Podcast
Questions and Answers
What important joint is involved in upper limb biomechanics that allows for shoulder movement?
What important joint is involved in upper limb biomechanics that allows for shoulder movement?
Which joint primarily facilitates movement between the scapula and the rib cage?
Which joint primarily facilitates movement between the scapula and the rib cage?
In upper limb biomechanics, which method of teaching is not mentioned as a facility for instruction?
In upper limb biomechanics, which method of teaching is not mentioned as a facility for instruction?
What type of learning approach will NOT primarily focus on biomechanics understanding in the course?
What type of learning approach will NOT primarily focus on biomechanics understanding in the course?
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What overarching theme is represented in the text?
What overarching theme is represented in the text?
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Which of the following is not categorized as a method of teaching within the biomechanics course?
Which of the following is not categorized as a method of teaching within the biomechanics course?
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Which institution is highlighted in the text?
Which institution is highlighted in the text?
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Which of the following joints is commonly associated with the movement of the arm but is not specifically highlighted in upper limb biomechanics?
Which of the following joints is commonly associated with the movement of the arm but is not specifically highlighted in upper limb biomechanics?
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Which facility is indicated to support the teaching of biomechanics but does not involve interactive learning?
Which facility is indicated to support the teaching of biomechanics but does not involve interactive learning?
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What is the primary focus of the repeated phrase in the text?
What is the primary focus of the repeated phrase in the text?
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What can be inferred about the setting from the text?
What can be inferred about the setting from the text?
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What message does the use of capital letters convey in the text?
What message does the use of capital letters convey in the text?
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What phrase is repeated throughout the content?
What phrase is repeated throughout the content?
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Which institution is mentioned repeatedly in the content?
Which institution is mentioned repeatedly in the content?
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What is the main theme expressed in the repeated statements of the content?
What is the main theme expressed in the repeated statements of the content?
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How often is the phrase 'The future starts here' presented in the content?
How often is the phrase 'The future starts here' presented in the content?
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What visual layout is suggested by the arrangement of letters in the content?
What visual layout is suggested by the arrangement of letters in the content?
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What aspect of education is implied through the phrase 'The future starts here'?
What aspect of education is implied through the phrase 'The future starts here'?
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In terms of motivation, what sentiment does the phrase convey?
In terms of motivation, what sentiment does the phrase convey?
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Which concept could be inferred from repeated phrases associated with Galala University?
Which concept could be inferred from repeated phrases associated with Galala University?
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Which feeling is least likely conveyed by the repetitive nature of the phrases?
Which feeling is least likely conveyed by the repetitive nature of the phrases?
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What type of message does the phrase's repetition suggest about Galala University's vision?
What type of message does the phrase's repetition suggest about Galala University's vision?
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Study Notes
Biomechanics Overview
- Presented by Karim Ghuiba
- At Galala University
Upper Limb Biomechanics
- Lecture focuses on scapulothoracic and glenohumeral joints
Learning Objectives
- Students will identify scapulothoracic joint.
- Students will identify glenohumeral joint.
Teaching Methods
- Lectures
- Labs
- Open discussions
- Assignments
Teaching Facilities
- Data show
- Boards
Scapulothoracic Joint
- Formed by the articulation of the scapula and thorax
- Not a true anatomical joint
- Depends on the integrity of the AC and SC joints
Scapulothoracic Joint (continued)
- The SC and AC joints are interdependent with the ST joint
- The clavicle attaches to the axial skeleton through the SC joint.
- Movement at either the AC or SC joint affects the entire ST joint
Scapulothoracic Joint (continued)
- The scapula positions relative to the thorax/ribs.
- 2 inches from midline between the 2nd and 7th rib.
- Internally rotated -30 to 45 degrees from the coronal plane
- Anteriorly tipped 10-20 degrees from the frontal plane
- Upward rotated - 10 to 20 degrees from the sagittal plane
Scapulothoracic Joint: Resting Position
- Scapula is positioned:
- 30-45° relative to the coronal plane
- 10-20° upward rotated relative to the sagittal plane.
