The crossed extensor reflex is an important spinal reflex that assists in withdrawing a limb away from a painful stimulus [1]. When a noxious stimulus is applied to one leg, such as stepping on a tack, it activates nociceptive afferent fibers that synapse on interneurons in the ipsilateral side of the spinal cord [1][3]. These…
Reflexes
Moro reflex
The Moro reflex is an infantile reflex triggered by sudden changes in head position, loud noises, or other abrupt stimuli [1]. It involves extension and abduction of the arms, followed by flexion and adduction as the arms are brought together in an “embracing” motion [2][3]. This is accompanied by crying, with initial breath holding and…
Plantar reflex
The plantar reflex is a reflex elicited when the sole of the foot is stimulated with a blunt instrument, and this procedure tests the integrity of the corticospinal tracts [1]. In infants, stimulation of the lateral plantar surface normally elicits plantar flexion of the toes, known as the flexion withdrawal response [2]. As the corticospinal…
Tonic neck reflex
The tonic neck reflex is an important postural reflex that helps maintain balance and orientation in response to head position [1][2]. When the head is turned to one side, the reflex causes extension of the limbs on the side the head is turned towards, and flexion on the opposite side [3][4]. For example, turning the…
Stepping reflex
The stepping reflex is an innate alternating leg movement pattern that can be elicited in newborns and infants when they are held upright with their feet touching a flat surface [1][2]. When the balls of the feet contact the surface, it triggers stepping motions of flexion and extension in the legs [3]. This reflex emerges…
Crawl reflex
The crawl reflex is an early motor pattern in infants that emerges around 2-3 months of age [1][2]. When an infant is placed prone on a flat surface, they will make crawling motions by lifting their head and chest and moving their arms and legs in an alternating pattern [3][4]. This reflexive crawling enables infants…
Glabellar reflex
The glabellar reflex, also known as the nasopalpebral reflex, involves blinking in response to tapping on the forehead skin [1][3]. The afferent limb is the trigeminal nerve, which senses stimuli applied to the glabella region between the eyebrows [2][4]. The efferent response travels via the facial nerve to cause bilateral contraction of the orbicularis oculi…
Palmomental reflex
The palmomental reflex involves contraction of the ipsilateral mentalis muscle and protrusion or wrinkling of the ipsilateral lower lip when the thenar eminence is stroked briskly [1]. This cutaneous-to-motor reflex is elicited most sensitively by stimulating the thenar eminence, though other bodily regions can evoke it as well [2][5]. The wrinkling resembles the start of…
Vestibulo-ocular reflex (VOR)
The vestibulo-ocular reflex (VOR) is a fundamental oculomotor mechanism that maintains stable vision during head movements by generating compensatory eye movements in the opposite direction to head motion. This reflex keeps our perception of the world stable despite continuous head and eye movements during daily activities (1, Introduction). When the head moves, eye muscles are…