Brachial Plexus Injuries, Thoracic Wall/Cavity, Lungs

Airways

Trachea → bifurcation (~T4/5) → left and right main (primary) bronchi → lobar/secondary bronchi → segmental/tertiary bronchus → bronchiole → alveoli Carina Trachealis muscle INFO: Trachealis muscle = smooth muscle → gives form and flexibility for esophagus (primarily) and tracheal expansion Right lung has three secondary bronchi where left has 2 Carina = cartilaginous projection of the last tracheal ring; sits in sagittal plane Trachea is located in superior mediastinum

What are brachial plexus injuries attributed to?

Tumors Trauma/Excess traction Wounds/Bleeding Inflammation

What spinal nerves are associated with upper and lower trunk lesions? Which is more common? What often causes each?

Upper trunk lesions (usually involve C5,C6) → occur more commonly than lower trunk lesions. Lesions affecting the upper trunk are usually caused by trauma Mechanism of action of traumatic upper trunk brachial plexus lesions: excessive, forceful increase in the angle between the neck and shoulder that causes severe stretching/traction or tearing of the C5, C6 roots or the upper trunk. In the case of newborn delivery, the head arrives first but the shoulder is stuck against the mother's pubic bone and requires significant manipulation to pass below it. Excess traction may cause injury known as shoulder dystocia or obstetric palsy. Dystocia literally means "difficult (dys) + childbirth (ocia)". Lower trunk lesions (usually involve C8,T1) → Lesions affecting the lower trunk may also be caused by trauma, but also by malignant infiltration of tumor cells from a tumor of the apex of the lung, the breast, or by a thoracic outlet syndrome (e.g., cervical rib, hypertrophy of the scalene muscles). They occur traumatically when the raised or abducted arm is forcibly pulled upward (hyperabducted) as when breaking a fall from a significant height or when a baby's arm is pulled excessively during delivery (i.e., increased angle between the arm and trunk of the body).

What are the neurovascular compression signs of the subcoracoid/sub-pectoralis minor space?

---Signs and symptoms here typically arise from prolonged hyperabduction of the arm (hyperabduction syndrome) with compression of the axillary vessels and cords of the brachial plexus become compressed beneath the coracoid process. Classic examples of this is during sleep or performance of a manual task (e.g., painting a ceiling). ---Tight pec minor can lead to this (not a lot of space between second or third rib and pec minor)

What are the neurovascular compression signs of the costoclavicular space?

--A narrowed space between the medial clavicle and first rib, which acts like a nutcracker. --Compressive conditions and deficits at this site usually result from poor shoulder posture (stooped, forward and downward posture) or chronic depression of the shoulders because of carrying heavy backpacks.

What is Klumpke's paralysis (palsy)? What is the appearance and associated sensory loss?

--Injury to the lower roots of the brachial plexus (C8-T1) causes total clawing of the hand because of paralysis of several of the intrinsic muscles (supplied by T1) of the hand, in particular, the lumbrical muscles. --These muscles modify the pull of the long flexors (primarily C8) and long extensors (primarily C7) of the fingers. Paralysis of the lumbricals results in a loss of this modifying influence producing flexion of the interphalangeal joints and hyperextension at the metacarpophalangeal joints (aka, the "knuckles") --Sensory loss would occur along the medial aspect of the forearm (T1), medial surface of the hand (C8 dermatome), and to the little finger

What symptoms may be evident with brachial plexus injuries?

--May present as pain in the shoulder, loss of sensation, and motor weakness depending on site of injury --The hand, arm and forearm may weaken, atrophy (degenerate or shrink from disuse) or develop paraesthesia (a sensation of pricking, tingling or creeping on the skin).

What are the neurovascular compression signs of the interscalene triangle?

--Neurogenic (95%) - caused by compression of lower portion of BP; e.g., cervical rib (1% pop.), scalene muscle hypertrophy. Pain, paresthesia --Arterial (1%) - caused by compression of subclavian a. Pallor, reduced pulse. Most serious form. Potential for thrombosis/embolism/aneurysm. --Venous (4%) - caused by compression of subclavian v. Characterized by edema in upper limb, cyanosis, venous congestion, heaviness of arm

What are bronchopulmonary segments? What is an important feature of these and how many are there?

-Discrete pyramidal-shaped units formed by thin connective tissue septa dividing the lobes of the lungs -Right lung = 10 -Left lung = 8-10 -Each segment is an anatomically and functionally independent respiratory unit, allowing for surgical resection of individual segments

What is pleural effusion and its treatment?

