Anatomy 2200 - Midterm

Spinal nerve

mixed nerve carrying motor and sensory information between spinal cord and body

Segments of the spine

cervical (8 nerves, 7 vertebrae), thoracic, lumbar, sacral, coccygeal

Spinal nerve components

spinal cord - dorsal/ventral rootlets - dorsal/ventral roots - spinal nerve - dorsal/ventral ramus

Dorsal vs. ventral roots

dorsal - sensory - posterior
ventral - motor - anterior

Paresthesia

compression of nerve - abnormal sensation (burning, prickling, tingling, numbness)

Paresis

partial or incomplete paralysis from damage or compression of nerve

Brachial plexus

network of nerves that supply upper limb - begins at neck and ends in axilla (armpit)

Composition of brachial plexus

Roots (C5, C6, C7, C8, T1)

Trunk (anterior and posterior)

Divisions (lateral, posterior, medial)

Cords

Branches (musculocutaneous, median, ulnar, axillary, radial)

Nerves of the brachial plexus

musculocutaneous (C5, C6, C7 - arm flexors - lateral forearm sensory)

axillary (C5, C6 - shoulder - shoulder sensory)

median (C5, C6, C7, C8, T1 - forearm + hand flexors - lateral palm, 1-3 digits, 1/2 of 4th digit)

radial (C5, C6, C7, C8, T1 - arm + forearm extensors - posterior arm, forearm, lateral hand)

ulnar (C8, T1 - forearm + hand flexors - medial hand, 1/2 of 4th digit, 5th digit)

What is the pectoral girdle and its function?

clavicle and scapula - attachment of upper limb to skeleton and movement flexibility

Describe clavicle and its function

"s" shaped bone - sternal end (medial, attach to sternum) - acromial end (lateral, attach to acromion process)

muscle attachment, "braces" - holds scapula and arms out laterally from trunk

Label scapula

Label humerus, what does it do

articulates with glenoid cavity

Muscles can be divided into:

prime mover/agonist: major action

antagonist: opposes action

synergist: assist muscle action

Posterior muscles of the scapula

levator scapulae, trapezius, rhomboids (major + minor)

Levator scapulae

Origin: upper neck, C1-C4
insertion: superior portion of medial border
action: elevates + rotates scapula
innervation: dorsal scapular + cervical nerves

Trapezius

origin: along spine C7-T12
insertion: clavicle, acromion, spine of scapula
action: elevate, rotate, retract scapula
innervation: accessory nerve

Rhomboids

origin: major (T2-T5) + nuchal ligament; minor (C7-T1)
insertion: medial border
action: retract scapula towards spine (medially), rotate
innervation: dorsal scapular nerve

Anterior muscles of the scapula

pectoralis minor, serratus anterior

Pectoralis minor

origin: upper ribs (3-5)
insertion: coracoid process
action: stabilize scapula, pull inferiorly and anteriorly
innervation: medial pectoral nerve

serratus anterior

origin: fleshy slips of upper ribs
insertion: medial border
action: protracts (punching), stabilize, upward rotation
innervation: long thoracic nerve

Rotator cuff muscles: what are they? what do they do?

subscapularis, suprascapularis, infraspinatus, teres major

encircle shoulder like a cuff, help anchor head of humerus into glenoid cavity

subscapularis

rotates arm medially, inserts into lesser tubercule, fills subscapular fossa, subscapular nerve

suprascapularis

abducts arm, inserts into greater tubercule, fills supraspinous fossa, suprascapular nerve

infraspinatus

rotates arm laterally, inserts into greater tubercule, fills infraspinous fossa, suprascapular nerve

teres minor

rotates arm laterally, inserts into greater tubercule, fills infraspinous fossa, axillary nerve

interosseous membrane

separation between muscles at front of forearm and muscles at back of forearm

What type of joint is the elbow?

synovial hinge joint (uniaxial motions - flexion + extension)

Positions in a flexed elbow

head of radius tucked into radial fossa, coronoid process tucked in coronoid fossa

Positions in an extended elbow

olecranon process fits into olecranon fossa

Label elbow joint

Proximal radio-ulnar joint

allows for supination and pronation

pronation: radius radiates over ulna, ends up more medial

Anterior muscles of the shoulder and arm

pectoralis major, coracobrachialis, deltoid

pectoralis major

origin: sternal end of clavicle, sternum and cartilage of ribs 1-6
insertion: lateral edge of intertubercule groove
action: arm flexion, medial rotation, arm adduction
innervation: medial + lateral pectoral nerve

coracobrachialis

origin: coracoid process
insertion: midshaft of humerus medially
action: arm flexion, adduction
innervation: musculocutaneous nerve (pierces it)

deltoid

origin: clavicle, acromion, spine scapula (posteriorly)
insertion: deltoid tuberosity
action: fiber dependent
- all = abduction
- anterior fibers = flexion + medial rotation
- posterior fibers = extension + lateral rotation

innervation: axillary nerve

Posterior muscles of shoulder and arm

latissimus dorsi, teres major

latissimus dorsi

origin: thoracolumbar fascia, iliac crest, T7-T12, lower ribs
insertion: intertubercule groove floor (ant)
action: arm extension, adduction, medial rotation
innervation: thoracodorsal nerve

teres major

origin: inferior angle of scapula
insertion: medial edge intertubercule groove (ant)
action: arm extension, adduction, medial rotation (lats little helper)
innervation: lower subscapular nerve

