Appendicular Skeleton (Upper Limb)

Question 1

What are the Features of a Clavicle?

Answer 1

• two curves help us identify what side is front what side is back and what side is medial and lateral
• clavicle has two ends - medial and lateral ends
• in the middle is the body or shaft of the bone
• the lateral end is also called the acromial end where the scapula articulates with lateral end of the clavicle (the acromion which is part of the scapula) - acromial head/end of the bone
• medial end articulates with the manubrium of the sternum - can be referred to as sternal end
• the medial curve is convex anteriorly whereas the lateral one is convex posteriorly - can easily palpate
• the most common site of fracture is on the middle third - the important, major nerves that supply the upper limb just pass below that - can damage some of the nerves

Question 2

Scapula - Anterior View

Answer 2

• surface is a little concave and not flat - to accommodate curve of your ribcage - subscapular fossa (shallow cavity)
• 3 borders and 3 angles for this triangular shaped bone
• superior border and medial border (sitting close to vertebral column so can also be called vertebral column)
• lateral border is also called axillary border - armpit is called axilla and that is where it is close to
• superior and inferior angle
• lateral angle carries a shallow cavity called glenoid fossa or cavity which will receive head of humerus which form your shoulder girdle
• finger-like projection that extends laterally and anteriorly (palpable) - called coracoid process
• acromion is the other bony process you can palpate at top of scapula

Question 3

Scapula - Posterior View

Answer 3

• separated into two regions by a bony plate called the spine of scapula - as it moves laterally it makes your acromion (lateral continuation of spine of scapula)
• above spine it is called supraspinous fossa (smaller) and below is called infraspinous fossa (bigger one)

Question 4

What are the 8 Carpal Bones?

Answer 4

Proximal Row
- lateral end - scaphoid (most common carpal bone to fracture - usually happens when you are losing your balance and fall on it where you stretch out your arm - falling on outstretched hand (FOSH)
- 60% of the movement of the wrist is from the scaphoid - not testable
- lunate is the most common carpal bone to dislocate (FOSH) - one of the big nerves of the hand that supplies muscle in the hand passes by lunate so it if you dislocate it it will compress the nerve and you lose the muscles in your hand as they become paralyzed
- when people lose their balance and fall down putting your hands up is an automatic reflex but this reflex is not present in children until 6 months where you hands automatically go up and raises arm when you fall - called the parachute reflex
- triquetrum and anterior to that is a small tiny bone called pisiform - can palpate on right in front of wrist on medial end of proximal row

Distal Row
- lateral (thumb): trapezium -> trapezoid -> capitate (largest carpal bone) -> hamate (has a hook)

Question 5

What are the Bones of the Hand?

Answer 5

Long Bones of the Hand
Metacarpals (5) - beyond carpals
- have proximal and distal ends - numbered 1st belongs to thumb and 5th is for pinky
- proximal end is also known as base
- distal end is referred to as head

Digits - Fingers
- in all digits except thumb we have 3 bones (small bones) - each are called phalanx (plural is phalanges)
- proximal - middle - distal phalanx
- thumb only has distal and proximal phalanx only
- each and every phalanx is considered a long bone
- the proximal end of each phalanx is called base and distal is called head