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82 Cards in this Set
- Front
- Back
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The clavicle crosses the brachial plexus at what level?
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The cords, so the roots, trunks, and divisions are supraclavicular (Mnemonic: Clavicle at the Cords)
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What spinal roots make up the plexus?
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C5-T1. Can be prefixed and start at C4 or postfixed and continue past T1
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What forms the upper, middle, and lower trunks?
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Upper: c5-c6
Middle: c7 Lower: c8-t1 |
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What forms the posterior cord of the plexus?
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The posterior divisions from all three trunks. Note that no peripheral nerves originate from the divisions
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What 3 peripheral nerves are supraclavicular on the brachial plexus?
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Long Thoracic, Dorsal Scapular, and Suprascapular
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What does the dorsal scapular nerve innervate?
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Levator scapulae, Rhomboid major and minor
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What does the long thoracic nerve innervate?
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Serratus Anterior. lesion leads to winging of the scapula (medial winging)
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Where is Erb's point and what nerve arises there?
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Erb's point is at the confluence of the C5 and C6 roots forming the upper trunk and the suprascapular nerve arises from here
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What does the suprascapular nerve innervate?
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Supraspinatus and infraspinatus
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What is the difference between preganglionic and postganglionic nerve root injury?
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Preganglionic: Injury occurs proximal to the dorsal root ganglion; postganglionic (aka extraforaminal injury) is damage of the spinal nerve distal to the dorsal root ganglion
Preganglionic is an injury with no prospect of repair or recovery |
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What are some tests that are poor prognostic indicators following brachial plexus injury?
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- Meningocele on cervical myelography
- EMG evidence of denervation of paracervical muscles and rhomboids - Winging of scapula - Horner's syndrome - Normal histamine response |
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How do you interpret a histamine test?
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Positive test: Vasodilation, wheal, and flare is a normal response
If positive with dermatomal anesthesia - Likely preganglionic lesion If negative with dermatomal anesthesia - Likely postganglionic |
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What is horner's syndrome?
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Damage at the level of T1 which disrupts the sympathetic innervation to the head leading to PAM: (ptosis, anhidrosis, miosis)
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Infraclavicular brachial plexus injuries (damage at and distal to the cord level) are most commonly associated with what injuries?
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Associated with fractures and dislocations. Prognosis for recovery good
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The naming of the cords of the brachial plexus (lateral, posterior, and medial) are relative to what?
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Relative to their relationship with the 2nd part of the axillary artery
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Describe the path of the lateral pectoral nerve and what it innervates
What does the medial pectoral nerve innervate? |
Arises from the lateral cord of the brachial plexus. Travels lateral to the axillary artery and innervates the clavicular and superior sternal portions of the pec major
Medial pectoral nerve innervates the pec minor and the inferior portion of the sternal head of the pec major |
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What 3 peripheral nerves originate from the middle cord?
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Upper subscapular, thoracodorsal, and lower subscapular.
Thoracodorsal innervates latissimus dorsi |
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The lateral, medial, and posterior cords terminate to form what peripheral nerves branches?
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Lateral: Musculocutaneous
Posterior: Axillary & Radial Medial: Ulnar Lateral and Medial combine to form the Median |
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What are the boundaries of the axilla?
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Base: hairy skin & sub-Q fat
Apex: Clavicle Anterior wall: Pec muscles Posterior wall: Lats, teres major, subscap Medial wall: Ribs 1-4 Lateral wall: intertuburcular groove of humerus |
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Where do the nerve roots of the plexus emerge?
