UPPER LIMB What is a limb? Skeleton Joints Shoulder/Scapula muscles Brachial plexus—getting spinal nerves out onto limb Muscles—anterior and posterior compartments Sensory innervation Surface anatomy From Royal Collection da Vinci drawings Frolich, Human Anatomy,UpprLimb

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) Frolich, Human Anatomy,UpprLimb

Upper Limb Skeleton Scapula Humerus Radius, ulna Carpals--proximal, distal Digits Metacarpals Phalanges Frolich, Human Anatomy,UpprLimb

Joints Frolich, Human Anatomy,UpprLimb

Frolich, Human Anatomy,UpprLimb

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 Frolich, Human Anatomy,UpprLimb

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) Frolich, Human Anatomy,UpprLimb

Rotator Cuff Muscles originate on fossae of scapula 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 Frolich, Human Anatomy,UpprLimb

Axilla = Armpit Region between arm and chest Boundaries Contents 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….the……Brachial plexus Frolich, Human Anatomy,UpprLimb

Frolich, Human Anatomy,UpprLimb

Brachial Plexus Posterior Compartment—posterior cord Anterior compartment—medial, lateral cords Name of cord is relative to axillary artery Frolich, Human Anatomy,UpprLimb

Brachial plexus organizes nerves out to muscles of upper limb One posterior nerve Radial n. Three anterior nerves Musculocutaneous n. Median n. Ulnar n. Frolich, Human Anatomy,UpprLimb

Muscles and nerves by compartment Frolich, Human Anatomy,UpprLimb

POSTERIOR AND ANTERIOR COMPARTMENTS Frolich, Human Anatomy,UpprLimb

Biceps—anterior compartment, flexion (M-C n.) Triceps—posterior compartment, extension (radial n.) Frolich, Human Anatomy,UpprLimb

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 Frolich, Human Anatomy,UpprLimb

Posterior Compartment of Forearm--extensors Lateral Epicondyle Brachioradialis Extensor digitorum Ext Carpi Radialis Longus Extensor carpi ulnaris Posterior View Frolich, Human Anatomy,UpprLimb

Muscles (radial nerve) 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 Frolich, Human Anatomy,UpprLimb

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 Frolich, Human Anatomy,UpprLimb

Sensory territory of nerves REMEMBER: Brachial plexus re-directs spinal routes into named nerves covering certain territory Cutaneous branches of medial cord/ulnar nerve Frolich, Human Anatomy,UpprLimb

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 - ape’s 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) Frolich, Human Anatomy,UpprLimb

Musculocutaneous Nerve UlnarArtery Median Nerve Ulnar Nerve Brachial Artery Musculocutaneous Nerve UlnarArtery Where’s Radial Nerve? Radial Artery Median Nerve Ulnar Nerve Frolich, Human Anatomy,UpprLimb

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 Frolich, Human Anatomy,UpprLimb

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) Surface Anatomy of Upper Limb Frolich, Human Anatomy,UpprLimb

Suggestion: a muscle table organized by. Joint crossed Suggestion: a muscle table organized by Joint crossed? Nerve innervating? Action? Compartments? All of the above? Frolich, Human Anatomy,UpprLimb

Frolich, Human Anatomy,UpprLimb