Weakness Around the Shoulder and Arm Without Pain

CLINICAL DIAGNOSTIC MANUAL

Weakness around the shoulder and arm without pain can result from various nerve injuries affecting the innervation of the shoulder and arm muscles. These injuries may involve nerve roots, plexuses, or peripheral nerves. Muscle weakness without pain may indicate a pure nerve injury, without significant inflammatory components. Accurate identification of the injury site is crucial for proper treatment and functional recovery.

Condition	Clinical Symptoms and Signs	Suspected Diagnosis	Confirmatory Diagnosis
C4-C5 root lesion	Weakness in deltoid and supraspinatus muscles, difficulty with arm abduction	Clinical history, neurological exam	Cervical MRI, nerve conduction studies
Erb’s palsy (C5-C6 root lesion)	Weakness in deltoid, biceps, and brachioradialis muscles, arm adducted and internally rotated	Clinical history, physical exam, characteristic arm posture	Cervical MRI, nerve conduction studies
C7 root lesion	Weakness in triceps, wrist and finger extensors, loss of triceps reflex	Clinical history, neurological exam	Cervical MRI, nerve conduction studies
Radial nerve lesion	Weakness in wrist and finger extension, wrist drop, sensory loss on the posterior arm and forearm	Clinical history, neurological exam	EMG, nerve conduction studies
Klumpke’s palsy (C8-T1 root lesion)	Weakness in intrinsic hand muscles, finger flexors, claw hand posture	Clinical history, physical exam, characteristic hand posture	Cervical MRI, nerve conduction studies