Table 5 Symptoms, signs and respective affected muscles in myopathies (Bertorini 2022; Gerth and Festman 2023; Nicolle 2016; Pasnoor and Dimachkie 2019)
From: Essential neuromuscular advice for pathologists (first of two parts)
Symptoms reported on anamnesis: difficulties to perform daily activities | Signs detected on neurological examination | Muscles affected |
|---|---|---|
Upper limb girdle weakness: Difficulties combing the hair and placing objects in high shelves | Shoulder-girdle weakness | Serratus anterior, pectoralis minor, levator scapulae, rhomboid major, rhomboid minor, trapezius |
Lower limb girdle weakness: Inability to rise from a low chair or a toilet seat. Difficulties descending stairs | Weakness of the hip extensors | Gluteus maximus, biceps femoris, semitendinosus, and semimembranosus |
Lower limb girdle weakness: Difficulties ascending stairs | Weakness of the hip flexors and quadriceps femoris muscles. Ask the patient to rise from the floor without holding on to nearby objects | Iliacus, psoas, iliocapsularis, sartorius, and quadriceps femoris (vastus lateralis, vastus intermedius, vastus medialis, and rectus femoris) |
Distal lower limb weakness: Steppage gait (step by step), difficulties walking on heels | Foot drop | Dorsiflexor muscles: tibialis anterior, extensor hallucis longus, extensor digitorum longus |
Distal lower limb weakness: Difficulties to reach objects on tiptoes | Difficulties walking on tiptoes | Gastrocnemius medialis, gastrocnemius lateralis, and soleus |
Distal upper limb weakness: Difficulties writing or grasping objects | Weakness of wrist flexors and extensors | Thenar muscles (abductor pollicis brevis, flexor pollicis brevis, and opponens pollicis), wrist flexors (flexor carpus radialis, flexor carpus ulnaris, and palmaris longus), wrist extensors (extensor carpi radialis longus, extensor carpi radialis brevis) |
Fatigability (impaired neuromuscular junction function): Should be distinguished from fatigue specially if weakness is more pronounced at the end of the day if spontaneously referred by the patient after a general question such as: "-Are there times when your weakness is better of worse?" | Fatigable ptosis may be detected when the examiner holds the test object up for at least 60Â s and watch for obvious worsening. Diplopia may appear withing 15 to 30Â s of sustained gaze | Levator palpebrae superioris |