When a patient flexes their neck, the head tips to the right...

Name: Problem 39, Chapter 16: Anatomy and Physiology of Animals
Uploaded: 2024-04-15T13:59:29-08:00
Duration: 3 min 15 s
Channel: Jennifer Stoner
Description: When a patient flexes their neck, the head tips to the right side. Also, their tongue sticks out slightly to the left when they try to stick it straight out. Where is the damage to the brain stem most likely located?

When a patient flexes their neck, the head tips to the right side. Also, their tongue sticks out slightly to the left when they try to stick it straight out. Where is the damage to the brain stem most likely located?

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Key Concepts

Medial Medullary Anatomy

The medial medulla is a critical region of the brainstem that houses several important neural structures, including the hypoglossal nerve nucleus and parts of the corticospinal and medial lemniscus tracts. Damage in this region can lead to a distinct clinical syndrome characterized by deficits such as tongue deviation, due to involvement of the hypoglossal nucleus, along with other motor or sensory deficits depending on the extent of the lesion.

Cranial Nerve XII (Hypoglossal Nerve) Function

Cranial nerve XII, the hypoglossal nerve, is primarily responsible for motor control of the tongue. When this nerve or its nucleus is impaired, the tongue deviates towards the side of the lesion on protrusion. This is a key diagnostic clue in localizing brainstem damage and is typically seen in lesions affecting the medial medulla.

Ipsilateral Neurological Deficits and Crossed Findings

Neurological signs in the brainstem often exhibit an 'ipsilateral versus contralateral' pattern. In the case of medial medullary involvement, structures such as the hypoglossal nucleus produce ipsilateral deficits (e.g., tongue deviation), while involvement of descending motor fibers may produce contralateral motor impairments. This concept of crossed signs helps in accurately localizing the lesion within the brainstem.

Please give Ace some feedback