Motion Flashcards
Lumbricals?
The lumbricals are innervated by the ulnar nerve (3rd and 4th) and the median nerve (1st and 2nd).
An ulnar nerve lesion can lead to weakness in the ability to extend the fingers at the interphalangeal joints and spread the fingers at the metacarpophalangeal joints.
How do you anesthetize the median nerve region?
The median nerve provides cutaneous sensory innervation to the skin of the palmar surface of the first three and one-half digits and the corresponding portion of the palm of the hand.
Application of local anesthetic at the distal forearm, before the median nerve enters the carpal tunnel, between the tendons of the palmaris longus and the flexor carpi radialis, will produce anesthesia in the cutaneous region supplied by the median nerve.
Describe the orientation of neural tube development.
The neural tube gives rise to the spinal cord, which is then divided into an alar and a basal plate.
The alar plate gives rise to the dorsal part of the spinal cord and becomes the sensory portion of the cord.
The basal plate gives rise to the ventral part of the cord and becomes the motor portion of the spinal cord.
Which immunologic / inflammatory molecule drives multiple sclerosis plaques?
Multiple sclerosis:
Autoimmune type IV hypersensitivity against myelin basic protein
TH1 cells secrete interferon-gamma, which activates macrophages.
Demyelination results.
A young girl complains of muscle cramps during exercise.
Muscle phosphorylase (myophosphorylase) catalyzes the phosphorolysis of 1,4-glucosyl residues from the outer branches of the glycogen molecule, liberating glucose-1-phosphate. Muscle phosphorylase deficiency (McArdle disease) is a rare autosomal recessive condition. The abnormal accumulation of glycogen in muscle tissue leads to painful cramps and myoglobinuria during strenuous exercise, with no increase in lactic acid in the blood as would normally be seen. The symptoms often lessen or disappear if exercise is moderated and is continued. Muscle will switch to using more fatty acids and less glucose after the initial period of exercise. This is often referred to as a “second wind” phenomenon.
I just went running for an hour. What can be measured to be elevated in my muscles for the next hour or so?
VEGF is an important growth factor for endothelial cells under normal physiologic conditions.
Endothelial cells do not usually make VEGF, but other types of cells secrete VEGF under hypoxic conditions.
High levels can be measured within an hour after exercise.
Regular exercise can lead to significant endothelial proliferation and growth of new capillaries in muscle.
A cervical disk dislocation may damage which structure?
A posterolateral herniation of the nucleus pulposus is the most common type of herniation. This herniation results in the nucleus pulposus occupying space within the intervertebral foramen. The spinal nerve in the intervertebral foramen between vertebrae C4 and C5 is the C5 spinal nerve. There are eight cervical nerves and seven cervical vertebrae. C1 to C7 cervical nerves exit above their respective vertebrae. C8 exits below the C7 vertebra and all other spinal nerves exit below their corresponding vertebrae.
What is the optimal spinal region to insert a lumbar puncture needle?
L4-L5 interspace.
The spinal cord ends at L1 or L2; when the spine is flexed, L4-L5 should be the largest space and does not risk damaging the cord (the cauda equina float freely in this region).
A man fell off a ladder and tried to break his fall by grabbing a tree. What did he damage?
Excessive stretching of the arm can cause injury to the lower trunk of the brachial plexus.
The lower trunk contributes to the formation of the ulnar and median nerves, leading to loss of function of all the intrinsic muscles of the hand supplied by these nerves.
The lower trunk of the brachial plexus contains nerve fibers from the 8th cervical and 1st thoracic spinal nerves. These nerve fibers innervate the intrinsic muscles of the hand, including the interosseous muscles (responsible for abduction and adduction of the digits) and the opponens muscle (responsible for opposition of the thumb). The lower trunk ascends from the lower neck and upper thorax to reach the axilla. Upward traction on the upper limb, such as that which occurred when this man grabbed the tree limb to break his fall, may stretch the lower trunk and injure these nerve fibers.
What does rickets look like?
The hallmark of rickets in children is widened osteoid due to poor mineralization of bone. Although the trabeculae are normal in number and size, they do not mineralize effectively; and the rim of uncalcified osteoid is much larger than normal. Osteomalacia/rickets has several causes, all of which cause abnormal mineralization of bone. The condition is very rare in the United States, but the most common causes are dietary deficiencies of calcium, vitamin D (which is needed to absorb calcium), or sunlight (which is needed to metabolize vitamin D); or disorders of parathyroid hormone. Evaluation usually demonstrates poorly mineralized bones with pathologic fractures.
Which nerve passes through the cubital tunnel?
The ulnar nerve!