- 10-20° tipped anteriorly from the frontal plane
Scapulothoracic Joint: Functional Coupling
- The scapula is linked to the AC and SC joints
- Prevents independent and translatory scapula movements
- e.g. abducting the arm causes scapula upward rotation, external rotation, and posterior tipping
Scapulothoracic Joint: Motions
- Upward/downward rotation - Primary
- Internal/external rotation - Secondary
- Anterior/posterior tipping - Secondary
- Elevation/depression
- Protraction/retraction
Scapulothoracic Joint: Upward/Downward Rotation
- Upward rotation of the scapula on the thorax is the principal motion during arm elevation.
- Approximately 60° of upward rotation
- Produced via clavicular elevation, posterior rotation of SC joint and AC joint rotation
Scapulothoracic Joint: Elevation/Depression
- Elevation and depression of the scapula is primarily related to the clavicle movement at SC joint & AC joint rotations.
- Scapular elevation/depression is commonly described as translatory motions along the ribs/ribcage.
Scapulothoracic Joint: Protraction/Retraction
- Protraction and retraction of the scapula is related to the clavicle movement at the SC joint.
- Movement is a translatory motion causing scapula movement away from/toward the vertebral column
Scapulothoracic Joint: Internal/External Rotation
- Internal/external rotation of scapula is coupled with the clavicle movements and occurs primarily at the AC/SC joint.
- Winging scapula (prominence of vertebral border of scapula) - suggests impaired neuromuscular control of ST muscles
Scapulothoracic Joint: Anterior/Posterior Tipping
- Anterior tipping of the scapula might occur in poor neuromuscular control or abnormal posture
- Attempting to lift the arm might cause anterior tipping due to inferior angle elevation and visibility.
Glenohumeral Joint: Stability
- Glenoid cavity (glenoid fossa)
- Posterior tilt of glenoid fossa & humeral head
- Capsule & glenoid labrum
- Rotator cuff muscles
Glenohumeral Joint: Capsule & Ligaments
- Capsule surrounds the GH joint, taut superiorly but slack anteriorly & inferiorly in the resting position.
- Superior, Middle, Inferior Glenohumeral ligaments (GH ligaments)
- Coracohumeral ligament
- Transverse humeral ligament
Osteokinematics & Arthrokinematics
- Osteokinematics refers to joint motion
- Arthrokinematics refers to joint surface motion
- Ex: abduction - convex humeral head rolls superiorly and slides inferiorly on concave glenoid
Shoulder Joint: Close/Loose Packed Position
- Close packed position - maximal congruency status of joint surfaces; maximal stability. (Ligaments taut, 90° shoulder abduction & external rotation)
- Loose packed position - minimal congruency status; supporting structures are lax. (55° semi abduction and 30° horizontal adduction)
Muscles of the Shoulder Girdle
- Supraspinatus
- Subscapularis
- Infraspinatus
- Teres minor
Scapulo-Humeral Rhythm
- Ratio between GH joint motion and scapulothoracic joint motion.
- 2° of GH abduction corresponds to 1° of scapula-thoracic upward rotation
- Ratio changes based on arm elevation & load.
Purpose of Scapulo-Humeral Rhythm
- Distributes motion between joints, enables large ROM
- Holds glenoid fossa in optimal position for humeral head
- Allows proper length tension relationship of muscles; reduces active insufficiency.
Kinetics of the Shoulder
- Forces generated by surrounding muscles to support limb:
- 10 times body weight at 60° abduction
- 8.2 times body weight at 90° abduction
- Extensor strength (5:4 ratio to flexion strength)
- Internal rotator strength (3:2 ratio to external rotator strength)
- Adductor strength (2:1 ratio to abductor strength)
Shoulder Pathological Mechanisms
- Shoulder Dislocation: Anterior/inferior dislocation due to laxity of capsule and rotator cuff weakness.
- Painful Arc Syndrome: Pain when abducting the arm (60-120°)
- Combined Serratus Anterior and Trapezius Paralysis: Difficulty raising the arm above the head caused by loss of scapular rotation
References
- Basic Biomechanics
- Kinesiology for Human Movement
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Description
This quiz covers the biomechanics of the upper limb, focusing on the scapulothoracic and glenohumeral joints. Students will explore the anatomy, movements, and interdependencies of these crucial joints. Engage with key concepts presented by Karim Ghuiba at Galala University.
