Anatomy of the Shoulder and Pectoral Girdle

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which bones comprise the pectoral girdle?

Humerus and Scapula

Radius and Ulna

Clavicle and Scapula (correct)

Clavicle and Humerus

What function do the scapulo-humeral muscles serve?

Connecting the pectoral girdle to the humerus (correct)

Supporting neck movements

Stabilizing the elbow joint

Facilitating scapular movements

Which of the following describes a key outcome related to shoulder injuries?

They are often caused by excessive elbow movement

Most common injuries are related to wrist fractures

Common injuries include rotator cuff tears (correct)

They usually do not have complications

What are the primary components found in the scapular region?

Muscles, nerves, and blood vessels Signup and view all the answers

What is the main function of the shoulder joint?

To allow extensive movement of the arm Signup and view all the answers

Which of the following accurately describes the structural characteristics of the shoulder joint?

It is a ball and socket joint with very mobile structure. Signup and view all the answers

What is the main role of the glenoid labrum?

To provide stability and reduce joint friction. Signup and view all the answers

Which rotator cuff muscle is responsible for medial rotation of the humerus?

Subscapularis Signup and view all the answers

Which structure is most likely to suffer damage during an anterior-inferior dislocation of the shoulder joint?

Axillary nerve Signup and view all the answers

Which ligament is associated with the sternoclavicular joint?

Costoclavicular ligament Signup and view all the answers

What is the primary purpose of bursae in the shoulder joint?

To reduce friction between bone and soft tissue. Signup and view all the answers

Which of the following statements about the clavicle is correct?

It is smooth on the underside. Signup and view all the answers

Identify the primary nerve supplying the supraspinatus muscle.

Suprascapular nerve Signup and view all the answers

Which muscle is known as the chief medial rotator of the shoulder?

Subscapularis Signup and view all the answers

What is the primary function of the supraspinatus muscle in shoulder movements?

Abduction (0-15°) Signup and view all the answers

Which artery does the axillary artery give rise to at its third part?

Anterior circumflex humeral artery Signup and view all the answers

What movement is primarily associated with the pectoralis major (sternal part)?

Adduction Signup and view all the answers

Which part of the deltoid is responsible for flexion of the shoulder?

Anterior part Signup and view all the answers

Which of the following muscles is primarily involved in the extension of the shoulder?

Latissimus dorsi Signup and view all the answers

What is the role of the trapezius in shoulder abduction after 90°?

Elevation Signup and view all the answers

Which space is an important clinical anatomical region in the shoulder?

Triangular space Signup and view all the answers

Study Notes

Scapular Region and Shoulder Joint

Class: Year 1
Course: Medicine – BMF Module
Title: Scapular Region and Shoulder Joint
Lecturer: Prof. Oran D. Kennedy (Dr Claire Conway)
Date: 29/11/2024

Housekeeping/Admin

Anatomy Room reminders:
- Return instruments after each session
- Close white-bags and cover cadavers after each session
- Bring your gloves

Barker Prize Competition

Barker Prize is an annual award for a 'dissection of surgical importance'
Dates for competition and details for applications will be announced in Jan/Feb
Typically takes place the week or two after summer exams
Prof Fabio Quondamatteo will be organizing the competition

Gateway: Boundaries/Contents

Nerves: Nerves to the upper limb, the Axillary inlet, Superior margin of the scapula
Vein: Axillary vein
Artery: Axillary artery

Learning Outcomes

Describe the osteology, joints, and muscles of the pectoral girdle
Summarize scapular movements and the responsible muscles
Describe the structure and function of the scapulo-humeral muscles
Describe the course and function of neurovascular structures in the scapular region
Describe the structure and function of the shoulder joint
Recognize common injuries in the shoulder area and discuss their cause and complications

Terminology

Pectoral Girdle = Clavicle & Scapula
Acromioclavicular Joint
Coracoid process
SC Joint
Scapula
Scapulothoracic Joint
Glenohumeral Joint

Osteology of Scapula

Acromion process
Coracoid process
Glenoid fossa
Subscapular fossa
Lateral surface
Anterior/Ventral Surface
Medial surface
Vertebral levels (not specified)
Superior angle
Supraspinous fossa
Spine
Infraspinous fossa
Medial border
Lateral angle
Lateral border
Inferior angle

