Muscles and Nerves Flashcards
What are some examples of appendicular muscles?
Deltoid and Pectoralis major
What are some examples of axial muscles?
Oblique, Rectus abdominis and Intercostal muscles
What is the upper and more medial bony attachment described as?
Proximal/ superior attachment
Also known as the origin of the muscle
What is the lower and more lateral bony process described as?
Distal/ inferior attachment
Insertion of the muscle
What attaches a muscle to bone?
By a tendon - non-fleshy, fibrous and dense regular connective tissue
How does the tendon not tear easily?
Fibres of the tendon are embedded in the periosteum of the bone
This anchors the muscle and spreads the force of contraction
What is an aponeurosis tendon?
Anterior of the abdominal obliques
Muscle is flat, thin and broad
Which bones are the tendons of biceps brachii attached?
Radius and scapula
Describe agonist and antagonist muscles
Agonist contracts
Antagonist relaxes due to agonist contracting
Describe synergists
Help perform joint movement like an agonist
Stabilise the muscle movement and makes sure range of movement is safe
Assists movement of agonist
Describe fixator/ stabilising muscles
Stabilise joint so can move efficiently without dislocation
Ex. rotator cuff muscles around shoulder joint
Each muscle surrounding shoulder is capable of own individual movement
What are muscles generally compartmentalised into?
1 - intermuscular fascial septa (separate them into compartments)
2 - common nerves
3 - common actions
Where does the brachial plexus originate?
From spinal roots C5-T1
Where does the lumbosacral plexus originate?
From spinal nerve root L1-S4
What direction do rectus abdominis fibres travel?
Vertically
What is the function of an aponeurosis tendon?
Attaches broad/flat muscle to bone and also attaches two broad muscles to each other
Where is the serratus posterior muscle?
2 distinct wing shapes on back of torso
How many number of origins does biceps have?
2 heads - biceps brachii - anterior compartment of the arm
How many number of origins does the triceps have?
3 heads - triceps brachii - posterior compartment of the arm
How many number of origins does the quadriceps have?
4 heads - quadriceps femoris - anterior compartment of the thigh
What shape does the deltoid muscle have?
Triangular
What does teres mean?
Means rounded
How does the diaphragm attach?
Attaches centrally to 3-leafed central tendon and peripherally to various bony structures
Where is the extensor digitorum?
In the posterior forearm - has tendons which extend to the fingers
Describe a sphincter muscle
Muscle fibres are arranged circularly and thickened around wall of the structure
When fibres contract - they close off internal diameter of the tube
Where can sphincter muscles be found?
Between stomach and duodenum in GI tract, the anal canal and the anus, urethra and in blood vessels
What type of muscle is sphincter muscles made of?
Mostly composed of smooth muscle within the body but can be skeletal when controlling fluids to outside body
What bones does the sternocleidomastoid attach to?
Sternum
Mastoid process
Clavicle
Describe skeletal muscle
Striations
Peripheral nuclei
Multinucleated
Non -branching fibres
Describe cardiac muscle
Striations
Intercalated discs seen
Cells of cardiac muscle have one nucleus
Describe smooth muscle
No striations
Fibres lying parallel
One nucleus per fibre
Define the term motor unit
Individual motor neuron and all the muscle fibres it innervates
What can be seen in a motor unit?
Nerve fibres - motor or sensory
Muscle fibres
Neuromuscular junction (nucleus/ motor end plate)
What functional muscle group is lost function when a wrist drop happens?
Posterior forearm
What type of information is carried in the anterior horn and posterior horn of the spinal cord?
Anterior -motor
Posterior - sensory
What type of information id carried in the dorsal root and ventral root?
Dorsal root - sensory
Ventral root - motor
Dorsal root ganglion - sensory
What type of information is carries in the mixed spinal nerve, anterior and posterior ramus?
Mixed - both
Anterior and posterior ramus - both motor and sensory
Explain the dorsal ramus
Passes posteriorly to segmentally to supply the main muscle of back and skin overlying it with motor and sensory fibres
Describe the ventral ramus?
Passes laterally and then forward to segmentally innervate the muscles of anterolateral thoracic, abdominal walls and skin overlying these muscles
Describe cutaneous innervation
Refers to the area of the skin which is supplied by a specific cutaneous nerve - fibres from spinal nerve (combination)
What is a dermatome?
An area of skin served by a signal spinal nerve - arising from only one level of the spinal cord
Where are cutaneous and dermatomes the same?
In the thorax and abdomen
Because cutaneous nerves supplying that area are single spinal nerves
Why is cutaneous and dermatomes nerve supply not the same?
Dermatomal area is narrower - more specific area as by a single spinal nerve
What joint occurs in the midline of the trunk at dermatome?
Shoulder
What surface feature of the body is found at dermatome T4?
Nipples
What surface body marks are at dermatome T10?
Belly Button
What is seen in the structure of a nerve?
Epineurium, axon, blood vessels, Fasciculus, Perineurium and endoneurium
Describe myelin
Fatty white substance that surrounds axon of some nerve cells, forming an electrically insulating layer
Secreted by Schwann cells
What is the endoneurium?
Layer of delicate connective tissue around myelin sheath of each nerve fibre
What is a fascicle?
Bundle of fibres
What is the perineurium?
A protective sheath which surround a bundle of fibres - fascicle
What is the epineurium?
Sheath containing fatty tissue and blood supply surrounding large nerves - multiple fascicles
What is in the structure if a neuron cell body?
Axon hillock, soma and dendrite
What type of nerves would you find at vertebral level L4 in the spinal nerve?
Motor, sensory and sympathetic