-Excess fluid in the pleural space (congestive HF or liver and renal failure) -Thoracentesis = procedure to drain excess fluid where a needle or chest tube is inserted into the pleural cavity -->Done along the superior border of rib to avoid neurovascular bundle

What is shingles?

-Herpes zoster infection of the spinal ganglia Reactivation of chickenpox virus -Follows the dermatomal distribution of the affected spinal ganglion -Produces a skin rash from vesicular eruptions and is associated with pain and itching

What are the location, symptoms, cause, and intervention of rib fractures?

-Location = anywhere, though anterior to rib angle is the weakest point -Symptoms = pain when breathing, laughing, coughing, sneezing -Cause = generally blows/crushing injuries, resulting in broken edge potentially piercing viscera -Intervention = usually movement restriction

What makes up the scalene triangle?

-Outlet created by anterior and middle scalene muscles attaching to 1st rib -Upper/Middle/Lower trunks and Subclavian Artery exit here -Subclavian Vein: Passes anterior to triangle

What are the two thoracic apertures and what do they include?

-Superior thoracic aperture → thoracic inlet = allows structures to pass between neck and thoracic cavity -Inferior thoracic aperture → thoracic outlet = structures must pass through diaphragm to move between abdomen and thoracic cavity

What are the symptoms, causes, and intervention of pneumothorax?

-Symptoms = sudden chest pain, shortness of breath -Cause = pleural cavity becomes filled with air due to trauma or lung disease → changes the pressure differential → air sucked in due to negative air pressure in pleural cavity → lung collapse -Intervention = insertion of a chest tube to remove excess air, allowing lung to reinflate

Explain how someone gets a "winged scapula".

-The serratus anterior is innervated by the long thoracic nerve (C5-7), which courses superficially on its surface. This nerve is vulnerable to injury during surgery in the axilla or to blows to the lateral chest wall. -Paralysis to this muscle produces a clinical presentation called "winged scapula" where the medial border of the scapula forms a ridge beneath the skin on the affected side. -When one attempts to push against a wall (a maneuver to test this), the medial border is unable to be firmly fixed to the rib cage and is levered posteriorly. -Paralysis nearly abolishes the ability to raise the arm above the horizontal. This deficit would make it difficult for the patient to comb/brush their hair, for example

Differentiate between the thoracic wall and cavity.

-Thoracic wall = bony muscular cage that encloses and protects thoracic contents; includes sternum, 12 pairs of ribs, and 12 thoracic vertebrae -Thoracic cavity = space containing viscera that opens to the neck but separated from the abdomen by the diaphragm

What is Erb's Palsy? What appearances are associated with this?

-Usually affects C5 and 6 nerves "Waiter's tip position" -This large‐for‐gestational‐age infant experienced shoulder dystocia, resulting in a traumatic delivery that damaged the upper trunk of his left brachial plexus, affecting C5 and C6, and resulting in Erb's palsy. Appearance -Arm is adducted, due to loss of shoulder abductors, and unopposed action of pectoralis major and latissimus dorsi. -Arm is medially rotated, due to loss of lateral rotators and unopposed action of pectoralis major and latissimus dorsi. -Upper limb is extended - intact triceps, latissimus dorsi -Forearm is pronated, due to loss of supinators (biceps brachii, supinator) and unopposed action of forearm pronators (pronator teres and pronator quadratus), which causes palm to face posteriorly. Wrist is often flexed due to weakened wrist extensors and stronger, intact forearm wrist flexor muscles -Sensory loss would occur along the lateral surface of the upper arm (C5 dermatome), the lateral surface of the forearm, and the thumb and index finger

Based on the following sites of injuries/causes of the ulnar nerve, determine if there will be deficits associated with ulnar deviation, wrist flexion, DABS/PADS and lumbricals, hypothenar muscles, or sensory to palmar surface of little finger and medial side of hand. Explain where needed.

1. Ulnar nerve lesion: elbow (cubital tunnel syndrome/ fracture of medial epicondyle) 2. Ulnar nerve lesion: at wrist

Diaphragm (respiratory)

Any Special Features Listed: Aortic hiatus Caval opening/foramen Esophageal hiatus Information: Cavel opening = inferior vena cava (~T8) Esophageal hiatus = esophagus and vagal trunks (T10) Aortic hiatus = aorta and thoracic duct (~T12)

Lung, Left

Any Special Features Listed: Apex Superior lobe Inferior lobe Major/oblique fissure Base Cardiac notch (impression) Hilum Groove for esophagus Groove for aorta (aorta impression) Pulmonary vessels Diaphragmatic surface Pulmonary ligament Lingula Information: Hilum = point where bronchi and pulmonary arteries enter and the pulmonary veins leave (bronchi have thicker walls than arteries) Pulmonary ligament = extension of root of lung where the two pleura come together Pulmonary arteries enter heart more superiorly than veins Lingula = thin, tongue-like process created by the cardiac notch; slides in and out of the costomediastinal recess

Subcostal m.

