MSK - Shoulder anatomy and related conditions

Question 1

What type of joint is the shoulder joint and what are its features?

Answer 1

• Glenohumeral Joint
• Ball and socket.
• Socket - Glenoid fossa of the scapula
• Ball - Head of the humorous
• High ROM at the cost of lower stability.
• hyaline cartilage on articulating surfaces and glenoid labrum.

Question 2

What is the shoulder joint capsule composed of and what is their significance ?

Answer 2

• Synovial membrane - allow for friction free movement.
• Bursae.
• Ligaments.
• See notes for more details.

Question 3

What movements is the shoulder capable of and which muscles are responsible for this ?

Answer 3

• Abduction - 0-15 suprasprinatous, 15-90 medial deltoid, and over 90 need serratous anterior.
• Adduction - Lats
• Extension -
• Flexion -
• Internal rotation -
• External rotation -

Question 4

What contributes to stability and mobility of the shoulder joint?

Answer 4

• Mobility - Ball and socket. Golf ball and tee analogy - discrepancy in surface sizes.
• Stability - Joint capsule (ligaments/bursae/synovial membrane ), rotator cuff muscles and glenoid labrum.

Question 5

What is the neurovascular supply of the joint?

Answer 5

• Axillary artery - Anterior and posterior circumflex humeral arteries and axillary nerve .

Question 6

Describe motor and sensory functions of the axillary nerve.

Answer 6

• Sensory - upper lateral cutaneous nerve - regimental badge area sensation
• Motor - Supplies the deltoid muscles (abduction/flexion/extension)

Question 7

Discuss rotator cuff tears.

Answer 7

• Tendons of the rotator cuff muscles torn
• Most commonly due to age related detonated blood supply in conjunction with micro trauma which has less ability to heal.
• Can be due to repetitive movements in the shoulder plain such as painters and weightlifters
• Presents with pain when abducting, flexing and extending the arm.
• Anterolateral pain radiating down arm.
• MRI/ ultrasound scans
• Rest,analgesia, physio

Question 8

Discuss frozen shoulder.

Answer 8

• Inflammation/scar tissue in joint capsule
• Reduces ROM greatly
• Cause unknown
• Constant pain, exacerbated by use and cold weather and worse at night.
• Physiotherapy, pain relief, anti - inflammatory drugs. cCan have surgery in some instances to break up scar tissue and adhesions.

Question 9

Discuss shoulder osteoarthritis.