Arm bone

Arm Bone

The arm bone or the humerus is the long bone in the upper arm. It is located between the shoulder joint and the elbow joint. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections.

Anatomy of the Arm Bone

The arm bone is divided into three parts: the proximal end, the shaft, and the distal end.

Proximal End

The proximal end of the humerus connects to the scapula at the shoulder joint. It is characterized by the head of the humerus, which is a round, smooth surface designed for articulation with the glenoid cavity of the scapula.

Shaft

The shaft of the humerus is the long, cylindrical part of the bone. It is slightly curved, allowing for the natural curve of the arm. The shaft also houses the radial groove, which protects the radial nerve and the deep brachial artery.

Distal End

The distal end of the humerus connects to the radius and ulna at the elbow joint. It is characterized by two articulating surfaces: the trochlea and the capitulum. The trochlea articulates with the ulna, and the capitulum with the radius.

Function of the Arm Bone

The arm bone plays a crucial role in the movement and functionality of the arm. It allows for flexion, extension, abduction, and adduction of the arm at the shoulder joint, and flexion and extension of the forearm at the elbow joint. The humerus also provides structural support and protection for many of the arm's major nerves and vessels.

Related Conditions

Several medical conditions can affect the arm bone, including fractures, osteoporosis, and arthritis. Treatment for these conditions can range from conservative management to surgical intervention.

See Also

• Bone
• Human skeleton
• Upper limb