detre blogspot com Organization of the Upper Limb

d-etre. blogspot. com Organization of the Upper Limb Audrone Biknevicius, Ph. D. Dept. Biomedical Sciences, OU HCOM at Dublin Clinical Anatomy Immersion 2014

“Anatomical Tool-Kit” www 2. warwick. ac. uk www. medicinenet. com www. telegraph. co. uk virtuallaboratory. colorado. edu www. cedars-sinai. edu 2

Week 5 Week 7 RULE #1 Limbs are outgrowths of the ventral body wall that undergo distal growth and rotation differentiation… [More detailed limb embryology in MS course] 3

The upper limbs are innervated by : A. Dorsal rami of spinal nn. B. Ventral rami of spinal nn. 4

DEVELOPMENTAL/EVOLUTIONARY BASIS Primitive Pectoral Limb Developmentally-ventral limb mm. Stern Essential of Gross Anatomy Developmentally-dorsal limb mm.

DEVELOPMENTAL/EVOLUTIONARY BASIS Stern Essential of Gross Anatomy • 90◦ lateral rotation (forearm mm. undergo incomplete rotation) • Limb adduction 6

RULE #2 A: Ventral vs. dorsal limb mm. Developmentally-dorsal muscles: • Lie posterior to the long bones in anatomical position (* exceptions) Stern Essential of Gross Anatomy Developmentally-ventral muscles: • Lie anterior to the long bones in anatomical position * 7

Anterior Upper Limb Muscle Compartments Humerus ARM Posterior Anterior Radius FOREARM Ulnar Stern Essential of Gross Anatomy Posterior Anterior HAND 5 th metacarpal 8

Anterior Humerus ARM Posterior Some posterior compartment mm. are found on the anterolateral aspect of the forearm (*brachioradialis, supinator) * Radius Anterior FOREARM Ulnar Stern Essential of Gross Anatomy Posterior No posterior compartment in the hand Anterior HAND 5 th metacarpal 9

RULE #2 B: Innervation of anterior vs. posterior compartment mm. Spinal nerve Dorsal primary ramus Ventral primary ramus (C 5 -T 1) Anterior division Posterior division Stern Essential of Gross Anatomy limb axis 10

“Roots of BP” (=ventral rami) C 5 Brachial Plexus (right side; simplified) “Randy Travis Drinks Cold Beer” Trunks C 6 U C 7 Divisions M Cord Terminal Branches Lat L C 8 T 1 Post Stern Essential of Gross Anatomy Med Anterior (ventral) division Posterior (dorsal) division 11

“Roots of BP” (=ventral rami) C 5 Brachial Plexus (right side; simplified) Trunks C 6 U C 7 Divisions M Cord Terminal Branches Musculocutaneous n. Lat L C 8 T 1 Post Stern Essential of Gross Anatomy Median n. Radial n. Ulnar n. Anterior (ventral) division Posterior (dorsal) division 12

Anterior MOTOR INNERVATION Muscle Compartments of the Upper Limb Musculocutaneous n. Humerus Radial n. Posterior Anterior Median n. & Ulnar n. Radius Ulna Stern Essential of Gross Anatomy Radial n. Posterior Anterior Ulnar n. & Median n. 5 th metacarpal Posterior

Musculocutaneous Nerve (arm) All mm. in anterior (flexor) compartment of arm MRI of arm 1. Biceps brachii m. 2. Brachialis m. 3. Brachial a. 4. Humerus. 5. Triceps brachii m. www. med. umich. edu 14 http: //emedicine. medscape. com/article/1877731 -overview#aw 2 aab 6 b 3

Radial Nerve (arm) Radial nerve All mm. in posterior (extensor) compartment of arm BB B TMed TLat TLong 15 http: //emedicine. medscape. com/article/1877731 -overview#aw 2 aab 6 b 3

The brachialis m. is innervated by which division of the brachial plexus: : A. Anterior division B. Posterior division www. aokainc. com 16

The brachialis m. is innervated by: A. B. C. D. Median n. Musculocutaneous n. Radial n. Ulnar n. www. aokainc. com 17

The triceps brachii m. is innervated by: A. Musculocutaneous n. B. Radial n.

Radial Nerve (forearm) All mm. in posterior (extensor) compartment of forearm Also * brachioradialis and supinator mm. * 19 http: //emedicine. medscape. com/article/1877731 -overview#aw 2 aab 6 b 3

Ulnar Nerve (forearm) Limited mm. in anterior (flexor) compartment of forearm: - Flexor carpi ulnaris - Flexor digitorum profundus (medial ½) Med 1/2 20 http: //emedicine. medscape. com/article/1877731 -overview#aw 2 aab 6 b 3

Median Nerve (forearm) All anterior (flexor) compartment mm. of forearm except: - Flexor carpi ulnaris m. - Flexor digitorum profundus m. (med ½) en. wikipedia. org 21 http: //emedicine. medscape. com/article/1877731 -overview#aw 2 aab 6 b 3

RULE #2 C www. acacpt. com 22

The extensor digitorum m. lies in the posterior compartment, originates on the lateral epicondyle, and is innervated by: A. Median n. Lateral epicondyle B. Musculocutaneous n. C. Radial n. Extensor digitorum m. D. Ulnar n.

