Muscle And Nerves

Question 1

What type of muscle is the rectus abominis

Answer 1

Strap muscle, separated by tendinitis intersections

Question 2

What are the advantages of a bipenennate muscle as opposed to a strap or unipennate muscle

Answer 2

Increases in the number of muscle fibers that can be applied therefore increasing the power that can be generated

Question 3

Deltoid is a good example of which type of muscle ? What actions does a deltoid have upon glenohumeral joint ?

Answer 3

Multipennate
Primary role is abduction but if the anterior fibers contract solely then flexion will occur and if only posterior fibers, extension will occur

Question 4

What are the two functions of flat muscles, give an example

Answer 4

Produce movement of the skeleton and to enclose a cavity eg external oblique muscle

Question 5

What is the main function of trapezius and what other actions does trapezius bring about if muscles fibers in certain area contracted alone

Answer 5

Retracts the scapula and upwardly rotates. If the upper fibers contract alone will elevate and upwardly rotate the scapula as well as extending the neck. Middle fibers retract the scapula, lower fibers will depress and upwardly roared the scapula

Question 6

What type of muscle is often associated with walls of tubes such as blood vessels or part of the GI tract

Answer 6

Spincter

Question 7

What is the function of the rotator cuff muscles

Answer 7

Stabilization of glenohumeral joint

Question 8

What is the definition of an antagonist

Answer 8

A muscle which acts against the contraction of a prime mover

Question 9

Muscles from which compartment brings about abduction of the wrist joint, what about abduction ?

Answer 9

For both abduction and addiction muscles in both extensor and flexor compartments contract.

Adduction: muscles on the ulnar side contract for abduction muscles on radial side contract

Question 10

How many joints does biceps brachii cross, state it’s action over each joint

Answer 10

3
Shoulder - flexes
Elbow - flexes
Proximal radioulnar - supinates

Question 11

What nerves has been damaged in the conditions “wrist drop” ? What muscle group has been affected

Answer 11

Radial nerve

Extensor group of muscles

Question 12

What dermatome lies a lie the umbilicus

Answer 12

T9

Question 13

What nerves form the brachial plexus and what does it supply

Answer 13

C5-T1

Muscles and skin of upper limbs

Question 14

What nerves form the lumbar plexus and what does the lumbar plexus supply

Answer 14

L1-L4

Muscle and skin of lower limbs

Question 15

How many cervical vertebrae are there and how many cervical nerves are there

Answer 15

7 vertebrae and 8 spinal nerves

Question 16

How many thoracic vertebrae and thoracic nerves/lumbar vertebrae and lumbar nerves and sacral vertebrae and sacral nerves

Answer 16

12 thoracic v & 12 thoracic nerves
5 lumbar v & 5 lumbar nerves
5 sacral v & 5 sacral nerves

Question 17

Do the spinal nerves exit above or below their associated vertebrae

Answer 17

For spinal nerves C1-C7 they exit above associated vertebrae eg spinal nerve C2 exits above vertebrae C2
C8 exits believe vertebrae C7
All other spinal nerves exit below their associated vertebrae eg spinal nerve T1 exits believe vertebrae T1

Question 18

What dermatome supplies the tip of the thumb which peripheral nerve supplies the tip of the thumb? What is the root value of the peripheral nerve?

Answer 18

C6 dermatome
Median nerve
Median nerve root value is C6-T1

Question 19

Explain why the dermatologist and root value of the peripheral nerve are not identical

Answer 19

While median nerves carries nerve fibers originating from C6 to T1, only C6 fibers (carried via the median nerve) supply sensory fibers to the tip of the thumb. The other fibers go elsewhere and do other things. Therefore traumatic damage to C6, will produce loss of sensation restricted to the C6 dermatome, while traumatic damage to median nerve distal to the brachial plexus will impact on some but not necessarily all the C6-T1 dermatomes, depending on the location of the injury.

Question 20

What are the common examples of muscle shapes

Answer 20

Strap/parallel eg sartorius (anterior thigh)
Fusiform eg biceps brachii
Unioennate eg extensor digitorium longus
Bipennate eg rectus femoris
Multipennate eg deltoid
Flat eg external oblique
Circular eg orbicularis oris

Question 21

Why do muscles have different shapes

Answer 21

Shape of muscle determines the degree of muscle contraction and the amount of force that can be generated within

Question 22

An example where tendons go round a corner

Answer 22

Extensor hallucis longs - thin muscle extends from fibulae to big toe ( extends big toe)

Question 23

Example of a flat tendon

Answer 23

Aponeurosis

Question 24

Example of a muscle being away from point of function

Answer 24

Calf muscle responsible for plantar flex ion. Contraction of muscle results in translational force through the Achilles’ tendon

Question 25

Describe the function of the diaphragm during respiration

Answer 25

During full inspiration the diaphragm contracts and flattens and thoracic cavity enlarges (decreases pressure to allow air in)
This contraction creates a vacuum pulls air into the lungs.
Upon expiration the diaphragm relaxes and returns to some shape and air is forced out the lungs

Question 26

What bony structures does the diaphragm attach to

Answer 26

Anteriorly to the xiphoid process and costal margin of 11th and 12th ribs
Posteriorly to lumbar vertebrae

Question 27

Define a plexus

Answer 27

A nerve plexus is a branching network of intersecting nerves
Spinal nerves feed into a “junction box” called a plexus. Nerves of the proximal side are spinal nerves, nerves of the distal side are peripheral nerves
It is where spinal nerves become peripheral nerves and vice versa

Question 28

Difference between a spinal nerve and peripheral nerve

Answer 28

Spinal- specific innervation (dermatology) area of the skin in which sensory nerves derive from a single spinal nerve route
Peripheral - contain various spinal nerves. Tells you how that info gets to plexus