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CONTENT
QUIZ
MATERIALS
Quick Facts
Brachial Plexus
Major Nerves
Cutaneous Innervation
Our daily symphony of movements, from the delicate strumming of a guitar to the powerful lift of a weight, is orchestrated by an intricate network of nerves. The upper limb, with its remarkable dexterity and strength, is innervated by a complex array of neural pathways. Let’s embark on a journey through the main nerves of the upper limb and uncover their critical roles.
The Brachial Plexus: The Nerve Network Hub The story of upper limb innervation begins with the brachial plexus, a network of interlacing nerves that originate from the spinal cord and branch out to supply the arm.
- Roots, Trunks, Divisions, and Cords: The brachial plexus is organized into roots (C5-T1), trunks, divisions, and cords, which give rise to the major nerves of the arm. This network is the central hub for upper limb nerve distribution.
The Major Nerves of the Upper Limb: Each nerve emerging from the brachial plexus has a unique territory and function.
- Axillary Nerve: Supplies the deltoid and teres minor muscles and provides sensation to the shoulder region.
- Musculocutaneous Nerve: Innervates the front muscles of the arm (like the biceps brachii) and controls sensation over the lateral forearm.
- Radial Nerve: Responsible for innervating the muscles that extend the wrist and fingers. It also supplies sensation to the back of the hand and forearm.
- Median Nerve: Travels down the middle of the arm and forearm, innervating most of the flexor muscles. It’s well known for its passage through the carpal tunnel and is associated with the clinical condition carpal tunnel syndrome.
- Ulnar Nerve: Runs along the medial aspect of the arm and supplies the forearm and hand muscles involved in fine movements. Famously known as the nerve that causes the ‘funny bone’ sensation.
The Cutaneous Innervation: A Map of Sensation Beyond muscle control, these nerves provide the sensory feedback that enables the hand’s remarkable touch and temperature sensitivity.
- Sensory Territories: Each nerve has a specific cutaneous innervation territory, often overlapping to ensure no loss of sensation in case of injury.