Lecture 5 - Shoulder girdle, Shoulder joint and Movements Flashcards
What is the difference between the axial and appendicular skeleton?
Axial (refers to axis):
• Skull
• Vertebral column
• Thoracic cage
Appendicular (refers to appendages,
i.e., extremities):
• Pectoral (Shoulder) girdle
• Upper limb
• Pelvic girdle
• Lower limb
What does the shoulder (pectoral) girdle (L and R) consist of?
Each shoulder (pectoral) girdle (L and R) consists of a scapula (shoulder
blade) and a clavicle (collar bone). The shoulder girdle attaches the upper limb
to the axial skeleton.
Note that humerus is not
part of the shoulder girdle.
What are the different parts of a scapula?
Identify the structures.
Parts:
• Superior and inferior angle (labelled 1 and 2)
• Spine
• Acromion
• Coracoid process
• Glenoid cavity
What are the different joints of the clavicle?
Joints:
1. Sternoclavicular joint (synovial with
fibrocartilaginous disc)
2. Acromioclavicular joint (synovial)
3. Coracoclavicular joint (syndesmosis) –
pair of short ligaments between clavicle
and coracoid process
What are some important notes for the clavicle?
Note:
• strut function
• shoulder separation (AC joint!)
• fracture—relation to major vessels and nerves of the upper extremity
- The clavicle is the only bone that does the attachment of the axial skeleton.
- A broken clavicle is the most common fracture on a cyclist.
What are the different possible movements of the scapula?
- Elevation
- Depression
- Protraction
- Retraction
- Lateral rotation (inferior angle* moves laterally)
- Medial rotation (inferior angle moves medially,
i. e., returns to anatomical position)
What are the possible movements of the clavicle?
Movement is at:
- Sternoclavicular joint
- Acromioclavicular joint
Movement is in 3 planes:
• anterior – posterior
• superior – inferior
• rotation
Movements of the clavicle:
1. Elevation and depression of the distal
end of the clavicle
2. Anterior and posterior movement of
the distal end
3. Anterior and posterior rotation along
the long axis
Note: When the scapula moves so does the clavicle!
What are the different muscles that move the scapula?
- Trapezius - elevates, retracts and depresses scapula
- Rhomboids (major and minor) - retract scapula
- Levator scapulae - elevates scapula
- Serratus anterior – protracts scapula
- Pectoralis minor – protracts and stabilizes
TRAPEZIUS !!!
Attachements :
Action:
Nerve:
RHOMBOID MAJOR AND RHOMBOID MINOR!!!
LEVATOR SCAPULAE!!!
SERRATUS ANTERIOR!!!
PECTORALIS MINOR!!!
Explain the shoulder (glenohumeral) joint.
Synovial joint, ball-and-socket type
• Multiaxial joint; the widest range of motion of all joints
• Articulating bones:
1. head of humerus
2. glenoid fossa of scapula
• Glenoid labrum: fibrocartilaginous rim attached to the margin of glenoid fossa,
it deepens the socket.
What are the movements of the arm
at the shoulder joint?
- Flexion
- Extension
- Abduction
- Adduction
- Medial rotation
- Lateral rotation
- Circumduction
What are the muscles that move the arm at the shoulder joint?
1) Muscles that attach upper limb to the axial skeleton:
1.
2.
2) Muscles that attach upper limb to the shoulder girdle:
1.
2.
3.
1) Muscles that attach upper limb to the axial skeleton:
• Pectoralis major
• Latissimus dorsi
2) Muscles that attach upper limb to the shoulder girdle:
• Deltoid
• Rotator cuff muscles (4)
• Teres major
PECTORALIS MAJOR!!!
Identify the structures on the humerus.
LATISSIMUS DORSI!!!
DELTOID!!!
ROTATOR CUFF MUSCLES
Group of 4 “SITS” muscles:
- Supraspinatus
- Infraspinatus
- Teres minor
- Subscapularis
Identify the rotator cuff muscles.
What is the function and innervation of the rotator cuff muscles?
- Supraspinatus: initiates abduction of the arm (first 15 degrees; deltoid is the
main abductor). Nerve: Suprascapular nerve (C5, C6). - Infraspinatus: lateral rotation or arm. Nerve: Suprascapular nerve.
- Teres minor: lateral rotation or arm. Nerve: Axillary nerve (C5, C6).
- Subscapularis: main medial rotator of the arm. Nerve: Upper and lower
subscapular nerves (C5, C6)
TERES MAJOR!!!
