T1 Nerve Root (T1)
Motor Innervation
Dermatome
Lesion
“Sensory disturbances occur on the medial arm. Paresis occurs variably in the following muscles: abductor pollicis brevis, opponens pollicis, flexor pollicis brevis, all lumbricals and interossei, abductor digiti minimi, opponens digiti minimi, flexor digiti minimi, and adductor pollicis [16]. The finger flexor reflex (C8 T1) may be depressed. Sympathetic fibers destined for the superior cervical ganglia are interrupted, resulting in an ipsilateral Horner syndrome.”2
Examination
Muscle Strength
“Hand Intrinsics (T1) The patient is asked to squeeze the clinician’s fingers between their fingers while the clinician tries to pull their fingers away (Fig. 25-30). Based on the findings from the history, systems review, and key muscle testing, a sensory examination may be necessary (see Chapter 3).”3