Macleod s examination of the motor system of the lower limbs

Summary

This video provides a detailed guide for performing a comprehensive lower limb neurological examination. The process includes assessing tone, reflexes, muscle power, and coordination, with specific tests for clonus, deep tendon reflexes, and the plantar response. It emphasizes a systematic approach, ensuring both sides are compared. The examination is designed to detect abnormalities like spasticity, rigidity, and ataxia, and incorporates techniques such as reinforcement to elicit reflexes. The video is aimed at medical professionals seeking a structured and thorough method for evaluating lower limb neurological function.

Takeaways

• 😀 The lower limbs should be examined for asymmetry, deformities, and wasting or hypertrophy to assess muscle and circulation health.
• 😀 Tone in the lower limb is assessed by moving the leg and lifting the knee to check for variations such as spasticity or rigidity.
• 😀 Clonus is tested by pressing the patella towards the foot and looking for rhythmic contractions.
• 😀 Ankle clonus is tested by dorsiflexing and evading the foot while supporting the knee and ankle at 90 degrees.
• 😀 Deep tendon reflexes are tested after assessing muscle tone and before checking for power in the limbs.
• 😀 The knee-jerk reflex tests the L3 and L4 nerve roots, with reinforcement techniques used if the reflex appears absent.
• 😀 The ankle jerk reflex tests the S1 nerve root and is also assessed using reinforcement techniques.
• 😀 The plantar response is tested by running a blunt object along the foot’s sole, with the normal response being flexion of the toes.
• 😀 Power in the muscle groups of the lower limbs is tested by asking the patient to lift their leg and against resistance in isometric contractions.
• 😀 The heel-shin test is performed to assess muscular coordination and cerebellar function, with abnormalities indicating ataxia.
• 😀 Abdominal reflexes are tested by stroking the abdomen in a medial direction, expecting muscle contraction and movement of the umbilicus.

Q & A

What is the purpose of examining the lower limbs in this script?

The purpose is to assess the lower limbs for any asymmetry, deformities, wasting, hypertrophy, circulation issues, and involuntary movements such as fasciculation. The examination aims to check for tone, reflexes, strength, and coordination in the lower limbs.

How do you assess muscle tone in the lower limbs?

Muscle tone in the lower limbs is assessed by rotating or rolling the limb from side to side and briskly lifting the knee to a flexed position. Increased or decreased tone can indicate spasticity or rigidity.

What is clonus, and how is it tested?

Clonus is a rhythmic series of muscle contractions that can be elicited by a sudden stretch of the muscle. To test for clonus, the knee is extended and the patella is pushed towards the foot. A few beats of clonus are normal in healthy individuals.

What is ankle clonus, and how is it tested?

Ankle clonus is tested by supporting the patient's leg at 90 degrees at the knee and ankle, then briskly dorsiflexing and everting the foot. Sustaining the pressure will allow for the assessment of clonus.

Why is it important to test reflexes after tone but before power?

Testing reflexes after tone and before power is important because anxiety or pain can increase reflex responses. This sequence ensures a more accurate and reliable assessment of the patient's neurological condition.

What are the key reflexes tested in the lower limbs?

The key reflexes tested are the knee-jerk (L3 and L4 nerve roots), ankle jerk (S1 nerve root), and the plantar response. Each reflex helps assess the functioning of specific nerve roots and the integrity of the nervous system.

How do you perform the plantar response test?

The plantar response test is performed by running a blunt object along the lateral border of the sole of the foot towards the little toe. The normal response is the flexion of the great toe and the other toes.

What does the heel-shin test assess, and how is it performed?

The heel-shin test assesses muscular coordination, specifically checking for cerebellar ataxia. It is performed by asking the patient to run their heel down the shin in a straight line. Any deviation from the line may indicate cerebellar issues.

What is the significance of using reinforcement when testing reflexes?

Reinforcement is used when a reflex appears absent or weak. The patient is asked to interlock their fingers and pull one hand against the other to enhance the reflex response. This helps provide a more accurate reflection of the neurological function.

Why is it important to assess strength in the lower limb muscles?

Assessing muscle strength in the lower limbs helps determine the patient's ability to move and perform daily activities. It also helps identify any neurological issues that may affect muscle power, such as nerve damage or disorders affecting muscle function.