The eye is a fluid-filled sphere enclosed by three layers of tissue. Most of the outer layer is composed of a tough white fibrous tissue, the sclera. At the front of the eye, however, this opaque outer layer is transformed into the cornea, a specialized transparent tissue that permits light rays to enter the eye. The middle […]

Decorticate posture is an abnormal posturing in which a person is stiff with bent arms, clenched fists, and legs held out straight. The arms are bent in toward the body and the wrists and fingers are bent and held on the chest. This type of posturing is a sign of severe damage in the brain. […]

There are multiple types of normal and abnormal respiration. They include apnea, eupnea, orthopnea, dyspnea, hyperpnea, hyperventilation, hypoventilation, tachypnea, Kussmaul respiration, Cheyne-Stokes respiration, sighing respiration, Biot respiration, apneustic breathing, central neurogenic hyperventilation, and central neurogenic hypoventilation. Each pattern is clinically important and useful in evaluating patients. Function Evaluating respiratory patterns assists the clinician in understanding the […]

A traumatic brain injury (TBI), also known as an intracranial injury, is an injury to the brain caused by an external force. TBI can be classified based on severity (ranging from mild traumatic brain injury to severe traumatic brain injury), mechanism (closed or penetrating head injury), or other features (e.g., occurring in a specific location or over a widespread area).  Head injury is a broader category that […]

The Cushing reflex (vasopressor response, Cushing reaction, Cushing effect, and Cushing phenomenon) is a physiological nervous system response to acute elevations of intracranial pressure (ICP), resulting in Cushing’s triad of widened pulse pressure (increasing systolic, decreasing diastolic), bradycardia, and irregular respirations. The Cushing reflex was proposed in 1901 by Dr. Harvey Cushing. He believed that […]

Introduction The cranium (Latin term for skull) is the most cephalad aspect of the axial skeleton. It is composed of 22 bones and divided into two regions: the neurocranium (which protects the brain) and the viscerocranium (which forms the face). The skull also supports tendinous muscle attachments and allows neurovascular passage between intracranial and extracranial anatomy. The […]

Basilar skull fractures, usually caused by substantial blunt force trauma, involve at least one of the bones that compose the base of the skull. Basilar skull fractures most commonly involve the temporal bones but may involve the occipital, sphenoid, ethmoid, and the orbital plate of the frontal bone as well. Several clinical exam findings highly predictive […]

Introduction The Glasgow Coma Scale was first published in 1974 at the University of Glasgow by neurosurgery professors Graham Teasdale and Bryan Jennett.  The Glasgow Coma Scale (GCS) is used to objectively describe the extent of impaired consciousness in all types of acute medical and trauma patients. The scale assesses patients according to three aspects of responsiveness: eye-opening, motor, […]

Intracranial hypertension (IH) is a clinical condition that is associated with an elevation of the pressures within the cranium. The pressure in the cranial vault is measured in millimeters of mercury (mm Hg) and is normally less than 20 mm Hg. The cranium is a rigid structure that contains three main components: brain, cerebrospinal fluid, […]