Clavicle

Superior View: Smooth on top; conoid tubercle
Inferior View: Rough underneath; impression for the costoclavicular ligament
Ends: Acromial end, Sternal end

Clavicle - Injury

Possible causes of clavicle fracture include gravity, pull of sternocleidomastoid (SCM), and pull of pectoralis major.
Common types of fractures are anterior view, fracture of clavicle

Joints of the Pectoral Girdle

Sternoclavicular joint: Atypical synovial joint with fibrocartilage disc; costoclavicular ligament (connecting clavicle to rib 1)
Different ligaments involved
- Interclavicular ligament
- Anterior sternoclavicular ligament

Humerus - Arm

Parts: Greater tuberosity, Lesser tuberosity, Intertubercular Groove, Anatomical neck, Surgical neck

Shoulder Joint

Tissue type: Synovial
Mobility: Very mobile
Structure: Ball-and-socket

Stability-Mobility

Shoulder joint components: Glenoid fossa, Head of the humerus, Acetabular fossa, Acetabulum (socket), Head of the Femur

Glenoid Labrum

Fibrocartilaginous ring around the glenoid fossa

Glenoid Labrum - Injury

Common injuries include Labral tear, SLAP Tear

Rotator Cuff Muscles

Most important factor in stabilizing the shoulder: allow the humerus to 'S.S.I.T.' (superior, superior, inferior, inferior) against the glenoid cavity
Muscles: Subscapularis, Supraspinatus, Infraspinatus, Teres minor
Nerve supply:
- Supraspinatus: suprascapular nerve
- Infraspinatus: suprascapular nerve
- Teres minor: axillary nerve
- Subscapularis: subscapular (upper & lower) nerves

Rotator Cuff Injury

Diagnosis may involve MRI

Shoulder - Injury

Anterior-inferior dislocation of the shoulder joint is common
Axillary nerve can be damaged

Bursa(e)

Fluid-filled pouch
Reduce friction between bones and soft tissue
Between bone and tendons/muscles, or bone and skin

Superficial Muscles

Trapezius
Deltoid

Movements - Scapula

Elevation: Superior trapezius, Levator scapulae, Rhomboids
Depression: Pectoralis minor, Inferior trapezius, Serratus anterior (inferior part)
Protraction: Pectoralis minor, Serratus anterior
Retraction: Rhomboids, Middle trapezius, Latissimus dorsi

Rotations - Shoulder

Chief medial rotator: Subscapularis, Teres major, Pectoralis major
Chief lateral rotator: Infraspinatus, Teres minor, Posterior deltoid

Flexion of Shoulder

Muscles: Pectoralis major (clavicular part), Deltoid (anterior part), Coracobrachialis, Biceps

Extension of Shoulder

Muscles: Latissimus dorsi, Deltoid (posterior fibres), Teres major, Triceps

Adduction/Abduction of the Shoulder

Adduction: Pectoralis major (sternal part), Latissimus dorsi, some teres major, Biceps brachii, Serratus anterior.
Abduction: Supraspinatus (0–15°), Deltoid (15–90°), Trapezius & serratus anterior, Infraspinatus, Teres minor, Lower deltoid fibres

Shoulder - Blood Supply

Subclavian artery: ends lateral to 1st rib
Axillary artery: ends at teres major (lower boarder)
Branches:
- Superior thoracic artery
- Lateral thoracic artery
- Thoracoacromial artery
- Anterior and posterior circumflex humeral arteries
- Subscapular artery

Important Clinical/Anatomical Regions

Quadrangular space
Triangular interval
Triangular space
Circumflex scapular artery
Axillary nerve
Posterior circumflex humeral artery
Profunda brachii artery
Radial nerve

Shoulder - Vascular

Different arteries and veins involved (e.g., subclavian artery, axillary artery, axillary vein, cephalic vein, basilic vein, median cubital vein, brachial artery, etc.)

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the anatomy and functions of the pectoral girdle and shoulder joint. This quiz covers essential questions regarding bone composition, muscle functions, and common injuries related to the shoulder region. Perfect for students studying human anatomy or aspiring medical professionals.