Podcast
Questions and Answers
Which nerve roots are involved in innervating the ulnar nerve?
Which nerve roots are involved in innervating the ulnar nerve?
- C8 and T1 (correct)
- C6 and T2
- C5 and C7
- C3 and C4
What is the primary sensory function of the ulnar nerve?
What is the primary sensory function of the ulnar nerve?
- Innervates the lateral aspect of the hand
- Innervates the thumb and index finger
- Innervates the posterior arm
- Innervates the medial one and a half fingers (correct)
Which muscles are affected in an upper brachial plexus injury like Erb's Palsy?
Which muscles are affected in an upper brachial plexus injury like Erb's Palsy?
- Flexor carpi radialis and extensor digitorum
- Pectoralis major and latissimus dorsi
- Deltoid and teres minor (correct)
- Triceps and anconeus
Which position of the upper limb is typical for a patient with an upper brachial plexus injury?
Which position of the upper limb is typical for a patient with an upper brachial plexus injury?
Which nerves are primarily affected in an upper brachial plexus injury?
Which nerves are primarily affected in an upper brachial plexus injury?
What indicates an upper brachial plexus injury during assessment?
What indicates an upper brachial plexus injury during assessment?
What structure should be observed during a dissection of the brachial plexus for orientation?
What structure should be observed during a dissection of the brachial plexus for orientation?
What motor functions are significantly affected by an upper brachial plexus injury?
What motor functions are significantly affected by an upper brachial plexus injury?
What structure is formed by the anterior divisions of the superior and middle trunks in the brachial plexus?
What structure is formed by the anterior divisions of the superior and middle trunks in the brachial plexus?
Which nerve innervates the biceps brachii muscle?
Which nerve innervates the biceps brachii muscle?
The posterior cord of the brachial plexus is formed by the posterior divisions of which trunks?
The posterior cord of the brachial plexus is formed by the posterior divisions of which trunks?
What is the function of the axillary nerve?
What is the function of the axillary nerve?
Which major branch of the brachial plexus derives from roots C6 to T1?
Which major branch of the brachial plexus derives from roots C6 to T1?
What sensory function does the median nerve perform?
What sensory function does the median nerve perform?
Which muscle is NOT innervated by the musculocutaneous nerve?
Which muscle is NOT innervated by the musculocutaneous nerve?
To which region does the lateral cutaneous branch of the forearm provide sensory innervation?
To which region does the lateral cutaneous branch of the forearm provide sensory innervation?
What spinal nerves contribute to the formation of the brachial plexus?
What spinal nerves contribute to the formation of the brachial plexus?
Which part of the brachial plexus is formed by the convergence of roots?
Which part of the brachial plexus is formed by the convergence of roots?
What is the role of the anterior rami of the spinal nerves in the brachial plexus?
What is the role of the anterior rami of the spinal nerves in the brachial plexus?
Which structure is NOT innervated by the brachial plexus?
Which structure is NOT innervated by the brachial plexus?
How many trunks does the brachial plexus form?
How many trunks does the brachial plexus form?
What part of the brachial plexus does each trunk divide into?
What part of the brachial plexus does each trunk divide into?
Which spinal roots combine to form the superior trunk of the brachial plexus?
Which spinal roots combine to form the superior trunk of the brachial plexus?
What is the primary function of the brachial plexus?
What is the primary function of the brachial plexus?
Flashcards
What is the brachial plexus?
What is the brachial plexus?
A network of nerves formed by the anterior rami of the lower four cervical nerves and the first thoracic nerve (C5, C6, C7, C8, and T1). It extends from the spinal cord into the armpit, supplying the upper limb.
What muscles does the brachial plexus innervate?
What muscles does the brachial plexus innervate?
The brachial plexus is responsible for providing motor innervation to all muscles of the upper limb except the trapezius and levator scapulae.
How is the brachial plexus organized?
How is the brachial plexus organized?
The brachial plexus is divided into five parts, or levels: Roots, Trunks, Divisions, Cords, and Branches.
What makes up the roots of the brachial plexus?
What makes up the roots of the brachial plexus?
Signup and view all the flashcards
How are the trunks of the brachial plexus formed?
How are the trunks of the brachial plexus formed?
Signup and view all the flashcards
What are the divisions of the brachial plexus?
What are the divisions of the brachial plexus?
Signup and view all the flashcards
How are the cords of the brachial plexus formed?
How are the cords of the brachial plexus formed?
Signup and view all the flashcards
What are the branches of the brachial plexus?
What are the branches of the brachial plexus?