Bony Attachments: PA: internal surface of lower rib DA: superior border of 2nd or 3rd rib Action: Depress ribs (forced expiration) Innervation: Intercostal nerve Vessels: Intercostal artery Other Info

External intercostal m.

Bony Attachments: Proximal attachment: inferior border of ribs Distal attachment: superior border of rib below Action: Elevate ribs (inspiration) Innervation: Intercostal nerve Vessels: ntercostal artery Other Info: Perpendicular fibers to internal intercostals Accessory inspiratory muscle

costal margin of ribs

Bottom edge of rib cage formed by cartilage of ribs 7-10; attachment for diaphragm

Rib

Any special features listed: Typical ribs (4-10): Head = neck + tubercle (both have articular facets) Costal Angle Costal groove (location of intercostal v./a./n. External/internal surface Atypical ribs (1, 2, 11, 12): Rib 1: Scalene tubercle; grooves for subclavian a/v Rib 2: superior surface for serratus anterior m. attachment Rib 12: no neck or tubercle Articulations: Typical ribs (4-10): Head = neck + tubercle (both have articular facets) Costal Angle Costal groove (location of intercostal v./a./n. External/internal surface Atypical ribs (1, 2, 11, 12): Rib 1: Scalene tubercle; grooves for subclavian a/v Rib 2: superior surface for serratus anterior m. attachment Rib 12: no neck or tubercle Sternum via costal cartilages Tubercles (1-10) + transverse costal facets of same numbered thoracic vertebra Heads (2-10) + superior costal facet (same numbered thoracic vertebra) + inferior costal facet (thoracic vertebra above) Heads (1, 11, 12) + complete costal facets of same numbered thoracic vertebra Muscle attachments: Serratus anterior (1-8) Serratus posterior inferior (inferior border 8-12) Serratus posterior superior (upper border of 2-4) Latissimus dorsi (9-12) Longissimus Iliocostalis (angles) Pectoralis major Pectoralis minor (sternal ends of 3-5) External intercostal m. (inferior and superior borders) Internal intercostal m. Innermost intercostal m. Scalene m. Subcostal m. Other info: 1-7 = true ribs (attach directly to sternum via costal cartilages) (vertebrosternal) 8-10 = false ribs (vertebrochondral) (attach to the 7th costal cartilage) 11-12 = floating ribs (vertebral); no anterior attachment Rib 6 = transverse costal facet of thoracic vertebra 6 (via tubercle), superior costal facet of thoracic vertebra 6 (via head), and inferior costal facet of thoracic vertebra 5

Sternum

Any special features listed: Angle Body Manubrium (Suprasternal (jugular) notch and clavicular notch) Costal notches Xiphoid process Costal cartilages Articulations: Sternal end of clavicle and clavicular notch Costal notches and costal cartilages (1-7) Muscle attachments: Transversus thoracic m. (posterioinferior sternum and internal surface cartilages 2-6) Diaphragm (xiphoid process) Other info: Xiphoid process is subject to fracture during CPR Jugular notch separates sternoclavicular joints Sternum forms anterior boundary of mediastinum

Lung, Right

Apex Middle lobe Superior lobe Inferior lobe Horizontal fissure Major/oblique fissure Base Hilum Groove for esophagus Pulmonary vessels Diaphragmatic surface Pulmonary ligament

What innervates the visceral pleura of the lungs?

Autonomic nerves

Bronchial vein

Azygos and accessory hemiazygous veins

Innermost intercostal m.

Bony Attachments: PA: inferior border of ribs DA: superior border of rib below Action: Depress ribs (forced expiration) Innervation: Intercostal nerve Vessels: Intercostal artery Other Info: Perpendicular fibers to external intercostals

Diaphragm

Bony Attachments: Origin: costal margin, vertebral bodies (L1-3), medial and lateral arcuate ligaments, and the xiphoid process Insertion: central tendon Action: Primary muscle of inspiration Innervation: Phrenic nerve Vessels Other Info: Other special features

Trasnversus thoracic m.

