What causes winging of the scapula?
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Injury to the long thoracic nerve, especially when a person pushes against a wall with resistance.
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What causes winging of the scapula?
Injury to the long thoracic nerve, especially when a person pushes against a wall with resistance.
What occurs when the whole brachial plexus is stripped from its roots?
Complete paralysis of the upper limb.
What characterizes the post-fixed type of brachial plexus variation?
In the post-fixed type, the plexus is one spinal segment lower than usual, with the superior root being C6 and the inferior root being T2.
What will happen if the superior parts of the brachial plexus are injured?
Injury to the superior parts of the brachial plexus can lead to weakness or paralysis of the shoulder and arm muscles, resulting in conditions such as Erb's Palsy.
What is Erb's paralysis?
Erb's paralysis is an injury at Erb's point that stretches or tears the upper part of the brachial plexus.
Where does the injury occur in Erb's paralysis?
The injury occurs at Erb's point, where six nerves meet, affecting the upper trunk.
What is a characteristic posture associated with Erb's paralysis?
The characteristic posture is called Waiter's tip or Porter's tip.
What is the result of a lesion at C8 and T1?
It leads to claw hand, which is associated with lower trunk injury or Klumpke’s paralysis.
Where do the cords of the brachial plexus lie?
The cords lie in the axilla related to the 1st and 2nd part of the axillary artery.
What is the effect of an axillary nerve injury?
An axillary nerve injury results in the loss of abduction of the arm above 15 degrees.
Which nerves innervate the anterior aspect of the forearm (flexors)?
The Median and Ulnar nerves innervate the anterior aspect of the forearm (flexors).
Which nerves are responsible for the innervation of the palm of the hand?
The Median and Ulnar nerves are responsible for the innervation of the palm of the hand.
What nerve innervates the posterior aspect of the arm and forearm?
The Radial nerve innervates the posterior aspect of the arm and forearm.
Where do the roots of the brachial plexus lie?
In the neck between the scaleneus anterior and medius muscles.
Where do the trunks of the brachial plexus lie?
In the posterior triangle of the neck.
What is the pre-fixed type of brachial plexus variation?
In the pre-fixed type, the plexus is one spinal segment higher than usual, with the superior root being C4 and the inferior root being C8.
What is the purpose of brachial plexus blocks?
Brachial plexus blocks provide regional anesthesia as an alternative to general anesthesia for surgeries of the shoulder, arm, forearm, wrist, and hand.
Which nerve is responsible for supplying the serratus anterior?
Nerve to serratus anterior or long thoracic nerve (C5,6,7)
What do the posterior divisions of the brachial plexus unite to form?
The posterior divisions unite to form the posterior cord.
Which nerves are responsible for the nerve supply of the palm of the hand?
Median and Ulnar nerves
How does an increase in the angle between the upper limb and trunk affect the lower trunk?
It stretches the lower trunk, potentially leading to injury.
How are opposing muscles innervated in relation to spinal segments?
Their opponents, which produce opposite actions, are supplied by spinal segments in numerical sequence. For example, the flexor of the elbow is supplied by C5, C6, while the extensor of the elbow is supplied by C7, C8.
What are some techniques for blocking the nerves of the brachial plexus?
Techniques include interscalene block on the neck, supraclavicular block above the midpoint of the clavicle, infraclavicular block below the clavicle, and axillary block in the axilla.
What continues as the medial cord of the brachial plexus?
The anterior division of the lower trunk continues as the medial cord.
What nerves supply the anterior aspect of the forearm?
Median and Ulnar nerves
What is the cause and effect of a posterior cord injury?
A posterior cord injury, often due to poor fitting crutches or pressure, leads to 'Saturday night palsy' which involves the radial nerve and results in 'wrist drop' with a flexed elbow.
What is a general rule about the innervation of most muscles?
Most muscles are supplied by one or two spinal segments.
What are the branches of the posterior cord of the brachial plexus?
What will happen if the inferior parts of the brachial plexus are injured?
Injury to the inferior parts of the brachial plexus can result in weakness or paralysis of the hand and wrist muscles, leading to conditions such as Klumpke's Palsy.
What is the nerve supply for the posterior aspect of the arm?
RADIAL
Which nerve supplies the anterior aspect of the arm?
Musculocutaneous nerve
What is the nerve supply for the posterior aspect of the forearm?
RADIAL
What are the branches of the medial cord of the brachial plexus?
How do the upper limbs rotate during the fetal period?
The upper limbs rotate 90 degrees laterally, making the ventral surface anterior and the preaxial border lateral.
What innervates the flexors and pronators of the upper limb?
They are innervated by the anterior branches of ventral rami spinal nerves.
Which spinal nerve levels would most likely be affected by a fracture of the first rib damaging the inferior trunk of the brachial plexus?
D. C8 - T1
What nerve supplies the rhomboids?
Dorsal scapular nerve (C5)
What happens when there is a forceful widening of the angle between the trunk and arm?
It can stretch or tear the lower trunk, causing paralysis of small muscles of the hand.
Which nerves supply the supraspinatus and infraspinatus muscles?
Suprascapular nerve (C5 & 6)
What happens in a thoracodorsal nerve injury?
A thoracodorsal nerve injury causes paralysis of the Latissimus dorsi, making it impossible for the person to pull up the trunk to arm level.
Which nerve innervates the anterior aspect of the arm (flexors)?
The Musculocutaneous nerve innervates the anterior aspect of the arm (flexors).
How are muscles that share a common movement on a joint innervated?
They are supplied by the same spinal segment, for example, the flexors of the shoulder joint (Pectoralis major, Biceps, and Coracobrachialis) are supplied by C5, C6, C7.
Which spinal segments supply joints that are distal in a limb?
Joints distal in a limb are supplied by lower segments of the spinal cord, for example, the shoulder joint by C5, C6 and the elbow joint by C7, C8.
How does an increase in the angle between the neck and shoulder affect the upper trunk?
An increase in the angle between the neck and shoulder stretches the upper trunk, which can lead to injury.
What does the posterior division of the brachial plexus supply?
The extensor compartment of the upper limb.
What forms the lateral cord of the brachial plexus?
The anterior division of the upper and middle trunk unite to form the lateral cord.
What nerve supplies the subclavius muscle?
Nerve to subclavius (C5 & 6)
What is the summary of the formation of the brachial plexus?
The brachial plexus is formed by the union of the ventral rami of C5 to C8 and T1.
What are the branches of the lateral cord of the brachial plexus?
What forms the muscular elements of the limbs?
Muscular elements are formed by somatic mesoderm which invades the limb bud.
What are the common causes of upper trunk injury in the brachial plexus?
Upper trunk injury can result from excessive separation of the neck and shoulder during delivery, carrying heavy weights on the shoulder, or high-speed motorcycle accidents.
What muscles are found on the ventral side of the upper limb?
The ventral side contains flexors and pronators of the upper limb.
What muscles are found on the dorsal side of the upper limb?
The dorsal side contains extensors and supinators of the upper limb.
What innervates the extensors and supinators of the upper limb?
They are innervated by the posterior branches of ventral rami of spinal nerves.
What does the anterior division of the brachial plexus supply?
The flexor compartment of the upper limb.
What happens to each trunk of the brachial plexus?
Each trunk divides into anterior and posterior divisions behind the middle third of the clavicle.
What are the ventral rami that form the roots of the brachial plexus?
The ventral rami of C5, C6, C7, C8, and T1.
