As they emerge, the anterior primary rami of C8 and T1 join to form the inferior (lower) trunk of the brachial plexus.
| Feature | C8-T1 Lesion | C5-C6 (Upper Brachial Plexus) Lesion | | :--- | :--- | :--- | | | Claw Hand | Waiter’s Tip (Erb’s Palsy) | | Main Deficit | Loss of hand dexterity/grip | Loss of shoulder abduction/elbow flexion | | Sensory Loss | Medial arm/forearm/hand | Lateral arm/forearm/hand | | Reflexes Affected | None specifically (Finger jerk may be absent) | Biceps and Brachioradialis reflexes | | Associated Signs | Horner’s Syndrome (T1) | None specific |
Issues at these levels, such as (pinched nerves), often mimic ulnar neuropathy (cubital tunnel syndrome) because both affect the inner hand. Differentiating C8–T1 Radiculopathy from Ulnar Neuropathy
Understanding the nuances of is critical because its symptoms often mimic more common issues, such as ulnar neuropathy or carpal tunnel syndrome, leading to misdiagnosis. 1. Anatomy: The C8 and T1 Nerve Roots The C8 and T1 nerve roots are essential for hand function. Location: The C8 nerve root exits the spinal cord below the C7cap C sub 7 vertebra, while the T1cap T sub 1 root exits below the T1cap T sub 1
The C8-T1 nerve roots are vital for the functional independence of the hand. While they do not power the large muscles of the shoulder or elbow, their integrity is essential for the intricate movements that define human dexterity. Diagnosis of C8-T1 pathology requires a careful examination of grip strength, finger abduction, and sensory mapping of the medial hand, alongside screening for associated signs like Horner’s Syndrome or apical lung pathology.