Muscular compartments of the arm

posterior: triceps, extensors, innervated by radial nerve

anterior: biceps + brachialis, flexors, innervated by musculocutaneous nerve

biceps brachii

origin: long head = supraglenoid tubercule of scapula; short head = coracoid process
insertion: radial tuberosity
action: supination, elbow flexion
innervation: musculocutaneous nerve

bicep injuries

proximal tendon rupture - aka popeye deformity, young ppl in baseball, weightlifting - old people from wear and tear

distal tendon rupture - severe hyperextension of elbow forced

brachialis

origin: anterior surface of distal humerus
insertion: coronoid process of ulna
action: primary elbow flexion
innervation: musculocutaneous nerve

triceps brachii

origin: long head - infraglenoid tubercule of scapula; lateral head - post. shaft of humerus above radial groove; medial head - post. shaft of humerus below radial groove (deep)
insertion: olecranon of ulna
action: extension of forearm; long head - extension and adduction
innervation: radial nerve

Nerves of the arm compartments

radial nerve - C5-T1, posterior compartment, runs in radial groove

musculocutaneous - C5-C7, anterior compartment, pierces coracobrachialis

Label radial notch and ulnar notch, radio-ulnar joints, radial styloid process, ulnar styloid process

Label the bones of hand

flexor retinaculum

holds contents of wrist in place

Describe the anterior forearm

3 layers: superficial, middle, deep

actions: flexion (elbow, wrist, fingers), pronation

innervation: median nerve (2 exceptions)

anterior compartment superficial muscles

pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris

pronator teres

origin: medial epicondyle of humerus + coronoid process of ulna
insertion: distal lateral radius
action: weak elbow flexion, pronation
innervation: median nerve

flexor carpi radialis

origin: medial epi
insertion: base of 2nd metacarpal
action: wrist flexion, hand abduction
innervation: median nerve

palmaris longus

origin: medial epi
insertion: palmaris aponeurosis
action: wrist flexion, tighten aponeurosis
innervation: median

flexor carpi ulnaris

origin: medial epi and olecranon
insertion: base of metacarpal 5, carpal bones
action: wrist flexion, hand abduction
innervation: ulnar nerve

anterior forearm deep muscles

flexor pollicus longus, flexor digitorum profundus, pronator quadratus

flexor pollicus longus

origin: anterior radius, inteross. membrane
insertion: distal thumb
action: flexes thumb, weak wrist flexion
innervation: median nerve

flexor digitorum profundus

origin: ulna
insertion: distal palmar phalanges of II, III, IV, V
action: wrist flexion, finger flexion of 2, 3, 4, 5 (MCP, PIP, DIP)
innervation: 2, 3 - median; 4, 5 - ulnar

pronator quadratus

origin: distal ulna
insertion: distal radius
action: pronation
innervation: median

Brachioradialis

origin: distal humerus
insertion: radial styloid process
action: elbow flexion
innervation: radial nerve

posterior forearm superficial muscles

extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor carpi ulnaris

extensor carpi radialis longus

origin: lateral supracondylar ridge humerus
insertion: base 2nd metacarpal
action: extend + abduct hand at wrist
innervation: radial nerve

extensor carpi radialis brevis

origin: lateral epi humerus
insertion: base 3rd metacarpal
action: extend + abduct hand at wrist
innervation: radial nerve (posterior interosseous)

extensor digitorum

origin: lateral epi of humerus
insertion: extensor expansions of 4 fingers
action: extends 4 fingers at MCP joint + extend wrist
innervation: radial nerve (post. inter.)