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From spinal canal through intervertebral foramen then exit between the anterior and middle scalenes just superior to rib 1
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Describe the formation of the axillary artery
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On the left side the subclavian artery branches directly from the aorta and on the right it branches from the brachiocephalic trunk behind the SC joint. The subclavian artery passes through the anterior and middle scalenes and becomes the axillary artery when it passes over the first rib. The axillary artery is broken up into 3 parts (Mnemonic: She Tastes Like Sweet Apple Pie):
1st part: Prior to pec minor has 1 branch: Superior thoracic artery which supplies the serratus anterior and pec muscles 2nd part: posterior to pec minor has 2 branches: The thoracoacromial arch which has 4 branches: The acromial, clavicular, deltoid, and pectoral. Lateral thoracic (runs with long thoracic nerve to the serratus anterior) The 3rd part of the axillary artery is beyond the pec minor and has 3 branches: The subscapular (branches into thoracodorsal (which runs with thoracodorsal nerve to supply latissimus dorsi) and circumflex scapular (which travels through the triangular space and forms part of the scapular anastamosis)) and anterior and posterior humeral circumflex. The anterior humeral circumflex has an ascending branch which supplies the humeral head and the posterior humeral circumflex travels through the quadrangular space with the axillary artery The axillary artery continues to become the brachial artery at the lower border of the teres major |
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What are the 5 major branches of the subclavian artery broken into the 3 parts of the subclavian?
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Mnemonic: VITamin C & D
1. From origin to medial border of anterior scalene: (VIT) Vertebral arteries which enter the foramen transversarium from C6 through C1 and form the basilar artery; Internal Thoracic Artery; Thyrocervical trunk (which divides into SIT: Suprascapular artery (which runs over the transverse scapular ligament to supply the rotator cuff), inferior thyroid artery, and transverse cervical artery(which runs posteriorly to supply the levator scapulae and trapezius)) 2. Deep to anterior scalene: Costocervical trunk which splits into superior intercostal and deep cervical artery 3. From lateral margin anterior scalene to 1st rib: Dorsal scapular artery (25% of the time arises from transverse cervical artery) which runs posteriorly to supply the levator scapulae and the rhomboids |
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Describe the axillary vein -- And remember to find out about if lymph drainage is necessary
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Axillary vein joins with veins corresponding to all named branches of the axillary artery then becomes the subclavian vein at the lateral border of rib 1. It joins the internal jugular forming the brachiocephalic vein and empties into the superior vena cava. On the left the the thoracic duct drains into the subclavian vein at the junction of the internal jugular
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Superior trunk injuries of the brachial plexus lead to what? What is the mechanism?
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Erb's palsy which is manifested as shoulder internal rotation, elbow extension, and hand flexion (waiter's tip)
Mechanism: Forceful lateral rotation of the neck away from the affected side combined with forceful depression of the affected shoulder |
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Inferior trunk injuries (C8 and T1) result in what?
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Klumpke's Palsy: Claw hand (extension of MCPs and flexion of IPs)
Horner's syndrome may be present |
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What has a better prognosis, supra or infraclavicular brachial plexus injuries?
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Infraclavicular have almost 90% recovery
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What is the origin (nerve root), course, and innervation for the following nerve:
Dorsal scapular nerve |
- Origin: C5
- Course: Pierces middle scalene, descends deep to levator scapulae - Innervation: Levator scapulae, rhomboids |
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What is the origin (nerve root), course, and innervation for the following nerve:
Long Thoracic Nerve |
- Origin: C5-C7
- Course: Descends posterior to C8 to T1 roots, descends on external surface of serratus anterior - Innervation: Serratus Anterior |
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What is the origin (nerve root), course, and innervation for the following nerve:
Nerve to Subclavius |
- Origin: C5-C6
- Course: Descends posterior to clavicle, anterior to brachial plexus and subclavian artery - Innervation: Subclavius, SC joint |
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What is the origin (nerve root), course, and innervation for the following nerve:
Suprascapular nerve |
- Origin: C5-C6
- Course: Passes laterally through posterior triangle of the neck, traverses suprascapular notch under transverse scapular ligament - Innervation: Supraspinatus, Infraspinatus, GH joint |
