MOTOR EXAMINATION
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- The bare minimum: Look for muscle atrophy and check extremity tone. Assess upper limb strength by checking for pronator drift and strength of wrist or finger extensors. Test for lower limb strength by asking pt to walk normally and on heels and toes and testing power of the toe extensors.
Power should be systematically tested for major movements at each joint (Table 180-1). Strength should be recorded using a reproducible scale (e.g., 0 = no movement, 1 = flicker or trace of contraction with no associated movement at a joint, 2 = movement present but cannot be sustained against gravity, 3 = movement against gravity but not against applied resistance, 4 = movement against some degree of resistance, and 5 = full power; 4 values can be supplemented with + and – signs to provide additional gradations). Speed of movement, ability to relax contractions promptly, and fatigue with repetition should all be noted. Loss in bulk and size of muscle (atrophy) should be noted, as well as the presence of irregular involuntary contraction (twitching) of groups of muscle fibers (fasciculations). Any involuntary movements should be noted at rest, during maintained posture, and with voluntary action.
Muscle | Nerve | Segmental Innervation | Function | |
---|---|---|---|---|
Shoulder | Supraspinatus | Suprascapular n. | C5,6 | Abduction of upper arm |
Deltoid | Axillary n. | C5,6 | Abduction of upper arm | |
Forearm | Biceps | Musculocutaneous n. | C5,6 | Flexion of the supinated forearm |
Brachioradialis | Radial n. | C5,6 | Forearm flexion with arm between pronation and supination | |
Triceps | Radial n. | C6,7,8 | Extension of forearm | |
Ext. carpi radialis | Radial n. | C5,6 | Extension and abduction of hand at the wrist | |
Ext. carpi ulnaris | P. interosseous n. | C7,8 | Extension and adduction of hand at the wrist | |
Ext. digitorum | P. interosseous n. | C7,8 | Extension of fingers at the MCP joints | |
Supinator | P. interosseous n. | C6,7 | Supination of the extended forearm | |
Flex. carpi radialis | Median n. | C6,7 | Flexion and abduction of hand at the wrist | |
Flex. carpi ulnaris | Ulnar n. | C7,8,T1 | Flexion and adduction of hand at the wrist | |
Pronator teres | Median n. | C6,7 | Pronation of the forearm | |
Wrist | Ext. carpi ulnaris | Ulnar n. | C7,8,T1 | Extension/adduction at the wrist |
Flex. carpi radialis | Median n. | C6,7 | Flexion/abduction at the wrist | |
Hand | Lumbricals | Median + ulnar n. | C8,T1 | Extension of fingers at PIP joint with the MCP joint extended and fixed |
Interossei | Ulnar n. | C8,T1 | Abduction/adduction of the fingers | |
Flex. digitorum | Median + A. interosseous n. | C7,C8,T1 | Flexion of the fingers | |
Thumb | Opponens pollicis | Median n. | C8,T1 | Touching the base of the 5th finger with thumb |
Ext. pollicis | P. interosseous n. | C7,8 | Extension of the thumb | |
Add. pollicis | Ulnar n. | C8,T1 | Adduction of the thumb | |
Abd. pollicis | Median n. | C8,T1 | Abduction of the thumb | |
Flex. pollicis br. | Ulnar n. | C8,T1 | Flexion of the thumb | |
Thigh | Iliopsoas | Femoral n. | L1,2,3 | Flexion of the thigh |
Glutei | Sup. + inf. gluteal n. | L4,L5,S1,S2 | Abduction, extension, and internal rotation of the leg | |
Quadriceps | Femoral n. | L2,3,4 | Extension of the leg at the knee | |
Adductors | Obturator n. | L2,3,4 | Adduction of the leg | |
Hamstrings | Sciatic n. | L5,S1,S2 | Flexion of the leg at the knee | |
Foot | Gastrocnemius | Tibial n. | S1,S2 | Plantar flexion of the foot |
Tibialis ant. | Deep peroneal n. | L4,5 | Dorsiflexion of the foot | |
Peronei | Deep peroneal n. | L5,S1 | Eversion of the foot | |
Tibialis post. | Tibial n. | L4,5 | Inversion of the foot | |
Toes | Ext. hallucis l. | Deep peroneal n. | L5,S1 | Dorsiflexion of the great toe |
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