insertion proximally. You see them here from the posterior view. Distally, the ulna articulates with the radius which, in turn, connects to the carpal bones.
There are eight carpal bones which make up the wrist and each has a unique shape and name – scaphoid, lunate, triquetrum or triquetral, pisiform, trapezium, trapezoid, capitate, and hamate. They are stacked in two rows of four.
The metacarpals connect the wrist with the fingers and are numbered from medial to lateral based on the finger or phalanx they connect with. So, the one proximal to the thumb is the first metacarpal, the index finger is the second metacarpal, the middle finger is the third metacarpal, the ring finger is the fourth metacarpal, and the pinky is the fifth metacarpal.
The phalanges are the terminal bones for the upper limb, meaning this is the end of the road. There are three sets of phalanges – the proximal, the middle, and the distal. The exception is the thumb which has no middle phalanx, just distal and proximal.
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