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What is the origin (nerve root), course, and innervation for the following nerve:
Lateral Pectoral Nerve |
- Origin: C5-C7
- Course: Pierces clavipectoral fascia, reaches deep surface of pectoral muscle - Innervation: Pectoral major |
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What is the origin (nerve root), course, and innervation for the following nerve:
Medial pectoral nerve |
- Origin: C8-T1
- Course: Passes between axillary artery and vein, enters deep surface of pec minor - Innervation: Pec minor and major |
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What is the origin (nerve root), course, and innervation for the following nerve:
Medial brachial cutaneous nerve |
- Origin: C8-T1
- Course: Runs along medial side of axillary vein - Innervation: Skin of medial arm |
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What is the origin (nerve root), course, and innervation for the following nerve:
Medial antebrachial cutaneous nerve |
- Origin: C8-T1
- Course: Runs between axillary artery and vein - Innervation: Skin of medial forearm |
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What is the origin (nerve root), course, and innervation for the following nerve:
Upper subscapular nerve |
- Origin: C5-C6
- Course: Passes posteriorly and enters subscapularis - Innervation: Subscapularis |
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What is the origin (nerve root), course, and innervation for the following nerve:
Thoracodorsal nerve |
- Origin: C6-C8
- Course: Arises between superior and inferior subscapular nerves - Innervation: Latissimus dorsi |
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What is the origin (nerve root), course, and innervation for the following nerve:
Lower subscapular nerve |
- Origin: C5-C6
- Course: Passes inferolaterally, deep to subscapular artery and vein - Innervation: Subscapularis, Teres Major |
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What is the origin (nerve root), course, and innervation for the following nerve:
Musculocutaneous nerve |
- Origin: C5-C7
- Course: Pierces coracobrachialis, descends between biceps brachii and brachialis - Innervation: Coracobrachialis, Biceps brachii, Brachialis, Skin of lateral forearm |
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What is the origin (nerve root), course, and innervation for the following nerve:
Median Nerve |
- Origin: C6-T1
- Course: Formed from lateral cord head joining medial cord head, descends medially to biceps brachii - Innervation: Most flexor muscles in forearm, radial half of flexor digitorum profundus, thenar muscles and lumbricals 1 and 2, skin of lateral palm (LOAF muscles: Lumbricals 1&2, Opponens, Abductor pollicis brevis, flexor pollicis brevis) |
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What is the origin (nerve root), course, and innervation for the following nerve:
Ulnar nerve |
- Origin: C7-T1
- Course: Descends medial to brachial artery, runs posteriorly to medial epicondyle of humerus - Innervation: FCU, ulnar half of flexor digitorum profundus, hand intrinsics |
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What is the origin (nerve root), course, and innervation for the following nerve:
Axillary nerve |
- Origin: C5-C6
- Course: Passes through quadrangular space and winds around surgical neck of humerus - Innervation: teres Minor, Deltoid, GH joint, Skin of inferior deltoid |
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What is the origin (nerve root), course, and innervation for the following nerve:
Radial nerve |
- Origin: C5-T1
- Course: Descends posterior to axillary artery, enters radial groove with deep brachial artery, passes between long and medial heads of triceps brachii - Innervation: Triceps brachii, Anconeus, brachioradialis, Extensor muscles of forearm, Skin of posterior arm, forearm, hand |
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What is the name of the disease in which there is an idiopathic brachial plexus problem which has been attributed to a viral etiology?
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Parsonnage-Turner Syndrome
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Are preganglionic injuries amenable to repair?
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Preganglionic is a root avulsion and not amenable to surgical repair. Findings include horner’s syndrome, absence of Tinel’s sign, Serratus Ant and Rhomboid paralysis.
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How long does it take for EMG findings to be evident after root avulsion injury? What will they show?
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3 weeks after injury. It will show denervation motor potentials which are sharp waves and fibrillation and intact sensory potentials (because the dorsal root ganglion and the sensory nerve cell bodies within are spared)
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Are SNAP (sensory nerve action potentials) spared or destroyed with root avulsions?
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SNAP are preserved
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Is an elevated hemidiaphragm and normal histamine response a pregnanglionic or postganglionic sign of injury?
