CLINICAL DIAGNOSTIC MANUAL
Diminished sensation in a dermatome of the arm refers to the partial or total loss of sensitivity in a specific area of the arm that is innervated by a particular nerve root.
Each posterior nerve root along the spinal cord is responsible for sensation in a specific region of the skin, known as a dermatome.
Injuries to these roots can result from various pathologies and manifest clinically with numbness, tingling, and reduced sensation in the area corresponding to the affected dermatome.
Pathology | Clinical Symptoms and Signs | Suspected Diagnosis | Confirmatory Diagnosis |
Posterior root injury of C5 | Diminished sensation in the shoulder and lateral part of the arm, possible weakness in the deltoid | Medical history, neurological examination, radicular pain in C5 | Cervical MRI, nerve conduction studies |
Posterior root injury of C6 | Diminished sensation in the lateral part of the forearm and thumb, possible weakness in the biceps | Medical history, neurological examination, radicular pain in C6 | Cervical MRI, nerve conduction studies |
Posterior root injury of C8 | Diminished sensation in the little finger and medial part of the forearm, possible weakness in the intrinsic muscles of the hand | Medical history, neurological examination, radicular pain in C8 | Cervical MRI, nerve conduction studies |
Posterior root injury of T1 | Diminished sensation in the medial part of the arm and forearm, possible weakness in the intrinsic muscles of the hand | Medical history, neurological examination, radicular pain in T1 | Thoracic MRI, nerve conduction studies |
Posterior root injury of T2 | Diminished sensation in the upper chest and armpit, possible weakness in the chest muscles | Medical history, neurological examination, radicular pain in T2 | Thoracic MRI, nerve conduction studies |
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