UPPER LIMB

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UPPER LIMB

• What is a limb?
• Skeleton
• Joints
• Shoulder/Scapula muscles
• Brachial plexusgetting spinal nerves out onto
  limb
• Musclesanterior and posterior compartments
• Sensory innervation
• Surface anatomy

From Royal Collection da Vinci drawings
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What is a limb?

• Ventral somatic outgrowth of outer tube
• Bones (made of bony tissue, cartilage, and other
  tissues)
• Joints
• Muscles
• Nerves (with motor neurons to muscles, sensory
  neurons to skin, proprioceptors)
• No viscera--all innervation is somatic (motor or
  sensory) from ventral ramus of spinal nerve
  (except autonomics to blood vessels)

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Upper Limb Skeleton

• Scapula
• Humerus
• Radius, ulna
• Carpals--proximal, distal
• Digits
• Metacarpals
• Phalanges

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Joints
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Muscle origins and insertions

• Muscle crosses joint
• Origin is usually proximal and insertion is
  usually distal
• Origin is considered fixed in analyzing muscle
  action
• Muscle action (concentric) is given by movement
  of insertion relative to origin across joint
• Remember
• Sometimes insertion might be fixed
• Muscle may be active isometrically and
  concentrically giving different real function
  during real activity

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Muscles of Scapula

• If INSERTION on scapula, muscle moves scapula
• Trapezius
• Rhomboids
• Pectoralis Minor
• Serratus Ventralis
• Levator Scapulae
• If ORIGIN on scapula, muscle moves arm
• Teres Major
• Latissimus Dorsi (partially on scapula)

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Rotator Cuff

• Supraspinatus
• Infraspinatus
• Teres minor
• Subscapularis

• Muscles originate on fossae of scapula
• Help support open socket of shoulder joint
• Insert around ball of femur
• Medial and lateral rotation of upper limb
• Typical baseball pitcher injury

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Axilla Armpit

• Region between arm and chest
• Boundaries
• Ventral - pectoral muscles
• Dorsal latissimus dorsi, teres major
  subscapularis
• Medial serratus ventralis
• Lateral bicipital groove of humerus
• Contents
• Axillary nerves and blood vessels
• Axillary lymph nodes
• And.theBrachial plexus

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Brachial Plexus

• Posterior Compartmentposterior cord
• Anterior compartmentmedial, lateral cords
• Name of cord is relative to axillary artery

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Brachial plexus organizes nerves out to muscles
of upper limb

• One posterior nerve
• Radial n.
• Three anterior nerves
• Musculocutaneous n.
• Median n.
• Ulnar n.

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Muscles and nerves by compartment
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POSTERIOR AND ANTERIOR COMPARTMENTS
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• Bicepsanterior compartment, flexion (M-C n.)
• Tricepsposterior compartment, extension (radial
  n.)

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Anterior Compartment Forearm--flexors
Medial Epicondyle


Brachioradialis
Pronator Teres
Flexor Carpi Radialis

Flexor Carpi Ulnaris
Flexor Retinaculum
Flexor Digitorum Superficialis is deep to other
flexors
Anterior View
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Posterior Compartment of Forearm--extensors
Lateral Epicondyle
Brachioradialis
Extensor digitorum
Ext Carpi Radialis Longus
Extensor carpi ulnaris
Posterior View
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• ANTERIOR MUSCLES
• M-C nerve
• Biceps
• brachialis
• Median nerve
• Forearm flexors
• Thumb intrinsics (1M nerve)
• Ulnar nerve
• Flexor carpi ulnaris
• Hand intrinsics

• POSTERIOR MUSCLES
• Muscles (radial nerve)
• Triceps
• Anconeus
• Brachioradialis
• Carpal, digit extensors

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Sensory from limb (dermatomes/sensory skin
segments from spine)

• Dermatomes extend over limbs
• Twisted orientation reflects twisting of limb
  during development
• Named nerves generally innervate skin over
  muscles that they innervate

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Sensory territory of nerves
REMEMBER Brachial plexus re-directs spinal
routes into named nerves covering certain
territory
Cutaneous branches of medial cord/ulnar nerve
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Routes of nerves (in human)

• M-C between biceps brachii and brachialis
• Median medial/posterior to biceps, branches
  into forearm flexors at elbow then to hand
  through carpal tunnel
• Recurrent median (1M) superficial at wrist to
  thumb over thenar emminence) deficit - apes hand
• Ulnar medial in arm, posterior to medial
  epicondle of humerus (funny bone) down medial
  forearm medial to carpal tunnel into palm
• Radial deep posterior arm around lateral
  epicondyle of humerus to forearm (deep and
  superficial branches)

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Median Nerve
Ulnar Nerve
Brachial Artery
Musculocutaneous Nerve
UlnarArtery
Wheres Radial Nerve?
Radial Artery
Median Nerve
Ulnar Nerve
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Surface Anatomy of Upper Limb

• Biceps Triceps brachii
• Olecranon Process
• Medial Epicondyle
• Cubital Fossa
• Anterior surface elbow
• Contents
• Brachial Artery
• Median Nerve
• Boundaries
• Medial Pronator teres
• Lateral Brachioradialis
• Superior Line between epicondyles

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Surface Anatomy of Upper Limb

• Carpal Tunnel
• Carpals concave anteriorly
• Carpal ligament covers it
• Contains long tendons, Median nerve
• Inflammation of tendons compression of Median
  nerve
• Anatomical Snuffbox
• Lateral E.pollicis brevis
• Medial E. pollicis longus
• Floor scaphoid, styloid of radius
• Contains Radial Artery (pulse)

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Suggestion a muscle table organized by Joint
crossed? Nerve innervating? Action? Compartment
s? All of the above?
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