Muscles of the Neck & Spinal Cord Flashcards
What are the 3 Muscles of the Neck?
Sternocleidomastoid
Platysma
Sacelenes (A,M,P)
Sternocleidomastoid (SCM):
Location:
runs from the sternum (sterno-) and clavicle (cleido-) to the mastoid process of the temporal bone.
Functions:
Acts unilaterally to tilt and rotate the head to the opposite side.
Bilateral contraction flexes the neck forward.
Elevates the sternum and helps increase the thoracic volume during deep inhalation.
Accessory Nerve
Scalenes
Location: The scalene muscles are a group of three pairs of muscles located in the lateral neck region.
Functions (A, M, P):
Neck Flexion (Anterior):
Assists in Neck Rotation (Anterior and Middle)
Elevates Ribs during Forced Inhalation (Posterior):
Anterior Rami
Platysma:
Functions:
Facial Expression: Helps tense the skin of the neck and lower face, contributing to facial expressions like surprise or tension.
Assists in Opening the Mouth: May help depress the mandible when the mouth is opened widely.
Facial Nerve
What are Spinal Meninges?
The spinal meninges are protective layers of tissue that surround and encase the spinal cord
Layers of the Spinal Meninges
Dura Mater; Outer Layer
Arachnoid mater: Middle Layer
Pia Mater: Innner: Layer
Dentricuate Ligament
The denticulate ligaments are paired structures in the spinal cord meninges. (21 pairs on each side)
They extend from the pia mater and attach to the dura mater
Function: The denticulate ligaments play a role in providing lateral support and stability to the spinal cord within the vertebral canal. They help suspend the spinal cord in the cerebrospinal fluid and prevent excessive movement, contributing to the protection of the spinal cord from sudden shifts or trauma.
Alternate Angle
Antolateral
Somatic Fibers
Somatic Motor (Efferent) Fibers:
Function: These fibers carry signals from the central nervous system (CNS), specifically the spinal cord, to the skeletal muscles. They are responsible for voluntary muscle contractions and movement.
Somatic Sensory (Afferent) Fibers:
Function: These fibers carry sensory information from the body’s periphery (skin, muscles, joints, and proprioceptors) to the CNS, providing feedback about the external environment and the body’s position in space.
Perception: Sensations such as touch, temperature, pain, and proprioception (awareness of body position) are conveyed through somatic sensory fibers.
What are Dermatomes
Dermatomes are specific regions of the skin that are innervated by a single spinal nerve. Each spinal nerve carries sensory information from a particular dermatome to the brain.
dermatomes of the arm:
dermatomes of the arm:
What are Myotomes?
Myotomes refer to the specific groups of muscles that are innervated by a single spinal nerve
Difference Between Myotomes and Dermatomes?
Myotomes refer to specific muscle groups innervated by a single spinal nerve, used to assess muscle strength and function, while dermatomes denote distinct regions of skin innervated by a single spinal nerve and are essential in evaluating sensory function and diagnosing neurological conditions affecting the skin.
Myotomes
