Label the following diagram.
What are the three different joints of the scapula?
- Glenohumeral (shoulder)
What muscles insert and originate from the scapula coracoid process?
Insert: Pec minor and coracobrachialis
Origin: Short head biceps brachii
What are the important bony landmarks of the lateral surface of the scapula?
- Glenoid fossa: head of humerus articulates here with glenoid lavbrum
- Supraglenoid tubercle: site of origin of long head of biceps
- Infraglenoid tubercle: site of origin of long head triceps
Where is the anatomical neck of the humerus?
Between the head of the humerus and the tubercles
Label the different bony landmarks of the humerus.
How do fractured scapulas occur and what is the best way to treat them?
- Severe chest trauma, e.g high speed road collisions, crushing injuries
- Tone of muscles surrounding holds fragments in place whilst healing occurs so no fixation needed
Label this AP x-ray of the shoulder joint.
What factors are responsible for the mobility and stability of the shoulder joint?
Mobility: (makes unstable)
- Shallow glenoid fossa
- Lax capsule
- Disproportion of articular surfaces
- Muscles of rotator and others
What is the function of the clavicle and where does it attach to?
- Attach upper limb to trunk as part of shoulder girdle
- Protect underlying neurovascular to upper limb
- Transmit force from upper limb to axial skeleton
Label the important bony landmarks of the clavicle and state what each end articulates with.
- Long S bone
- Medial aspect convex anteriorly, lateral is concave
What is the coracoclavicular ligament?
TWO PARTS - suspending weight of upper limb from clavicle
- Conoid tubercle: conoid ligament, medial coracoclavicular ligament
- Trapezoid line: trapezoid ligament, lateral coracoclavicular ligament
What muscles and ligaments originate or insert onto the clavicle?
- Pec maior
What type of joint is the acromioclavicular joint and what makes it atypical?
- Plane type synovial
- Palpated 2-3cm medially from tip of shoulder
- Articular surface lined with fibrocartilage not hyaline
- Joint cavity partially divided by articular fibrocartilage disc
Where is the joint capsule of the acromioclavicular joint?
- Loose fibrous layer that gives rise to articular disc
- Lined internally by synovial membrane
- Posterior aspect of joint reinforced by trapezius fibres
What are the ligaments of the acromioclavicular joint?
Intrinsic: Acromioclavicular ligament superiorly
Extrinsic: Conoid and trapezoid ligament
What movement occurs at the acromioclavicular joint?
- Small degree of axial rotation and anteroposterior movement
- Passive movement as no muscles cross it
What type of joint is the sternoclavicular joint?
- Saddle type synovial
- Manubrium of sternum, clavicle and upper medial first costal cartilage
-Only attachment of upper limb to skeleton so strong
- Fibrocartilage lining not hyaline and articular disc
Why is there an articular disc in the sternoclavicular joint?
Allows clavicle and manubrium to slide over each other more freeling allowing rotation in 3 axes rather than 2 like a normal saddle
What are the possible movements of the shoulder that require the sternoclavicular joint to move too?
- Elevation of shoulder joint (e.g shrugging shoulders or abducting arm over 90)
- Depression of shoulders
- Protraction/Retraction of shoulder
- Rotation (e.g arm over head)
Label this diagram of the proximal humerus and state what passes through the intertubercular sulcus?
- Tendon of the long head of biceps brachii
- Edges of the groove are know as the lips and different muscles insert onto them, see on diagram
A LADY BETWEEN TWO MAJORS
What is the danger of fracturing the surgical neck of the humerus?
- Blund trauma to shoulder from falling on outstretched hand
- Axillary nerve and circumflex humeral vessels in close proximity
- Nerve damage results in paralysis of deltoid and teres minor so hard to abduct limb. Will also have loss of sensation of regimental badge area over deltoid
What is being pointed to here on the humerus and what is it the landmark for?
- Radial groove
- Radial nerve and profunda brachii artery lie in this groove
What muscles attach to the humeral shaft and where?
Posteriorly: Lateral and medial head of triceps, with spiral groove between
Anteriorly: Corachobrachialis, deltoid, brachioradialis, brachialis
What defines whether a muscle is intrinsic or extrinsic in the shoulder?
Extrinsic: Originate from torso and insert onto bones of shoulder (humerus, clavicle, scapula)
Intrinsic: Originate from scapula and/or clavicle and insert onto the humerus
What are the extrinsic muscles of the shoulder?
All on back of the trunk and organised into two layers
What are the superficial extrinsic muscles of the shoulder, their innervation, their origin/insertion and their actions?
What are the deep extrinsic muscles of the shoulder, their innervation, their origin/insertion and their actions?
How do you test the trapezius muscle?
Ask patient to shrug shoulders whilst you push down on them
What are the intrinsic muscles of the shoulder? (scapulohumeral group)
- 4 rotator cuff muscles
- Teres Major