Ascending Pathways in the Central Nervous System, Anatomy of the Appendicular Skeleton and Upper Extremity

Central Nervous System (CNS)

Main control center for sensory and motor functions.

Ascending Pathways

Neural pathways carrying sensory information to the brain.

Spinothalamic Tract (ST)

Pathway for touch, pressure, temperature, and pain.

First-order Neurons

Neurons starting in the body, entering spinal cord.

Dorsal Root Ganglion

Cluster of sensory neuron cell bodies.

Second-order Neurons

Neurons that cross to opposite side, ascend to thalamus.

Thalamus

Brain relay station for sensory information.

Third-order Neurons

Neurons from thalamus to somatosensory cortex.

Somatosensory Cortex

Brain area processing sensory information from body.

Post-central Gyrus

Location of the primary somatosensory cortex.

Dorsal Column Medial Lemniscus (DCML)

Pathway for vibration and joint position sense.

Fasciculus Gracilis

DCML component for lower body sensory information.

Fasciculus Cuneatus

DCML component for upper body sensory information.

Afferent Neurons

Neurons carrying sensory information to the CNS.

Decussate

Crossing over of neurons to opposite side.

Stereognosis

Ability to identify objects by touch.

Pacinian Corpuscles

Receptors for vibration and deep pressure.

Exteroceptors

Receptors detecting external stimuli.

Sensory Dendrites

Nerve endings that receive sensory stimuli.

Afferent Fiber

Nerve fiber carrying information towards the CNS.

Pectoral Girdle

Connects upper limbs to axial skeleton.

Clavicles

Collarbones that stabilize shoulder and arms.

Scapulae

Flat, triangular bones on rib cage's dorsal surface.

Anterior Compartment

Muscles located on forearm's anterior surface.

Posterior Compartment

Muscles located behind the femur.

Extrinsic Shoulder Muscles

Stabilize scapula and enhance arm movement.

Elevation

Raising the scapula upward.

Depression

Lowering the scapula downward.

Protraction

Moving scapulae forward and away from spine.

Retraction

Moving scapulae backward toward the spine.

Rotator Cuff Muscles

Stabilize shoulder joint and prevent dislocation.

Supraspinatus

Muscle that assists in arm abduction.

Infraspinatus

Muscle that externally rotates the arm.

Teres Minor

Muscle that aids in arm rotation.

Subscapularis

Muscle that internally rotates the arm.

Brachialis

Primary muscle for elbow flexion.

Biceps Brachii

Major forearm flexor muscle.

Triceps Brachii

Main muscle for elbow extension.

Flexor Muscles

Anterior muscles that flex wrist and fingers.

Extensor Muscles

Posterior muscles that extend wrist and fingers.

Intrinsic Hand Muscles

Control fine movements of fingers and thumb.

Thenar Eminence

Muscles at the base of the thumb.

Hypothenar Eminence

Muscles at the base of the little finger.

Acromian

highest projection

Coracoid Process

projection that hooked like a ravens beak

glenoid cavity

socket part of the ball and socket joint, articulates with the head of the humerous

suprascapular notch

indentation at the top of the scapula

supraspinous fossa

scooped out area above the spine

infraspinous fossa

scooped out the area below the spine

acromian

highest projection

gelnoid cavity

better viewed laterally

what clues can you use to tell if you're looking at the anterior humerus verses the posterior humerus?

Look at the distal end of the bone. The Anterior has a rounded bowtie. The posterior is indentation.

What clues can you use to tell which side of the humerus is medial versus lateral?

The head of the humerus ALWAYS points medially toward the body

What type of the is formed as the head of the humerus articulates with the glenoid fossa? What type of movement could you expect to see at that joint?

Ball and socket joint, specifically the glenohumeral joint.

1. Flexion and extension

2. Abduction and adduction

3. Medial and lateral rotation

4. Circumduction

Greater tubercle

bigger bump

intertubecular sulcus

groove between the bumps

Lesser tubercle

smaller bump

capitum

capit = head, articulate with the radial head: rotation

Trochlea

"pulley" articulation with the ulna: flexion and extension

coronoid fossa

scooped out area that a beak-like bone fits into

Head

Articular surface. the ball of the ball and socket joint

Deltoid tuberosity

bump the deltoid muscle made

olecranon fossa

scooped out area the olecranon process fits into

radial tuberosity

bump on radius

interosseous membrane

membrane between bones

styloid process

pen-like protrusion

What clues can you use to tell if you're looking at the anterior view versus the posterior view?

ANTERIOR: radius, right --> ulna, left

what clues can you use to tell which side is medial versus lateral

Look for a radial head. radius had a head that looked like a wheel. radius is always lateral

How are the digits numbered

first digit is always the thumb

What clues can you use to tell which side is medial versus lateral?

Radius flares distally and is larger at 2 bones that articulates with carpals.

Which bones make up the pectoral girdle?

Clavicle, scapula

Which feature of the scapula divides the posterior aspect into superior and inferior portions?

The spine of the scapula

Which features of which bones form the hinge joint at the elbow?

The trochlea of the humerus--> trochlear noten of the ulna

The capitum of the humerus--> head of the radius

Which feature of the ulna prevents hyperextension of the elbow?

Olecranon process

Which features of which bones form the pivot joint at the elbow?

the pivot joint

subclavius

under the clavicle and stabilizes scapula

pectoralis minor

chest, smaller, pulls scapula toward and downward

Serratus anterior

serrated, jagged, on the first, attaches to scapula

Trapezius

trapezoid shape, elevates scapula, rotates scapula

Larger rhomboid

rhomboid-shaped, rotates scapular

Levator scapula

levator: lifts, elevates, and adducts

deltoid

triangle, prime mover of ABduction

Pectoralis Major

ADDuction, prime mover for shoulder FLEXION

Superspinatus

above spine

Infraspinatus

below spine

Latissimus dorsi

broadest back, broadest muscle in back

Teres Minor

round smaller

Biceps Brachialis

2 attachments at shoulder, arm, elbow FLEXION

Brachialis

located deep to biceps, forearm FLEXION

Brachioradialis

arm, on side with radius, elbow FLEXION

triceps brachii

3 attatchments at shoulder, arm, elbow EXTENSION

Anconeus

elbow, tiny muscle, elbow EXTENSION

Pronator quadratos

rotation, palms down, 4 sided, prime mover-pronation

Pronator Teres

Rotation, palms down, round, adds to pronation

Supinator

Supinates, palms turn up, supination

In forearm/ hand images, what clues can you use to determine anterior verses posterior views?

No muscles on the back of the hand

What is the function of the flexor carpi radialis?

Causes wrist flexion

What is the function of the palmaris longus?

Weak wrist flexion

What is the function of the flexor carpi ulnaris?

Wrist flexion of the 5th digit

What is the function of the flexor digitorum superficialis?

Finger flexion of digits 2-5