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Preganglionic
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More than 90% of cases of brachial plexus palsy eventually resolve without intervention. What are 2 poor prognostic indicators?
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Lack of biceps function at 6 months after injury and the presence of Horner syndrome
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What bony problem should be prevented in a patient with brachial plexus palsy?
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Position of the humeral head within the glenoid should be maintained. Posterior subluxation with erosion of the glenoid should be prevented
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What is the origin, insertion, action, and innervation for the following muscle?
Platysma |
- Origin: Inferior border of the mandible and subcutaneum
- Insertion: Fascia over the pec major and deltoid - Action: Controls grimace expression; tightens the skin of the neck - Innervation: Facial nerve |
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What is the origin, insertion, action, and innervation for the following muscle?
Trapezius |
- Origin: Occipital bone, nuchal ligament, C7-T12
- Insertion: Lateral one third of the clavicle; acromion and spine of the scapula - Action: Rotates, elevates, adducts, and depresses the scapula - Innervation: Spinal accessory nerve (XI) |
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What is the origin, insertion, action, and innervation for the following muscle?
Sternocleidomastoid |
- Origin: Clavicle and manubrium
- Insertion: Mastoid process of the temporal bone - Action: Individually, sidebend toward and rotate away, together they draw head forward - Innervation: CN X1 |
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What is the origin, insertion, action, and innervation for the following muscle?
Omohyoid |
- Origin: Superior border of the scapula medial to the scapular notch
- Insertion: Inferior border of the body of the hyoid - Action: Depresses the hyoid - Innervation: Ansa Cervicalis |
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What is the origin, insertion, action, and innervation for the following muscle?
Anterior scalene |
- Origin: Transverse process of C3-C6
- Insertion: Rib 1 - Action: Elevate the ribs; laterally flex the neck, bilaterally stabilize the neck - Innervation: Anterior rami nerves C4-C7 |
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What is the origin, insertion, action, and innervation for the following muscle?
Middle Scalene |
- Origin: Posterior tubercles of the transverse processes of C4-C6
- Insertion: Rib 1 - Action: Elevate the ribs; laterally flex the neck, bilaterally stabilize the neck - Innervation: Anterior rami nerves C3-C7 |
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What is the origin, insertion, action, and innervation for the following muscle?
Posterior Scalene |
- Origin: Posterior tubercles of the transverse processes of C4-C6
- Insertion: Rib 2 - Action: Elevate the ribs; laterally flex the neck, bilaterally stabilize the neck - Innervation: Anterior rami nerves C5-C7 |
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What is the origin, insertion, action, and innervation for the following muscle?
Levator Scapulae |
- Origin: Transverse process of C1-C4
- Insertion: Superior angle of the scapula - Action: Elevates the scapula - Innervation: Dorsal Scapula Nerve |
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What is the origin, insertion, action, and innervation for the following muscle?
Splenius Capitis |
- Origin: Lower half of the nuchal ligament; spinous processes of C7-T4
- Insertion: Mastoid process, skull below the lateral 1/3 of the superior nuchal line - Action: Individually, they sidebend toward and rotate toward, together they draw head back - Innervation: Posterior rami of the middle cervical nn |
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What are the 4 areas of deep cervical fascia?
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Investing fascia: Envelops the SCM & trapezius
Pretracheal fascia: Covers anterior aspect of neck (thyroid, trachea, esophagus) Prevertebral fascia: Covers the prevertebral muscles & is continuous with fascia covering floor of posterior triangle Carotid sheath: Contains common carotid, internal jugular, vagus nerve, and part of the ansa cervicalis |
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How is the retropharyngeal space defined?
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Potential space between the pretracheal fascia and prevertbral fascia
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What are the boundaries of the posterior triangle?
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Anterior: SCM
Posterior: Trapezius Inferior: Middle 1/3 of clavicle Roof: Investing fascia (covers scm & trap) Floor: Deep cervical fascia |
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What vein is found in the posterior triangle?
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External jugular vein
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What arteries are found in the posterior triangle?