“Be specific” thepainsource. com 24

The flexor carpi radialis m. is in the anterior compartment, attaches to the medial epicondyle, and is innervated by: A. Median n. B. Radial n. C. Ulnar n. www. rad. washington. edu 25

The flexor digitorum profundus m. is the anterior compartment, attaches to the medial epicondyle, and is innervated by: A. Median n. B. Median n. & Ulnar n. C. Ulnar n. healthfavo. com 26

The brachioradialis and supinator mm. lie in the anterior aspect of the forearm but attach to the lateral epicondyle of the humerus. They are innervated by: A. Median n. B. Radial n. C. Ulnar n. www. pelhamrehab. com 27

Median Nerve (hand) Limited hand mm. : - Thenar mm. - Lateral two lumbricals www. studyblue. com 28 http: //emedicine. medscape. com/article/1877731 -overview#aw 2 aab 6 b 3

Ulnar Nerve (hand) cnx. org All hand mm. not innervated by median n. 29 http: //emedicine. medscape. com/article/1877731 -overview#aw 2 aab 6 b 3

What about the most proximal muscles of the upper limb? medicine. academic. ru 30

RULE #2 D Developmentally-dorsal muscles: • Lie posterior to the long bones in anatomical position (* exception = brachioradialis, supinator) -or • Arise from: – scapular blade ossification – vertebral column 31 Stern Essential of Gross Anatomy * Developmentally-ventral muscles: • Lie anterior to the long bones in anatomical position -or • Arise from: – coracoid ossification – sternum and costal cartilages

Given the attachments of the latissimus dorsi muscle, its innervation will be from which of division of the brachial plexus: A. Anterior division B. Posterior division blog. corewalking. com 32

Brachial Plexus (branches) C 5 C 6 supraspinatus & infraspinatus mm. suprascapular n. * C 7 C 8 T 1 Stern Essential of Gross Anatomy ** axillary n. upper subscapular n. thoracodorsal n. lower subscapular n. deltoid & teres minor mm. subscapularis m. latissimus dorsi m. subscapularis & teres major mm.

Given the attachments of the pectoralis muscle, its innervation will be from which of division of the brachial plexus: A. Anterior division B. Posterior division www. bnchiro. com 34

Brachial Plexus rhomboid mm. (branches) dorsal scapular n. C 5 C 6 suprascapular n. * pectoralis mm. C 7 C 8 lateral pectoral n. T 1 musculoskeletal n. ** axillary n. ulnar n. medial pectoral n. pectoralis mm. upper subscapular n. thoracodorsal n. lower subscapular n. 35 Stern Essential of Gross Anatomy long thoracic n. medial n. radial n. serratus anterior m.

posterior anterior RULE #3 Proximal-to. Distal Rule Upper “roots” of the brachial plexus (C 5 -6 ventral rami) innervate proximal muscles (shoulder, elbow) Somatic motor nerve (GSE, with GSA) Cutaneous nerves (GSA, GVE, GVA) Lower “roots” of the brachial plexus (C 8 -T 1 ventral rami) innervate distal muscles (hand)

MYOTOME - group of muscles innervated by a single spinal nerve root sciartmag. blogspot. com 37

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Brachial Plexus (all branches) Dorsal scapular n. C 5 C 6 Suprascapular n. * Lateral pectoral n. C 7 C 8 T 1 Musculoskeletal n. Stern Essential of Gross Anatomy Long thoracic n. Medial n. ** Medial pectoral n. Upper & lower subscapular nn. Thoracodorsal n. Axillary n. Ulnar n. * Nerve to subclavius Radial n. ** Medial brachial & antebrachial cutaneous nn. 39

posterior anterior RULE #3 “MIXED FUNCTIONAL MODALITIES” Most terminal branches of the brachial plexus are mixed fiber nerves: 1. Somatic motor and somatic sensory (prioception) to skeletal mm. Somatic motor nerve (GSE, with GSA) Cutaneous nerves (GSA, GVE, GVA) 2. Then, cutaneous innervation with somatic sensory and sympathetics to skin

Musculocutaneous n. Tank et al. Lippincott Williams & Wilkins Atlas of Anatomy 41

Some purely cutaneous brs. of brachial plexus Tank et al. Lippincott Williams & Wilkins Atlas of Anatomy 42

RULE #5: Dermatome vs. Cutaneous Nerve Distribution Segmental innervation (C 5 -T 1) Dermatomes

Segmental (Dermatome) Innervation of Upper Limb Foerster (1933) – based on clinical findings (used by neurologists) 44 Moore et al. Essential Clinical Anatomy Keegan and Garrett (1948) – based on limb development

Segmental (Dermatome) Innervation of Upper Limb Preaxial: C 5 -C 7 Postaxial: C 8 -T 1 Thumb: C 6 5 th Digit: C 8 45 Moore et al. Essential Clinical Anatomy 3 rd Digit: C 7

Dermatomes vs. Cutaneous Nerve Distribution Segmental innervation (C 5 -T 1) Dermatomes Terminal branches Cutaneous nn.

Peripheral (Cutaneous ) Innervation of Upper Limb Posterior Moore et al. Essential Clinical Anatomy Anterior 47

Test for Peripheral Nerve Sensory Function: M U R Ulnar n. – Tip of 5 th digit (little finger) Median n. – Tip of 2 nd digit (index finger) Radial n. – Webbing b/w thumb & index finger (dorsum)

C 7 M C 8 U C 6 R 49

Stretch Reflex Reciprocal inhibition of antagonist muscles apbrwww 5. apsu. edu/

academic. scranton. edu Stretch Reflex Bicipital reflex (C 6 cord level) Triceps reflex (C 7 cord level)

UPPER LIMB RADICULAR SYNDROMES Cranial Caudal IVD C 4 -C 5 Root C 5 Sensory Loss Shoulder Motor Weakness Shoulder weakness C 5 -C 6 Anterior upper arm, Lateral forearm, thumb Forearm flexion Biceps reflex C 6 -C 7 3 rd digits Forearm extension Triceps reflex Wrist extension Hand grip C 7 -C 8 5 th digits Medial forearm Wrist flexion Intrinsic hand mm. Source: Devinsky et al. Neurologic Pearls Proximal Distal