extensor carpi ulnaris

origin: lateral epi
insertion: base 5th finger
action: extends + adducts hand at wrist
innervation: radial nerve (post. inter)

posterior forearm deep muscles

supinator, abductor pollicis longus, extensor indicis, extensor pollicus longus, extensor pollicis brevis

supinator

origin: lateral epi, ulna
insert: lateral, post, ant. surfaces of proximal 1/3 radius
action: supination
innervation: radial nerve

extensor indicis

origin: post. surface ulna
insert: extensor expansion of index finger
action: extend index finger, extend hand
inn: radial nerve

abductor pollicis longus

origin: post surface ulna, radius
insert: base of thumb
action: abducts thumb, extends it
innervation: radial nerve

extensor pollicus longus

origin: ulna
insertion: base of distal part of thumb
action: extend distal part of thumb
innervation: radial nerve

extensor pollicis brevis

origin: radius
insertion: base proximal part of thumb
action: extend proximal part of thumb
inn: radial nerve

anatomical snuff box

indent in thumb from ext. poll. longus + brevis tendons

access point for radial artery, cutaneous branch of radial nerve, scaphoid bone

extrinsic vs intrinsic muscles

extrinsic: muscle bellies located in forearm not in palm
intrinsic: muscle bellies located in palm

groups of intrinsic muscles

thenar: fleshy part on palm below thumb
hypothenar: fleshy part below pinky
palmar muscles: lumbricals + interossesous (3 PAD, 4 DAB)

thenar muscles

abductor pollicis brevis, flexor pollicis brevis, opponens pollicis (median nerve)

adductor pollicis (ulnar nerve)

hypothenar muscles

abductor digiti minimi, flexor digiti minimi brevis, opponens digiti minimi (ulnar nerve)

palmar muscles - interosseous

3 palmar interossi: adducts fingers toward middle finger

4 dorsal interossi: abducts fingers away from middle finger

palmar muscles - lumbricals

allow flexion at MCP while maintaining extension at IP - 4 in each hand

1,2 = median nerve ; 3,4 = ulnar nerve

wiring of upper limb

musc. n. -> arm (anterior compartment) -> forearm (cutaneous/sensory)

median n. -> forearm (anterior compartment, pronators/flexors except 1 1/2) -> hand (3 lateral thenars + 2 lateral lumbricals)

ulnar n. -> forearm (flex. carpi ulnaris, medial 1/2 flex. digitorum profundus) -> hand (all remaining intrinsic hand muscles)

radial n. -> arm (post. compartment + brachioradialis) -> forearm (muscles of post. compartment) -> hand (cutaneous/sensory)

Label pelvic girdle

Label the femur

Label the tibia and fibula

Compartments of the thigh

anterior: hip flexors, knee extensors

posterior: hip extensors, knee flexors

medial: adductors

Anterior muscles of the thigh

iliopsoas, sartorius, 4 quadriceps muscles (rectus femoris, vastus medialis, vastus lateralis, vastus intermedius

Iliospoas

origin: iliacus; iliac fossa + ala
insert: lesser trochanter
action: prime mover thigh flexion + flexing trunk
inn: femoral nerve

sartorius

origin: ASIS
insertion: medial tibia
action: flex thigh at hip mainly
innervation: femoral nerve

rectus femoris

origin: ASIS, superior acetabulum
insert: patella and tibial tuberosity
act: extend knee and flex thigh at hip
innervation: femoral nerve

vastus medialis

origin: linea aspera, medial supracondyle
insertion: patella and tibial tuberosity
act: exend knee
inn: femoral nerve

vastus lateralis

origin: linea aspera, greater trochanter
insertion: patella and tibial tuberosity
act: exend knee
inn: femoral nerve

vastus intermedius

origin: anterior + lateral surfaces of shaft of femur
insertion: patella and tibial tuberosity
act: exend knee
inn: femoral nerve

Patellofemoral Syndrome

pain in knees - rectus femoris pulls patella laterally, vastus medius pulls patella medially to straighten it out - if muscle is weak then patella doesn't track straight -> pain

more common in women because women have wider hips (wider pull)

medial muscles of the thigh

adductor longus, pectineus, gracilis, adductor brevis, adductor magnus

adductor longus

superficial

origin: pubis
insertion: linea aspera
action: adduction and flex thigh
innervation: obturator nerve

pectineus

superficial

origin: pectineal line of pubis
insert: lesser trochanter to linea aspera
act: adducts and flex thigh
inn: femoral and sometimes obturator

gracilis

origin: pubis
insertion: tibia
act: adduct thigh, flex leg at knee, med rotation of leg
inn: obturator nerve

adductor brevis

deep

origin: inferior ramus, pubis
insertion: linea aspera
act: adducts thigh
inn: obturator nerve

adductor magnus

origin: ischial tuberosity
insert: linea aspera, down femur
action: ant fibers (adduct, med rotation and flex thigh); post fibers (assist hammys in extension)
inn: sciatic nerve + obturator

tensor fasciae latae

sandwiched in IT band
origin: ASIS, anterior iliac crest
insert: IT band
act: flex hip, keep IT band tight to stabilize knee
inn: superior gluteal nerve

gluteus maximus

origin: dorsal ilium, sacrum and coccyx
insertion: gluteal tuberosity of femur, IT band
action: major thigh extensor, lat rotation + abduction
inn: inferior gluteal nerve

gluteus medius

origin: lateral surface of ilium
insertion: greater trochanter
action: abducts, med rotates thigh, steady pelvis when walking
inn: superior gluteal nerve