Clinical Limb Joints Flashcards
Identify these parts
1- clavicle
2- scapular spine
3- acromion
4- scapula superior angle
5- coracoid process
6- glenoid fossa
7- humerus head
8- greater tubercle
9- lesser tubercle
10- surgical neck
11- infraglenoid tubercle
12- supraglenoid tubercle
What joint is affected by fall on the point of the shoulder?
- AC acromioclavicular joint separates, if someone falls on point of the shoulder
- Or could affect glenohumeral joint, humerus comes out anteriorly and inferiorly
AC joint
Where is it?
When is it in danger?
- The acromioclavicular joint is at the top of the shoulder
- The junction between the acromion (part of the scapula that forms the highest point of the shoulder) and the clavicle
- Affected by fall on the top of the shoulder (ex: football player)
What is the largest and most clinically significant joint of upper limb?
- The glenohumeral, “shoulder joint”
- Glenoid fossa of the scapula articulates with humerus head
- Ball and socket joint, allows motion in all 3 planes
- Clinically significant because the structure has sacrificed stability for range of motion.
- Shallow glenoid fossa, much larger head of the humerus
- Both covered by hyaline articular cartilage
X-ray: #6 = glenoid fossa, #7= head of humerus
superior angle of scapula
4 on xray
- Where the levator scapulae attaches, for elevation of pectoral girdle
acromion
*
coracoid process
- which muscles attach there?
5 on xray
- coracoid process is a small hook-like structure on the lateral edge of the superior anterior portion of the scapula (coracoid = “like a raven’s beak”)
- 3 muscles attach, which cross anterior aspect of glenohumeral joint and act on it
- pectoralis minor, coracobrachialis, short head of biceps brachii
greater and less tubercles of the humerus
- rotator cuff muscles attach there
xray: #s 8 and 9
surgical neck of humerus
10 on xray
- clinically significant - surgical neck of the humerus
- famous because it’s where the axillary nerve and the posterior circumflex artery course around the humerus, on their way into the deltoid and teres minor
- If pt FOOSH –> fracture surgical neck of humerus –>
- What contributes to strength of glenohumeral joint?
- Where is the weakest point?
- What happens when you dislocate the humerus at this joint?
STRENGTH
-
4 tendons of rotator cuff muscles (SITS) play biggest role in strengh of joint
- Supraspinatus supports superiorly - initiates ABduction (first 15*)
- Infraspinatus, teres minor (lateral/external rotators), subscapularis
- Glenoid labrum = fibrocartilagous rim to increase surface area of glenoid fossa/cavity
- Also enclosed by articular capsule
- Strengthened by glenohumeral bands - thickening of the articular capsule
WEAKNESS
- Weakest point = anteriorly and inferiorly
- When you fold at point of shoulder, separate AC joint OR dislocate head of humerus –> head of humerus goes out of anterior and inferior head of the capsule
glenoid labrum
- Glenoid labrum = fibrocartilagous rim to increase surface area of glenoid fossa/cavity
What nerves might be stretched when you dislocate head of humerus?
- Either the axillary nerve or the radial nerve
- More the axillary than the radial
- Because they’re situated near the surgical neck or the midshaft portion of the humerus, when it’s dislocated anteriorly and inferiorly.
elbow joint
- Kind of joint?
- Muscles that act there?
-
pure hinge joint that only permits flexion and extension
- humeroradial, humeroulnar joints
- Anterior arm muscles flex forearm at elbow - biceps brachialis, brachioradialis (forearm)
- Posterior arm muscle (just the triceps) extends the forearm at the elbow
- PRonation and supination take place at the proximal radioulnar joint
which bone attaches more securely at elbow joint?
What is the most powerful muscle that acts at the elbow joint?
- the ulna is the more massive bone articulating at elbow joint, and the one providing the more secure articulation
- trochlear notch of ulnea attaches to trochlea of humerus
- The more powerful muscles that act at the elbow attach to the ulna
- Brachialis = most powerful flexor of the forearm at the elbow
- Whereas the biceps brachii attaches to radial tuberosity.
Why is “biceps curls” kind of wrong?
- We’re flexing biceps, but actually also flexing brachialis, which is the strongest flexer of the forearm at the elbow
What are the 3 joints of the elbow?
-
Proximal radioulnar joint—allowing for articulation between the radius and ulnar bones.
- Pronation and supination - the radius moves. Ulna remains stationary.
- Humeroradial joint—allowing for movement between the humerus and radius bones.
- Humeroulnar joint—allowing for movement between the Humerus and the ulnar bones.
at which joint do pronation and supination occur?
Which bone moves?
What are the muscles?
- At the proximal radioulnar joint
- Only the radius moves
- 2 supinators = biceps brachii and the supinator
- 2 pronators = pronators in anterior forearm