In a Human Arm the Phalanges Are What to the Humerus

November 10, 2023
David Sunnyside

In a human arm the phalanges are what give us the dexterity to pick up a pencil and type on a keyboard. Each finger has two phalanges and the thumb has two as well. They are found in vertebrate limbs, including those of humans and other primates, and are the thickest, longest bones in the fingers and thumb. The phalanges are attached to the carpals and metacarpals of the hand and form joints that allow for movement and dexterity in the thumb, fingers, and palm of the hand. The phalanges are also connected to the tendons and ligaments that control the movements of the fingers.

The humerus is the single bone that makes up your upper arm and articulates with the shoulder blade -- the scapula -- at the front of your body, and with the ulna and radius bones of your forearm at the elbow. The humerus has a rounded end that fits into your shoulder socket, and a long shaft with a flat area at the middle that forms your elbow joint. The upper end of the humerus has a blunt, C-shaped area called the head (also known as the humeral ball).

At the top of the humerus is an articulation surface called the trochlear notch, which forms the proximal radioulnar joint with the ulna bone in your lower arm. This joint allows you to twist your elbow. There are also two bony projections on the distal (lower) end of the humerus, called the medial and lateral epicondyles. These areas provide attachment points for muscles that act on your forearm, wrist, and hand.

David Sunnyside
Co-founder of Urban Splatter • Digital Marketer • Engineer • Meditator
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