Upper limb

Upper Limb

The upper limb of the human body is a complex structure that includes the shoulder, arm, forearm, and hand. It is primarily responsible for a wide range of movements and functions, including manipulation, sensation, and interaction with the environment.

Anatomy

Bones

The upper limb consists of 30 bones, which are divided into the following regions:

• Pectoral girdle: Composed of the clavicle and scapula, the pectoral girdle connects the upper limb to the trunk.
• Arm: The arm contains the humerus, which is the longest bone in the upper limb.
• Forearm: The forearm consists of two bones, the radius and ulna.
• Hand: The hand is made up of the carpals (wrist bones), metacarpals (palm bones), and phalanges (finger bones).

Joints

The upper limb contains several important joints, including:

• Shoulder joint: A ball-and-socket joint that allows for a wide range of motion.
• Elbow joint: A hinge joint that permits flexion and extension of the forearm.
• Wrist joint: A complex joint that allows for flexion, extension, and other movements of the hand.

Muscles

The muscles of the upper limb are responsible for its movement and strength. Key muscle groups include:

• Deltoid muscle: Responsible for lifting the arm.
• Biceps brachii: Involved in flexing the elbow.
• Triceps brachii: Responsible for extending the elbow.
• Forearm muscles: Involved in movements of the wrist and fingers.

Nerves

The brachial plexus is a network of nerves that supplies the upper limb. It originates from the spinal cord and branches into several major nerves, including the median nerve, ulnar nerve, and radial nerve.

Blood Supply

The upper limb receives blood from the subclavian artery, which continues as the axillary artery and then the brachial artery. Venous return is through the cephalic vein, basilic vein, and other veins.

Function

The upper limb is essential for a variety of functions, including:

• Manipulation: The hand and fingers allow for precise movements and manipulation of objects.
• Sensation: The skin of the upper limb is rich in sensory receptors, providing tactile feedback.
• Communication: Gestures and hand movements are important for non-verbal communication.

Evolution

The upper limb has evolved significantly in primates, allowing for increased dexterity and manipulation. In humans, the opposable thumb is a key adaptation that enhances the ability to grasp and manipulate objects.

Related Pages

• Lower limb
• Human anatomy
• Musculoskeletal system

Gallery

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  Bones of the upper limb

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  Muscles of the upper limb

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  Diagram of the pectoral girdle

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  Nerves of the upper limb

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  Bones with articular cartilage

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  Superficial muscles of the arm

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  Arteries of the upper limb

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  3D animation of the human wrist

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  Bones of the human hand

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  Branches of the brachial plexus

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  Veins of the upper limb

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  Comparative arm skeletons

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  Chimpanzee

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  Gibbon

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  Bushpig

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  Hippopotamus

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  Lynx

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  Sloth

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