Bony Attachments: DA: posterioinferior sternum PA: internal surface cartilages 2-6 Action: Weakly depress ribs (forced expiration) Innervation: Intercostal nerve Vessels: Intercostal artery Other Info: Possible proprioceptor

Scalene m.

Bony Attachments: Origin: middle and posterior - transverse processes C5-7 Insertion: ribs 1+2 Action: Flex neck laterally Elevate ribs 1+2 during inspiration Innervation: Anterior rami cervical nerve Vessels Other Info: Anterior, middle and posterior Accessory inspiratory muscle

Internal intercostal m.

Bony Attachments: PA: inferior border of ribs DA: superior border of rib below Action: Depress ribs (forced expiration) Innervation: Intercostal nerve Vessels: Intercostal artery Other Info: Perpendicular fibers to external intercostals

What are the parts of the pulmonary cavities?

Cervical, costal, diaphragmatic, and mediastinal

3. Median nerve injury: carpal tunnel syndrome

Deficits? Pronation: no Wrist flexion: no Finger flexion: no Thumb opposition: yes Index finger distal palmar surface sensation: yes

4. Median nerve injury: median recurrent nerve

Deficits? Pronation: no Wrist flexion: no Finger flexion:no Thumb opposition: yes - weakens thumb abduction and flexion Index finger distal palmar surface sensation: yes

2. Median nerve injury: anterior interosseous nerve

Deficits? Pronation: weak Wrist flexion: weak -Weak pronation because pronator teres still intact; weak wrist flexion and finger flexion because flexor digitorum profundus still half intact → Benediction hand Finger flexion: weak Thumb opposition: no Index finger distal palmar surface sensation: no

1. Median nerve injury: high lesion (supracondylar function of humerus)

Deficits? Pronation:yes Wrist flexion: weak+ulnar deviation --Weak wrist flexion because flexor carpi ulnaris still intact; finger flexion is still capable (flexor digitorum profundus still half intact) → conduct an "active" test to test (claw shaped hand with active hand) = Benediction hand Finger flexion: yes Thumb opposition: yes Index finger distal palmar surface sensation: yes

2. Ulnar nerve lesion: at wrist

Deficits? Ulnar deviation: no Wrist flexion: no DABS/PADS and lumbricals: yes - lumbricals not function = no extension of IP joints in passive hand → changed appearance of passive hand (claw shaped without making fist) Hypothenar muscles: yes Little finger palmar surface and Hand medial side: yes

1. Ulnar nerve lesion: elbow (cubital tunnel syndrome/ fracture of medial epicondyle)

Deficits? Ulnar deviation: yes Wrist flexion: weak +radial deviation -Weak wrist flexion because flexor carpi radialis still intact; finger flexion is still capable (flexor digitorum profundus still half intact) → changed appearance of passive hand (claw shaped without making fist) DABS/PADS and lumbricals: yes Hypothenar muscles: yes Little finger palmar surface and Hand medial side: yes

Tracheobronchial nodes

Drain into paratracheal nodes

Paratracheal nodes

Drains into bronchomediastinal trunks

Bronchomediastinal trunks

Drains into jugulosubclavian venous junction

Bronchopulmonary nodes

Drains into tracheobronchial nodes

Superficial lymphatic plexus

Drains pleura and lung tissue into tracheobronchial nodes

Deep lymphatic plexus

Drains structures of lung root into bronchopulmonary nodes

What do costal cartilages provide?

Elasticity

4. Injury to posterior interosseous nerve.

Elbow extension: No Wrist extension: weak: - Weak extension because extensor carpi radialis brevis and longus nerves still intact Supination: no Thumb/digits extension: yes 1st dorsal web space sensation: no

3. Laceration injury: superficial radial nerve

Elbow extension: no Wrist extension: no Supination: no Thumb/digits extension: no 1st dorsal web space sensation: yes Superficial radial nerve only provides sensory information

2. Mid-humerus injury: spiral groove fracture

Elbow extension: no Wrist extension: yes Supination: Weak: 2 - Weak supination because biceps still have function, elbow extension because radial branches to triceps not effected → wrist drop Thumb/digits extension: yes 1st dorsal web space sensation: yes

Injury Type/Site 1. Armpit injury: incorrect use of crutches

Elbow extension: yes Wrist extension: yes Supination: weak: 1 - Weak supination because biceps still have function Thumb/digits extension: yes 1st dorsal web space sensation: yes

What is thoracic outlet syndrome and the three potential sites of neurovascular compression?