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- 3rd part of the subclavian
- Transverse cervical runs superficially and laterally across the posterior triangle to supply scapular region muscles - Suprascapula artery: Branches from thyrocervical trunk passes across the inferior part of the posterior triangle but may also arise from the 3rd part of the subclavian artery - Occipital artery: Branch from the external carotid |
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What nerves are found in the posterior triangle?
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- CN XI: From lower half of posterior triangle. Enters near posterior border of SCM. Passes posteroinferiorly through the posterior triangle
- Cervical plexus: Deep to internal jugular vein - Phrenic nerve |
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What muscles are in the posterior triangle?
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Omohyoid. The omohyoid divides the posterior triangle into 2 smaller triangles: The occipital triangle (through which the occipital artery passes) and the supraclavicular triangle (subclavian artery lies deep to this)
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What muscle is found at the apex of the posterior triangle?
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Splenius capitis
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Where is the levator scapulae found in relation to the splenius capitis? What is found along its surface?
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Inferior and parallel to the splenius capitis. The spinal accessory nerve is usually found on the surface of the levator scapulae
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What are the borders of the interscalene triangle and what is found here?
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Borders: Anterior scalene, middle scalene, first rib
Brachial plexus and subclavian artery travel through here |
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What is the origin, insertion, action, and innervation for the following muscle?
Mylohoid |
Origin: Mandible
Insertion: Hyoid bone Action: Supports and elevates the floor of the mouth; elevates hyoid Innervation: Mylohoid nerve |
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What is the origin, insertion, action, and innervation for the following muscle?
Geniohyoid |
Origin: Mandible
Insertion: Hyoid Action: Opens mandible Innervation: C1 |
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What is the origin, insertion, action, and innervation for the following muscle?
Stylohyoid |
Origin: Styloid process of temporal bone
Insertion: Hyoid Action: Elevates hyoid Innervation: Facial N. |
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What is the origin, insertion, action, and innervation for the following muscle?
Digastric |
Origin: Anterior belly: Mandible; Posterior belly: mastoid process of temporal bone
Insertion: Tendon between 2 bellies then hyoid Action: Opens mouth by lowering mandible Innervation: Anterior belly: mylohoid n. Posterior belly: facial n. |
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What is the origin, insertion, action, and innervation for the following muscle?
Sternohyoid |
Origin: Manubrium
Insertion: Hyoid Action: Depresses hyoid Innervation: Ansa Cervicalis |
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What is the origin, insertion, action, and innervation for the following muscle?
Omohyoid |
Origin: Superior scapula medial to scapular notch
Insertion: Hyoid Action: Depresses and stabilizes hyoid Innervation: Ansa Cervicalis |
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What is the origin, insertion, action, and innervation for the following muscle?
Sternothyroid |
Origin: Manubrium
Insertion: Thyroid cartilage Action: Depresses hyoid & larynx Innervation: Ansa Cervicalis |
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What is the origin, insertion, action, and innervation for the following muscle?
Thyrohyoid |
Origin: Thyroid cartilage
Insertion: Greater horn of the hyoid bone Action: Depresses hyoid & elevates thyroid cartilage Innervation: Anterior ramus of C1 |
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What are the borders of the anterior triangle?
What are the 4 smaller sub-triangles? |
Midline of the neck
Mandible SCM Smaller triangles: Carotid, Muscular, Submental, Submandibular |
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What are the boundaries of the carotid triangle?
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Superior belly of omohyoid, posterior belly of digastric, anterior border of SCM
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The superior belly of the omohyoid muscle runs transversely at what cervical levels?
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C6-C7
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If exposure above C4 is necessary, what artery and vein will need to be ligated?
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Superior thyroid and vein
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When exposing very proximal segments of cervical spine, what arteries amy need to be ligated?
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Lingual artery and facial nerve
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What are the branches of the external carotid?
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SALFOPSM
Superior thyroid Ascending pharyngeal Lingual Facial Occipital Posterior auricular Superficial temporal Maxillary |