Signup and view all the flashcards
Ulnar nerve: Sensory function
Ulnar nerve: Sensory function
Signup and view all the flashcards
Ulnar nerve: Motor function
Ulnar nerve: Motor function
Signup and view all the flashcards
Median nerve: Sensory function
Median nerve: Sensory function
Signup and view all the flashcards
Median nerve: Motor function
Median nerve: Motor function
Signup and view all the flashcards
Brachial Plexus
Brachial Plexus
Signup and view all the flashcards
Anatomic landmark: Brachial Plexus 'M'
Anatomic landmark: Brachial Plexus 'M'
Signup and view all the flashcards
Upper Brachial Plexus Injury: Erb's Palsy
Upper Brachial Plexus Injury: Erb's Palsy
Signup and view all the flashcards
Lower Brachial Plexus Injury
Lower Brachial Plexus Injury
Signup and view all the flashcards
Brachial Plexus: Trunks
Brachial Plexus: Trunks
Signup and view all the flashcards
Brachial Plexus: Divisions
Brachial Plexus: Divisions
Signup and view all the flashcards
Brachial Plexus: Cords
Brachial Plexus: Cords
Signup and view all the flashcards
Brachial Plexus: Major Branches
Brachial Plexus: Major Branches
Signup and view all the flashcards
Musculocutaneous Nerve
Musculocutaneous Nerve
Signup and view all the flashcards
Axillary Nerve
Axillary Nerve
Signup and view all the flashcards
Median Nerve
Median Nerve
Signup and view all the flashcards
Radial Nerve
Radial Nerve
Signup and view all the flashcards
Study Notes
Brachial Plexus
- The brachial plexus is a network of nerves formed by the anterior rami of the lower four cervical nerves (C5, C6, C7, C8) and the first thoracic nerve (T1).
- This network extends from the spinal cord through the cervicoaxillary canal in the neck, over the first rib, and into the armpit.
- It supplies the skin and muscles of the upper limb.
Parts of the Brachial Plexus
- Roots: The anterior rami of the spinal nerves that comprise the plexus. These are C5, C6, C7, C8, and T1.
- Trunks: At the base of the neck, the roots converge to form three trunks: superior (combination of C5 and C6 roots), middle (continuation of C7), and inferior (combination of C8 and T1 roots). They traverse laterally, crossing the posterior triangle of the neck.
- Divisions: Each trunk divides into anterior and posterior divisions within the posterior triangle of the neck.
- Cords: The anterior and posterior divisions enter the axilla and combine to form three cords (lateral, posterior, and medial) identified by their position relative to the axillary artery.
- The lateral cord is formed by the anterior division of the superior trunk and anterior division of the middle trunk.
- The posterior cord is formed by the posterior divisions of the superior, middle, and inferior trunks.
- The medial cord is formed by the anterior division of the inferior trunk.
- Branches: The cords give rise to the major branches of the brachial plexus.
Major Branches
- Musculocutaneous Nerve: Innervates the brachialis, biceps brachii, and coracobrachialis muscles. Sensory to the lateral half of the anterior forearm and a small portion of the posterior forearm. (Roots: C5, C6, C7)
- Axillary Nerve: Innervates the teres minor and deltoid muscles. Sensory to the inferior region of the deltoid. (Roots: C5 and C6)
- Median Nerve: Innervates most flexor muscles in the forearm, thenar muscles, and two lateral lumbricals. Sensory to the lateral part of the palm and the lateral three and a half fingers. (Roots: C6 - T1)
- Radial Nerve: Innervates the triceps brachii, and the posterior compartment muscles of the forearm (primarily wrist and finger extensors). Sensory to the posterior aspect of the arm and forearm, and the posterolateral aspect of the hand. (Roots: C5 - T1)
- Ulnar Nerve: Innervates muscles of the hand (excluding thenar and two lateral lumbricals), flexor carpi ulnaris, and medial part of flexor digitorum profundus. Sensory to the anterior and posterior surfaces of the medial one and a half fingers, and the associated palm area. (Roots: C8 and T1)
Clinical Significance
- Brachial Plexus Injuries: Two main types: upper (Erb's palsy, commonly affecting C5 and C6 roots, often due to birth trauma or shoulder trauma; leading to weakened arm abduction) and lower (Klumpke's palsy, affecting lower roots, notably T1, often from excessive arm abduction, causing a "claw hand")
- Practical Relevance: The brachial plexus can sometimes be challenging to dissect, but recognizing the "M" shape formed by the musculocutaneous, median, and ulnar nerves can be helpful.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz covers the anatomy and functions of the brachial plexus, focusing on its formation from cervical and thoracic nerves. You'll explore the various parts, including roots, trunks, divisions, and cords that are essential for upper limb function. Test your knowledge on this crucial network of nerves!