The paraspinal muscles and their role in the maintenance of global spinal alignment. Another wrinkle in an already...

The back muscles that lie deep into the thoracolumbar fascia are called intrinsic or true back muscles. These muscles are divided into four layers: superficial, intermediate, deep, and deepest layers.
Superficial Layer:
The superficial layer consists primarily of the splenius muscles, which include the splenius capitis and splenius cervicis. These muscles are mainly responsible for the head and cervical spine movements, including extension, rotation, and lateral bending. The splenius capitis...

The muscles that move the head are a dynamic and complex group of structures that work together to facilitate a wide range of head movements, including rotation, flexion, extension, and lateral bending.
The bilateral sternocleidomastoid, or SCM, and the suprahyoid and infrahyoid muscles are significant head flexors. The SCM muscles originate at the sternum and clavicle and attach to the mastoid process of the temporal bone. The SCM contracts bilaterally to bend the head forward, whereas...

Skeletal muscles, the key players in our body's movement, can be classified into two groups based on their location and function: axial muscles and appendicular muscles. These classifications reflect the primary roles the muscles play in the body's structure and movement.
Axial Muscles
Axial muscles, situated along the body's midline, are intricately connected to the axial skeleton, which includes the skull, spine, ribs, and sternum. These muscles facilitate facial expressions and...

The indirect motor or extrapyramidal pathways originate in the brainstem, the lower portion of the brain that connects it to the spinal cord. They consist of several distinct tracts, each with specialized functions. The four main tracts of the indirect motor pathways are the vestibulospinal tract, the reticulospinal tract, the tectospinal tract, and the rubrospinal tract.
The vestibulospinal tract originates in the vestibular nuclei of the brainstem. The vestibular system detects changes in...

Skeletal muscle relaxants are a group of drugs that can reduce muscle stiffness and induce temporary paralysis to relieve pain. These agents can act centrally to reduce muscle tone or spasms in painful conditions such as multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), or spinal injuries; they are called antispasmodics or spasmolytics.
Peripherally acting skeletal muscle relaxants interfere with the neurotransmission at the neuromuscular end plate to induce paralysis during...

Centrally acting muscle relaxants reduce muscle tone and tension by interfering with the postsynaptic reflexes in the central nervous system.
Centrally acting drugs are classified into spasmolytic and antispasmodic drugs. Spasmolytic drugs such as baclofen, diazepam, and tizanidine inhibit spinal motor neurons and decrease muscle tone. Spasmolytic drugs are administered for severe and chronic spasms due to multiple sclerosis, cerebral palsy, stroke, and spinal cord and muscle injuries. However,...