Nerve plexus and branches Flashcards
What is the basic structure of peripheral nerves?
Axon -> Myelin sheath (schwann cells) -> Endoneurium -> Perineurium (blood vessels found within) = fasicle -> epineurium
How to tendons looks on the human body?
Tight, white, bright structures
How do you tell the difference between nerves and blood vessels?
In nerves, you can see the fasicle bundles. Arteries will also stay open due to elastic walls.
What does myelination in the PNS?
- Schwann cells
What are unmyelinated sheaths encased in in the PNS?
Still encased by schwann cell but just a single cell membrane layer
What is the flow of stimulus through the nervous system?
- Sensory (stretch) receptor (stimulus on skin)
- Sensory (afferemt) neuron
- Integration center
- Motor (efferent) neuron
- Effector
What are the 12 pairs of cranial nerves?
Olfactory Optic Occulomotor Trochlear Trigeminal Abducens Facial Vestibulocochlear Glossopharyngeal Vagus Accessory Hypoglossal
Where do the spinal nerves come out?
In the foremena inferior to the vertebrae. The exception is a nerve that comes between the occipital bone and the atlas. Therefore 8 spinal nerves in the cervical region, but 7 vertebrae
What are the three layers around the brain and spinal cord
Pia mater -> arachnoid mater -> dura mater
Where do the dorsal rami supply?
The posterior of the head and neck
Where do the central rami supply?
Supply the main component of the trunk and limbs
What are dermatomes?
- The area of skin innervated by a single spinal nerve
What are the nerve plexus of the body?
- Cervical (C1-C5)
- Brachial (C5-T1)
- Lumbar (T12-L4)
- Sacral (L4-S4)
What is the cervical nerve we need to know?
The phrenic nerve
Where does the phrenic nerve innervate?
The diaphragm
What are the three nerves in the ‘M’ of the brachial plexus - lateral to medial and where do they innervate?
Musculo-cutaneous (anterior flexor muscles)
Median (anterior forearm muscle)
Ulnar (flexor carpi ulnaris, supples extrinsic muscles of hand)
What nerves come from the posterior branch of the brachial plexus
Axillary (goes to armpit - deltoid, scapula)
Radial (extensor muscles)
What are the two nerves off the lumbar plexus?
- Obturator nerve (adductor muscles of the middle compartment of the thigh)
- Femoral nerve (runs into anterior thigh; rectus femorus)
What are the nerves of the sacral plexus
Sciatic nerve (connective tissue sheath) contains the tibial nerve and the fibular nerve
Where does the tibial nerve innervate?
Hamstring mucles, plantar flexors