Group of poorly categorized disorders produced by compression of neurovascular structures between the base of neck and axilla 3 potential sites Interscalene triangle Costoclavicular space Subcoracoid/sub-pectoralis minor space

What happens if a tumor extends to the sympathetic chain and stellate ganglion?

If the tumour extends to the sympathetic chain (a series of ganglia [masses of nerve cells] that run parallel to the vertebrae) and stellate ganglion, Horner syndrome may develop on the face and hand of one side of the body. Horner syndrome is characterised by drooping eyelids (ptosis), absence of sweating (anhidrosis), sinking of the eyeball (enophthalmos), and excessive smallness or contraction of the pupil of the eye (miosis).

Based on the following sites of injuries/causes of the radial nerve, determine if there will be deficits associated with elbow extension, wrist extension, supination, extension of thumb and digits, or sensory to the 1st dorsal web space. Explain where needed.

Injury Type/Site 1. Armpit injury: incorrect use of crutches 2. Mid-humerus injury: spiral groove fracture 3. Laceration injury: superficial radial nerve 4. Injury to posterior interosseous nerve.

Based on the following sites of injuries/causes of the median nerve, determine if there will be deficits associated with pronation, wrist flexion, finger flexion, opposition of thumb, or sensory to distal palmar surface of index finger. Explain where needed.

Injury Type/Site 1. Median nerve injury: high lesion (supracondylar function of humerus) 2. Median nerve injury: anterior interosseous nerve 3. Median nerve injury: carpal tunnel syndrome 4. Median nerve injury: median recurrent nerve

Anterior/posterior intercostal vein

Into what does it empty: Internal thoracic veins (anterior) Accessory hemiazygos and hemiazygos veins (L. posterior intercostal veins) Azygos vein (R. posterior intercostal veins)

Anterior/posterior intercostal nerve

Origin: Anterior primary rami Source (spinal cord level): T1-11 What it supplies: External intercostal m. Internal intercostal m. Innermost intercostal m. Transversus thoracic m. Subcostal m. Diaphragmatic pleura of lung Terminal branches: Anterior and lateral cutaneous branches to skin of thorax Effect of Lesion Other info

Subcostal nerve

Origin: Anterior primary rami Source (spinal cord level): T12 What it supplies: Sensory information

Phrenic nerve

Origin: Anterior primary rami Source (spinal cord level):C3-5 What it supplies:Diaphragm (motor and sensory) Somatic sensory to mediastinal pleura and pericardium Terminal branches Effect of Lesion Other info: Enter thorax on anterior surface of anterior scalene → mediastinum between heart and lungs, anterior to the root of the lung Located in superior, middle mediastinum

Musculophrenic artery

Origin: Internal thoracic artery Branches Structures Supplied Other info

Superior epigastric artery

Origin: Internal thoracic artery Branches Structures Supplied Other info

Pericardiophrenic artery

Origin: Internal thoracic artery Branches** Structures Supplied** Other info: Located in middle mediastinum

Anterior intercostal artery

Origin: Internal thoracic artery and musculophrenic artery Branches** Structures Supplied: Intrinsic muscles of thoracic wall Other info**

Internal thoracic artery

Origin: Subclavian artery Branches: Superior epigastric artery Musculophrenic artery Anterior intercostal artery Pericardiophrenic artery Structures Supplied** Other info: Runs through both sides of the sternum (posterior portion of anterior thoracic wall)

Posterior intercostal artery

Origin: Superior intercostal artery and thoracic aorta Branches** Structures Supplied: Intrinsic muscles of thoracic wall Other info**

Bronchial artery

Origin: Thoracic aorta Branches** Structures Supplied: Bronchial tree Lung tissue Visceral pleura Other info**

What is pleura? What are the types that line the lungs and heart? What is the pleural cavity? What is endothoracic fascia?

Pleura = fibroserous membrane that surrounds each lung and lines the pulmonary cavities Parietal pleura = outer layer lining inner wall of the thoracic cavity and mediastinum Visceral pleura = inner layer covering surface of lung and extends into its fissures Pleural cavity = potential space enclosed by the visceral and parietal pleura containing serous fluid Endothoracic fascia = connective tissue between thoracic wall and parietal pleura

Why do aspirated objects tend to travel down the right bronchus?

Right main bronchus is shorter, wider, and 25-30o from vertical whereas the left main bronchus is longer, narrower, and 45o from vertical

Costodiaphragmatic recess

Space between the diaphragm and the thoracic wall

What two arteries arise from the thoracic and abdominal aortas respectively?

Superior and inferior phrenic arteries